ALBERT

Notes: 1 The effects of the immunosuppressants, tacrolimus (FK506) and cyclosporin A (CsA), on catecholamine (CA) release were examined in cultured bovine adrenal chromaffin cells. 2 In intact cells, FK506 (1–30 μm) inhibited CA release stimulated by acetylcholine (ACh; 100 μm), 1,1-dimethyl-4-phenyl-piperazinium (DMPP, 10 μm) or high K+ (40 mm). CsA (1–30 μm) had a little inhibitory effect on the ACh- or DMPP-stimulated CA release, whereas it enhanced the high K+-stimulated CA release. 3 In β-escin-permeabilized cells, FK506 inhibited CA release stimulated by Ca2+ (1 and 10 μm) in the presence and absence of MgATP (2 mm). CsA induced CA release under Ca2+-free condition and enhanced the Ca2+-stimulated CA release in the presence and absence of MgATP. 4 It is known that the Ca2+-dependent exocytosis involves at least two distinct steps, ATP-requiring priming stage and ATP-independent fusion step in adrenal chromaffin cells. Therefore, it is suggested that FK506 inhibits the Ca2+-dependent exocytosis probably at the fusion step whereas CsA induces CA release from bovine adrenal chromaffin cells.

Notes: 1 Prolonged bed rest or exposure to microgravity may cause several alterations in autonomic nervous system response (ANSR). 2 Hindlimb unloading (HU) rats were used as an animal model of simulated microgravity to investigate ANSR changes. The experiments were carried out to investigate the effects of simulated microgravity on the autonomic nervous response of the perfused mesenteric vascular bed (MVB), vas deferens and the colon and duodenum from 2-week HU rats. 3 In MVB preparations of HU rats, the frequency-dependent increases in perfusion pressure with perivascular nerve stimulation (PNS; 8–40 Hz) were inhibited, whereas the noradrenaline (NA) concentration-dependent (1–100 μm) perfusion pressure increases were potentiated. The latter most probably reflected up-regulation of α-adrenergic receptor function. Relaxant responses of NA-precontracted MVB to PNS (4–30 Hz) or isoprenaline were not different between control and HU preparations, while vasodilation induced by the endothelial agonist ACh was reduced. 4 Transmural stimulation (2–40 Hz) induced frequency-dependent twitches of the vas deferens which were reduced in vas deferens of HU rats, while the sensitivity to NA-induced contraction was significantly increased. 5 In the gastroenteric system of HU rat, direct contractile responses to carbachol or tachykinin as well as relaxant or contractile responses to nervous stimulation appeared unchanged both in the proximal colon rings and in duodenal longitudinal strips. 6 In conclusion, HU treatment affects peripheral tissues in which the main contractile mediators are the adrenergic ones such as resistance vessels and vas deferens, probably by reducing the release of neuromediator. This study validates NA signalling impairment as a widespread process in microgravity, which may most dramatically result in the clinical phenotype of orthostatic intolerance.

Notes: 1 This double-blind, cross-over, placebo-controlled study on six healthy male volunteers was designed to evaluate the effects of α2-adrenoceptor antagonism on cardiac parasympathetic regulation. 2 The subjects received atipamezole intravenously as a three-step infusion, which aimed at steady-state serum concentrations of 10, 30 and 90 ng ml−1 at 50-min intervals. 3 Drug effects were assessed with repeated recordings of blood pressure and electrocardiogram, in which the high-frequency (0.15–0.40 Hz) R-R interval variation is supposed to reflect cardiac parasympathetic efferent neuronal activity. 4 At the end of the three steps of the infusion, the mean (±SD) concentrations of atipamezole were 10.5 (3.9), 26.8 (5.6) and 81.3 (21.1) ng ml−1. 5 Within this concentration range, atipamezole appeared to reduce slightly the high-frequency R-R interval fluctuations, indicating a minor vagolytic effect in the heart. 6 Atipamezole increased systolic and diastolic arterial pressure, on average by 20 and 14 mmHg (maxima at the second step of the infusion), which evidently reflects an overall sympathetic augmentation.

Notes: 1 Our previous report showed that in acute cholestasis, the subsensitivity to morphine inhibitory effect on electrical-stimulated contractions develops significantly faster in guinea-pig ileum (GPI) and in mouse vas deferens (MVD) (45.2 and 29.9 times, respectively) compared with non-cholestatic subjects. 2 The possible contribution of α2-adrenoceptor and nitric oxide (NO) pathways on the development of tolerance was assessed in GPI and MVD of cholestatic subjects. 3 Daily administration of naltrexone (20 mg kg−1), yohimbine (5 mg kg−1), and Nω-nitro-l-arginine methyl ester (l-NAME) (3 mg kg−1) to cholestatic animals significantly (P-value 〈 0.05) inhibited the process of subsensitivity in all groups. 4 Consistent with the literature, it was concluded that both the α2-adrenergic system and NO have close interaction with the opioid system and may underlie some of the mechanisms involved in the subsensitivity development to opioids in acute cholestatic states.

Notes: 1 We examined the role of the NO/cyclic GMP (cyclic GMP) pathway in nitric oxide (NO)- and vasoactive intestinal peptide (VIP)-induced relaxation of feline lower oesophageal sphincter (LES). Furthermore, it was studied whether methylene blue, LY83583 and ODQ, which are soluble guanylate cyclase (sGC) inhibitors, could inhibit NO-induced relaxation.2 The nitric oxide synthase (NOS) inhibitor, N-nitro-l-arginine (l-NNA) had no effect in sodium nitropruside (SNP)-induced relaxation, but 3-morpholinosydnonimine-N-ethylcarbamide (SIN-1)-induced relaxation was decreased by the pretreatment of l-NNA, which showed that SIN-1, not SNP, could activate NOS to cause relaxation. Methylene blue and LY83583 did not inhibit the relaxation by SNP and SIN-1. However, the more specific sGC inhibitor ODQ blocked the relaxation induced by NO donors.3 To identify the relationship of NOS, sGC and adenylate cyclase in VIP-induced relaxation, tissue were pretreated with l-NNA and ODQ and SQ22536. These inhibitors produced significant inhibition of this response to VIP. The adenylyl cyclase inhibitor SQ 22536 also inhibited relaxation by VIP.4 In conclusion, our data showed that SNP- and SIN-1-induced relaxation was mediated by sGC. Of sGC inhibitors, methylene blue and LY83583 were not adequate for the examination of NO donor-induced feline LES smooth muscle relaxation. VIP also caused relaxation by the pathway involving NO and cGMP and cAMP.

Notes: 1 The vasoconstrictor response to periarterial nerve electrical stimulation (PNS) and neurotransmission by ATP are discussed and illustrated, using canine isolated and perfused splenic arterial preparations. 2 The conditions for appearance of dominant purinergic constrictor response to PNS are discussed. 3 Modulation of the purinergic vasoconstrictor responses to PNS by several kinds of presynaptic receptor agonists and antagonists is reviewed. 4 Influences of purinergic responses to PNS by guanethidine, reserpine, tetrodotoxin (TTX) or ω-conotoxin GVIA (ωCTX) are also reviewed. 5 Effects of imipramine and removal of the endothelium are discussed. 6 Evidence is presented for selective inhibition of purinergic responses to PNS by an adequate cold storage of the vessel. 7 The roles of ATP released by PNS in isolated canine splenic arteries are proposed.

Notes: 1 The aim of the present study was to investigate the role of several possible neurotransmitters in mediating non-adrenergic, non-cholinergic (NANC) relaxation, and the effects of phosphodiesterase (PDE) III and V inhibitors on adrenergic and NANC relaxation in branch pulmonary artery (PA) of guinea-pig. 2 Under the NANC conditions, electrical field stimulation (EFS, 60 V, 0.2 ms, 20 Hz) induced a tetrodotoxin-sensitive relaxation of the histamine-precontracted PA rings. The nitric oxide (NO) synthase inhibitor NG-nitro-l-arginine methyl ester (l-NAME, 10−4 m) and the guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, 10−5 m) partially inhibited the EFS-induced relaxation. The inhibitory effect of l-NAME was reversed completely by l-arginine (10−3 m), but not d-arginine (10−3 m). 3 This NANC relaxation was attenuated by 8-phenyltheophylline (10−5 m), a P1-purinoceptor antagonist. 4 The NANC response was potentiated by 10−6 m zaprinast, a type V PDE inhibitor, but was unaffected by 3 × 10−6 m milrinone, a type III PDE inhibitor. 5 Sodium nitroprusside (SNP) caused a concentration-dependent vasodilator effect which was potentiated by zaprinast, but unaffected by milrinone. Moreover, the effect of combination of zaprinast with milrinone was not significantly different from that observed with zaprinast alone. 6 Isoprenaline produced a concentration-dependent vasodilatation in branch PA of guinea-pig which was potentiated by both zaprinast and milrinone, the efficacy of milrinone being greater than zaprinast. 7 These results suggest that both nitrergic and purinergic pathways are involved in mediating the NANC relaxation in branch PA of guinea-pig. The combination of PDE III or V inhibitors with vasorelaxant drugs may be a hopeful approach for the treatment of pulmonary hypertension.

Notes: 1 The aim of this study was to characterize the histamine receptor type mediating relaxation of the vascular bed of the nasal mucosa from the guinea-pig, and to determine the role of cyclo-oxygenase products and nitric oxide in this relaxant response to histamine. These studies were performed in isolated nasal mucosae examined in vitro to obtain potencies of histamine receptor-type selective agonists in causing vasorelaxation and to determine affinities of histamine receptor antagonists for inhibiting histamine-induced relaxation. 2 After contraction of nasal mucosae with noradrenaline, histamine caused a maximal relaxation response that was 75 ± 6% of the contraction caused by noradrenaline with a mean EC50 value of 4.3 ± 0.5 μm. Neither dimaprit (H2-receptor selective) nor R-α-methylhistamine (H3-receptor selective) caused significant relaxation of nasal mucosae. In contrast, betahistine (H1-receptor selective) caused an 81 ± 7% relaxation of noradrenaline-induced tone with an EC50 value of 15 ± 1 μm. 3 pA2 experiments were performed to obtain KB values of chlorpheniramine (H1-receptor selective) and diphenhydramine (H1-receptor selective) for blocking histamine-stimulated relaxation of nasal mucosae. KB values for chlorpheniramine (0.87 nm) and diphenhydramine (7.4 nm) were consistent with their interaction at the H1-receptor type. Additionally, neither 10 μm cimetidine (H2-receptor selective) nor 1 μm thioperamide (H3-receptor selective) had any effect on the relaxation curve for histamine. 4 In the presence of 10 μm indomethacin (cyclo-oxygenase inhibitor), histamine caused a maximal relaxation response of 73 ± 5% of the noradrenaline-induced tone with an EC50 value of 2.9 ± 0.2 μm, which was not different from control values (EC50 = 5.0 ± 0.4 μm; maximal relaxation = 71 ± 6%). In contrast, 200 μm NG-nitro-l-arginine (nitric oxide synthase inhibitor) completely inhibited histamine-induced relaxation of nasal mucosae. 5 In conclusion, data from the present study suggest only the H1-receptor type mediates relaxation of nasal mucosal blood vessels to histamine, and histamine-induced relaxation of nasal mucosae is entirely dependent on nitric oxide production.

Notes: 1 This study was aimed at evaluating the effect of rutin and harmaline (1-methyl-7-methoxy-3,4-dihydro-β-carboline) on the development of the surgically induced reflux oesophagitis, on gastric secretion, lipid peroxidation, polymorphonucleocytes (PMNs) accumulation, superoxide and hydroxyl radical production in PMNs, cytokine [interleukin-1β (IL-1β), tumour necrosis factor-α (TNF-α)] production in blood and [Ca2+]i mobilization in PMNs. 2 Rutin and harmaline significantly prevented the development of reflux oesophagitis and gastric secretion. Treatments of oesophagitis rats with rutin and harmaline inhibited lipid peroxidation, and myeloperoxidase (MPO) in the oesophagus in comparison with untreated rats. 3 Superoxide anion and hydrogen peroxide production in 1 μm formylmethionylleucylphenylalanine (fMLP)- or 0.1 μg ml−1N-phorbol 12-myristate 13-acetate (PMA)-activated PMNs was inhibited by rutin and harmaline in a dose-dependent fashion. Rutin and harmaline effectively scavenged the hydroxyl radical and hydrogen peroxide. Treatments of oesophagitis rats with rutin and harmaline inhibited IL-1β production in the oesophagus in comparison with untreated rats, but TNF-α production was not affected by rutin and harmaline. The fMLP-induced elevation of [Ca2+]i was inhibited by rutin. 4 The results of this study suggest that rutin and harmaline may have beneficial protective effects against reflux oesophagitis by the inhibition of gastric acid secretion, oxidative stress, inflammatory cytokine production (i.e. IL-1β), and intracellular calcium mobilization in PMNs in rats.

Notes: 1 Although monumental efforts have been made to define the action sites of cough, the importance of neurotransmitter systems in the cough reflex has received limited attention. We studied the roles for four major neurotransmitters [acetylcholine, histamine, serotonin (5-hydroxytryptamine, 5-HT) and dopamine] in the modulation of the cough reflex. 2 Atropine (muscarinic cholinergic blocking agent), pyrilamine maleate (PM, histamine H1 blocker), cimetidine (histamine H2 blocker), 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT, specific 5-HT1A receptor agonist) and SCH-23390 (selective dopamine D1 receptor antagonist) were examined on the cough response to inhaled capsaicin in conscious guinea-pigs. 3 All the drugs significantly decreased the number of capsaicin-induced coughs in a dose-dependent manner. To compare the sensitivity of these drugs on cough response, we calculated the effective doses for 50% inhibition of cough (ED50) when the animals were exposed to 3 × 10−4 m capsaicin. The ED50 values were 0.03 μm kg−1 for atropine, 0.2 μm kg−1 for 8-OH-DPAT, 6.2 μm kg−1 for SCH-23390, 8.5 μm kg−1 for PM and 13.9 μm kg−1 for cimetidine. 4 These findings indicated that all these four neurotransmitters may be involved in the regulation of the cough reflex. Multiple changes of these neurotransmitters in disorders of the central nervous system might synergically affect the cough reflex.

Notes: Abstract. Brownfield sites often require a geochemical survey to assess the extent of contamination that is present as a result of previous industrial activities. These measurements are subsequently assessed to ascertain whether the site presents the possibility of causing significant harm to those who may use the site for specified purposes. The measurement process comprises both field sampling and chemical analysis, with sampling being of crucial importance, since previous studies have repeatedly shown that it is the sampling phase that generates the highest component of uncertainty. A variety of methods are currently available for sampling brownfield sites, such as different sampling patterns and the choice of depth and mass recovered. An investigator may also choose to employ more innovative sampling methods, such as in situ measurement strategies that can significantly reduce the overall time taken to complete the survey. The general aim of a sampling strategy is to take representative samples for chemical analysis, although this is rarely achieved due to the inherent heterogeneity of contaminants within any given site. Since it is practically impossible to sample an entire site, and thus achieve a truly representative sample, it is becoming increasingly understood that the uncertainty of the measurements should be estimated, to provide a more reliable interpretation of the survey. Various methods are currently available to estimate the measurement uncertainty that arises from both sampling and analysis, which vary in terms of complexity and cost. The level of uncertainty estimated during a site investigation should also be judged on its fitness-for-purpose (i.e. whether subsequent decisions based upon it are acceptable). The ‘optimized contaminated land investigation’ (OCLI) method is a new approach that can be used to balance the site-specific variables of any given investigation, such as the measurement costs against the level of uncertainty and costs that may arise from misclassification. This provides an objective and traceable judgement of whether the measurements are fit-for-purpose.

Notes: Abstract. Nuclear weapons' testing, mineral extraction industries and nuclear power generation are among the activities which have led to radioactively contaminated land. In the United Kingdom (UK), current activities such as the decommissioning of nuclear licensed sites and the sale of Ministry of Defence land require that the legislation, remediation and management of radioactively contaminated land be addressed. With an emphasis on the UK, this paper reviews potential management/remediation strategies for radioactively contaminated land, including consideration of the environmental mobility of potentially important radionuclides.

Notes: Abstract. Methods that can be used to determine the distribution of metal species in soil solution are critically reviewed and assessed. They are divided into two groups: those that can provide free ion activity, and those that measure labile species in solution. Ion selective electrodes have long been regarded as a promising technique, but there are practical problems in performing accurate measurements and only the Cu electrode has been used routinely. The Donnan membrane technique is capable of measuring the free ion activity of many metals, but adequate sensitivity can be a problem. Although resin competition methods are versatile, care must be exercised to avoid perturbing the solution excessively. Anodic stripping voltammetry (ASV) measures labile species, so the approximation involved in interpretation as simple inorganic species, from which free ion activities can be derived, should be recognized. Diffusive gradients in thin-films also measures labile species, but it is applicable to a much wider range of metals than ASV. It requires larger volumes of solution, but it can be used directly on the whole soil where it also measures the metal that can be rapidly supplied to solution. Other techniques such as permeable liquid membranes have yet to be used for measurements on soil solution. All of these methods have strength and weaknesses, and measure different aspects of speciation. Knowledge of the availability of the metals to biota is likely to be best advanced by the critical use of one or more of these speciation methods with a thorough understanding of exactly what is being measured.

Notes: Abstract. Effective use and recycling of manures together with occasional and judicious use of supplementary fertilizing materials forms the basis for management of phosphorus (P) and potassium (K) within organic farming systems. Replicated field trials were established at three sites across the UK to compare the supply of P and K to grass–clover swards cut for silage from a range of fertilizing materials, and to assess the usefulness of routine soil tests for P and K in organic farming systems. None of the fertilizing materials (farmyard manure, rock phosphate, Kali vinasse, volcanic tuff) significantly increased silage yields, nor was P offtake increased. However, farmyard manure and Kali vinasse proved effective sources of K to grass and clover in the short to medium term. Available P (measured as Olsen-P) showed no clear relationship with crop P offtake in these trials. In contrast, available K (measured by ammonium nitrate extraction) proved a useful measurement to predict K availability to crops and support K management decisions.

Notes: Abstract. Sodic and saline–sodic soils are characterized by the occurrence of sodium (Na+) at levels that result in poor physical properties and fertility problems, adversely affecting the growth and yield of most crops. These soils can be brought back to a highly productive state by providing a soluble source of calcium (Ca2+) to replace excess Na+ on the cation exchange complex. Many sodic and saline–sodic soils contain inherent or precipitated sources of Ca2+, typically calcite (CaCO3), at varying depths within the profile. Unlike other Ca2+ sources used in the amelioration of sodic and saline-sodic soils, calcite is not sufficiently soluble to effect the displacement of Na+ from the cation exchange complex. In recent years, phytoremediation has shown promise for the amelioration of calcareous sodic and saline–sodic soils. It also provides financial or other benefits to the farmer from the crops grown during the amelioration process. In contrast to phytoremediation of soils contaminated by heavy metals, phytoremediation of sodic and saline–sodic soils is achieved by the ability of plant roots to increase the dissolution rate of calcite, resulting in enhanced levels of Ca2+ in soil solution to replace Na+ from the cation exchange complex. Research has shown that this process is driven by the partial pressure of CO2 (PCO2) within the root zone, the generation of protons (H+) released by roots of certain plant species, and to a much smaller extent the enhanced Na+ uptake by plants and its subsequent removal from the field at harvest. Enhanced levels of PCO2 and H+ assist in increasing the dissolution rate of calcite. This results in the added benefit of improved physical properties within the root zone, enhancing the hydraulic conductivity and allowing the leaching of Na+ below the effective rooting depth. This review explores these driving forces and evaluates their relative contribution to the phytoremediation process. This will assist researchers and farm advisors in choosing appropriate crops and management practices to achieve maximum benefit during the amelioration process.

Notes: Abstract. Large nitrogen (N) inputs to outdoor pig farms in the UK can lead to high nitrate leaching losses and accumulation of surplus N in soil. We investigated the residual effects of three contrasting outdoor pig systems as compared to an arable control on nitrate leaching and soil N supply for subsequent spring cereal crops grown on a sandy loam soil during 1997/98 and 1998/99 harvest seasons. Previously, the pig systems had been stocked for 2 years from October 1995 and were designated current commercial practice (CCP, 25 sows ha−1 on stubble), improved management practice (IMP, 18 sows ha−1 on undersown stubble) and best management practice (BMP, 12 sows ha−1 on established grass). Estimated soil N surpluses by the end of stocking in September 1997 were 576, 398, 265 and 27 kg ha−1 N for the CCP, IMP, BMP and continuous arable control, respectively. Nitrate leaching losses in the first winter were 235, 198, 137 and 38 kg ha−1 N from the former CCP, IMP and BMP systems and the arable control, respectively. These losses from the former pig systems were equivalent to 41–52% of the estimated soil N surpluses. Leaching losses were much smaller in the second winter at 21, 14, 23 and 19 kg ha−1 N, respectively. Cultivation timing had no effect (P〉0.05) on leaching losses in year 1, but cultivation in October compared with December increased nitrate leaching by a mean of 14 kg ha−1 N across all treatments in year 2. Leaching losses over the two winters were correlated (P〈0.001) with autumn soil mineral N (SMN) contents. In both seasons, spring SMN, grain yields and N offtakes at harvest were similar (P〉0.05) for the three previous pig systems and the arable control, and cultivation timing had no effect (P〉0.05) on grain yields and crop N offtake. This systems study has shown that nitrate leaching losses during the first winter after outdoor pig farming can be large, with no residual available N benefits to following cereal crops unless that first winter is much drier than average.

Notes: Abstract. Soil organic carbon stocks to 1 m for Brazil, calculated using an updated Soil and Terrain (SOTER) database and simulation of phenoforms, are 65.9–67.5 Pg C, of which 65% is in the Amazonian region of Brazil. Other researchers have obtained similar gross results, despite very different spatial patterns mapped due to use of different methods.

Notes: Abstract. The effects of rice-straw management (incorporation, burning or removal) on soil organic carbon content and physical and hydraulic properties were determined after five years of rice–wheat cropping in a sandy loam soil in northwest India. Soil organic carbon content was greater with straw incorporation and straw burning than with straw removal, and aggregation status, total porosity, pore-size distribution, bulk density, dispersion ratio and soil strength were correspondingly improved. The treatment effects were confined mainly to the 0–5 cm depth. Water retention was less with straw burning than straw removal, owing to increased water repellency of the soil surfaces. Cumulative infiltration and its rate after five hours were greater with straw incorporation than straw burning or removal. Air entry values were unaffected by straw management; however, the values were greater after rice harvest than after wheat harvest.

Notes: Abstract. A field study was conducted to assess the effect of the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP), applied at a rate of 1 kg ha−1, on nitrous oxide (N2O) emissions, forage production and N extraction from a grassland soil after cattle slurry applications in autumn and spring. Nitrous oxide emissions were measured daily or weekly using the closed chamber technique. DMPP efficiency after slurry application was lower in spring (16.7 °C mean soil temperature) than in autumn (11.4 °C mean soil temperature). Thus, DMPP was able to maintain soil mineral N in the ammonium form for 22 days and reduce cumulative N2O emissions by 69% in autumn, while in spring its effect on soil mineral N lasted for 7–14 days, reducing cumulative N2O losses by 48%. Furthermore, application of DMPP after slurry did not decrease biomass yield or N uptake.

Notes: Abstract. Nutrient losses from arable land are important contributors to eutrophication of surface waters, and phosphorus (P) and nitrogen (N) usually act together to regulate production of Cyanobacteria. Concentrations and losses of both nutrients in drainage water from pipe drains were studied and compared in 15 crop rotations on a clay soil in southwest Sweden. Special emphasis was placed on P and it was possible to evaluate critical components of the crop rotations by flow-proportional water sampling. Total P concentrations in drainage water were generally small (0.04–0.18 mg L−1), but during two wetter years out of six, high P concentrations were measured following certain management practices, including ploughing-in lucerne (Medicago sativa L.) and fertilizing in advance without incorporation into the soil to meet the needs of several subsequent crops. This resulted in average flow-weighted concentrations of total P between 0.3 and 0.7 mg L−1. In crop rotations containing green manures, green fallow or leguminous leys, there was also a risk for increased P losses after these crops were ploughed in. The losses increased in the order: cash crops 〈 dairy with grass 〈 dairy with lucerne 〈 monoculture with barley 〈 organic farming with cattle slurry 〈 stockless organic farming with green manure. P balances varied between −9 and +8 kg P ha−1 and N balances between +4 and +35 kg N ha−1. The balances were not related to actual leaching losses. Phosphorus losses in drainage from set-aside were 67–82% of those from cash crops grown in ploughed and P-fertilized soil at the same site, indicating a high background P loss from this clay soil.

Notes: Abstract. Changes in surface soil properties of a savanna Alfisol under cultivation with applications of manure and inorganic NPK fertilizer were evaluated after 45 years of annual cropping. Soils from treatments with fertilizer only, fertilizer in combination with farmyard manure (FYM) at both high and low rates were compared to soil from a control receiving neither fertilizer nor manure. The high rate of FYM and fertilizer significantly improved soil aggregation, increased C, N and P status, while reducing soil penetration resistance. The results showed that there is a need to use both manure and inorganic fertilizer to maintain soil fertility in savanna soils under continuous cultivation.

Notes: Abstract. Vertisols are among the most common, high-potential soils in the central highlands of Ethiopia, where over 88% of human and 77% of the livestock population are located. Productivity from these soils is constrained by severe waterlogging due to their physical properties and intensive rainfall in summer. Traditionally, farmers plant late in the season to avoid the waterlogging, which results in harvest yields that are far below optimal. To bridge this yield gap, the broad-bed and furrow system for surface drainage has been introduced. Despite reported yields of various crops, little is known of the on-site and off-site impacts of this system. Consequently, four land preparation methods viz. (i) broad-bed and furrow (BBF), (ii) green manure (GM), (iii) the traditional system of ridge and furrow (RF) and (iv) reduced tillage (RT) were compared on standard runoff plots for 5 years (1998–2002) at Caffee Doonsaa in the central Highlands of Ethiopia. Runoff, sediment, organic carbon and nutrient (organic nitrogen and available phosphorus) losses were determined during the last two years (2001 and 2002). Over 50% of the seasonal rainfall was lost as runoff, regardless of the treatment, with significantly more of the excess water running off BBF and RT treatments in both years. The BBF system drained 67% and 54% of rainfall as runoff in 2001 and 2002, respectively, compared with 61% and 53% from the RT system during the measurement period. Although not statistically significant, the largest sediment and total nutrient losses tended to be from the BBF. The effect of the treatments on total nutrient loss and enrichment ratio was inconsistent. The nutrient concentration in the eroded sediment was greater than that of the originating surface soil but was strongly correlated. The effect of the land preparation methods was significant and varied with crops. Recommended options for best crop productivity are BBF for lentil and RT for wheat and tef.

Notes: Abstract. Soil organic matter (SOM) controls the physical, chemical and biological properties of soil and is a key factor in soil productivity. Data on SOM quantity and quality are therefore important for agricultural sustainability. In 1990, an experiment was set up at Saria, Burkina Faso on a sandy loam Lixisol to evaluate long-term effects of tillage (hand hoeing or oxen ploughing) with or without 10 t ha−1 yr−1 of manure and fallowing on SOM and N concentrations and their distribution in particle size fractions. The field was sown annually to sorghum (Sorghum bicolor [L.] Moench). Ten years later, total organic C and total N, SOM fractions and their N concentrations, and sorghum yield were determined. Continuous sorghum cultivation without organic inputs caused significant losses of C and N in the hoed and ploughed plots. However, addition of manure to hoed plots was effective in maintaining similar levels of C and N to fallow plots. Without manure, SOM was mainly stored in the size-fraction 〈0.053 mm (fine organic matter, FOM). SOM was mainly stored in the size-fraction between 0.053 and 2 mm (particulate organic matter, POM). In plots with manure and in fallow plots, the addition of manure more than doubled POM concentrations, with levels in tilled plots exceeding those of the fallow plots, and the highest levels in manually hoed plots. Nitrogen associated with POM (POM-N) followed a similar trend to POM. Hoeing and ploughing led to a decline in sorghum grain yield. Manure application increased yields by 56% in the hoed plots and 70% in the ploughed plots. Grain yield was not correlated with total SOM but was positively correlated with total POM. This study indicated that POM was greatly affected by long-term soil management options.

Notes: Abstract. The impact of different tropical farming systems on soil quality was examined using a systematic sampling strategy. Total organic C, pH, extractable P, exchangeable K, bulk density, water stable aggregates, microbial biomass C, cation exchange capacity, soil depth, and clay content were determined. An assessment framework, including a minimum data set, linear scoring functions and weighted additive indices, was used to evaluate the soil quality of a tropical farm growing various crops in Hainan, China. Soil quality was evaluated according to four functions: water availability, nutrient availability, rooting suitability, and erosion resistance. Our results showed that soils were intrinsically lacking in nutrients and vulnerable to degradation, and that these problems were exacerbated by inappropriate management. There was strong evidence that long-term rubber farming caused soil acidification, soil compaction, and depletion of organic matter and nutrients. By contrast, conservation practices in coffee plantations protected or improved organic matter concentration and soil structure, resulting in higher soil quality indices.

Notes: Abstract. The practice of large phosphorus (P) additions to agricultural land has resulted in an increased depletion of limited mineable rock phosphate resources, P accumulation in soils with an increased risk for P losses, and intensified eutrophication and deterioration of water quality in recipient water bodies. A number of measures have been used to reach balance between P inputs and outputs in agricultural systems, with the goal of achieving improved P use efficiency, sustained high crop yields and reduced P losses. This paper discusses how this goal may be achieved. Results from a Swedish long-term fertility experiment combined with results of a P leaching study using a selection of soils from the fertility experiment are used to evaluate the effects of a balanced P system on yields, soil P levels and P leaching. Three P fertilizer application strategies are compared (zero P, replacement P, and a treatment where surplus P fertilization was used to achieve a rapid increase in the soil P status). The replacement P strategy appeared to be the most sustainable system but P fixation in this system must be accounted for. When surplus P rates were applied, increased crop yields were counterbalanced by poorer use efficiency and P accumulation in soil. Topsoil P content was a poor predictor of P leaching. Instead, balancing P inputs and outputs represents a first step in the management of P losses, but additional, site-specific measures are required to counteract site-specific factors responsible for P losses.

Notes: Book reviewed in this article: Trees, crops and soil fertility: concepts and research methods. By G. Schroth and F.I. Sinclair (Editors).

Notes: Abstract. Current tillage erosion models account for the influence of tillage direction in the magnitude of the soil transport coefficient. It is argued that a re-modelling of tillage erosion is preferable in which the influence of tillage direction is separated from the soil transport coefficient, which is a measure of tillage intensity. This has been achieved here by developing a two-dimensional tillage erosion model that incorporates tillage direction in the measure of slope and uses soil transport coefficients that are independent of tillage direction and based on relationships between transport and the slope in the direction that bisects tillage direction and the overturning direction. Mean tillage erosion, associated with a single pair of opposing tillage directions and pair of overturning directions, can be described by a two-dimensional diffusion-type equation if the dimensions are defined as the tillage direction and the direction perpendicular to tillage. Application of the model to a real-world case allows quantification of the potential soil conservation benefits associated with optimization of tillage direction. The scope for amelioration is related to the ratio between the coefficients for transport in the direction of tillage and perpendicular to tillage. As this ratio approaches unity, the potential for amelioration reduces towards zero. For the study site investigated, use of the experimentally derived ratio of 0.66 indicated that a 12% reduction in tillage erosion could be obtained by ploughing across the dominant field slope as compared to ploughing up and down the dominant slope. For an implement with a coefficient ratio of 0.2 the reduction in tillage erosion intensity, associated with optimizing the tillage direction, reaches 28%. Nevertheless, such benefits must be considered in the context of other management considerations. The tillage direction that minimizes erosion is associated with lateral slopes of 10°, or more, over 20% of the field. To the land-user this disadvantage may outweigh the soil conservation benefits.

Notes: Abstract. Efforts to understand the fate of organochlorine compounds in arable soil have concentrated on anthropogenic compounds, in spite of the fact that organochlorine compounds are both produced and mineralized in soil through natural processes. In order to understand the fate of chlorinated pesticides, it is necessary to take account of the natural chlorine cycle. The present study is a first attempt to illuminate the relationship between the natural chlorine cycle and agricultural practices. The concentration and storage of organic chlorine (Clorg) and chloride (Clinorg) were determined in topsoil of a paddy field compared to an adjacent afforested hill at a sampling site in the Meicun area, Anhui Province, China. The concentration of Clorg, as well as the chlorine-to-carbon ratio, was significantly lower in the paddy field samples than in the forest soil samples. A weak relationship between the concentration of Clorg and the organic carbon content was observed in the paddy field, in contrast to the observations made in the adjacent forest soil as well as those made in previous studies, which have suggested a positive correlation between organic carbon content and Clorg. The similarity between our results at the forest site and the previous studies, which have been carried out in temperate regions, suggests that it is the land use rather than the climate that makes the current paddy soil results different. Our results suggest that the contribution of Clorg to the paddy soil from above-ground litter and from production within the soil are small or negligible compared with the contribution from pesticide application and wet and dry deposition.

Notes: Book reviewed in this article: The Identification of Soils for Forest Management. By Fiona Kennedy.

Notes: Abstract. A no-tillage (NT) system was developed in semiarid Morocco to improve the soil fertility and stabilize yield through conservation of water. Results in two long-term trials (4 and 11 years) were able to show the effects of a no-tillage system in increasing total soil organic matter and total nitrogen. Over time, the quality of the NT soil surface was improved compared with that under conventional tillage (CT) with disc harrows. This effect was the result of an increase in soil organic carbon (SOC) and a slight decline in pH. However, over time, nitrogen decreased in both tillage practices, especially in the 0–25 mm layer (from 0.59 to 0.57 t ha−1 and from 0.44 to 0.42 t ha−1 under NT and CT, respectively). After 4 years of NT an extra 5.62 t ha−1 of SOC was sequestered in the 0–25 mm layer, and after 11 years the SOC increased further to 7.21 t ha−1.

Notes: Book reviewed in this article: Agriculture, Hydrology and Water Quality. By P.M. Haygarth and S.C. Jarvis (Editors).

Notes: Abstract. For an efficient abatement of diffuse N pollution from arable land, it is important to have practical and reliable tools that can quantify the effect of different management practices on leaching, and also analyse the effect of alternative management scenarios aimed at reducing leaching. We present here an application of soilndb, a management-oriented model for quantifying nitrate leaching from arable land. Simulations with soilndb were compared with measurements of pipe-drain discharge of nitrate taken in a 14-year field experiment on a sandy loam soil in south-west Sweden. Following adjustment of parameters connected to litter and faeces decomposition and mineralization, the model gave satisfactory predictions of nitrate leaching for all 10 treatments. The temporal pattern was generally well captured by the model, as was confirmed by high model efficiency values (average = 0.59). This application also supports the model's ability to simulate the long-term influence of different crops and catch crops as well as different manure strategies on leaching. However, further studies should be done to evaluate the model under additional agro-environmental conditions (e.g. soils, climates, and crops).

Notes: Abstract. The Phosphorus Indicators Tool provides a catchment-scale estimation of diffuse phosphorus (P) loss from agricultural land to surface waters using the most appropriate indicators of P loss. The Tool provides a framework that may be applied across the UK to estimate P loss, which is sensitive not only to land use and management but also to environmental factors such as climate, soil type and topography. The model complexity incorporated in the P Indicators Tool has been adapted to the level of detail in the available data and the need to reflect the impact of changes in agriculture. Currently, the Tool runs on an annual timestep and at a 1 km2 grid scale.We demonstrate that the P Indicators Tool works in principle and that its modular structure provides a means of accounting for P loss from one layer to the next, and ultimately to receiving waters. Trial runs of the Tool suggest that modelled P delivery to water approximates measured water quality records. The transparency of the structure of the P Indicators Tool means that identification of poorly performing coefficients is possible, and further refinements of the Tool can be made to ensure it is better calibrated and subsequently validated against empirical data, as it becomes available.

Notes: Abstract. We present a semi-quantitative visual and tactile method for assessing soil physical fertility in terms of soil structure, root growth and soil surface condition. A block of topsoil is dug out with a spade. Horizontal layers (usually 2–4) are then identified as they appear. A brief one-page description of the soil is produced. Using a key, structural and rooting scores are assigned to each soil layer from the appearance of the soil and from its response to tactile assessment. These scores are then combined across depths, with weighting appropriate for the depth of each layer. A separate score was made of soil surface condition. Thus, overall soil physical fertility is assessed as three scores for topsoil structure, rooting and surface condition. The usefulness and sensitivity of the procedure were tested in two ley-arable organic rotation experiments on sandy loams in northeast Scotland.

Notes: Abstract. Eleven precipitated phosphates were evaluated as sources of phosphorus (P) for plant growth by comparing their effectiveness with that of monocalcium phosphate, a source of water soluble P that is generally considered to be fully plant available. The precipitated phosphates comprised struvites recovered from waste water discharges (mainly magnesium ammonium phosphate), laboratory synthesised struvites, a synthetic iron phosphate and a recovered calcium phosphate. Precipitating phosphates in these forms could be a way for removing P from waste water before it is discharged to rivers, so reducing the risk of eutrophication. Application to agricultural land would be one potential use for such phosphates. Evaluation was by pot experiments with a sandy loam soil and with a sandy clay loam soil using perennial ryegrass (Lolium perenne) as the test crop. The soils differed in pH (6.6 and 7.1) and in Olsen P (28 and 11 mg L−1). Measured variables were grass dry matter (DM) yield and grass P concentration which were used to calculate offtake of P in the harvested grass. DM yields of ryegrass and P offtakes given by the synthetic and recovered struvites were not significantly different statistically either between themselves or to MCP applied at the same rate. On this basis these struvites could be used to recycle P to similar soils and the effect of the P on crop yield should be similar to that of MCP

Notes: Abstract. The main inputs, outputs and transfers of potassium (K) in soils and swards under typical south west England conditions were determined during 1999/00 and 2000/01 to establish soil and field gate K budgets under different fertilizer nitrogen (N) (0 and 280 kg ha−1 yr−1) and drainage (undrained and drained) treatments. Plots receiving fertilizer N also received farmyard manure (FYM). Potassium soil budgets ranged, on average for the two years, from −5 (+N, drained) to +9 (no N and undrained) kg K ha−1 yr−1 and field gate budgets from +23 (+N, drained) to +89 (+N, undrained). The main inputs and outputs to the soil K budgets were fertilizer application (65%) and plant uptake (93%). Animals had a minor effect on K export but a major impact on K recycling. Nitrogen fertilizer application and drainage increased K uptake by the grass and, with it, the efficiency of K used. It also depleted easily available soil K, which could be associated with smaller K losses by leaching.

Notes: Abstract. Crops on sandy soils (〈5% clay) are exposed to K deficiency due to the small release and high leaching losses of K. Reliable tools are needed to improve the K management in cropping systems with limited K input, such as organic farming where import of nutrients are restricted according to the EC regulations. We investigated K balances and exchangeable K (Kexch) changes in an organic crop rotation experiment. Potassium leaching decreased from 42 kg ha−1 in 1998/99 to 21 kg ha−1 in 2000/01 as an average of a crop rotation (spring barley, grass-clover, winter wheat and pea/barley) with manure application and without catch crops. In the same period, spring Kexch decreased from 5.0 to 3.0 mg K 100 g soil−1 (0–20 cm). The retention of the straw K left in the field after harvest increased with decreasing levels of Kexch. The cereal crops did not respond to K application but in the pea/barley mixture the pea yield increased by 46%. The concordance between measured K balances and changes in Kexch was weak. Exchangeable K is suitable as a tool for K management on a rotational basis, and a Kexch above 3 mg 100 g soil−1 in the autumn should be avoided to minimize K leaching.

Notes: Abstract. Diagnosis of soil salinity and its spatial variability is required to establish control measures in irrigated agriculture. This article shows the usefulness of electromagnetic (EM) and soil sampling techniques to map salinity. We analysed the salinity of a 1-ha plot of surface-irrigated olive plantation in Aragon, NE Spain, by measuring the electrical conductivity of the saturation extract (ECe) of soil samples taken at 22 points, and by reading the Geonics EM38 sensor at 141 points in the horizontal (EMH) and vertical (EMV) dipole positions. EMH and EMV values had asymmetrical bimodal distributions, with most readings in the non-saline range and a sharp transition to relatively high readings. Most salinity profiles were uniform (i.e. EMH=EMV), except in areas with high salinity and concurrent shallow water tables, where the profiles were inverted as shown by EMH 〉 EMV, and by ECe being greater in shallow than in deeper layers. The regressions of ECe on EM readings predicted ECe with R2 〉 84% for the 0–100 to 0–150 cm soil depths. We then produced salinity contour maps from the 141 ECe values estimated from the electromagnetic readings and the 22 measured values of ECe. Owing to the high soil sampling density, the maps were similar (i.e. mean surface-weighted ECe values between 3.9 dS m−1 and 4.2 dS m−1), although the electromagnetically estimated ECe improved the mapping of details. Whereas soil sampling is preferred for analysing the vertical distribution of soil salinity, the electromagnetic sensor is ideal for mapping the lateral variability of soil salinity.

Notes: Abstract. The effects of soil management on soil losses from olive plantations in southern Spain were evaluated using the Revised Universal Soil Loss Equation (RUSLE), a review of published experiments, and preliminary results of an on-going field trial. Experimental data were used to parameterize the RUSLE for olive orchards under various soil management regimes. The predictions agreed qualitatively with the data available, and the model provided a simple way to assess the effects of soil management on erosion. Our results showed that no-tillage caused the greatest soil loss, while cover crops showed the least. Tillage and planting following contours proved only partially effective and did not reduce soil erosion as much as protective crops. One scenario studied suggests that, on slight to moderate slopes, land transformed from row crops to olive orchards may remain below the maximum tolerable soil erosion limit, if a cover crop is included between the trees. A scenario for marginal olive orchards located on steep slopes suggests that effective erosion control could only be achieved with a cover crop system that would have the side-effect of reducing the yield of rain-fed olives. Quantifying the effects of soil management on soil erosion in olive orchards is uncertain because very few experimental results are available. Further research that monitors soil loss in carefully selected long-term experiments at different scales and follows the changes in key soil parameters is urgently required to develop effective erosion control policies.

Notes: Abstract. Rainfall simulation experiments on a laboratory soil flume were conducted to test the hypothesis that the incorporation of slurry into the soil would reduce bacterial transport in overland flow. Presumptive faecal coliform (PFCs) concentrations were higher in the runoff from the surface applied treatment than from the incorporated treatments. The transport of PFCs and organic sediment were strongly correlated, with values of r ranging from 0.72 to 0.91.

Notes: Abstract. Land evaluation is the prediction of land performance over time under specific uses, to guide strategic land use decisions. Modern land evaluation has a 30 year history, yet the results have often been disappointing. Land users and planners have been reported to ignore land evaluations, perhaps reflecting poor quality, low relevance, or poor communication. To test the success of a large land evaluation exercise undertaken as part of micro-catchment project in Santa Catarina State, southern Brazil, we queried agricultural extensionists, considered as the primary land evaluation clients. We used a questionnaire with both structured and open questions, to determine their experiences with, and attitudes to, the current land evaluation method. The soil resource inventory and associated land evaluation had some usefulness, but were not in general used for their intended purpose, namely farm planning. This was mainly because they did not contain crucial information necessary to such planning in the actual context of the farmer taking decisions. The primary deficiencies were identified as:〈list xml:id="l1" style="custom"〉1no estimate of environmental degradation risk;2no financial analysis;3no social analysis of decision-makers' attitudes and preferences;4no risk assessment for weather, yields, profits and market; and5insufficiently-specific alternative land uses.These deficiencies could have been avoided with a demand-driven approach, evaluating and reporting according to the true needs and opportunities of the decision-makers.

Notes: Abstract. The residual value of mineral N fertilizer applied in the spring was investigated in a field experiment where four cereals (winter wheat, winter barley, spring barley and spring oats) had been grown at reduced (0.7N), normal (1N) or high (1.3N) N fertilizer rates for 20 to 28 years. The effect of previous N fertilizer dressing was tested in two succeeding years by replacing the original N rate with five test N rates ranging from 0 to 240 kg N ha−1 for winter cereals and 0 to 200 kg N ha−1 for spring cereals. In the first test year, winter wheat grown on plots previously supplied with the high rate of mineral fertilizer (202 kg N ha−1 yr−1) yielded more grain and straw and had a higher total N uptake than wheat on plots previously supplied with the normal (174 kg N ha−1 yr−1) or reduced (124 kg N ha−1 yr−1) rate. The grain yield response and N uptake was not significantly affected by the N supply in the test year. The winter wheat grown in the second test year was unaffected by the previous N supply. Grain and straw yield response and total N uptake for spring barley, winter barley and oats, were almost identical irrespective of the previous N rate.After 20 to 28 years there were no significant differences in soil C and N (0 to 20 cm) between soil receiving three rates of N fertilizer. Soil from differently fertilized oat plots showed no significant differences in N mineralizing capacity. Nitrate leaching losses from the soils at the three N rates were estimated and the N balances for the 20 to 28 years experimental period calculated. The data indicated a reduction in overall loss of 189 to 466 kg N ha−1 at the normal and high N rates compared with the reduced N rate. We conclude that the N supplying capacity and soil organic matter content of this fertile sandy loam soil under continuous cereal cropping with straw removal was not significantly affected by differences in N fertilizer residues.

Notes: Abstract. This paper compares nitrate leaching losses from organic farms, which depended on legumes for their nitrogen inputs (66 site years) with those from conventional farms using fertilizers under similar cropping and climatic conditions (188 site years). The conventional farms were within Nitrate Sensitive Areas in England, but sites following special practices associated with that scheme were excluded. Nitrate losses during the organic ley phase (including the winter of ploughing out) were similar (45 kg N ha–1) to those from conventional long-term grass receiving fertilizer N inputs of less than 200 kg N ha–1 (44 kg N ha–1) and from the grass phase of conventional ley-arable rotations (50 kg N ha–1). Losses from conventional grass receiving higher N inputs were greater than from organic or less intensive grass. Nitrate losses following arable crops averaged 47 and 58 kg N ha–1 for the organic and conventional systems respectively, with part of the difference being due to the greater proportion of non-cereal break crops in the latter. Thus under similar cropping, losses from organic systems are similar to or slightly smaller than those from conventional farms following best practice.

Notes: Abstract. In the Sahel, promising technologies for agricultural intensification include millet stover mulching and ridging. A four year on-farm experiment was set-up in order to assess the effect of various combinations of these two technologies on crop development and yield in a millet (Pennisetum glaucum (L.) R. Br.) - cowpea (Vigna unguiculata (L.) Walp.) intercropping system. Treatments included bare surface, ridging, a surface applied banded millet stover mulch (2 t ha–1) and a banded millet stover mulch (2 t ha–1) buried in ridges. The latter three treatments were implemented exclusively in the cowpea rows, with an annual rotation between the millet and cowpea rows. On bare and ridged plots, millet yields fell below 100 kg grain ha–1 after the first year. This was ascribed mainly to soil acidification and loss of soil organic matter rather than to soil physical constraints or water availability despite extensive surface crusting and high soil penetration resistance and bulk density. Compared to the bare plots, ridging increased cowpea hay production by 330% over the four years which was attributed to lower soil penetration resistance and bulk density but also to a reduction of 0.15 cmol+ kg–1 exchangeable acidity in the ridges. Except during the severe drought year of 1997, millet grain yield in the banded mulch treatment remained fairly stable over time at 526 ± 9 kg ha–1. However, a detailed analysis revealed yield compensation mechanisms between various yield components depending on the timing of occurrence of the abiotic stresses. Cowpea productivity was always higher in buried banded mulch plots than in surface applied banded mulch plots but the former treatment appeared unable to sustain millet yields. This decline was attributed to a greater nutrient uptake by cowpea and more rapid acidification in the buried mulch treatment compared to the banded mulch treatment.

Notes: Abstract. Nutrient balance calculations have been advocated as indicators of the risk of nitrate loss from agricultural land. To explore this concept, a spatially distributed UK agricultural nitrogen balance was derived using annually updated statistics. The mean UK N surplus for 1995 was 115 kg N ha–1, made up of 51 kg ha–1for arable land, 140 kg ha–1 for agricultural grassland (excluding rough grazing) and an additional 14 kg N ha–1for agricultural land from pig and poultry units. Nitrogen surpluses were greater in lowland grassland (mainly in western, wetter areas) than in arable areas. However nitrate concentrations in rivers were generally greater in arable areas. The relationship between N balance and nitrate leaching was very different for grassland and arable systems, and was also sensitive to climate, level of inputs and management practices. Nitrogen surplus was therefore weakly or even negatively correlated with river nitrate concentrations or loads. A positive correlation was found only where the comparison was restricted to grassland-dominated catchments. Nitrogen surplus calculations identified areas of very high livestock densities, which would be associated with increased risk of pollution. However their use in isolation as indicators of N leaching, or of progress towards mitigation, could be misleading especially if comparing areas differing in land use, climate or soil type.

Notes: Abstract. Dynamic simulation models are increasingly used in environmental and agricultural science. Here we present a method that allows models to be used to determine optimum timing of sampling for field trials. The model is used to decide when to concentrate sampling effort before the field trial begins. The model chosen to design sampling strategy should include an appropriately sensitive description of all processes that influence measurements significantly. The simulation is run, using predicted weather data, to generate the full time series before the trial begins. Every point in the simulation is considered initially to be a potential sampling point. The potential error due to not including a measurement at each point is calculated using the ‘dot-to-dot’ method of b10Smith et al. (2002) by omitting simulated values consecutively. The calculated potential error provides a measure of the priority that should be given to sampling at each point. Where the error introduced by omitting the simulated value exceeds an acceptable error, the value at the last discernible time step should be measured so that all statistically significant changes in the system can be observed. The output from the calculation is a plan of sampling times needed to capture all statistically significant events that are likely to occur over the course of the trial.

Notes: Abstract. In grazed dairy pasture systems, a major source of NO3– leached and N2O emitted is the N returned in the urine from the grazing animal. The objective of this study was to use lysimeters to measure directly the effectiveness of a nitrification inhibitor, dicyandiamide (DCD), in decreasing NO3– leaching and N2O emissions from urine patches in a grazed dairy pasture under irrigation. The soil was a free-draining Lismore stony silt loam (Udic Haplustept loamy skeletal) and the pasture was a mixture of perennial ryegrass (Lolium perenne) and white clover (Trifolium repens). The use of DCD decreased NO3–-N leaching by 76% for the urine N applied in the autumn, and by 42% for urine N applied in the spring, giving an annual average reduction of 59%. This would reduce the NO3–-N leaching loss in a grazed paddock from 118 to 46 kg N ha–1 yr–1. The NO3–-N concentration in the drainage water would be reduced accordingly from 19.7 to 7.7 mg N L–1, with the latter being below the drinking water guideline of 11.3 mg N L–1. Total N2O emissions following two urine applications were reduced from 46 kg N2O-N ha–1 without DCD to 8.5 kg N2O-N with DCD, representing an 82% reduction. In addition to the environmental benefits, the use of DCD also increased herbage production by more than 30%, from 11 to 15 t ha–1 yr–1. The use of DCD therefore has the potential to make dairy farming more environmentally sustainable by reducing NO3– leaching and N2O emissions.

Notes: Abstract. 15N labelled NH4NO3 (fertilizer N) was applied at a rate of 50 kg N ha–1 to an Ando-Humic Nitisol and two maize crops grown on it. About 20 months later, soil cores were taken to a depth of 2.5 m. Leached fertilizer N was found between 1.4 m and 1.8 m deep and was delayed relative to net drainage by between 4.2 and 4.9 pore volumes. Anion exchange capacity (AEC) increased ten-fold down the profile, up to 2.9 cmolckg–1. The delay to fertilizer N leaching was predicted to be between 4.1 and 5.3 pore volumes when calculated from the AEC and from an equation relating delay due to AEC in laboratory columns of repacked soil obtained by Wong et al. (1990b). It was concluded that the nitrate leaching delay equation was also valid in undisturbed field profiles. Two concentration maxima for mineral N were found, which did not usually coincide with the fertilizer N and were thought to result from mineralization of soil organic matter and plant residues at the end of each season. The delay equation overestimated their leaching delay but the results were considered close enough to support the hypothesis for their formation.

Notes: Abstract. Regions in the Po Valley, Northern Italy, are characterized by intensive crop-livestock farming systems. A simulation model has been chosen for an inter-regional project, which should help in defining groundwater vulnerability and pollution risk on a regional scale, in relation to agricultural land use, by allowing the prediction of nitrate leaching under different climate, soil, crop and management scenarios. The model derives from the coupling of a hydrological model, MACRO, simulating water flow and solute transport in structured soils, with a model simulating soil N dynamics, SOILN. The aim of this work was to test the model's ability to simulate nitrate leaching through soil after land spreading of pig slurries. A dataset obtained from lysimeter experiments which had been carried out in the period 1976–1981 was used for this purpose. Four soil types were compared (silty clay, sandy loam, loam and sand) in factorial combination with four rates of pig slurry (0, 142, 284, 426 g of N m–2, accumulated values from 1976 to 1979) for a seven crop sequence. The efficiency of the MACRO model ranged from 0.96, in the sandy-loam soil, to 0.81, in the sand. Percolation was usually under-estimated, the relative error ranging from 0.7 to 14.6, depending on the soil. The low efficiency of the SOILN model in simulating nitrate leaching is attributed to the lack of knowledge of the mechanisms regulating N transformation processes and especially the mineralization of pig slurry N. This lack of knowledge hampers the correct setting of the N transformation parameter values. A remarkable improvement of the model's performance was obtained by changing a few coefficients which control the mineralization-immobilization turnover of the faeces-organic N. The model efficiency, following this recalibration, ranged from –0.62 to 0.84, and the relative error ranged from –56 to 35, depending on soil and treatment. N leaching was under-estimated at the low pig slurry N application rates and over-estimated at the high ones.

Notes: Abstract. The effectiveness of contour grass strips in erosion control was investigated in a field experiment involving two grass treatments (Festuca ovina and Poa pratensis) and a bare soil control on an erodible sandy loam soil on a 5° slope using simulated rainstorms of 40 mm h–1 for 45 minutes duration. The grass strips resulted in significantly (P 〈 0.05) lower runoff and soil loss than the bare soil but there was no significant difference in the performance of the two grasses, despite their differences in density, height and leaf size. The effect of the lower density of the Poa pratensis was offset by its larger stem diameter so that the surface area facing the flow was similar for both grasses. Instead of acting as a filter with sedimentation occurring within the barrier, the grass strips operated by ponding water upslope of the barriers. Deposition then occurred in the ponded area above the barrier.

Notes: Abstract. Since the 1980s, land use in rural areas of China has changed greatly as the result of political initiatives. These changes have caused soil nutrient changes which are examined in this paper for Zunhua County, northern China from 1980 to 1999. The areas of farmland, grassland, and paddy decreased greatly and were replaced by increases in forest and residential land. The soils under forest in 1999 transformed from farmland in 1980 increased in organic matter by 21%, total nitrogen by 18%, available nitrogen by 65%, available phosphorus by 17% and available potassium by 17%. Similarly, in the area which was converted from farmland in 1980 to grassland in 1999, soil organic matter, total nitrogen, available nitrogen, available phosphorus, and available potassium increased by 38%, 37%, 71%, 2% and 28%, respectively. Changes from farmland to forest and grassland not only changed land cover but also improved soil fertility and probably reduced soil nutrient losses.

Notes: Abstract. Much of the low-lying farmland around the coastline of south-east England was once inter-tidal salt marsh, which was subsequently reclaimed from the sea and converted to farmland. It is becoming increasingly uneconomic to maintain the embankments which protect this land from the sea. ‘Managed retreat’ involves relocating the embankments further inland and recreating inter-tidal habitat in front of them. Salt marsh not only provides a protective buffer for these sea walls by dissipating wave energy, but is also important as a habitat for birds and as a source of organic matter for fish and inter-tidal fauna. When ‘managed retreat’ takes place, the creation of inter-tidal habitat occurs on soils that have undergone physical and chemical changes, some of which are irreversible. However, the indications are that rapid sedimentation creates conditions in which salt marsh plants germinate and become established; soil salinity rises quickly to a level which restricts competition from terrestrial plants, and deposited sediment is relatively rich in available phosphorus. The physical properties of the old agricultural soil influence the subsequent development of creeks.

Notes: Abstract. When the farmers of the Highlands of Tigray (northern Ethiopia) consider rock fragment cover in their fields to be excessive, they remove some of them. In addition, large amounts of rock fragments of all sizes are removed from fields for building stone bunds. Semi-structured interviews indicate that the farmers are often reluctant to take away the smaller rock fragments (i.e. 〈 5 cm across) from their fields, since they believe these benefit soil moisture conservation and protect topsoil from erosion. A field experiment was carried out on a Vertic Cambisol (average slope: 0.125 m m–1), 2 km east of Hagere Selam (subhumid climate). Rock fragments were totally, partially or not removed from the 12 runoff plots (5 m × 6 m) before the beginning of the 1999 cropping season, during which a local mixture of wheat varieties (Triticum spp.) was sown. After harvest, erosion rates were assessed by measuring deposited sediment volume in trenches at the lower side of each subplot, and grain and straw yields were assessed. We found a significant negative relationship between rock fragment cover and soil loss by water erosion. However, the resulting positive relationship between rock fragment cover and grain and straw yield was weak. This might be explained by the fact that the plot did not suffer from drought due to soil and climatic conditions. Detailed analysis showed that cover by medium and large rock fragments (〉 2 cm diameter) showed an optimum percentage cover above which crop yields decrease. A recommendation resulting from this study is to rely on the farmers’ experience: smaller rock fragments should never be removed from the surface of fields during soil and water conservation works; instead rock fragment rich soil can be used to top the stone bunds.

Notes: Abstract. The fertilizer nitrogen requirement of winter wheat was assessed in sixteen experiments on marine silt soils in Eastern England. Eight experimental sites followed potatoes (Solanum tuberosum), six vining peas (Pisum sativum) and two wheat (Triticum aestivum). The yield response to nitrogen fertilizer was much less following peas than potatoes or wheat, five sites following peas showed little response to more than 30 kg N ha–1. Previous crop explained some 79.7% of the variation in nitrogen optima. When autumn soil mineral nitrogen was also taken into account 81.9% of the variation in optimum nitrogen rate was explained (P〈0.001). The study revealed noticeably higher levels of autumn soil mineral nitrogen following vining peas on some sites than those found elsewhere in the UK and as assumed in the standard national fertilizer recommendation system.

Notes: Abstract. The aim of this study was to investigate the effects of water submergence depth on radial oxygen loss (ROL), soil solution chemistry and rice growth performance in acid sulphate soils in southern Vietnam. ROL was measured in a solution culture. In a separate pot experiment the impact of water submergence depth on rice growth and soil solution chemistry was studied. Three submergence depths were used in the two experiments (5, 10 and 15 cm). ROL declined with submergence depth and was significantly greater in young roots (with no root hairs) than in older roots. In the pot experiment rice growth and soil solution chemistry were clearly affected by the submergence depth. During the first crop at 5 cm submergence, there was a significantly higher yield and a higher oxidation state (pe+pH) compared to 10 or 15 cm submergence. The Fe concentration was significantly greater at the 5 cm depth compared to the 10 or 15 cm depth. SO42– reduction was delayed at the 5 cm depth. Rice yield was c. 25% less at the 15 cm than at the 5 cm depth. During a second crop, there was a substantial SO42- reduction and H2S formation and almost no significant effects of submergence depth on either soil solution chemistry or crop yield. In a field experiment with a dry-season rice crop, yield and Fe, Al and SO42– concentrations were higher at a shallow submergence depth than at greater depths in the same field, showing similar depth trends to those found during the first crop in the pot experiment. Farmers should be advised to use a shallow submergence depth and, if possible, avoid deep-rooted rice varieties. A conceptual model is suggested, which summarizes the relationships between ROL and soil solution chemistry.

Notes: Abstract. Tillage displaces large amounts of soil from upper slopes and deposits soil in lower landscape positions, greatly affecting productivity in these areas. The long-term effect of tillage on soil erosion was studied in four field sites growing mainly rainfed wheat. The soil loss from landscape positions with slopes, ranging from 3 to 28%, was estimated by: (a) comparing data of horizon thickness described at the same position at different times; and (b) using soil movement tracers added to the soil. Existing empirical relationships were used for estimating soil loss by tillage and runoff water, and loss in wheat biomass production. The experimental data showed soil losses of 0.4 to 1.4 cm yr–1 depending on slope gradient, plough depth, and tillage direction. In two of the sites, soil depth has been reduced by 24–30 cm in a period of 63 years. The mean soil displacement of the plough layer (30 cm thick), measured by soil movement tracers, ranged from 31 to 95 cm yr–1 depending mainly on slope gradient, corresponding to a rate of soil loss of 0.3 cm to 1.4 cm yr–1. Soil eroded from the upper slopes was deposited on the lower slopes increasing soil thickness by 0.4 cm to 1.4 cm yr–1. The application of empirical relationships, estimating soil loss by tillage and water runoff, showed that soil erosion at the field sites can be mainly attributed to tillage. The loss in wheat biomass production due to erosion was estimated at 26% on upper slopes for a period of 63 years, while a 14.5% increase in wheat production was estimated due to deposition of soil material in the lower landscape.

Notes: Abstract. The most common way of assessing soil organic matter content is by loss on ignition, which is both simple and inexpensive. This method tends to overestimate organic matter content because additional weight losses occur during ignition. An alternative, more expensive and time-consuming method for determining soil organic matter content is by an acid dichromate oxidation. This paper compares the results of applying these methods to soil on different parent materials in two arable fields. Summary statistics and correlation coefficients showed that there were consistent relationships between the two sets of values: the stronger was for the sandy soil and the weaker was for the clay loam. This relationship can be used to improve the accuracy with which soil organic matter content is known while using fewer of the expensive measurements and more of the inexpensive ones. Two approaches to prediction were compared: the geostatistical method of cokriging, and simple linear regression. These were used to predict organic matter determined by an acid dichromate oxidation from the loss on ignition. The estimates from cokriging were more accurate but the method requires the spatial correlation to be modelled reliably. The regression results showed it to be a valuable and practical approach. Using the information from nine carefully selected sampling sites a regression line could be fitted that was representative of the full data.

Notes: Abstract. In 1983, an annual Survey of Fertiliser Practice in England and Wales was extended to Scotland, to provide comprehensive information on inorganic fertilizer, lime and also organic manure use in mainland Britain. It was based on an annual sample of about 1500 farms, selected from the Agricultural Census and stratified by farm type and size. Results from the first fifteen years (1983–97) show that fertilizer nitrogen (N) rates on both tillage crops and grassland peaked at 157 and 132 kg ha–1, respectively, in the mid 1980s and subsequently decreased by c.10%. The majority of N was applied in straight form (without P or K) to tillage crops and in compound form (containing two or more nutrients e.g. NPK; NK) to grassland. Total N use on cereals showed little change but autumn-applied N decreased on both winter cereals and winter oilseed rape. Total N rates decreased on oilseed rape and, to a smaller extent, on maincrop potatoes and sugarbeet. Between 1983–87 and 1993–97, mean phosphate (P2O5) rates declined by almost 10% on both tillage crops (from 58 to 53 kg ha–1) and on grassland (from 25 to 23kg ha–1). The corresponding mean potash (K2O) rates decreased slightly on both tillage crops (from 64 to 62 kg ha–1), and on grassland (from 32 to 31 kg ha–1), although annual usage was more variable on grassland. Sulphur use increased appreciably on cereal and oilseed rape crops between 1993, when S data were first recorded in the survey, and 1997 when 13% and 30%, respectively, of these crop areas received S-fertilizer. However, on grassland, S use remained very low. Average lime use increased on both tillage crops and grassland between the mid 1980s and mid 1990s, from 10 to 12% and 4 to 7% of the total area, respectively. The proportion of land receiving organic manures remained at c. 16% for tillage cropping but increased slightly for grassland, from a mean of 40% in 1983–87 to 44% in 1993–97. Manures were applied throughout the year but about half the applications to tillage land, and a quarter of those to grassland, were made in autumn when the risk of subsequent nitrate leaching loss is greatest.

Notes: Abstract. A two year field experiment was carried out in a semiarid Mediterranean area in order to evaluate, the effect on soil erosion of adding different urban organic wastes: a stabilized municipal waste (compost), an unstabilized municipal waste, and an aerobic sewage sludge. All the treatments significantly reduced soil erosion, compared to the control soil. The soil amended with compost was the most effective treatment, reducing soil loss by 94% and runoff by 54%.

Notes: Abstract. Cashew soils of South Eastern Tanzania become acidified due to sulphur used for controlling powdery mildew disease (Oidium anacardii Noack). The buffering capacity of surface and subsurface horizons of 35 soil profiles of major cashew growing areas –- the Makonde plateau, its piedmont and inland plains –- was studied. The buffering capacity of surface and subsurface horizons was strongly correlated with clay content and weakly with organic carbon content. In addition, it was only weakly correlated with total exchangeable bases and available P of the surface horizon, but strongly with soil pH, base saturation and cation exchange capacity of the clay fraction of the subsurface horizon. Highly weathered sandy soils, dominant on the Makonde plateau and common on the Piedmont, had the lowest buffering capacity. Soils from the inland plains had better buffering capacities as they are generally more clayey or are less weathered. The risk of severe acidification and of a decline in productivity of cashew and of food crops is highest on the Makonde plateau. Further development and dissemination of methods which can reduce the use of sulphur are required.

Notes: Abstract. Biomass productivity and soil microbial responses to long-term CO2 enrichment have been investigated in a Mediterranean natural forest ecosystem. Several biochemical parameters have been measured on soil samples taken from six open top chambers (OTCs), enclosing clumps of natural Mediterranean woody vegetation including: Quercus ilex L., Phillyrea angustifolia L., Pistacia lentiscus L. and Myrtus communis L. The CO2 concentration of the air inside the OTCs was either ambient or ambient plus 350 μmol mol–1 (c. 710 ppm as mean daily value). Microbial C biomass, microbial respiration, dehydrogenase, β-glucosidase, acid phosphatase and protease activities, inorganic N and soluble P, were tested in order to evaluate soil microbial size and activity. Statistically correlated seasonal patterns have been identified in some biochemical parameters in response to climatic conditions, soil nutritional status and the physiology of the vegetative cover. In situ soil respiration and above- and below-ground productivity were also measured. Microbial responses to CO2 enrichment were observed only at the beginning of the study and a general progressive reduction of the CO2 effect was recorded as monitoring continued. These results are in agreement with data from literature regarding similar studies on natural complex communities.

Notes: Abstract. The Century model was used for estimating soil carbon levels under grassland at the regional scale in the Pampean Region of Argentina. Predicted values were compared with observed soil carbon contents obtained from soil surveys and the differences considered to be the results of cropping on soil organic matter. The Pampean Region was divided into five major sub-regions and carbon in the top 20 cm of each estimated by Century using aggregated soil and climatic data. In four of the sub-regions small differences between predicted and observed carbon contents were obtained which suggested little land use effect on soils. In the Rolling Pampa, a northern portion of the Pampean Region, observed carbon content was about half of Century prediction. In this sub-region, the main agricultural area of the country, cropping intensity, rainfall and temperature are higher than in the rest of the Pampas. A degradation index constructed by a multiplicative approach, taking into account percentage of surface cropped, rainfall and temperature was 2–5 times higher in the Rolling Pampa than in the other pampean sub-region. The difference between predicted C and observed C in the Rolling Pampa was attributed to carbon losses by cropping in a warm and wet climate.

Notes: Abstract. Recent developments in in situγ ray spectrometry offer a new approach to measuring the activity of radionuclides such as 137Cs and 40K in soils, and thus estimating erosion or deposition rates and field moist bulk density (ρm). Such estimates would be rapid and involve minimal site disturbance, especially important where archaeological remains are present. This paper presents the results of a pilot investigation of an eroded field in Scotland in which a portable hyper pure germanium (HPGe) detector was used to measure γ ray spectra in situ. The gamma (γ) photon flux observed at the soil surface is a function of the 137Cs inventory, its depth distribution characteristics and ρm. A coefficient, QCs, derived from the forward scattering of 137Cs γ ray photons within the soil profile relative to the 137Cs full energy peak (662 keV), was used to correct the in situ calibration for changes in the 137Cs vertical distribution in the ploughed field, a function of tillage, soil accumulation and ρm. Based on only 8 measurements, the agreement between in situγ ray spectrometry and soil sample measurements of 137Cs inventories improved from a non significant r2=0.05 to a significant r2=0.62 (P〈0.05). Erosion and deposition rates calculated from the corrected in situ137Cs measurements had a similarly good agreement with those calculated from soil cores. Mean soil bulk density was also calculated using a separate coefficient, QK, derived from the forward scattering γ photons from 40K within the soil relative to the 40K full energy peak (1460 keV). Again there was good agreement with soil core measurements (r2=0.64; P〈0.05). The precision of the in situ137Cs measurement was limited by the precision with which QCs can be estimated, a function of the low 137Cs deposition levels associated with the weapons testing fallout and relatively low detector efficiency (35%). In contrast, the precision of the in situ ρm determination was only limited by the spatial variability associated with soil sampling.

Notes: Books Reviewed in this Article: Fertiliser recommendations for agricultural and horticultural crops (RB209) Published with the permission of MAFF by HMSO, 7th edition 2000.

Notes: Abstract. In organic farming, potassium (K) deficiency may become a significant problem due to nutrient import restrictions. Knowledge about potential K leaching in systems with different K budgets is therefore important for effective agricultural management. We investigated the effect of four organic farming systems (two livestock densities in combination with two types of organic manure) on crop yields, K leaching and K balances in a six course crop rotation from 1993/94 to 1997/98. Average K concentrations in soil water extracted by means of ceramic suction cups at 1 m depth were 0.6 mg K l−1 corresponding to a K leaching loss of 1.5 kg ha−1 yr−1 which was less than expected from values reported in the literature. Variation in K budgets from −12 to +30 kg ha−1 yr−1 did not affect K leaching. In an additional experiment with application of 988 kg K ha−1 as KCl, K leaching accounted for only 0.2% of the applied K although 40% of the accompanying Cl was leached. The main part of the applied K was retained in the topsoil. It was concluded that K leaching was a result of the fertilizer history rather than of the current K budget.

Notes: Abstract. Nitrate nitrogen (NO3-N) leaching from animal production systems in the northeast USA is a major non-point source of pollution in the Chesapeake Bay. We conducted a study to measure NO3-N leaching from dairy slurry applied to orchardgrass (Dactylis glomerata L., cv. Pennlate) using large drainage lysimeters to measure the direct impact of four rates of slurry (urine and faeces) N application (0, 168, 336, 672 kg N ha−1 yr−1) on NO3-N leaching on three soil types. We then used experimentally-based relationships developed earlier between stocking density and NO3-N leaching loss and leachate NO3-N concentration to estimate the added impact of animal grazing. Nitrate N leaching losses from only dairy slurry applied at the 0, 158, 336, and 672 kg N ha−1 yr−1 rates were 5.85, 8.26, 8.83, and 12.1 kg N ha−1 yr−1, respectively with corresponding NO3-N concentrations of 1.60, 2.30, 2.46, and 3.48 mg l−1. These NO3-N concentrations met the 10 mg l−1 US EPA drinking water standard. However, when a scenario was constructed to include the effect of NO3-N leaching caused by animal grazing, the NO3-N drinking water standard was calculated to be exceeded.

Notes: Abstract. The African oil palm (Elaeis guineensis) is relatively well adapted to the pedoclimatic conditions of central Amazonia. The clayey upland soils of the region are well supplied with nitrogen, although they are deficient in most other nutrients. Under these conditions, oil palm does not respond to N fertilization with yield increases. In this research, the N status of a central Amazonian upland soil was evaluated after having supported a productive oil palm plantation for 15 years without N fertilization. Mineral N in the upper 2 m of soil showed pronounced spatial patterns, with very low concentrations close to the palms, indicative of efficient N uptake by the palms, and evidence for nitrate leaching into the subsoil in the inter-tree spaces despite the near-absence of a leguminous cover crop during the previous ten years. The pronounced increases of mineral N with increasing tree distance were explained by increases in N mineralization and a strong decrease in fine root length density of the palms, especially in the subsoil. Failure of the palms to fully occupy the available soil volume with their roots was apparently related to fertilizer placement close to the stem base, which over the years had led to steep fertility gradients between the soil under the trees and the inter-tree spaces. Broadcast fertilization would have presumably favoured a more extensive lateral root development of the palms, and consequently improved nutrient and water uptake from the inter-tree spaces. The incomplete soil occupation by the palm roots also suggests that young oil palms can be associated with shade tolerant crops without much risk of root competition. These conclusions may be valid also for other tree crops and may help to reduce nitrate leaching and consequently the need for N fertilization in Amazonian tree crop agriculture.

Notes: Abstract. Four experiments studying ground preparation for the restoration of disturbed land to a woodland cover are described. They provide consistent evidence to suggest that methods of soil replacement which minimize compaction are preferable to conventional methods followed by deep ripping to relieve compaction induced in the placement operation. In addition, soil loosening using an excavator is more effective than that achieved by ripping. The research supports modern guidance which advocates ‘loose tipping’ as the best method of ground preparation for a woodland or forestry after-use on sites reclaimed after dereliction or mineral extraction.

Notes: 1 We have investigated the actions of the α1D-adrenoceptor selective antagonist BMY 7378 in comparison with yohimbine at α1- and α2-adrenoceptors. 2 In rat aorta (α1D-adrenoceptor), BMY 7378 (pA2 of 8.67) was about 100 times more potent than yohimbine (pA2 of 6.62) at antagonizing the contractile response to noradrenaline. 3 In human saphenous vein (α2C-adrenoceptor), BMY 7378 (pA2 of 6.48) was approximately 10 times less potent than yohimbine (pA2 of 7.56) at antagonizing the contractile response to noradrenaline. 4 In prostatic portions of rat vas deferens, BMY 7378 (10 μm) did not significantly affect the concentration-dependent inhibition of single pulse nerve stimulation-evoked contractions by xylazine (an action at prejunctional α2D-adrenoceptors). 5 In ligand-binding studies, BMY 7378 showed 10-fold selectivity for α2C-adrenoceptors (pKi of 6.54) over other α2-adrenoceptors. 6 It is concluded that BMY 7378, in addition to α1D-adrenoceptor selectivity in terms of α1-adrenoceptors, shows selectivity for α2C-adrenoceptors in terms of α2-adrenoceptors.

Notes: 1 To investigate anti-inflammatory activity of organic germanium, we measured the effect of germanium-concentrated yeast on arachidonic acid release, prostaglandin E2 (PGE2) production, histamine release, and intracellular H2O2 or hydroperoxide generation in RBL 2H3 cells, and carrageenan-induced paw oedema in rats. 2 Germanium-concentrated yeast dose-dependently inhibited carrageenan-induced paw oedema, suggesting that germanium-concentrated yeast has anti-inflammatory activity in acute inflammation. 3 Germanium-concentrated yeast significantly inhibited melittin-induced arachidonic acid release and PGE2 production in RBL 2H3 cells. 4 Germanium-concentrated yeast did not affect melittin-induced histamine release and silica-induced intracellular H2O2 or hydroperoxide generation in RBL 2H3 cells. 5 These results suggest that anti-inflammatory activity of germanium-concentrated yeast appears partly to be related to the inhibition of arachidonic acid release and PGE2 production in RBL 2H3 cells.

Notes: Abstract. Denitrifying enzyme activity (DEA) declined to a greater extent and was more variable in soils stored air-dried for 6 months than after storage at 4 °C. DEA was greatest in fertilized soils. The relative differences in DEA between soils were maintained after storage at 4 °C. We suggest that storage at 4 °C is more appropriate than air-drying.

Notes: Book reviewed in this articles: Agriculture, Fertilizers and the Environment. Edited by M. Lægreid, O. C. Bøckman and O. Kaarstad. Ramiran 98. Proceedings of the 8th International Conference of the FAO European System of Co-operative Research Networks in Agriculture (ESCORNENA) on Management Strategies for Organic Waste Use in Agriculture. Edited by J. Martinéz & M.-N. Maudet.

Notes: Abstract. The incidence of soil water erosion was monitored in 12 erosion-susceptible arable catchments (c. 80 fields) in England and Wales between 1990 and 1994. Factors associated with the initiation of erosion were recorded, and the extent of rills and gullies measured. Approximately 80% of the erosion events were on land cropped to winter cereals. In 30% of cases, the initiation of erosion was linked to valley floor features, which concentrated runoff. Poor crop cover, wheelings and tramlines were also assessed as contributory factors in 22%, 19% and 14% of cases, respectively. In c. 95% of cases rainfall events causing erosion were ≥10 mm day−1 and c. 80% were 〉15 mm day−1. Erosion was also associated with maximum rainfall intensities of 〉4 mm h−1 for c. 90% of cases and 〉10 mm h−1 for c. 20%. Mean net soil erosion rates were approximately 4 t ha−1 per annum (median value 0.41 t ha−1 per annum) and associated mean P losses 3.4 kg ha−1.

Notes: Abstract. A study of the leaching losses of nitrate under urine patches in irrigated and non-irrigated dairy pastures in the South East of South Australia was undertaken with repacked and monolith lysimeters 1 m deep, and with monolith lysimeters 150, 300 and 450 mm deep. The aim was to quantify differences in measurements of drainage and nitrogen fluxes for these different lysimeters. Drainage of water and N flux were found to vary significantly between types and depths of lysimeters. Drainage volumes in repacked lysimeters were 78% and 33% more than in monolith lysimeters in irrigated and non-irrigated paddocks, and N fluxes were 5 and 3 times higher in repacked lysimeters respectively. The results indicate that lysimeter estimates of recharge rates and N fluxes to water tables are best determined by leaching studies which are longer term, and use deep monolith lysimeters. Shorter term studies and the use of shallow or repacked lysimeters have potential to distort conclusions.

Notes: Abstract. Under the Kyoto Protocol, the European Union is committed to an 8% reduction in CO2 emissions, compared to baseline (1990) levels, during the first commitment period (2008–2012). However, within the overall EU agreement, the UK is committed to a 12.5% reduction. In this paper, we estimate the carbon mitigation potential of various agricultural land-management strategies (Kyoto Article 3.4) and examine the consequences of UK and European policy options on the potential for carbon mitigation.We show that integrated agricultural land management strategies have considerable potential for carbon mitigation. Our figures suggest the following potentials (Tg yr−1) for each scenario: animal manure, 3.7; sewage sludge, 0.3; cereal straw incorporation, 1.9; no-till farming, 3.5; agricultural extensification, 3.3; natural woodland regeneration, 3.2 and bioenergy crop production, 4.1. A realistic land-use scenario combining a number of these individual management options has a mitigation potential of 10.4 Tg C yr−1 (equivalent to about 6.6% of 1990 UK CO2-carbon emissions). An important resource for carbon mitigation in agriculture is the surplus arable land, but in order to fully exploit it, policies governing the use of surplus arable land would need to be changed. Of all options examined, bioenergy crops show the greatest potential. Bioenergy crop production also shows an indefinite mitigation potential compared to other options where the potential is infinite.The UK will not attempt to meet its climate change commitments solely through changes in agricultural land-use, but since all sources of carbon mitigation will be important in meeting these commitments, agricultural options should be taken very seriously.

Notes: Abstract. A method to predict field-saturated hydraulic conductivity (Kfs) from soil structure, as described in soil profile descriptions, was developed using 627 Kfs measurements. As the soil structure classes used are very similar to an international classification (FAO, 1990), the derived relationships (class pedotransfer functions) could be widely applicable. A total of 49 unique combinations of primary and secondary structures were identified but the relationship between these structures and Kfs was poor. However, this relationship became clearer when the structures were grouped according to both the ped size and ped orientation. It improved further with the removal of data from horizons with significant amounts of vertically orientated angular stones or very coarse roots. Soils with vertically orientated peds larger than 50 mm had a geometric mean conductivity of 0.33 cm day−1 while those with fractures in both the horizontal and vertical planes had a geometric mean conductivity of 4.1 cm day−1. Soils with peds between 20 and 50 mm had a geometric mean conductivity of 17.9 cm day−1 and those with peds 〈20 mm had a geometric mean conductivity of 53.0 cm day−1. Those soils with only horizontally orientated structures proved to be anomalous in that the conductivity increased as ped size increased.

Notes: Abstract. Bacterial contamination of water is a problem worldwide and is often acute in developing countries where human and animal waste is disposed of on land for use as fertilizer or because of poorly developed sanitation systems. Studying leaching risk through soils is difficult when no suitable microbiological laboratory is available. A method using the movement of ZnO particles through soils as a surrogate for studying bacteria directly was tested. ZnO particles with a similar size to bacteria can readily be detected by chemical analysis. For a range of nine different soil textures, leaching rates of ZnO particles under near saturated conditions were significantly correlated with leaching rates of Escherichia coli cells (P=0.013). For both ZnO and E. coli, leaching was generally greatest through fine textured soils.

Notes: Book reviewed in this article: SOILpak for Cotton Growers. Third edition 1998. Edited by David C. McKenzie.

Notes: Abstract. Preferential flow has been increasingly recognised as a major component of water movement in many soils, particularly clays. This paper reviews problems in the measurement of solute fluxes in these soils, and discusses the solutions that have been adopted in UK studies of cracking clay soils. The estimation of solute fluxes is subject to many sources of error, which are best reduced by replicated measurements, such as those available in multi-plot experiments.

Notes: Abstract. Soil cores from river marginal wetlands from three sites in the UK (Torridge and Severn catchments), sampled and restrained in PVC piping, were flooded with dilute aqueous potassium nitrate. Half of the cores were sterilized prior to flooding to destroy the denitrifying bacteria. The change in nitrate concentration in the flood-water was measured over time. It is argued that the observed nitrate depletion rates (from 1.2 to 4.7 kg ha−1 d−1) is the result of microbially-mediated denitrification. The results show the method to be a simple and direct procedure for the assessment of spatial variation in nitrate-sink capacity. The depth of the denitrifying layer at the soil–water interface was confirmed to be of the order of a few mm only. A one-dimensional model for the diffusive flux in the flooded soil was developed which, on differentiation, gave a predictive expression for denitrification rate in terms of the effective soil diffusion coefficient for nitrate, the flood-water depth and concentration, and the thickness of the microbially active zone.

Notes: Book reviewed in this article: The Soils and Land Use Potential of the Southern and Eastern Slopes of Kilimanjaro, Tanzania.

Notes: 1 The pressor action of noradrenaline and its blockade by selective α1-adrenoceptor antagonists in the pithed mouse were evaluated. 2 Chloroethylclonidine (α1B/D-adrenoceptor alkylating agent) or BMY 7378 (α1D-adrenoceptor antagonist), both at 1 mg kg−1, did not block the increase in blood pressure induced by noradrenaline. 3 5-Methylurapidil (α1A-adrenoceptor antagonist), at 0.1 mg kg−1, displaced the dose–response curve approximately six-fold to the right. 4 The results support the idea that the pithed mouse vasculature express α1A-adrenoceptors and suggest that it is a good model to study the roles of α1-adrenoceptors in gene knockout or overexpression.

Notes: 1 The aim of this paper was to determine the different signalling cascades involved in contraction of the rat urinary bladder detrusor muscle mediated via muscarinic acetylcholine receptors (muscarinic AChR). Contractile responses, phosphoinositides (IPs) accumulation, nitric oxide synthase (NOS) activity and cyclic GMP (cGMP) production were measured to determine the reactions associated with the effect of cholinergic agonist carbachol. The specific muscarinic AChR subtype antagonists and different inhibitors of the enzymatic pathways involved in muscarinic receptor-dependent activation of NOS and cGMP were tested. 2 Carbachol stimulation of M3 and M4 muscarinic AChR increased contractility, IPs accumulation, NOS activity and cGMP production. All of these effects were selectively blunted by 4-DAMP and tropicamide, M3 and M4 antagonists respectively. 3 The inhibitors of phospholipase C (PLC), calcium/calmodulin (CaM), neuronal NOS (nNOS) and soluble guanylate cyclase, but not of protein kinase C and endothelial NOS (eNOS), inhibited the carbachol action on detrusor contractility. These inhibitors also attenuated the muscarinic receptor-dependent increase in cGMP and activation of NOS. 4 In addition, sodium nitroprusside and 8-bromo-cGMP, induced negative relaxant effect. 5 The results obtained suggest that carbachol activation of M3 and M4 muscarinic AChRs, exerts a contractile effect on rat detrusor that is accompanied by an increased production of cGMP and nNOS activity. The mechanism appears to occur secondarily to stimulation of IPs turnover via PLC activation. This in turn, triggers cascade reactions involving CaM, leading to activation of nNOS and soluble guanylate cyclase. They, in turn, exert a modulator inhibitory cGMP-mediated mechanism limiting the effect of muscarinic AChR stimulation of the bladder.

Notes: 1 The objective was to investigate a possible contribution of a nerve-derived hyperpolarizing factor to the differences between non-adrenergic non-cholinergic (NANC) nerve-mediated relaxations in different states of active tone in the rat gastric fundus. 2 NANC relaxations induced by electrical field stimulation (ES: 0.1, 0.5 and 1 Hz; 25 V; 1 ms; 10 s) in 40% contracted strips (S40) were greater when compared with those in 80% contracted strips (S80). 3 ES-induced relaxations were effectively attenuated by Nω-nitro-l-arginine (l-NNA; 100 μm) in S40 and S80. Percentage reduction of the responses obtained in the presence of l-NNA in S40 group was less than that of S80. 4 In S40 group, nifedipine (0.5–1 μm) and verapamil (0.5–1 μm) inhibited the responses to 0.1 and 0.5 Hz. Nifedipine (1 μm) and verapamil (0.5 μm) caused no change in the responses to ES in S80. 5 In S40, when l-NNA (100 μm) and nifedipine or verapamil, either in 1 μm concentration, were administered together, the inhibition on the electrical relaxations were more than that of each drug alone. 6 In conclusion, NANC nerve-mediated relaxations are increased when studied in an active state of 40%, and a factor, sensitive to nifedipine seems to be responsible for this distinction.

Notes: 1 Experiments were carried out to characterize the possible adrenergic properties of the 5-HT1A antagonists WAY 100635 and MM-77 using the mouse isolated vasa deferentia preparation. 2 When vasa deferentia were preincubated for 10 min in the presence of MM-77 (10−8–10−6 m) or WAY100635 (10−8–7 × 10−7 m), a concentration-dependent inhibition of the contractile response to submaximal electrical field stimulation (10 Hz, 50 V, 50 ms) was observed with pIC50 values of 7.05 ± 0.01 and 6.85 ± 0.1 respectively. 3 MM-77 (10−8–10−6 m) antagonized the contractile responses of the vasa deferentia to phenylephrine (PE) (10−6–10−3 m) in a concentration-dependent manner. Schild plots of these data were linear and yielded a mean ρA2 value of 6.81 ± 0.084. The mean slope was 1.42 ± 0.22. 4 WAY100635 (10−8–10−6 m) antagonized the contractile responses of the vasa deferentia to PE (10−6–10−3 m) in a concentration-dependent manner. Schild plots of these data were linear and yielded a mean ρA2 value of 7.05 ± 0.08. The mean slope was 0.97 ± 0.1. 5 The results suggest that while WAY100635 acts as a competitive antagonist at α1-adrenoceptors, MM-77 displays non-competitive antagonist characteristics at this receptor subtype. 6 These results may have important implications for the use of these compounds as 5-HT1A receptor antagonists in in vivo studies.

Notes: 1 The aim of the present study was to examine the modulator influence of muscarinic M2 receptors on responses of rat urinary bladder detrusor muscle evoked by endogenous stimuli, i.e. by stimulation of the bladder innervation. 2 Responses were evoked by electrical field stimulation (EFS; 2–20 Hz, 0.8 ms, 60 V) of isolated strip preparations mounted in organ baths. The tension of the muscle strips was recorded digitally. EFS was performed by applying stimulation with either a short duration (5 s) or a longer duration (to reach peak response; approximately 20 s). 3 Effects of muscarinic receptor antagonists (muscarinic M1/M3 receptor selective: 4-diphenylacetoxy-N-methylpiperidine methobromide (4-DAMP); muscarinic M2 receptor selective: methoctramine), a β-adrenergic antagonist (propranolol) and an adenosine receptor antagonist (8-p-sulfophenyltheophylline) were assessed on contractile activity and on poststimulatory relaxations. 4 Low concentrations of methoctramine (10−8 m) reduced or tended to reduce the EFS-induced contraction, e.g. at 2 Hz by 12% while methoctramine at 10−7 m had no significant effect. In addition, in the presence of 4-DAMP (10−9 m), which tended to inhibit contractions at all frequencies (2–20 Hz; −17 to −25%), methoctramine at 10−8 and 10−7 m induced a further reduction of the contractile responses (−5 to −10%; 2–20 Hz). 5 The β-adrenergic receptor antagonist propranolol (10−6 m) and the adenosine receptor antagonist 8-p-sulfophenyltheophylline (10−6 m) both increased contractile responses by 9–21% (2–10 Hz, long duration; P 〈 0.05–0.001) as a consequence of antagonizing relaxatory stimuli. Neither antagonist affected the contractile responses to EFS with the short duration stimulation. Poststimulatory relaxations were reduced by 30–60% (P 〈 0.05) by propranolol and by 40–60% (P 〈 0.001) by 8-p-sulfophenyltheophylline, but for 8-p-sulfophenyltheophylline only after stimulation with the short duration. 6 In the presence of methoctramine (10−7 m), the 8-p-sulfophenyltheophylline-induced increases of the contractile response to long duration EFS were significantly enhanced at 10 Hz (+12 ± 4%; P 〈 0.05), whereas no such enhancement of the propranolol inhibitory effect occurred in the presence of methoctramine. However, poststimulatory β-adrenoceptor-evoked relaxations after short duration EFS were increased by about 35% in the presence of methoctramine, but not those after long duration. 7 Thus, muscarinic M2 receptor activation inhibits adenosine receptor- and β-adrenoceptor-evoked relaxations of the rat detrusor muscle. The inhibition occurs via a transient postjunctional mechanism that mainly affects responses with a short latency.

Notes: 1 To clarify the effects of doxapram on the baroreflex, we recorded carotid sinus nerve (CSN) activity in isolated and perfused carotid artery bifurcations of rabbits. 2 The CSN activity due to chemoreceptor stimulation was blocked by resection of the nerve branches from the carotid body. After the resection, the CSN activity was correlated to increase of carotid sinus (CS) pressure. 3 Administration of doxapram reduced the CSN activity originating from baroreceptors. The effect of doxapram on baroreceptors was dose dependent and reversible. 4 It is unlikely that doxapram altered CS wall mechanics because CS pressure did not change in the presence of the drug. 5 We conclude that doxapram acts on the cardiovascular system in part by inhibiting the negative feedback loop that originates in CS baroreceptors.

Notes: 1 Cardiac glycosides have been used for centuries as therapeutic agents for the treatment of heart diaseases. In patients with heart failure, digoxin and the other glycosides exert their positive inotropic effect by inhibiting Na+–K+-ATPase, thereby increasing intracellular sodium, which, in turn, inhibits the Na+/Ca2+ exchanger and increases intracellular calcium levels. As the therapeutic index of digitalis is narrow, arrhythmias are common problems in clinical practice. The mechanisms and mediators of these arrhythmias, however, are not completely understood. 2 The involvement of the sympathetic and parasympathetic nervous system in digitalis cardiac toxicity is reviewed. 3 Receptors, channels, exchange systems or other cellular components involved in digitalis-induced cardiotoxicity are also reviewed. 4 Possible mediators of digitalis-induced cardiac toxicity are discussed. 5 Management of digitalis toxicity in patients is summarized. 6 The determination of the possible mediators of digitalis-induced cardiac toxicity will enhance our knowledge and lead to the development of new therapeutic strategies to treat these lethal arrhythmias.

Notes: Abstract. A database of 1065 fields in all parts of Finland, two soil profiles (augerhole borings) per field, was screened for acid sulfate (a.s.) soils. Each field represented 2100 14;ha of cultivated land. Soil pH and redox potential were determined in the field, at intervals of 10 14;cm, to a depth of 200 14;cm. Of the maximum of 124 profiles considered as a.s. soils according to the Soil Taxonomy and ILRI (International Institute of Land Reclamation and Improvement) systems, 46 profiles exhibited pH 〈3.5. These represented 48 14;000 14;ha of land. More than half of these severely acidic soils were associated with reduced subsoils and probably contained actively oxidizing sulfidic materials within 150 14;cm of the soil surface, while the remaining profiles were oxidized at least down to 150 14;cm. Using Soil Taxonomy criteria, the total area of cultivated a.s. soils was 67 14;000–130 14;000 14;ha. The minimum estimates exclude soils that may be leached or too low in sulfide to meet the criteria of a.s. soils. Application of the ILRI system produced an estimate of 61 14;000–130 14;000 14;ha. In the maximum estimate, 27% of the profiles were raw, 61% ripe and 12% potential a.s. soils. According to the FAO/UNESCO system, the area of cultivated a.s. soils (pH 〈3.5 or assumed sulfidic materials) is considerably less: 43 14;000–78 14;000 14;ha. All these estimates are only a fraction of the area considered to be covered by a.s. soils by established Finnish criteria. The choice of estimate has important economic implications for liming subsidies and planning regulations for the drainage of a.s. soils.

Notes: 1 Microinjection of peptide YY (PYY) (0.23–2.3 nmol) into the posterior hypothalamic nucleus (PHN) of conscious rats evokes a dose-dependent pressor response and a bradycardia. 2 The increase in mean arterial pressure evoked by 2.3 nmol of PYY was not blocked by intravenous pretreatment with: (i) the nicotinic ganglionic receptor antagonist pentolinium (PENT, 10 mg kg−1) alone, or in combination with the muscarinic receptor antagonist methylatropine (MeATR, 1 mg kg−1); (ii) the α1-adrenoceptor antagonist prazosin (PRAZ, 0.2 mg kg−1); (iii) the V1-vasopressin receptor antagonist [d(CH2)5Tyr(Me)]AVP (AVPX, 20 μg kg−1); (iv) the combination of AVPX, PENT and MeATR; (v) the combination of PRAZ, AVPX, PENT, MeATR, and the α2-adrenoceptor antagonist yohimbine (0.3 mg kg−1); or (vi) the angiotensin II type 1 receptor antagonist ZD 7155 (1 mg kg−1). 3 Adrenal demedullation inhibited the PYY-evoked responses of drug-naïve rats, and rats pretreated with the combination of PENT, MeATR and AVPX. 4 Transection of the splanchnic nerve innervating the adrenal medullae attenuated the bradycardia, as did ZD 7155, but not the PYY-evoked pressor response. 5 Systemic pretreatment of rats with the neuropeptide Y1 receptor antagonist BIBP 3226 (1 mg kg−1) blocked the PYY-evoked cardiovascular changes, but not those evoked by microinjection of carbachol (5.5 nmol) into the PHN. 6 These results suggest that the cardiovascular changes evoked from the PHN by PYY requires the presence of the adrenal medullae, which are stimulated by: (i) a hormone to release an NPY-like substance that evokes the pressor response, and (ii) the splanchnic nerve to evoke the release of a substance that results in the bradycardia.

Notes: 1 We examined whether extremely low frequency electromagnetic fields (ELF-EMF) affect the basal level of cardiovascular parameters and influence of drugs acting on the sympathetic nervous system. 2 Male rats were exposed to sham control and EMF (60 Hz, 20 G) for 1 (MF-1) or 5 days (MF-5). We evaluated the alterations of blood pressure (BP), pulse pressure (PP), heart rate (HR), and the PR interval, QRS interval and QT interval on the electrocardiogram and dysrhythmic ratio in basal level and dysrhythmia induced by β-adrenoceptor agonists. 3 In terms of the basal levels, there were no statistically significant differences among control, MF-1 and MF-5 in PR interval, QRS interval, mean BP, HR and PP. However, the QT interval, representing ventricular repolarization, was significantly reduced by MF-1 (P 〈 0.05). 4 (−)-Dobutamine (β1-adrenoceptor-selective agonist)-induced tachycardia was significantly suppressed by ELF-EMF exposure in MF-1 for the increase in HR (ΔHR), the decrease in QRS interval (ΔQRS) and the decrease in QT (ΔQT) interval. Adrenaline (nonselective β-receptor agonist)-induced dysrhythmia was also significantly suppressed by ELF-EMF in MF-1 for the number of missing beats, the dysrhythmic ratio, and the increase in BP and PP. 5 These results indicated that 1-day exposure to ELF-EMF (60 Hz, 20 G) could suppress the increase in HR by affecting ventricular repolarization and may have a down-regulatory effect on responses of the cardiovascular system induced by sympathetic agonists.

Notes: 1 Cyclic AMP formation has consistently been reported to be desensitized in various tissues including heart of animal models of end-stage renal failure (ESRF). In contrast, reports on desensitization of cAMP formation in ESRF patients remain contradictory. Whether this discrepancy results from a difference between human ESRF and its animal models or from the use of circulating blood cells in the human and various solid tissues in the animal studies, remains unclear. Therefore, we performed three studies with heart and platelets of ESRF patients undergoing haemodialysis or continuous ambulatory peritoneal dialysis and age- and gender-matched controls with normal renal function (n = 11–13 each). 2 In platelets from haemodialysis patients adenylyl cyclase activity in response to receptor-dependent and -independent agonists was reduced by ≈30%, and this could be explained by an alteration at the level of adenylyl cyclase itself. However, no such desensitization was seen in platelets from peritoneal dialysis patients. 3 In hearts from ESRF patients undergoing haemodialysis, β-adrenoceptor density and subtype distribution, cAMP formation in response to the β-adrenoceptor agonist isoprenaline or various receptor-independent stimuli, were very similar to those in control patients but activity of G-protein-coupled receptor kinase was increased by ≈20%. 4 We conclude that conflicting reports on the desensitization of cAMP formation between ESRF patients and ESRF animal models are not explained by the use of solid tissues in animal studies vs. circulating blood cells in patient studies. Rather desensitization of cAMP formation seems to be a less consistent feature of human ESRF than of its animal models.