ALBERT

Description: SUMMARYThe influence of various nitrogen and phosphorus sources, applied at the preseeding stage with two placement methods, on maize yield and fertilizer utilization, was studied in two field experiments and a pot experiment with a calcareous, heavy to medium heavy textured recent alluvial soil.Phosphorus alone had no effect on crop yield. Nitrogen alone or nitrogen (various forms) and phosphorus had a clear positive effect on crop yield. As to the various sources the observed differences in the crop yield of the field experiments were not significant, while in the pot experiment ammonium sulphate gave the highest yields.The data on the phosphate concentrations in the tops derived from phosphate fertilizer (Pf) indicate that the presence of nitrogen increased the utilization of phosphorus fertilizer. From the tested placement methods the incorporation method appears clearly superior in the pot experiment with a similar trend in the field experiment for all sources except ammonium phosphate-sulphate.The utilization coefficients of the nitrogen fertilizer sources suggest that ammonium and urea were better utilized than nitrates, that the higher nitrogen utilization reflected higher yields and that phosphorus fertilizer exerted a beneficial effect on nitrogen fertilizer utilization. Finally they suggest that the addition of 120 kg N/ha enhanced the amount of soil nitrogen taken up in the maize grain by 53%.

Description: Singh & Taneja (1978a, 6, 1981) have reported on several aspects of salinity tolerance in Indian desert sheep breeds, for example, maintenance of body weight, feed and water intake, body water compartments and blood characteristics. No report is available in the literature on the effect of varying levels of salt intake from drinking water on reproductive performance in these animals. The earlier reports on salinity tolerance in sheep have been almost wholly based on the animals' response to different levels of sodium chloride in synthesized drinking waters. It is, however, generally agreed that the upper limit of total salt tolerance in sheep depends not only on the concentration of the most abundant salt constituent in the drinking water (usually sodium chloride), but also on the concentrations of the other constituents. Divalent cations (calcium and magnesium) and anions (sulphates and carbonates) in the water are believed to be more toxic than the monovalent cations and anions (sodium and chloride).

Description: SUMMARYThe effects of N, P, K and Na silicate fertilizers, and drought on the concentrations of K in the dry matter and tissue water of field-grown spring barley crops have been investigated. Percentage K in dry matter depended on the amounts of N, P, K or water received by the crops and was linearly related to fresh weight to dry weight ratio, but the slope of this relationship depended on whether or not the crops received K. Expressing K concentrations on the basis of tissue water eliminated differences between crops, except for those given insufficient K. Barley crops given fertilizer K maintained K concentrations in their tissue water of about 200 mmol/kg tissue water for most of the growth period but crops grown without K had only 50–70 mmol/kg tissue water. The results indicate that K concentrations in the tissue water are a more reliable indicator of tissue K status than % K in dry matter.Decreases in crop K content resulting from poor K supply were balanced by increases in Na and Ca (but not Mg) contents so that total cation concentrations in the tissue water were similar in low and high K crops. The extra Na and Ca are probably primarily involved in maintaining charge balance for anion absorption but once in the plant they may also substitute for K in its osmotic role.

Description: The main source of skin surface protein is sweat glands. Studies on skin surface proteins of domestic animals have been made by Joshi etal. (1968), Jenkinson, Lloyd & Mabon (1976, 1979), Lloyd, Mabon & Jenkinson (1977) and Rai, More & Singh (1982). However, information on sweat proteins (skin surface proteins) of goats is lacking. The present study is an effort to characterize sweat proteins of goats and to compare them with those of sheep.

Description: Vascular injection or infusion of isotopically labelled fatty acids into both ruminant and nonruminant species has been used as a method for determining the entry rate of non-esterified fatty acids (NEFA) into blood (Bickerstaffe, Annison & Linzell, 1974; Vranic, 1975). Results obtained in this way represent the release of fatty acids from several sources, principally adipose tissue. The predominant labelled end-products from [3H]– and [14C]fatty acid metabolism are water and carbon dioxide respectively. Both these metabolites enter extensive body pools and the label is unlikely to be reincorporated into plasma NEFA during the time course of conventional short-term experiments (2–4 h). During isotope dilution experiments, however, some labelled fatty acid could be incorporated into adipose tissue triacyglycerol (TAG) following synthesis of low-density lipoprotein in the liver. In addition, the contribution of NEFA carbon to endogenous acetate production could result in transfer of 14C in any C, or 8H attached to the C8 position in acetate, from the infused fatty acid to fatty acids synthesized by liver and adipose tissue.

Description: SUMMARYSeveral nitrification inhibitors were compared with nitrapyrin, which was taken as the standard, when injected with aqueous urea into ryegrass leys at Rothamsted during 1977–81 and at Liscombe Experimental Husbandry Farm, Dulverton, Somerset, during 1977–9. Injection was done in either autumn or winter or spring.All the inhibitors slowed down the rate of nitrate formation from the injected urea. Sodium trithioearbonate (STC) was less effective than nitrapyrin and potassium ethyl xanthate (KEtX) less effective than STC. A mixture of nitrapyrin and carbon disulphide was better than nitrapyrin alone, and a mixture of STO and KEtX was better than STC alone.At Rothamsted, injecting inhibitors in autumn or winter improved yields and N uptakes, probably because they prevented loss of nitrate N by leaching and perhaps by denitrification. STC, STC-KEtX mixture and etridiazole were as good as, and nitrapyrin–CS2 mixture better than, nitrapyrin alone. Injecting inhibitors in spring frequently decreased yields, perhaps because NH4:NO3 ratios were too large, and increased them only when more than 150 mm of rain fell afterwards.At Liscombe, where rainfall was higher, but soil temperatures were similar to those at Rothamsted, the benefits from using inhibitors in autumn were larger, but there were none from using them in spring.

Description: SUMMARYIn the application of the Scholander pressure chamber technique to cassava water relations studies, the leaf water potential measured on central lobules was initially compared with that measured on entire leaves (including petiole). Measurements made using both a Campbell-Brewster hydraulic press and a pressure chamber of the leaf water potential in six different cassava clones were also compared. Although the central lobules showed a greater sensitivity to moisture loss after sampling than entire leaves, their leaf water potential was in close agreement with those measured on the entire leaves (r3 = 0·96). Therefore, for routine and field estimates in cassava, measurements made on the central lobules may be used to avoid the large reduction in total leaf area. The Campbell-Brewster hydraulic press satisfactorily estimated leaf water potential in M.Col. 1684 clone, which had the longest and narrowest lobules, but in other clones the leaf water potential was overestimated at high leaf potential (〉 -12·5) and underestimated at low water potentials (〈 -12·5). Over a wide range of leaf water potentials, a poor relationship between leaf water potentials estimated with hydraulic press and with the pressure chamber was observed for cassava because press estimates are influenced by lobule length and lobule width.

Description: SUMMARYOne hundred and eighty triple test cross families arising from three barley crosses (C 164 x EB 1556, BG 25 x NP 21 and BH 15 x RD 103) were grown in two blocks of a randomized-block design in saline-alkali soil prepared in micro-plots. The families were evaluated for number of days from sowing to heading, plant height, number of tillers per plant, ear length, number of grains per ear, 100-grain weight and grain yield per plant. The cross BG 25 x NP 21 showed epistasis only for number of days toheading and number of grains per ear; in contrast, epistasis was present in all traits in BH 15 x RD 103. In cross C 164 x EB 1556, epistasis was detected for plant height, ear length and number of grains per ear. Thus, epistasis appears to be related to specific cross combination. The ‘j and l’ type epistasis was more pronounced than the ‘i’ type. Early generation selection may be used for number of days to heading which Exhibited epistasis marginally with preponderance of additive gene effects, while for the remaining traits selection should be deferred till an advanced generation.

Description: SUMMARYGeneralized lattice designs (a member of the class of incomplete block designs) have been used in 13 potato variety yield trials over 3 years. Results from these designs are shown to be generally more precise than from comparable complete block designs.

Description: SUMMARYWool follicles and fibres of pre-ruminant lambs abomasally fed isoenergetic diets with daily amounts of lysine ranging from 0·12 to 1·94 g/(kg live weight)0·75 were examined by light and electron microscopy. In lambs which received ca. 0·9 g lysine/kg 0·76 daily, the follicles appeared normal, whereas in those which received less than 0·9 g lysine/kg0·75 daily several follicle abnormalities developed and the percentages of follicles affected increased as the amount of lysine was decreased. These abnormalities included the formation of autophagic vacuoles (or apoptotic bodies) in follicle bulb cells, and retarded and incomplete keratinization of the wool fibres, which led to the kinking of fibres at the mid-dermal level and gross distortion and partial degradation of fibres in the distal parts of follicles with thickened outer root sheaths. Following the introduction of a low-lysine diet, autophagic vacuoles developed in most follicle bulbs within 24 h. Impaired keratinization and kinking of fibres were evident in increasing proportions of follicles after 2 days, and gross distortion of fibres after 3–4 days. When the lambs were returned to a diet with adequate lysine recovery of normal follicle structure followed a similar time pattern, except that gross distortion of fibres persisted in the distal parts of some follicles for longer than 1 week. In some lambs given more than 0·9 g lysine/kg0·75 daily a small percentage of follicles had short keratogenous zones. Clumping of fibres, which occurred in the proximal parts of a small number of follicles, was unrelated to the amount of lysine in the diet.

Description: SUMMARYResults are presented from two experiments (1973 and 1974) in which high potato yields were obtained (60–70 t/ha). In both, Désirée and Maris Piper accumulated much more N and K (〉 200 and 300 kg/ha respectively) than was applied as fertilizer (160 kg N and 189 kg K/ha). Increasing planting density (to levels above commercial practice) increased nutrient accumulation but had only small effects on yields. Thus, high yields are associated with but not necessarily caused by large accumulations of nutrients. As a general principle, increasing fertilizer rates above those shown to be optimal will not increase yields.

Description: The objective of this study was to examine the effect of the chemical growth regulator Terpal (a mixture of mepiquat chloride and ethephon or 2 chloroethyl phosphonic acid) on the pattern of branching, plant height and yield components of winter oil-seed rape (cv. Jet Neuf). Mepiquat chloride (a quaternary ammonium compound with similar antigibberellin properties to cycocel) was developed as a morphoregulator for cotton where it has been shown to reduce plant height, shorten internodes and increase boll retention (Willard et al. 1977). The activity of ethephon has been attributed to its release of ethylene which influences a wide range of developmental processes, for example fruit abscission and ripening (Chatterjee, 1977; Gvozdenovic, Dulic & Slavic, 1978), growth retardation (Van Andel & Verkerke, 1978) and also the extent of lodging in cereals (Hill, Joice & Squires, 1982).

Description: Early investigations into the effects of the growth retardant chlormequat on wheat and barley showed that in the absence of lodging the number of ears was frequently increased following treatment at the beginning of stem elongation (Humphries, Welbank & Witts, 1965; Alcock, Morgan & Jessop, 1967; Barrett, Meens & Mees, 1967). More recently, earlier applications, at the three-leaf stage, to barley have been shown to be more effective in increasing the number of ears (Koranteng & Matthews, 1982). However, there appears to be little information on the effects on number of ears of early application of chlormequat to winter wheat. Therefore, in 1982 three field experiments were carried out to investigate the effects of early application of chlormequat on the numbers of tillers and ears and grain yield of winter wheat.

Description: SUMMARYSheep were grazed for 2 years at stocking rates of 7, 14, 21 and 28/ha on a pasture comprising Lotononis bainesii and Digitaria decumbens cv. Pangola at Mt Cotton, south–east Queensland. There were six replicates of each treatment grazed in rotation with 3 days' grazing followed by 15 days' rest.The initial dominance of lotononis was lost after 6 months of grazing and lotononis failed to persist satisfactorily at any stocking rate. Demographic studies showed that lotononis behaved as a short-lived plant, predominantly annual, with some vegetative perennation as stolon-rooted units under heavy grazing. Soil seed reserves varied from 5800 to 400 m2 at the lightest and heaviest stocking rates respectively. Lotononis failed to regenerate under Pangola shading or inopportune high grazing pressure. Soil bulk density (0–7 cm) increased from 1·2 to 1·4 g/cm3 according to stocking rate.

Description: SUMMARYLeft and right 9–10–11 rib joints from 104 Madura, Ongole, Bali, Grati (or Friesian cross) and buffalo bulls were dissected into bone, muscular and fatty tissues and then ground and chemically analysed for water, ash, ether extract and protein contents. The carcasses from 48 of these bulls were also ground and analysed for these same chemical components. Within-breed relationships between dissectible and chemical composition in the rib and between dissectible composition of the rib and chemical composition of the carcass were tested by regression analyses.There were no breed differences in the relationships between bone and ash or between muscle and protein in the rib, but at the same content of rib fatty tissue, buffaloes had less predicted rib ether extract than Bali, Ongole or Madura cattle. At the same ash content of the rib, Madura bulls had the most carcass ash. Rib-muscle content was considered to be a poor predictor of carcass protein. At the same fat content of the rib, breed differences in predicted carcass ether extract were large with Grati having higher levels than Bali and all four cattle breeds having higher levels than buffaloes. Use of rib-fat or rib-energy contents to predict carcass energy yielded relative breed differences similar to those when rib fat was used to predict carcass ether extract.Differences in the distribution of fat within the carcass, particularly in the subcutaneous fat depot, were considered to have a major bearing on differences in the within-breed relationships. Therefore, published part-whole prediction equations should be used with caution when comparing genotypes likely to differ in the distribution of tissue within the carcass.

Description: SUMMARYThe effects of some plant growth regulators on the growth and development of two cultivars of oil-seed sunflower (cvs Flambeau and Luciole) were examined in 1977 and 1978. Sunflower is a marginal crop for the United Kingdom, being late maturing and susceptible to infection by grey mould (Botrytis cinerea) during the seed-filling period.An experiment in 1977 indicated that suitable growth regulators might improve sunflower husbandry principally by shortening the stem, allowing late applications of fungicide and insuring against lodging. A mixture of mepiquat chloride and ethephon (BAS 098 OOW) was the most effective stem shortener. Daminozide gave variable effects on yield depending on the rate and time of treatment. The number of seeds per m2 was the major determinant of yield; 1000-seed weights and oil contents were similar for all treatments. The proportion of linoleic acid in the oil was very high in all experiments.In 1978 a second experiment involving daminozide and two sunflower cultivars revealed seasonal and varietal differences in response. The timing of growth regulator application seemed critical to affect seed yield. The third experiment, in 1978, investigated the results of applying BAS 098 OOW to four plant population densities varying from 40000 plants/ha to 160000 plants/ha. High plant population density advanced maturation by 2 weeks, but in these plots the crop lodged in the absence of growth regulator treatment.

Description: SUMMARYThe residual effects of sulphur-coated urea (SCU) fertilizers were evaluated by measuring the pH and mineral-N in the soil profile after 2 years of application of these fertilizers to soils in the various ecological zones of the savannah of Nigeria. Changes of 0·2–0·3 pH units relative to the control (without applied N) were detected on the sandier soils at Kadawa and Mokwa but not on the heavier Samaru soils. There was little or no difference among the sulphur-coated urea and calcium ammonium nitrate in their acidification effects. Also residual nitrogen levels were low in plots that received SCU but did not differ significantly from those of calcium ammonium nitrate.

Description: SUMMARYTwo sources of sulphur-coated urea (SCU) were compared with calcium ammonium nitrate (CAN) as sources of N for cotton and sorghum in the savannah zone of Nigeria. At the lowest rate of N application (30 kg/ha for cotton and 40 kg/ha for sorghum), SCU-11 with a dissolution rate of 11% in 7 days was found to be more effective than SCU-30 having a dissolution rate of 30% in 7 days and CAN. A single application of SCU-11 produced a higher sorghum yield than a divided application of CAN at the same rate. These results indicate that a slow-release nitrogen fertilizer might be useful for improved grain sorghum and cotton varieties.

Description: SUMMARYHypocuprosis has been diagnosed for 4 years in calves of a beef suckler herd at Warren Farm, Berkshire. The copper (Cu) contents and distribution in the soil at that site, as well as changes in herbage Cu throughout the 1979 grazing season, were examined. The herbage Cu concentration was always less than 7·5 μg/g and decreased markedly to 3·0 μg/g during July. Serum Cu contents of both untreated cows and untreated calves also decreased markedly, but at a much earlier stage than the decrease in herbage concentration. One untreated calf developed severe anaemia, but recovered when treated with Cu Ca EDTA. Although changes in the coefficient of absorption of dietary Cu were caused by changes in S and Mo contents, the calculated availability of Cu was dominated by the Cu content per se. Thus the calculated availability remained relatively high during the period when serum concentration decreased.The decrease in serum Cu may have occurred as the result of a differing availability of Cu in ensiled and grazed herbages. However, coincident with the decrease in serum Cu was a high concentration of Fe in the grazed herbage which was largely associated with the surfaces of the leaves. It is therefore possible that the development of Cu deficiency immediately after the animals started to graze was precipitated either through an interaction between Cu and Fe in the animal, or because of a reduced availability of Cu through an interaction with ingested soil.

Description: SUMMARYCattle grazing buffel grass pastures during the dry season at Katherine lose large amounts of live weight during a short period following first rain. In Part 1 we showed that these losses were due mainly to reduction in gut contents. Part 2 examines the changes in pasture, diet and grazing behaviour to assess the probable change in nutritional status of cattle following rain.During the dry season the most valuable pasture component, green leaf, was very scarce and had a nitrogen concentration of about 1%. Diets of oesophageally-fistulated cattle contained less than 0·5% N. Shortly after first rain diet N doubled owing both to rapidly increasing amounts of green leaf and to the increase in N concentration in young leaf to over 3%. Although intake was not measured, literature is cited to show that this increase in dietary N would be expected to increase rumen digestion rates with a resultant marked increase in D.M. intake and a reduction in gut contents.Although availability of high quality herbage increased very rapidly following first rain, a period of increased nutritional stress immediately following rain could not be ruled out. However, any such decline in nutrition appears to be short-lived.

Description: SUMMARYFive selections of Stylosanthes guianensis var. guianensis with a short-day flowering response were grown at three sites at altitudes of 10, 280 and 1000 m on the island of Bali, Indonesia at latitude ca. 8° 30′ S. Mean site temperature was ca. 6 °C lower at the highest site whilst mean short-wave radiation was lowest at the intermediate site.Date of 50% floral initiation (FI) varied from 1 February to 21 June, when daylength (sunrise to sunset plus half civil twilight) decreased from 12·85 to 12·00 h. FI was independent of site for cv. Graham and cv. Cook, but at 1000 m it was 14 and 77 days earlier for cv. Endeavour and cv. Schofield respectively relative to the 280 m site. Little flowering of cv. Schofield occurred at 10 m, and it is suggested that cool temperatures promoted an increase in the critical photoperiod for this cultivar, or that warm temperatures inhibited flowering. FI was delayed at 1000 m in CPI 34906.The duration of the phase from FI to flower appearance (FA) varied from 29 to 75 days according to selection and to site, and was negatively related to mean temperature, radiation, and maximum temperature for cv. Graham, cv. Cook, and CPI 34906 (but not for cv. Endeavour). Number of nodes at FA in this determinate species generally reflected growing conditions in the pre-flowering phase and was positively associated with age at FA in plants of particular varieties.

Description: SUMMARYExperiments are described which study the effect of density and chop length on the rate of diffusion of oxygen into silage and equations are presented which enable the rate of diffusion to be calculated under laboratory conditions. The concept of zero porosity is also discussed and methods of calculating the density at which it occurs are given. The effect of carbon dioxide on the rate of diffusion is also discussed.

Description: SUMMARYIn Expt 1, four groups of seven hypocupraemic ewes were repleted with a semipurified diet containing 7·2 mg Cu, 3·5 gS and 0·5, 2·5, 4·5 or 8·5 mg Mo/kg D.M. as ammonium molybdate for 65 days. The first increment in Mo caused the largest reduction in plasma Cu repletion and the second completely inhibited repletion but the final increment led to a partial recovery. The highest Mo level caused marked increases in plasma Mo and reduced rumen sulphide concentrations.In Expt 2, five groups of four hypocupraemic ewes were repleted with hays containing 7–8 mg Cu, 3–3·4 g S and 0·4, 2·8, 4·3, 14·2 or 18·7 mg Mo/kg D.M. for 21 days. The hays were made in June from pasture sprayed earlier with 0–800 g Mo/ha as sodium molybdate. Qualitatively the changes in plasma Cu distribution and Mo content showed the same curvature with increases in dietary Mo as those in Expt 1.In Expt 3, four groups of five hypocupraemic ewes were repleted on pastures which had received a spring foliar dressing of 0–800 g Mo/ha. Herbage in the four plots was grazed in July, when it contained 0·7, 3·5, 5·9 or 12·4 mg Mo, 6'4 mg Cu and 2·7 g S/kg D.M. and again in September. Quadratic responses to Mo were demonstrated on both occasions, but, for a given Mo level, responses in caeruloplasmin synthesis were much lower than in Expt 2.It is concluded that Cu absorption is inhibited most by 4–6 mg Mo/kg D.M. and that inhibition of S2- production at higher Mo levels may give rise to a recovery in Cu absorption. Semi-purified diets give responses which lie roughly between those for fresh herbage and hay.

Description: SUMMARYThe incidence of lamb mortality from birth to 8 months of age has been studied over a 6-year period in an upland, grassland flock of sheep comprising the Scottish Blackface, Cheviot and Welsh Mountain breeds and the crosses among these breeds. Each breed and cross-bred type was maintained at varying levels of inbreeding. Approximately half the lambs which died were stillborn or dead on the day of birth, nearly 40% died thereafter but before weaning and about 10% after weaning.Post-mortem examinations on 586 of the 632 lambs which died from among the 2453 born attributed death on average to two causes per lamb. Approximately 11% of the causes were stillbirths or delayed births; 11% were cases of dystokia; congenital defects of various types accounted for about 10% of the causes; 25% made reference to weakly lamb, exposure or starvation; 14% to infectious diseases and 16% to noninfectious diseases. The extent to which causes of death occur together is examined.Breeds differed in mortality rate with the Welsh the lowest and Cheviot the highest. Cross-breds were better than the average of the pure breeds but this advantage emerged only in the period between 3 days and. 6 weeks of age. Inbreeding, both of dam and of lamb, increased mortality. Lambs from dams which were crosses of inbred lines had the best survival. Litter size, type of rearing, parity of dam, sex of lamb and birth weight also had significant effects on mortality rate.

Description: SUMMARYYield variability of spring barley and winter wheat varieties is investigated in National Institute of Agricultural Botany trials sown to assess the influence on varieties of fungicide treatment. The extent of the variation in relative variety performance due to years and centres is estimated for untreated and treated yields and for yield response to fungicide. The consequences for the design of future trials systems are considered.

Description: SUMMARYNitrosoguanidine-induced acid-tolerant mutants S1 and M1 of Lens esculenta Rhizobium leguminosarum were used for nodulation and symbiotic N2-fixation in acid soils having different pH and associated factors of acidity. The range of soil pH and associated acidity factors in which nodulation and N2-fixation responded varied, depending on mutant strains. However, strain M1 was more responsive and effective than S1. Antagonistic effect of Mn to Fe was found when the active Fe2+ and total Mn were determined in fresh nodules.

Description: Controversy exists in the literature concerning the validity of the nylon bag technique for investigating the nutritive value of feeds (Pidgen, Balch & Graham, 1980; Marten, 1981). Avariety of factors have been implicated in affecting results such as sample size, fineness of grinding and positioning of bags in the rumen. In addition basal ration has been shown to affect results (Lindberg, 1981 a, b; Siddons & Paradine, 1981). ørskov & Hovell (1978) showed that rate of digestion of hay in nylon bags was faster when the animals were fed on Pangola (Digitaria decumbena) hay rather than on sugar cane with its high sucrose content. In further work Ganev, ørskov & Smart (1979) reported that vegetable proteins degraded at a faster rate when incubated in nylon bags in sheep receiving dried grass rather than whole barley as their basal ration.

Description: A noticeable feature of mammalian skin surface lipids is the considerable variation in lipid and fatty acid compositions that exists between species (Nicolaides, Fu & Rice, 1968). The sebaceous lipids of oxen are characterized by the presence of relatively high levels of triglycerides, which, in contrast to those of other bovine tissues, contain a significant proportion (〉 20%) of linoleic acid (Noble, Crouchman & Moore, 1974; Smith, Noble & Jenkinson, 1975; O'Kelly, Reich & Mills, 1980). The uniqueness of these highly unsaturated triglycerides has indicated possible roles in the chemical and biological defence systems of the skin surface for linoleic acid released by hydrolysis (Jenkinson, 1980). The skin surface triglycerides of calves do not attain the high levels of linoleic acid displayed by adults until 4–5 weeks after birth (Noble et al. 1975). It is, however, not known if a new-born calf compensates for this difference by an increase in sebum triglyceride concentration and output or, in view of the decreased availability of linoleic acid at this Stage, produces a sebum of widely different composition from the adult.

Description: SUMMARYField studies were carried out to determine the sources of photosynthate for developing pods and to assess the effect of defoliation and flower removal at different stages on the performance of lentil. The leaves of flowering nodes were the primary source of assimilate to pods. Removal of 25–75% of leaves reduced seed yield by varying degrees depending on crop growth stage. The plants compensated for the loss of foliage to some extent, possibly through increased efficiency of the remaining leaves. One complete or 50% defoliation reduced seed yield to different extents at the vegetative, flowering, early pod formation and late pod formation stages, the greatest effect being seen at flowering and early pod formation. Plants compensated considerably by production of new leaves when defoliated at the vegetative phase. Increased moisture supply greatly enhanced the compensation ability of the lentil plants.Removal of all flowers up to 1–2 weeks after an thesis under unirrigated conditions and up to 3 weeks after anthesis in irrigated conditions did not adversely affect the seed yield. Flower removal beyond this period resulted in a significant reduction in seed yield. Little seed yield was obtained when flower removal was continued for either 6 or 8 weeks under unirrigated conditions. The plants compensated for the loss of earlier-formed flowers by setting pods from later-formed flowers. Compensation was greatly enhanced when the crop was irrigated during the reproductive phase. There was relatively little or no effect of the deflowering treatments on the number of seeds per pod or weight per seed. The flowering period of the deflowered plants was extended and their senescence was delayed. When 25% of the flowers were removed at different intervals during the reproductive phase, seed yield was not adversely affected. An increased intensity of flower removal decreased yield but the decrease was not proportional to the degree of flower removal. The plants apparently compensated by setting new pods.

Description: SUMMARYThree adjustment methods using control plots to adjust for soil variation in a modified augmented design (Lin & Poushinsky, 1983) were studied by simulation. The results show that adjustment by design structure (row and column correction factors) is best when soil variation is relatively uniform in one or two directions, while adjustment by regression analysis is best when the variation is multi-directional. Adjustment using the control plot as a fertility index is least satisfactory. A modified augmented design in a replicated experiment is generally inferior to a balanced lattice square design but is competitive when the percentage of environmental variation attributable to soil factors is less than 70% of the total variation.

Description: Pyrethrum is a small bushy perennial crop cultivated for its flowers which have insecticidal properties. Pyrethrins, the active principles in the flowers, are contact insecticides causing nervous breakdown leading to paralysis and death of insects. Kroll (1963) and Parlevliet, Muturi & Brewer (1968) have shown that the flower yields of pyrethrum could be improved by applying P fertilizer whereas N and K fertilizers did not increase the yields. On the other hand, Mwakha (1979a, b) showed that pyrethrum responds to N fertilizer on soils deficient in N. The present investigation was carried out to study the response of pyrethrum to various rates of application of N, P and K and sources of phosphorus.

Description: SUMMARYDiurnal and seasonal changes in the total, osmotic and turgor potentials of winter wheat leaves are compared in two seasons of mild and severe soil water stress. Gradients of total water potential in the soil-plant system are also presented. In both seasons the total water potential of the leaves decreased in parallel with the soil water potential, concurrently leaf osmotic potential also decreased sufficiently to maintain positive leaf turgor potential. Eventually, under severe water stress, soil water potential approached –1·5 MPa and leaf turgor potential tended to zero during the middle of the day.The potential drop across the soil-root system was twice that along the stem. Estimates of the water potential at the root surface varied diurnally and were often lower than the bulk soil water potential. In dry soil plants were unable to equilibrate with the soil water potential overnight. These results are consistent with the existence of significant resistance to water flow across the rhizosphere.

Description: SUMMARYBody heat storage changes of cattle were measured by means of simultaneous direct and indirect calorimetry and by thermometry in an environment that alternated in temperature between 12 and 25 °C. When the calorimeter temperature was increased deep body temperature (Tc) increased by approximately 0–5 °C, mean surface temperature (Ts) by 3 °C and mean body temperature (determined from calorimetry, Tb) by 1 °C, but these increases were not fully sustained during the next 24 h. Changes in the three temperatures were related by the equation: δTb = αδTc+(1-α) δTs where a was found to be 0·89±0·027 (S.E.).

Description: SUMMARYThe modelling of the redistribution of soluble salts in soils, in which it is assumed that the amount of water transferred from layer to layer is related to the excess over field capacity of the water content of a layer, is critically examined.The equation obtained from the dispersion equation by neglecting the diffusive term is solved for the leaching of surface-applied nitrates. It is shown that, by comparing the finite-difference form of this equation to the algebraic formulation of Burns' (1975) model, the two approaches are essentially the same, but that Burns makes approximations that are too inaccurate. In particular, it is incorrect to relate the transfer of water to the excess over the field capacity of the water content of the layer. Burns' model, when applied correctly, requiresmany calculations to be performed, which is costly of computer time. However, it is unnecessary in this problem as the analytic solution is simple and quick to apply.

Description: SUMMARYSpring barley straw treated with NaOH, either chopped and ensiled or ground and pelleted, was compared with long untreated straw and hay, in mixed diets of compound and forage fed to yearling dairy heifers. Protein allowance and source were varied by the inclusion of either fishmeal, soya-bean meal or urea in the diet.Growth rate was improved in two out of three trials by chopped ensiled straw treated with NaOH, compared with long untreated straw, and equalled that supported by hay. Dry-matter intake and digestibility were also improved, although rumen NH3-N concentrations were low. With ground pelleted straw treated with NaOH the effects were less decisive: growth rate was increased once and reduced once compared with long untreated straw, but dry-matter intake was substantially increased. Digestibility remained similar to that of long untreated straw, and was unchanged by rate of feeding. NaOH treatment resulted in small changes in molar proportions of VFA. Digestibility of hay fell when concentrates were added to the diet.Fishmeal increased growth rate with all forms of straw and hay and was more efficient in this respect than either soya-bean meal or urea.

Description: SUMMARYThe concentration of glutamate and of glutamine was measured in whole blood obtained from a maternal artery, a uterine vein, a foetal artery and an umbilical vein of chronically catherized ewes and foetuses from 100 to 140 days after conception. The activities of glutamate dehydrogenase, phosphate-dependent glutaminase, phosphateindependent glutaminase, glutamine synthetase, γ-glutamyl transferase and glutamine-oxo-acid aminotransferase were measured in placentomes obtained from ewes during a similar period of gestation.The concentrations of glutamate in blood from maternal vessels remained constant, whereas there was a significant decline (P 〈 0·001) in the concentration of glutamate in foetal blood. Glutamine concentrations declined significantly (P 〈 0·05) in maternal blood and in foetal arterial blood (P 〈 0·001), whereas the concentration of glutamine in umbilical venous blood remained constant.Mean arterio-venous differences for glutamate indicated that there was no net uptake from or release into maternal blood by the uterus. However, there was a significant (P 〈 0·02) uptake of glutamate by the placenta from the foetal circulation. Glutamine release from the placenta into the foetal circulation increased as the foetus matured.Significant activities of glutamate dehydrogenase, γ-glutamyl transferase, glutamine synthetase and phosphate-dependent glutaminase were found in the placenta but there was no significant relationship between the activities of these enzymes and the gestational age of the foetus. The enzyme profile indicated that the placenta has a substantial potential for net glutamine synthesis.It is concluded that, for a 140-day foetus, the release of glutamine from the placenta accounts for more than half of its nitrogen requirement. Direct placental transfer of glutamine from maternal blood accounts for only one-third of the glutamine released by the placenta into the foetal circulation of a 140-day foetus. Therefore, the remainder of the glutamine is synthesized in the placenta from glutamate. Only one-third of the glutamate required for this placental glutamine synthesis is from the glutamate released by the foetus. The remainder must be derived either from 2-oxoglutarate, as the result of aminotransferase or glutamate dehydrogenase activities, or from glutathione by the action of γ-glutamyl transferase.

Description: SUMMARYA series of trials were conducted during 1979–82 under semi-arid conditions in a Mediterranean-type environment to study the edge effects in mechanized durum wheat and barley variety trials when uncropped pathways are left between plots. Varietal differences in edge effects on grain yield were in most trials not significant. Thus, edge effects do not distort significantly the relative ranking of varieties.Edge effects were significant for all traits studied and higher in grain and straw yields. These effects were also higher in drier seasons. The overestimation of grain yield from whole plots was 13–18% in relatively high rainfall seasons and 29% in a dry season. In two seasons the scores on the two outer rows were higher than on the two central rows by 89 and 117 % for grain yield, by 72 and 73% for straw yield, by 44 and 48% for numbers of tillers, by 6% for 1000-grain weight and by 14 and 40% for number of grains per tiller. The edge effect was not confined to the outer rows, but it extended to the inner rows of the plot; the magnitude of this effect varied with season and trait.Rows adjacent to the pathway and unprotected from wind had a lower value for all traits than the opposite rows of the pathway, which were protected by the inner rows.

Description: SummarysLabelled fertilizer N (15N depleted ammonium sulphate) was used to investigate both soil and fertilizer N use by winter wheat established in contrasting seed beds, these being soil cultivated to 20 cm depth or left undisturbed. The crop's response to, and recovery of, a range of N levels from 0 to 280 kg/ha given as a divided application in spring, were measured over two seasons. It was found that during the first season the direct-drilled wheat took up, on average, more fertilizer N but less soil N than wheat in cultivated soil, probably through differences in organic-matter mineralization. The different cultivation systems produced similar grain yields at all rates of applied N; however, when no fertilizer N was given, dry-matter production and soil-N uptake by the crop in the undisturbed soil were substantially less than by the crop in the cultivated soil. Crop recovery of the fertilizer N at harvest was between 29 and 40% of that given. After harvest, an average of one third of the applied fertilizer N was found in the top 60 cm of the soil profile. In the following season on the same plots a second winter wheat crop, receiving no fertilizer N, was drilled. At harvest there was shown to be an increase in grain yield and soil- and fertilizer-N uptake at the higher srates of N given in the previous season. In spite of this the recovery of the labelled residues was small, no more than 6% of the original application, or 15% of the residues remaining in the soil, irrespective of cultivation system.

Description: SUMMARYThe effects of treading and the return of excreta on a Lolium perenne-Trifolium repens sward defoliated by sheep set-stccked at high and low stocking rates were examined. Sward performance was measured inside ‘graze-through’ cages which allowed defoliation without treading and excreta return, and outside where sheep grazed either fitted with harness to prevent the return of excreta or unharnessed to allow the normal return of excreta. Live-weight gain was measured from excreta return and non-return swards. The treatments imposed had large effects on herbage growth and botanical composition.At a stocking rate of 25 yearling wethers/ha, sheep excreted about 1·1 kg N/ha/day, which increased soil N and led to an increase in herbage growth of about 26 %. The return of excreta increased ryegrass tiller density and this was partly responsible for a 26% reduction in the proportion of clover in the sward; the weight of clover was 13% loss where excreta were returned, and on this treatment stolon length at the end of the experiment was similar to that at the beginning. Doubling the stocking rate increased the N returned via excreta to about 1·3 kg N/ha/day, and this increased herbage growth by 53% but suppressed the proportion of clover by 21%, though not the weight of clover. Clover stolon length decreased during the experiment at this stocking rate, both with and without the return of excreta. Sheep live-weight change benefited from the stimulus to herbage growth where excreta were returned at the high stocking rate, but not at the low stocking rate.Treading by 25 sheep/ha increased soil compaction but had no significant (P 〉 0·05) overall effect on herbage growth and botanical composition. However, treading by double the number of grazing animals significantly reduced herbage growth by 10%, plant root weight by 47% and the proportion of clover in the sward by 11%.Differences in sward performance between stocking rates were due more to the difference in defoliation intensity between these stocking rates than to either treading or the return of excreta.

Description: SUMMARYThe digestibility and rumen metabolism of diets containing as 50% of their organic matter (OM), cotton straw (CS) untreated, treated with sodium hydroxide and treated with ozone, were studied in sheep cannulated in the rumen and at the duodenum with simple cannulae. The concentration of total volatile fatty acids (VFA) in the rumen of sheep given the ozone and NaOH treatments was higher than in the untreated diet; however, the VFA profiles were not different. The rumen dehydrogenase activity, suggested to reflect general microbial activity, was higher by 83 and 81% in the ozone and NaOH treatments respectively, than in the untreated.Apparent digestibility of organic matter in the ozone-treated diet was 74·6%; 1·25 and 1·17 times higher than in the untreated and NaOH-treated diets respectively. The calculated values for organic matter and cell-wall digestibilities of the cotton straw in the complete diets were: 30·0, 20·0; 60·8, 60·0; and 39·6, 39·7%, respectively, for the untreated, ozone and NaOH-treated cotton straw. Nitrogen metabolism was not impaired by the presence of formic acid in the ozonated cotton straw; the apparent absorption of N from the intestine and the apparent digestibility of N were higher in the ozonetreated diet than in the untreated or NaOH-treated diet.The proportion of organic matter and cell walls digested in the rumen was higher in the NaOH and ozone treatments than in the untreated, and the possible reasons for that are discussed. A positive relationship was found between cell-wall digestion in the rumen (% of intake) and the rate of passage (% per h) of particulate matter from the rumen. The interpretation of this relationship is discussed in general and in view of the results of the present study.

Description: SUMMARYA diallel crossing system involving two Pinto and two Kidney common bean (Phaseolus vulgaris L.) cultivars was evaluated in the field. Pin toes were significantly different from the Kidneys in seed yield and numbers of pods and seeds per plant and 100·seed weight. All the traits showed statistical significance among crosses and in comparisons involving parental v. cross means. Heterosis values were large and significant for yield, numbers of pods and seeds per plant, number of seeds per pod and number of days from planting to flowering. The ratio of general to specific combining ability mean squares was low for yield, numbers of pods and seeds per plant and high for 100·seed weight and number of days to flowering. Significant reciprocal effects were found for seed yield and number of seeds per plant, but this effect was completely absent for 100·seed weight.

Description: SUMMARYAn experiment with two blocks containing phased sequences of continuous spring barley after beans or fallow was located on sandy soil over Lower Greensand on a gentle north to south (N–S) slope at Woburn Farm. Season had the greatest effect on yield with a 135% difference between the worst (1975, 1·73 t/ha) and the best (1974, 4·06 t/ha). years. N–S position was the next most important factor with average differences of 65 and 52% between the plots at the top and bottom of the site in blocks I and II respectively. The third most important factor was E–W position which gave a maximum difference of 35% in 1975.A fertility trend with a strong linear component, which was most conspicuous in drier years, followed the main slope of the experiment and was attributed to erosion (fieldwash). After 1972 as different cropping sequences were progressively introduced, yield variation due to crop sequence differences was confounded with this positional effect.Crops in the eastern block were taller by l·5–12·3% and, after adjustment for the linear trend, yield was on average 15·6% greater than in the western block. The site is astride a N–S soil boundary with Stackyard series to the east and Cottenham series to the west. The Stackyard soil has a greater available water capacity, and is subject to drought less frequently than the Cottenham soil. Using Penman's (1971) data for the Cottenham series at Woburn and estimates of profile available water for the two series elsewhere on the farm, theoretical yields were derived, which were generally greater than actual yields adjusted for the N–S linear trend (block means 1·47–4·32 t/ha), but which showed similar trends in the between-block differences. Explanations for discrepancies between theoretical and actual yields are discussed. The incidence and severity of take-all disease and differences in soil pH were always small and unlikely to have caused significant yield variations.

Description: SUMMARYIn a 2-year field experiment with potatoes measurements were made at successive harvests of the dry-matter yield of leaves and tubers and of the length of the root system. Experimental treatments were 150 kg N/ha, control plots receiving no N, and each with or without irrigation.In both years the crop gave increased yields with fertilizer N and irrigation. Fertilizer N increased the weight of leaves and embryonic tubers as early as 6 weeks after planting; it had little effect on water use. Irrigation, which was applied only in the mid-season after water deficits of about 100 mm had developed, increased yields and water use. Highest uptake rates of N, P and K (g/m2/day) occurred 4–6 weeks after crop emergence when they reached 0·62, 0·071 and 0·88 respectively. At harvest the tubers contained (g/m2) N: 8·7–21·1, P: 1·5–2·8 and K: 11·7–27·2. Uptake of all three nutrients was increased by application of N fertilizer and by irrigation.The average root length for all treatments throughout the season in both years was 12 km/m2 of soil surface, with 84% in the top 30 cm of soil. From values of inflow of water and NO3–-N1 calculated from depletion of successive 15 cm deep soil horizons, roots below 30 cm depth were substantially more active than those nearer the soil surface. During most of the growing season about half the nitrate reached the roots by mass flow.During crop growth NO3–-N concentration in the soil decreased to less than 10 μg/cm3 to 30 cm depth. Summation of crop N and soil NO3·N indicated net mineralization rates of soil N of between 0·07 and 0·17 g/W/day (average 012 g/m2/day). At final harvest the residue of N of about 9–10 g/m2 on plots that received N fertilizer, included crop residues, NO3–·N left in the soil and leaf fall.

Description: SUMMARYAzospirillum brasilense was treated with nitrosoguanidine and two mutants isolated which were resistant to 500 μg streptomycin/ml. Ultraviolet sensitivity, photoreactivation and effect of acriflavin on pre- and post-irradiation were studied. Chick pea showed an increase in grain yield, nodule dry weight, N2ase activity and active iron content of nodules when inoculated with A. brasilense or its mutants together with Rhizobium. The interaction between Rhizobium strains and genotypes of chick pea was significant.

Description: SUMMARYAn experiment has been made to study the effect of the pattern of distribution of a fixed amount of production compound on milk yield, milk composition and live-weight change in the first 20 weeks of lactation and any carry-over effects on performance in the remaining part. Adult British Friesian cows of predicted high yield potential were randomly allocated to a graded (G) or flat-rate (F) system of feeding.There was no significant effect of treatment on milk yield, milk composition or yield of milk constituents in the experimental period or in the whole lactation.Live-weight changes were not significantly different between treatments at any stage of lactation. Calculated energy balances showed losses until the 4th week of lactation. Thereafter positive balances occurred but it was not until the 9th week for treatment G and the 15th week for treatment F that the original zero balance was restored. The total balance was in good agreement with live-weight gain for treatment F but not for treatment G.Calculated efficiencies of utilization of metabolizable energy for milk production (Klo) were variable throughout lactation and lower than the currently accepted standards.

Description: SUMMARYBean cultivars Cargamanto (CIAT P590, indeterminate climbing, Type IV) and Puebla 152 (CIAT P498, indeterminate large vine, Type III) were grown at 20 and 60plants/m2 at two locations in Colombia; a cool, high rainfall, mountainous area (Popayan) and a hot, medium rainfall, valley (Palmira). The crop growth period was compressed and P590 failed to flower at Palmira.where plant shoot weights tended to be higher and root weights lower than at Popayan.Midday soil temperatures at 10 cm averaged 7·8 °C lower and N2(C2H2) fixation rate and nodule fresh weight over ten-fold higher at Popayan than at Palmira. Increasing the plant population density increased yield but reduced seed weight per plant and the fresh weight of all other plant parts, with shoots more severely affected than roots. Density had little effect on carbohydrate concentration or N2(C2H2) fixation per plant. The cultivars accumulated carbohydrates in different amounts but had similar rates of N2(C2H2) fixation. Concentrations of ethanol insoluble carbohydrates were several times higher in all plant parts at Popayan. Soluble carbohydrates showed similar, but smaller, differences.

Description: SUMMARYThe canopy of spring wheat grown with an ample supply of nitrogen was generally cooler than the canopy of a nitrogen-deficient crop. The warmer canopy matured 3–5 days earlier. The accumulated temperature difference was sufficient to account for the different times taken to reach maturity.

Description: SUMMARYA total of 25 steer carcasses from a wide range of breeds and carcass weight and fatness were used to examine the relationship between a range of fat thickness measurements and the dissected fat content of beef carcasses. Fat thickness measurements included those on the hot carcass suitable for ‘commercial’ use and others on the cold carcass commonly used in research.The mean of the measurements of fat thickness from the two sides of the hot carcass between the 12th and 13th ribs (12H) gave the most accurate prediction of carcass fat content (FPCT). The relationship was described by the equation FPCT = 14·61 + 1·85 (12H) (R2 = 0·92; S.E. of prediction of individual FPCT at the mean= ±2·17%).The mean of four fat thickness measurements made on the quartered surface between the 10th and 11th ribs of the cold carcass was the next most accurate predictor (S.E. = 2·28%) of fat content. Fat thickness measurements made on the hot carcass between the 10th and 11th ribs were the least satisfactory.Although the hot carcass measurements between the 12th and 13th ribs were made under commercial conditions and included a wide range of types of cattle the prediction of fat content from these measurements had a marginally lower standard error than the prediction based on measurements made under experimental conditions.

Description: Increased demand for steroidal drugs in recent years has prompted a worldwide search for sources of diosgenin other than from species of Dioscorea (Singh et al. 1980). Costus speciosus (Koen.) Sims, an erect perennial herb found growing wild throughout India, has been suggested as one possible alternative source of diosgenin (Dasgupta & Pandey, 1970; Sarin, Bedi & Atal, 1974; Kapahi et al. 1978). Efforts have been made at the Central Institute of Medicinal and Aromatic Plants to increase the diosgenin yield of Costus speciosus by improved agronomic methods. This note is a result of such experiments, in which the effect of different rates of application of N, P and K was studied.

Description: SUMMARYStudies were conducted to evaluate the effect of 50% restriction of normal daily water intake on nitrogen balance, plasma urea concentration and excretion of different urinary nitrogenous constituents (ammonia, creatine, creatinine, urea and undetermined nitrogen) in the Marwari breed of sheep of the Rajasthan desert, India. The results indicated that the reduction in feed intake in water-restricted sheep leads to a reduction in intake and excretion of nitrogen through faeces (P 〈 0·01) and urine (P 〈 0·01) of these animals. No sigficant differences in the excretion of most urinary nitrogenous constituents between ad libitum watered and water-restricted animals were observed, except for creatine which was excreted in significantly higher concentrations in the urine of the water-restricted animals. On offering water ad libitum for 3 days to the restricted animals, the plasma urea in these animals dropped from 33·0 to 20·7 mg/100 ml, i.e. almost to the level in the animals watered ad libitum (18·7 mg/ 100 ml). The daily dry-matter intakes of the ad libitum watered and restricted animals were 790 and 488 g, respectively. The digestibility coefficients for dry matter and crude protein of the feed were 47·1 and 27·2%, respectively in ad libitum watered and 56·6 and 39·5%, respectively, in restricted animals. This improvement in the efficiency of digestion in water-restricted sheep may not be due to any enhanced microbial activity in the rumen, but may possibly be due to an increased absorption of feed nutrients in the hind gut of these animals.

Description: SUMMARYThe extent and possible mechanism by which spring-sown oil-seed rape plants can compensate for insect or artificial injury to flower buds and pods were investigated by examination of the yield, and its components, of plants collected from commercial fields and those grown in field cages and glasshouses. Plants were able to compensate and in some instances overcompensate for all observed levels of M. aeneus injury or artificial bud removal by the production of more axillary racemes, which may be due to the loss of apical dominance. Artificial injury to the pods or infestation by C. assimilis larvae did not result in a significant reduction in the yield of seed and was compensated for partly by a slight increase in the number of axillary racemes and by slight increases in the number of pods on each axillary raceme and in the 1000-seed weight, and resulted mainly from the diversion of nutrients to other yield-bearing organs. Injury by D. brassicae larvae was partly compensated for in 1975 and at lower injury levels in 1974 and involved a similar mechanism to compensation for C. assimilis injury. These results are discussed in relation to the observed infestation levels in field surveys and current control practices.

Description: SUMMARYFour bruchid-susceptible and four bruchid-resistant cow-pea cultivars were crossed to produce 16 F1s and their reciprocals. From each cross, six generations, P1, P2, F1, F2, BC1, BC2, were obtained. Each cross was fitted to the additive-dominance model. Estimates of additive and dominance variances were obtained from the half and full sib analyses of the F1s and their reciprocals respectively. It was demonstrated that resistance to cow-pea weevils has additive, dominance and maternal components.

Description: SUMMARYYield calibration of soil tests in western Nigeria savannah has been difficult owing to low response to P and response to only low P rates despite low available P in the soils. A study on the distribution of P forms in 60 surface soils of the savannah derived from igneous and metamorphic rocks and grouped into 11 classes was made. Average total P was 0·018% and organic P, which varied between 44 and 114 mg/kg, constituted 41% of total P. Active P components made up 40% of total inorganic P, the bulk of which was in the Fe-P fraction. All P forms except non-extractable P correlated significantly with organic matter.The amounts of P needed to increase available P by 1 mg/kg in the soils, an index of P fixation, was correlated with pH and the free oxides of Fe and Al. The direct role of Fe-oxides and probable indirect effect of organic matter were indicated by regression analysis.There was minimal maize yield response to P application and this was obtained only at low P rates from which an optimum rate of 20 kg P/ha was suggested. An attempt to use phosphorus sorption capacity (PSC) for P recommendation was not successful probably because of the low PSC values. A quick P recommendation based on available P status, fertilizer factor of 3·0 mg/1 and an optimum available P level derived from the relative yield v. soil P calibration curve was therefore suggested.

Description: SUMMARYData from three dairy-cow nutrition experiments have been analysed in terms of the yields of milk, lactose, fat and protein. Yields of the three constituents varied linearly with milk yield. However, yields of fat from individual cows were much more variable at high milk yields than were the other two constituents. Patterns of feeding had relatively little effect on the pattern of protein yield in cows fed to their production potential but could be important in influencing yields of fat.Predicted responses of protein and fat yields to increments of feed were generally small in cows being fed according to their predicted yield potential and the conversion of metabolizable energy to milk constituents was of a low biological efficiency.

Description: SUMMARYUse of generalized lattice designs instead of complete block designs in 244 cereal variety trials grown in the U.K. since 1975 has resulted in an average reduction of 30% in variances of varietal yield differences. The lattice designs were most effective when the number of varieties was more than 50 but worthwhile reductions in variance, averaging about 24%, were obtained in trials with fewer than 20 varieties. The data also provide guidance on the choice of block size and the potential for improvement by neighbour methods.

Description: SUMMARYThe analysis of two experiments involving the response of bread-making wheat to application of nitrogenous fertilizer is discussed. It is shown that a step function is required to determine the amount of applied N which optimizes the profit to be obtained from the crop. Varieties varied in their yield response to N and in the amount of applied N at which the ‘step’ took place and it is argued that trials of varieties at a common rate of N application or the reporting of results which are averaged over a number of rates cannot lead to very precise recommendations for growers.

Description: SUMMARYThe C and N in the biomass of soils from eight grassland field experiments where lime had been applied was determined by the chloroform fumigation method. Lime application increased C and N in the biomass by approximately 30% overall, although there was no effect at two sites. In the unlimed plots basal CO2 production, biomass C, and flush of mineral N production (FN) increased with soil pH. Biomass C and FN were correlated with total N content but not with organic C.Differences in the apparent C/N ratio of the biomass were found in unlimed soils of pH ≤ 4·5 and in those of pH 〉 4·5, the ratios being 4·2 and 5·8 respectively. For limed soils the ratio was 5·2. It is probable that the chloroform fumigation method is not suited to soils of very low pH, and that the C/N ratio obtained in soils of pH 〈 4·5 is artificially low.

Description: SUMMARYGlyceraldehyde-3-phosphate dehydrogenase (G-3-PDH), αglycerophosphate dehydrogenase (αGPDH), lactate dehydrogenase (LDH), alcohol dehydrogenase (ADH) and secondary-alcohol dehydrogenase (SADH) were histochemically located in the testes of buffaloes, goats and rams. Two forms of αGPDH were observed: (i) NAD-dependent or cytoplasmic αglycero-phosphate dehydrogenase (αGPDHC) and (ii) NAD-independent or mitochondrial αglycerophosphate dehydrogenase (α GPDHM). The basic pattern of distribution of the various enzymes was similar in the three species; species-specific variations were observed but cell-specific variations were more pronounced. The main activities of G-3-PDH and αGPDHM were observed in the seminiferous tubules; interstitial tissue showed moderate (G-3-PDH) and trace to weak (αGPDHM) activity. In contrast, αGPDHC activity was more marked in the interstitial tissue and less in the seminiferous tubules, especially in the mature germinal elements. LDH and ADH respectively showed strong and moderate activities in the interstitial tissue and seminiferous tubules. SADH was noticeable only in the interstitial tissue of buffalo. The activities of all enzymes other than αGPDHC increased during spermiogenesis. The physiological significance of the results is discussed in relation to the carbohydrate metabolism of the testis.

Description: SUMMARYThree types of field instrument are described that are suitable for the automated and replicated in situ measurement of the soil properties: temperature, thermal conductivity and water pressure. Novel aspects of their design and construction are discussed, as are details of their installation and precautions necessary for successful use in the field. The principle of operation of each type of instrument is described and the method of controlling several instruments of the same type via a computer-based data acquisition system is indicated. Their accuracy and performance under field conditions are shown to be very adequate. Determination errors are approximately 0·1 K in the range 0–35 °C for temperature, 6–8% for thermal conductivity, and 1 mm water for water pressure, with a time constant of about 2 sec in a silty clay loam soil; reliability is measured as two sensor failures out of 236 over an operating period of several months. Examples are given of data collected during their deployment in an experiment to determine the physical effects of tillage on soil.

Description: SUMMARYThe body composition of 18 each of Mashona, Afrikaner and Hereford heifers was measured at the beginning and after 16 and 32 weeks of the experiment. The heifers not slaughtered at the beginning of the experiment were fed a complete diet containing 132 g crude protein and 12·0 MJ metabolizable energy/kg dry matter. Before slaughter, the animals were deprived of food and water for 24 h. Each animal was infused with 1 mCi of tritiated water (TOH) in order to measure total body water (TBW) and to estimate body fat.The growth rate of the three breeds of heifers was similar despite differences in age and initial live weight. Both TBW and fat proportions, however, differed significantly (P 〈 0·01) between slaughter stages for each breed and between breeds at each slaughter stage. At the first, second and final slaughter stages the proportions of TBW were: 68·0, 59·4 and 54·5% for Mashona; 70·;5, 64·3 and 58·3% for Afrikaner and 65·3, 57·6 and 46·2% for Hereford heifers respectively. The corresponding proportions of body fat were: 10·2, 18·4 and 24·2% for Mashona; 6·6, 12·0 and 20·0% for Afrikaner and 13·7, 20·8 and 25·8% for Hereford heifers respectively.There was a close relation between empty body weight and live weight at slaughter which was not influenced by breed. Both TBW and fat were estimated more accurately when TOH space and live weight were used jointly. However, the slopes of the prediction equations for each breed were significantly different (P 〈 0·05) in the case of both total body water and fat. It was necessary to use separate equations for each breed in order to predict either body water or fat. The significance of these findings for the estimation of body fat in live cattle is discussed.

Description: SUMMARYSelections for erect-(E) and lax-leaf (L) posture in winter wheat were made from a cross between parents which contrasted in the character. By the F5 generation there were consistent, heritable differences between E and L lines. The lines were evaluated in three field experiments and a glasshouse experiment.In an experiment in which plots were automatically sheltered from rain and in which there were three irrigation treatments, there was no treatment-posture interaction, and over all treatments E lines outyielded L lines by 0·26 t/ha. When fully irrigated the water use of both E and L lines between 1 May and maturity was approximately 280 mm. Withholding water caused a reduction in water use and a corresponding reduction in grain yield for both E and L lines.When the four most erect- and the four most lax-leaved lines were considered over all three field experiments, E lines maintained a slight, though not significant, grain yield advantage of 0·17 t/ha over L lines. However, the E lines produced significantly more biomass, averaging 0·7 t/ha more than L lines, and this extra biomass was not produced at the expense of additional water requirement. However, results from the glasshouse experiment suggested that the E lines may be more susceptible to a substantial pre-anthesis drought.It is concluded that varieties of winter wheat with the erect-leaf habit may provide an opportunity of increasing biomass production. In an environment in which a preanthesis drought is unlikely to occur, such varieties may give the highest yields. However, on light soils prone to early drought or at sites which would not permit the maximum expression of leaf area index at anthesis, varieties with a lax-leaf posture may give greater yield.

Description: SUMMARYNeem (Azadirachta indica juss) seed kernel cake was water treated and dried in the sun. It was palatable to cattle, despite its bitter smell.Twelve growing calves were divided into two equal groups; one group (control) had a standard concentrate mixture consisting of crushed maize 30 parts, groundnut cake 30 parts, wheat bran 38 parts and in the second group (experimental) the concentrate mixture had crushed maize 30 parts, neem seed kernel cake (water washed) 45 parts and wheat bran 23 parts. Both the mixtures had common salt and mineral mixture 1 part each. The roughage fed was the same in both groups.The mean growth rate of calves in 273 days was 403 g/day in the control group and 344 g/day in the experimental group which did not differ significantly (P 〉 0·05). The dry-matter intake, digestibilities of all the organic nutrients, total digestible nutrient values and the balances of nitrogen, calcium and phosphorus remained similar (P 〉 0·05) in the two groups. The blood haemoglobin, serum inorganic phosphorus and the activity of serum alkaline phosphatase, serum acid phosphatase, serum glutamic-pyruvic transaminase and serum glutamic-oxaloacetic transaminase also did not differ significantly (P 〉 0·05) in the two groups.It is concluded that water washing of neem seed kernel cake very largely removes toxic principles responsible for retardation in growth.

Description: SUMMARYThe effect of field layout and the orientation of seed-production blocks on outcrossing rates was investigated in Indian mustard. The study incorporated three male:female combinations, i.e. 1:2, 1:3 and 2:4 laid in east–west, north–south and circular directions. The experimental material consisted of four test cultivars (RLM 198, RLM 514, Varuna and TM 4) in a split-plot design. Male sterility was achieved by spraying 0·25% (v/v) ethrel twice before the emergence of the first flowering shoots. The proportion of hybrid seed set was maximal in the 2:4 combination in a circular design. Outcrossing varied from 19 to 79%. Heterosis was evident in yield trials, but F1 hybrids showed carry-over effects due to ethrel treatment. It is argued that ethrelinduced male sterility has only a limited role in screening parental combinations for their yield assessment.

Description: SUMMARYThe body composition of young mammals has been investigated in relation to environmental temperature and energy intake. Piglets were weaned at 14 days and then kept separately at 35 or 10 °C and fed either a high or a low energy intake. The animals were killed at 38, 48, 56 or 64 days of age and the carcass divided into four compartments: superficial tissue (skin and subcutaneous adipose tissue), muscle, contents of abdomen (gastro-intestinal tract, liver and kidneys), contents of thorax (heart and lungs). Each compartment was analysed for fat, nitrogen and energy content.The results were analysed using a non-orthogonal analysis of variance in oider to investigate the separate effects of environmental temperature and energy intake, to test for possible interactions between these two factors, and to assess the time it takes for any effects to develop.The total amount of fat stored in the body was greater in the pigs kept at the high temperature than in those kept at the low temperature and increased with an increase in food intake; there was no evidence of an interaction of temperature and diet, suggesting that their effects were exerted independently. The extra fat was stored mainly in the superficial tissue and muscle, but partly also in the deep body compartments. However, when expressed as a percentage of the total fat store a greater proportion was found in the deep body compartments of those kept at the low temperature and on the low intake, although the absolute quantities of fat involved were small.The nitrogen content was also greater at 35 than at 10 °C, and on the high than low intake. Most of the nitrogen was present in the muscle and the proportion of the total body nitrogen stored here was greater in the warm than in the cold, whereas it was unaffected by energy intake. The energy contents of the tissues measured by bomb calorimetry and estimated from the chemical composition were similar. For animals kept at 35 °C most of the energy was stored in the superficial tissue, with the muscle as the second highest store. By contrast, those in the cold stored most of their energy in the muscle.The present investigation has thus highlighted the large and partly independent effects that environmental temperature and food intake can have on the distribution of energy within the body and the chemical form in which it is stored.

Description: SUMMARYThe incidence of various infectious and non-infectious diseases as causes of death in lambs up to 8 months of age was studied in relation to breed, inbreeding and other factors. The data from an upland grazing flock covered 6 years and involved the Scottish Blackface, Cheviot and Welsh Mountain breeds and the crosses among them.Infectious and non-infectious diseases were directly responsible for almost a quarter of the mortality and their presence contributed to many more deaths. The organisms mainly responsible were Escherichia coli, Pasteurella spp. and Fusobacterium necrophorum.The incidence of infectious diseases in general and enteritis in particular varied significantly between the breeds and was lower in the cross-breds than in the purebreds. Variation between the breeds in the incidence of non-infectious diseases was statistically significant only in respect of digestive upsets for which there was a similar ranking of breeds to that for infectious disease.Inbreeding of the lamb (25–59%) significantly increased the incidence of infectious diseases, especially respiratory diseases, but not of non-infectious diseases. There was little difference between singles and twins in susceptibility to disease. The lower the birth weight of the lamb the greater the risk, particularly of non-infectious disease.

Description: Public concern continues to be expressed about the quality of water discharged from agricultural lands. High concentrations of nitrate nitrogen are often blamed on modern agricultural practice in general and to land drainage in particular (Royal Commission on Environmental Pollution, 1979, para. 4.38). However, undrained land also discharges water by flow within the soil and across the soil surface and it may discharge significant quantities of solutes.

Description: In the Mediterranean region, chickpeas are traditionally spring-sown since humid winter conditions encourage the development of Aschochyta blight which often causes complete crop failure. Lines resistant to this blight have been selected at the International Centre for Agricultural Research in Dry Areas (ICARDA) and thus winter planting has become feasible. The best selection, ILC 482, was sown in both winter and spring at three locations in northern Syria with contrasting precipitation patterns. Crop growth and soil moisture analyses were undertaken on all treatments, and relevant meteorological data were collected at each location. At all locations maximum greenarea and dry-matter production of the winter-sown crop was nearly double that of the spring sowing. Large differences were also observed between sites, with green-area and dry-matter production decreasing with precipitation. Depth of profile recharge, amount of extractable moisture and crop evapotranspiration also decreased with precipitation, but only small differences in these moisture variables were observed between winter and spring sowing. Duration of green-area production, as determined by the onset of rapid leaf senescence, was closely related to the fraction of extractable moisture in the soil profile, rapid senescence occurring in all treatments when extractable moisture fell below 40% of its maximum value. Differences in the maximum rates of green-area production are discussed both in relation to the depth of profile recharge, hence the depth of rooting and moisture extraction and to the ambient evaporative demand. The differences observed in green-area and dry-matter production was clearly reflected in final seed yield. The components of yield, number of pods, percentage of empty pods and seed size are related to the variations in moisture stress experienced by the crop.

Description: SUMMARYOne hundred and forty different varieties of grass, from seven species, were harvested in spring, in 1, 2 or 3 years, at a D-value of 67 and dried at 25 °C. Moisture content was determined every 3 h for at least the first 48 h and less frequently thereafter until the grass was about dry enough to store as hay.Rate of drying was in the order tall fescue 〉 Italian ryegrass = meadow fescue 〉 timothy = cocksfoot 〉 perennial and hybrid ryegrass. The perennial and hybrid ryegrass took twice as long to dry as did tall fescue. Tetraploid varieties of the ryegrasses took appreciably longer to dry than the diploid varieties. Apart from this there were some differences between varieties within a species in rate of drying. Differences in moisture content at cutting, in the proportion of leaf blade and in the number of leaf sheaths per ‘stem’ may have accounted for some of the differences between species and varieties in rate of drying. Further research is suggested.

Description: SUMMARYField and pot investigations of the vegetative and early reproductive growth of a winter wheat and a winter rye cultivar over three seasons (1978–9, 1980–2) have shown that higher and earlier forage yields of rye are due to a combination of factors, notably more rapid rates of germination, crop emergence, leaf appearance and leaf expansion coupled with higher leaf area ratios. There was no evidence, from studies of net assimilation rate, that the photosynthetic apparatus of rye plants is better adapted than wheat to the low temperature and light conditions of winter and early spring. However, the earlier initiation of rye stem extension was associated with significant increases in net assimilation rate, which compensated for reductions in the leaf area ratio. Practical aspects of these results are discussed briefly.

Description: SUMMARYA pot experiment was made to study the effect of green manuring and iron application on the pE, pH, Fe concentration and iron equilibria in a calcareous and a noncalcareous soil. Green manuring drastically decreased the pE and pH and increased the Fe concentration of the equilibrium soil solution to a greater extent than submergence alone. Addition of Fe decreased pE, pH and increased Fe concentration both with and without green manuring. In calcareous soil pE and pH were high and Fe concentration was low compared with non-calcareous soil. In the absence of green manure and added iron, although there were wide variations in pE, pH and Fe concentration, Fe(OH)3-Fe2+; Fe3(OH)8-Fe2 + and Fe(OH)3-Fe3(OH)8 systems were controlling the solubility of Fe after 1 week of submergence in both the soils. But on green manuring all the above systems in calcareous soil and only Fe(OH)3-Fe3(OH)8 system in non-calcareous soil were operating at 1 week of submergence and continued afterwards. Addition of iron, with and without green manure, failed to bring an appreciable effect on these systems in calcareous and as well as in non-calcareous soil.

Description: SUMMARYFive experiments which studied the effects of a wide range of dates of planting on contrasting potato varieties in Pembrokeshire are reported. In three experiments (1976–7) four early varieties (Home Guard, Arran Comet, Irish Peace and Ulster Sceptre) were sprouted from the end of dormancy and compared at four dates of planting, which began as soon as soil conditions allowed (February in 1975 and 1976 and March in 1977). In these experiments all early-emerging treatments were damaged by frost and in 1975 and 1976 date of planting had little effect on leaf area index or yield. In 1977 planting in late April delayed and increased peak leaf area index but reduced yields throughout harvesting. In all experiments the emergence of varieties was affected by date of planting. The varieties with the longest sprouts emerged first only from the earliest plantings; at late plantings all varieties emerged together, which suggests that rate of post-planting sprout elongation decreased in this old seed as planting was delayed despite increasing soil temperatures. The implications for testing of early varieties are discussed.In two further experiments two early varieties (Home Guard in both years and Red Craigs Royal and Arran Comet in 1 year) were compared with three maincrop varieties (Désirée, Maris Piper, Stormont Enterprise) using seed which did not begin to sprout until January at dates of planting beginning in March. Sprout length was again poorly related to earliness of emergence. Delaying planting delayed and increased peak leaf area index in all varieties but only increased yields in the early varieties which had the smallest leaf areas. In maincrop varieties date of planting had little effect on final yields. In these years there were long periods without rain and in 1976 yields were limited by the amount of water available from the soil, for as each treatment exhausted this supply bulking ceased.

Description: SUMMARYA pasture of Lotononis bainesii and Digitaria decumbens cv. Pangola at Mt Cotton, south-east Queensland was mown on six occasions at intervals of ca. 3 months and after each mowing was subjected in 1 day to the treading intensity expected from sheep grazing at 0, 7, 14, 21 and 28/ha. A movable corridor and folds were employed to walk the sheep the required number of times on eight replicates of each treatment.Lotononis regrowth was negatively related to sheep treading intensity, whereas Pangola was highly resistant to treading and grew vigorously from underground buds on rhizomes and from persisting stolons. Young lotononis seedlings were more vulnerable than older seedlings which had branched; plants developed from autonomous nodal roots were more resistant than seedlings. Attention is drawn to the contractile growth of the hypocotyl following epigeal germination which leads to a buried crown.Lotononis plants were short-lived, and seedling regeneration of ca. 27 and 47 plants/m2 occurred in the late summer of the 2nd and 3rd year after sowing. Soil seed reserves averaged 16900/m2. Studies might be undertaken of management systems directed to favouring lotononis plant replacement through accretion to seed reserves, seedling regeneration through the creation of ‘gaps’, and seedling survival through judicious timing of grazing.

Description: SUMMARYFat thickness measurements, taken over the M. longissimus between the 6th and 13th ribs by the automatic-recording probes, SFK Meat-Fat probe (MF), Hennessy and Chong Fat Depth Indicator (FDI) and Ulster probe (UP), and a simple ruler probe (RP), were compared with one another and a visual fat score (VSC) in terms of the precision with which carcass lean and subcutaneous fat percentages were predicted. The comparisons were made in four separate trials with RP and VSC common to all of them. A total of 182 carcasses were involved; 130 of these were probed both hot and cold. Comparisons were made among carcasses of the same weight.VSC was the best single predictor in most circumstances. Fat thickness measurements taken on the cold carcass provided a more precise prediction than those taken on the hot carcass. There was an interaction between the relative precision of the MF and RP probes and the condition of the carcass: the former generally gave the more precise prediction on cold carcasses and the latter on hot carcasses. Measurements taken by FDI tended to be better predictors than those taken by RP on both hot and cold carcasses. The use of two fat thickness measurements gave an improvement in precision over the best individual fat thickness measurements. There was also an improvement in precision in most circumstances when a fat thickness measurement was used in addition to VSC.There was little indication that specific fat measurements were particularly precise predictors when taken by specific probes, and no fat measurement was consistently the best predictor. A measurement taken 7·5 cm from the dorsal mid line at the 6th rib occurred most commonly in pairs of measurements giving the most precise prediction.

Description: SUMMARYThree varieties of triticale (TL-238, TL-257 and TL-319) bred by the Plant Breeding Department of Punjab Agricultural University were studied for nutrient composition and metabolizable energy (ME) content for egg-type chicks. A feeding trial was also conducted to study the suitability of triticale as a replacement for maize in conventional high- and low-cereal diets for different classes of egg-type chickens.The crude protein contents of TL-238, TL-257 and TL-319 were respectively 13·4,14·4 and 2·1%. Corresponding values for starch content were 51·5, 49·2 and 54·3%, respectively. ME in triticale varieties closely followed the trend of starch content. Accordingly TL-319 was higher in ME (13·58 MJ/kg D.M.) than TL-238 and TL-257 (12·91 and 12·49 MJ/kg D.M. respectively). There were no significant differences in body-weight gain or in food conversion of chicks fed diets containing different varieties of triticale. The substitution of triticale for maize in a conventional high-cereal diet improved growth and food conversion of starter chicks. In a low-cereal diet, however, triticale had an adverse effect on the growth rate and food conversion of starter chicks. At the end of 18 weeks of age, the differences in body-weight gain, food conversion and efficiency of protein utilization by chicks on all the treatments were not significantly different (P 〉 0·05). Results of the production phase showed that egg production, egg mass, food conversion and energetic efficiency were significantly (P 〈 0·05) improved by feeding triticale.

Description: Supermarkets in the U.K. want uniform heads of crisp lettuce weighing at least 450 g and preferably 600 g but it is difficult to meet these requirements consistently throughout the season because there can be considerable variation in head weight both between and within sowings. In the butterhead lettuce crop the synchronization of seedling emergence, which was responsible for a large proportion of the variation in head weight at maturity (Gray, 1976), was improved by fluid sowing pre-germinated seed (Gray, 1978a, 6). Finch-Savage & Cox (1983) have also shown with butterhead lettuce that pre-germinated seed emerged earlier and produced earlier-maturing, heavier heads than dry seed and that the addition of sodium phosphate to the gel further advanced maturity and increased head weight. Therefore, fluid sowing pre-germinated seed of crisp lettuce in a gel containing phosphate might be expected to reduce variation in seedling emergence and to improve head weight and the uniformity of head weight at maturity.

Description: As part of their normal behaviour, buffaloes need to wallow in water or mud for a period of the day and, in general, show a greater affinity for water than other domestic ruminants. It has been reported (McFarlane, 1971) that buffaloes turn over more water than other domestic ruminants. This, in turn, should make them more susceptible to deprivation of water, even for short periods. Requirements for water are also known to change with the physiological state of animals. The experiment described in this paper was carried out to compare the effects on the daily turnover of body water in growing, pregnant and lactating buffaloes, under normal management, when denied wallowing and when drinking water was restricted.

Description: Barley (Hordeum vulgare L.), an important cereal crop in India, is grown mostly under rainfed conditions on about 3 million hectares. Vigorous and rapid development of roots of cereals contribute considerably to drought resistance (Genkel, 1961; May, Milthorpe & Milthorpe, 1962; Abdel Rahman, Batanouny & Ezzat, 1967; Bhan, Singh & Singh, 1973; Chang & De Datta, 1975). Many workers (e.g. Abdou & El-Kobbia, 1976; Basu & Gupta, 1974; May et al. 1962; Bozhenko, 1965; Woodruff, 1969; Salim & Todd, 1968; Hussain, May & Aspinall, 1968; Shkolnik & Bozhenko, 1974) have reported that pre-sowing seed treatments increase plant vigour and grain production. The production of barley under rainfed conditions in winter (November–February) depends greatly on the extent to which it can exploit the stored soil moisture after the harvest of the previous crop grown with monsoon rains in India during June–October. The main objective of the study was to dermine to what extent the increase in seedling vigour caused by pre-sowing treatments of seeds can be exploited for increasing the production of barley which has to depend mainly on the continuously depleting soil moisture, after the cessation of monsoon rains, and to investigate the possible reasons for such variations.

Description: SUMMARYHeat stored in the body of cattle subjected to a daily 10 CC range of environmental temperature was measured by calorimetry and thermometry. The daily range of bodycore temperature of the animals was of the order of 0·5 °C but mean skin temperature cycled with a range of approximately 6 °C. Calorimetric estimates of changes in mean body temperature showed good agreement with thermometric estimates when core and mean body temperature changes were weighted in the ratio a: (1 – α) where α was found to be 0·85. This result is consistent with the findings of another study where cattle were subjected to abrupt changes in environmental temperature, the combined best estimate of a from the two studies being 0·86 ± 0·014 (s.E.). The 10 °C range of daily environmental fluctuation resulted in a daily variation of approximately 1 °C in mean body temperature, which is equivalent to the amount of heat produced by the animals every 40 min. It is suggested that a weighting factor α = 0·86 could be employed, using thermometry only, to estimate fluctuations in body heat storage which are likely to occur in animals subjected to fluctuating environmental conditions in the field.

Description: SUMMARYInformation is assembled on how much wheat yields vary from place to place, from year to year and between years in England and Wales. Some indication of the practical importance of this variation is given by comparisons with the yield differences caused by individual management decisions as measured in comparative experiments, and with plot-to-plot variation in such experiments.

Description: SUMMARYIn this paper, the first of a series of three in which fat deposition is examined in 42 castrate male Hereford and Friesian cattle, details are given on the experimental material and procedures used in all papers. Whole body composition (anatomical and chemical) and the partitioning of fat within the body are also reported in this paper.Four, two and 15 animals were slaughtered at 6, 13 and 20 months of age, respectively, after ad libitum feeding of a complete pelleted diet.The Friesians were heavier than the Herefords, having 10%, 20% and 14% heavier empty bodies at 6, 13 and 20 months, respectively.At the same age, the Friesians had a greater percentage of empty-body weight as carcass muscle, carcass bone, total body water and total body ash than the Herefords but a lower percentage as dissectible fat and total body lipid. An analysis of linear body measurements showed no difference between breeds in the stage of development of external body dimensions at 20 months of age, and it was concluded that at the same age and stage of development of live weight or size, the Friesians were leaner than the Herefords.Relative growth coefficients of the fat depots showed late developmental growth in some intra-abdominal depots (omental and perirenal–retroperitoneal) but not in another (mesenteric). Relative growth coefficients of the omental, mesenterie and intermuscular depots were different between breeds. The Herefords deposited more dissectible fat subcutaneously than the Friesians whereas the Friesians deposited more in the intraabdominal depots. A multivariate index of fat partitioning, which was not influenced by age or stage of development of the fat depots, was not significantly correlated with fatness, suggesting no direct link between the pattern of fat partitioning and body-fat content.Breed differences in the distribution of fat within the subcutaneous and intermuscular depots were minor compared with the large difference in the partitioning of fat between depots. It was thus concluded that the factors controlling fat partitioning do not influence the distribution of fat within depots.

Description: SUMMARYDuring 1973–8 six field experiments examined the effect of 0, 41, 82, 124, 166 and 207 kg N/ha with and without irrigation on the growth, yield and quality of sugar beet. The culture of the crops was planned to produce a large yield in order to determine the optimal nitrogen application for the above-average crops which many growers are now seeking to produce. Ammonium nitrate was used as the nitrogen source, broadcast in one dose before sowing as was recommended practice in the early 1970s. The growth of the crop was monitored from the seedling stage to harvest in December, as was nitrogen uptake by the crop, and water removal from the soil using a neutron probe.In 3 years when the weather was dry after drilling, the fertilizer significantly depressed the number of plants which established but plant weights showed that some nitrogen fertilizer was needed early for rapid seedling growth. Changes in the method of applying fertilizer for sugar beet are therefore suggested and are being tested. Soil analyses in the plough layer during establishment (May–June) indicated an optimum concentration of mineral nitrogen of about 40 mg N/kg soil at this stage.Nitrogen fertilizer was very important for a high yield; throughout the growth of the crop it greatly increased total dry-matter yield and at final harvest this was reflected in sugar yield. Considering the six years together, sugar yield was linearly related to both dry-matter yield and total nitrogen uptake. However, within a year, increasing nitrogen uptake above 200 kg N/ha with nitrogen fertilizer did not increase sugar yield; maximum yields of sugar each year were normally obtained with 125 kg N/ha fertilizer or less, and irrigation had little effect on the optimum amount. Explanations for the lack of responsiveness of sugar beet to greater applications of nitrogen fertilizer are being sought in further more detailed analyses of the crop and its environment.

Description: SUMMARYA scheme was developed to describe how the rate at which apical primordia are initiated in cereals depends on temperature and photoperiod. It was used to analyse initiation in field crops of winter wheat (Triticum aestivum L., cv. Maris Huntsman).For the initiation of leaves and spikelets, a straightforward linear regression of initiation rate R against mean air temperature (Ta) gave base temperatures (Tb) close to 0 °C for leaves and for spikelets. However, initiation rate was also correlated with mean photoperiod (P) and base photoperiods (Pb) of –0·5 h and 4h were established for leaf and spikelet initiation. When R was correlated with the index (T – Tb) (P – Pb), r2 was 0·62 for both leaves and spikelets.

Description: SUMMARYFertilization of four field bean cultivars was examined in irrigated and non-irrigated plots. The overall fertilization of the ovules examined was 33%; in irrigated plots it was 25% and in non-irrigated plots, 41%. Only 48% of fully formed flowers had at least one fertilized ovule. Fertilized ovules occurred most frequently at the first ovule position in the ovary (nearest the stigma), and this frequency declined at successive ovule positions. There was in general a higher fertilization percentage at the upper flowering nodes while fertilization percentage dropped from the first flower position in a raceme to the last. At all the flowering nodes and raceme-flower positions, the cultivars Erfordia and Outlook generally had a higher fertilization frequency than Maris Bead or TI. The significance of these results is discussed.

Description: Rape (Brassica campestris L.) is well adapted to the Bangladesh climate and is an important oil crop of the northern part of Bangladesh. It requires a shorter growing season than any other crop of this kind but is less resistant to drought, which causes considerable damage to the crop by reducing total green area during late December and January and results in a poor yield. Considerable increase of rape-seed production will be possible through the elimination of drought by irrigation, the right supply of nutrients and application of proper cultural practices. We report here on studies of the effect of fertilizer under irrigated and non-irrigated conditions on the seed yield, oil content and some seed yield associated characters of rape and the importance of irrigation in rape cultivation in Bangladesh.

Description: SUMMARYIn two field experiments, ground limestone (2·5–20 t/ha), dolomite (4·25 t/ha) and gypsum (3·75 t/ha) were applied to acid krasnozems (Forthside, pH 5·6 and Elliott, pH 5·1), and poppy capsule and morphine yields, leaf nutrient contents and soil chemical properties were measured.Capsule and morphine yield increased more than two-fold at Forthside as the pH in the surface soil (0–150 mm) increased from 5·6 to 6·1, and by 30-fold at Elliott where the pH increased from 5·1 to 6·0. Capsule morphine concentration was depressed by high rates of ground limestone at both sites but maximum morphine yields of 15·7 kg/ha at Forthside and 11·3 kg/ha at Elliott occurred at the highest rate of ground limestone. Gypsum did not increase yield at Elliott, but at Forthside the gypsum and ground limestone treatment of equivalent calcium content increased yields to the same extent.The lowest yields at each site were associated with calcium concentration in the leaves at flowering of less than 1% and marginal or high amounts of extractable soil Al at Forthside and Elliott respectively. Concentrations of Ca, P and Mo in leaves were increased by lime applications but leaf concentrations of N, P, Mn, B and Mo on low yielding plots were considered to be in the normal range.Poppy yield responses to liming were attributed primarily to alleviation of aluminium toxicity but the effects on yield of reductions in soluble Al and increases in available Ca were confounded by application of ground limestone.

Description: SUMMARYFive feeding and metabolism trials were conducted on buffaloes fed different amounts of groundnut oil as a source of supplemental fat. Ca and P retentions were determined. The first two trials were conducted on 12 and 16 milch buffaloes and the other three trials on 15, 15 and 4 buffalo bulls. The dietary fat ranged from 1·32 to 6·00% of the ration in milch buffaloes and 0·51 to 6·33% in buffalo bulls. The retentions of Ca and P did not differ significantly with the percentage of fat in the ration. This showed that the phenomenon of formation of Ca soaps with fatty acids in non-ruminants with consequent wastage of Ca does not seem to be applicable to ruminants which have a much lower pH in the duodenum and upper jejunum. It is concluded that under practical conditions of feeding, within the usual range of dietary fat in ruminants, there is no likelihood of an adverse effect on Ca and P nutrition such as is encountered in non-ruminants on high-fat diets.

Description: SUMMARYSequential dry-matter measurements for winter wheat crops grown at different sites during different seasons were plotted against accumulated potential evaporation. A relation consisting of two intersecting straight lines represented the observations. Early crop growth had a gentle slope due to an incomplete leaf canopy. Later growth occurred at a rate which depended upon the amount of applied nitrogen, the amount of radiation and the availability of water. The intersection occurred consistently at a leaf area index of 1·25.

Description: SUMMARYEffects of supplementary irrigation at three periods of grain sorghum development (a) from emergence to a time after floral initiation was completed (b) during heading and flowering and (c) from ending of flowering to maturity, during two seasons, were tested. Grain yield and its components and straw yield were significantly affected by the irrigation treatments, which were themselves considerably affected by rainfall.The results suggest that water deficits during the three periods, as were specified in this study, had affected grain yield primarily through effects on number of grains during the first period and size of grains in the second period. Effects in the third period were apparently complementary to those of the first and/or the second periods, being either very substantial or negligible, depending on the rain conditions in these periods. Straw yields were mostly affected by irrigation during the third period, mainly as a result of development of late tillers.High yields of rain-grown sorghum can be obtained if water deficits are avoided by supplementary irrigation during one or more of its growth periods.

Description: SUMMARYThe incidence of Sclerotinia sclerotiorum (Lib.) de Bary infection in poppies (Papaver somniferum L.) was assessed 9 days before dry maturity in a field experiment which incorporated the effect of nitrogen and phosphorus fertilizer and fungicidal sprays. Infection occurred mainly on the lower stem in the leaf axils.Nitrogen fertilizer (100 kg N/ha) had no effect on the incidence of Sclerotinia infection but phosphorus fertilizer (100 kg P/ha) increased the incidence from 19% of plants infected to 39%. Fungicides (2 kg benomyl, 50% a.i., plus 2 kg mancozeb, 80% a.i./ha) applied at 10-day intervals from flowering till harvest reduced the incidence of Sclerotinia infection to one third that of non-sprayed treatments.Sclerotinia infection occurred late in the crop and had little effect on the dry-matter yields of terminal main-stem capsules, lateral branch capsules or stem and leaves but it did influence the distribution of morphine within the plant. The morphine concentration of terminal capsules was lowered by 13% but the concentration of lateral capsules increased by a similar amount giving a total capsule morphine concentration and yield which was similar in both infected and non-infected plants.The morphine concentration of the stem and leaves of infected plants was 75% greater than that of uninfected plants but the overall morphine concentration of total plant was similar in both infected and non-infected plants. This distribution pattern was interpreted as a result of the restrictive influence of Sclerotinia infection on the vascular system which disrupted the normal translocation of morphine.

Description: SUMMARYThe incidence of lamb mortality from weakness at birth, underdevelopment, exposure and starvation was examined over 6 years in an upland flock and analysed in relation to breed, breeding system and other factors. These causes accounted for more than a quarter of the deaths and contributed to many more.The frequency of death due to these causes was greater in lambs light at birth. The incidence of these causes of death differed significantly between the breeds, Scottish Blackface, Cheviot and Welsh Mountain and their crosses, but for the separate categories breed variation was significant only for the incidence of death by starvation, which was also less frequent in cross-breds than purebreds. Mortality from several of these causes was increased by inbreeding (25–59%), but decreased by crossing inbred lines. Lambs born to line-cross or other non-inbred dams had a relatively low incidence of these various causes of death. For underdeveloped lambs variation due to maternal inbreeding was significant. When classes were adjusted for difference in birth weight, breed variation in mortality was greatly enhanced but variation due to inbreeding much reduced.Slightly more twins than single-born lambs died from these causes and triplets fared worst, but such variation was significant only for death from exposure. Mortality from these causes varied significantly with parity of dam, being highest in the first, and mortality in males was slightly but not significantly higher than in females.

Description: SUMMARYThe variation in setting fruit and immature fruit abscission at successive nodes of an individual panicle, and in panicles at different directions of the canopy in an individual tree, were studied in cashew (Anacardium occidentale L.). The numbers of perfect flowers and fruits set increased from the proximal to the distal end with the maximum yield at the fifth or sixth nodes in a panicle of 8–10 branches. The productivity of an entire inflorescence or a whole fruiting branch was related to its orientation with respect to the sun. The numbers of nodes and fruits set and the percentage of fruit retained were maximal in panicles located on the western and southern sides of the canopy. Tea mosquito damage was also less on these sides of the canopy but the physiological disorder of ‘apple’ cracking was higher here than on the eastern and northern sides. These variations are discussed in relation to the differences in the incident photosynthetically active radiation on these sides.

Description: Little reliable information is available on the range and variability of the copper content of the wool of sheep (Underwood, 1977), although the effect of Cu deficiency on keratinization and pigmentation of wool is well known (Ryder & Stephenson, 1968) and the Cu content of hair has been suggested as a possible aid in diagnosis of hypocuprosis. Results from Kellaway, Sitorus & Leibholz (1978) showed that, in cattle, Cu in hair and plasma decreased in animals when the concentration of Cu in the liver fell below 20 mg/kg D.M. An experiment carried out jointly by the Animal Breeding Research Organisation and the Animal Diseases Research Association to investigate breed differences in the long-term accumulation of Cu in sheep gave an opportunity to investigate both the range of Cu concentrations in wool and the relationship between the Cu content of the liver and wool Cu.

Description: SUMMARYA branching peduncle individual was observed in a population of cow pea Vigna unguiculata (L.) Walp. cv. Ife Brown. Normal plants have unbranched peduncles with flowers arranged in alternate pairs at distal ends of the peduncles. However, the mutant plant has branched peduncles with flowers arranged in pairs alternately along the branches as well as at the ends of the branches. The branches arise in the axils of stipulate trifoliate leaves which develop on the peduncles. The normal plant has between one and four pods per peduncle, whereas the mutant is capable of carrying between two and ten pods per peduncle. The branching trait is under genetic control, involving a single gene with the normal peduncle completely dominant over the mutant. Evidence for the genetic control and its possible usage is discussed. Data on some agronomic properties of the mutant are also presented.

Description: SUMMARYA correlation coefficient of r = 0·985 (P 〈 0·01) between the number of fertilized ovules at each cultivar-ovule position (Rowland, Bond & Parker, 1983) and the number of mature seeds for each cultivar-ovule position indicated an extremely close relationship between fertilized ovules and seed set in four field bean cultivars. This suggests that unreliability in seed yield in field beans could be due to variability in frequency of fertilization as well as in frequency of abortion of seeds and of whole pods.Frequency of ovule abortion occurred differentially among cultivars and this abortion rate varied according to the flowering node and flower position within a raceme. Under stress conditions single-seeded pods were preferentially aborted. The data suggest that a way to increase the average number of seeds per pod is through increased frequency of ovule fertilization.

Description: SUMMARYChlorophyll contents per unit leaf area and unit dry weight, chlorophyll a:b ratio, visual colour rating, specific leaf area, and leaf fresh weight: dry weight ratios were estimated for 12 couch (bermudagrass) varieties (Cynodon spp. L.) in winter (July) and spring (October). Net photosynthetic and dark respiration rates were estimated in winter only.The chlorophyll contents per unit leaf area were higher in all varieties in spring than in winter, but per unit weight were more variable. The varieties differed substantially in the net photosynthetic and dark respiration rates. The specific leaf areas were greater in winter than in spring in five varieties: in others it changed little. The fresh: dry weight ratios of the leaves were almost constant between varieties in the spring but varied greatly during the winter. Visual colour ratings were well correlated with chlorophyll contents per unit area but not with weight. The net photosynthetic rate was closely correlated with chlorophyll content (per unit area) but not so closely with colour rating.