ALBERT

Notes: A field plot experiment was carried out on an established grassland sward from 1983–88 inclusive to examine the effects of time of application, chemical form of nitrogen (N) and cattle slurry dry matter (DM) content on yield and efficiency of N use. Four forms of fertilizer N (a semi-organic fertilizer, a combined 2.1:1 (w/w) semi-organic/calcium ammonium nitrate (CAN) fertilizer, CAN and urea, each supplying 300 kg N ha−1 year−1, were applied with or without unseparated or separated cattle slurry at 93 and 73 g kg−1 DM respectively, both supplying approximately 150 kg N ha−1 year−1. All fertilizers and slurries were applied in three equal dressings (February/March, May/June and July/August). The efficiency of use of fertilizer and slurry N was evaluated by measuring DM yield, N uptake and apparent recovery of N in herbage at all harvests during each growing season.Fertilizer N application significantly increased (P〈0.001) the mean yields of herbage at each harvest in all years. The form of fertilizer N had no significant effect (P〉0.05) on first harvest and total herbage yields, nor on N uptakes by herbage at the first harvest in any year. The performance of urea and of CAN was more variable at the second and third harvests relative to that of the semi-organic or combined 2.2:1 (w/w) semi-organic/CAN sources which had similar efficiencies of N use. Lower DM production was associated with reduced uptake of N. Values for mean overall apparent recovery of N ranged from 57.9 ± 2.67% for the semi-organic fertilizer to 50.2±3.05% for CAN.Unseparated cattle slurry and separated cattle slurry produced similar herbage yields and N responses that were lower and more variable than with fertilizer N. The overall mean apparent recovery of N from unseparated cattle slurry was 25.5 ± 5.03% compared to 5.0 ± 4.74% for separated cattle slurry. Efficiency of N use was highest with spring applications and least with mid-season applications. Recoveries ranged from −29% for separated cattle slurry applied in June 1984 to 56% for unseparated and separated cattle slurry applied in February 1988 and June 1987 respectively. No interactions were recorded between cattle slurry and fertilizer N in terms of DM production or N uptake by herbage.The results of this study support the use of a fertilizer N source, selected on a least-cost basis, in combination with slurry to promote spring herbage production. For subsequent production, N should be supplied in fertilizer form only. The use of urea is risky under low rainfall conditions. Mechanical separation did not improve the efficiency of use of slurry N.

Notes: Eight field-plot experiments were carried out on established grassland swards between 1984 and 1988 to examine the effects of date and rate of application of calcium ammonium nitrate (CAN) on herbage dry matter (DM) yield and apparent efficiency of nitrogen (N) use at first-cut silage.CAN application significantly increased (P 〈0 ·001) the mean yields of herbage and N uptakes by herbage in all experiments. Herbage yields were similar (P 〉 0·05) with N rates of 100 kg ha−1, 125 kg ha−1 or 150 kg ha−1 in five experiments but in the other three there were increases above 100 kg ha−1. Date of N application had a significant effect on DM yield in three experiments; this effect was inconsistent for both single and split dressings. Lower production was associated with reduced uptake of N, a trend that primarily reflected lower DM yields and not wide herbage N content variation.It is concluded that selection of the date on which to apply fertilizer N in early spring to obtain optimum herbage yields at first-cut silage often required little precision. The use of fertilizer N rates 〉100 kg ha−1 should be questioned where there are likely to be appreciable quantities of available N derived from non-fertilizer sources.

Notes: The effects of forage matting on rate of grass drying and silage fermentation, digestibility, and intake were examined using perennial ryegrass swards. Treatments compared were: forage mats, where grass was processed through a laboratory scale macerator prior to matting and wilting to 228 g dry matter (DM) kg−1 (FM treatment); unconditioned grass which was direct ensiled at 163 g DM kg−1 (DE treatment); unconditioned grass which was wilted for the same period as FM to 213 g DM kg−1 (UC treatment); unconditioned grass which was wilted to 234 g DM kg−1 (UC25, treatment). All forages were dried on black plastic sheeting. For each treatment a total of approximately 80 kg grass DM was ensiled in seven 290 I plastic bins for 136 d prior to feeding to wether sheep. A further total of 14 kg grass DM from each treatment was ensiled in twenty-one plastic pipes (152 mm diameter, 762 mm long) to give a total of 84 pipes. Rate of silage fermentation was determined by destructively sampling pipes following 1, 2, 4, 6, 13, 20 and 50 d of ensilage. Over the mean wilting period of 6·9 h, grass from the FM treatment dried significantly faster (P 〈 0·001) and required less solar energy per unit of moisture loss than unconditioned grass. The rate of grass drying was highly correlated with solar radiation. The FM treatment did not influence the rate or extent of silage fermentation. The intakes and digestibilities of FM, UC and UC25 were not significantly (P 〈 0·05) different from each other but were higher than for the DE treatment (P 〈 0·05 for digestibility and NS for intake). In Northern Ireland it is unlikely that there will be sufficient solar radiation to allow forage mats to be made, wilted to a level to prevent effluent production and harvested within one working day. Further work is required to optimize mat-making technology for more rapid drying and to determine the effect of adverse weather on nutrient losses from mats.

Notes: An experiment was carried out during 1986 and 1987 to examine the effects of mid-season slurry injection and fertilizer-nitrogen (N) application on herbage dry matter (DM) yield and N recovery. Cattle and pig slurry were injected at 56 and 112 m3 ha−1 into an established sward. Five rates of fertilizer-N, as calcium ammonium nitrate, ranging from 0 to 120 kg ha−1 in 30-kg increments, were superimposed on these treatments, and in both years DM yield was measured in one cut after 70 d regrowth. Slurry treatments increased herbage DM yields significantly (P 〈 0-001). The efficiency of slurry total N compared with calcium ammonium nitrate-N averaged 53% in 1986 and 86% in 1987. The mean apparent recovery of slurry total N in herbage was 55% in 1986 and 40% in 1987. Fertilizer-N application increased (P 〈 0.001) the mean yields of herbage in both years but when combined with some of the slurry treatments, DM yields over the five N-levels did not differ significantly, giving rise to interactions in 1986 (P 〈 0-001) and 1987 (P 〈 001). It is concluded that mid-season injection of slurry can be an effective means of utilizing slurry-N in terms of herbage DM production and consequent N use.

Notes: Roots of red clover seedlings grown on plates of water agar, or water agar containing benomyl or prochloraz, were inoculated with conidia of Trichocladium basicola and examined by light and transmission electron microscopy. Penetration of host epidermal cells occurred from about 16 h after inoculation of untreated or fungicide-treated seedlings. Intracellular hyphae were constricted at septa and had a beaded appearance. They invaginated the host plasmalemma, but had no obvious deleterious effect on the cytoplasm until they had grown to fill much of the lumen, when host cells degenerated and died. As colonization of the cortex progressed, straight, unconstricted hyphae were formed and from these reproductive hyphae developed, which produced endoconidiophores and chlamydospores on the root surface. Penetration of host cell walls appeared to involve localized action of fungal enzymes. Papillae were often found at sites of penetration, but these rarely obstructed fungal development. Seedlings treated with prochloraz had fewer sites of fungal penetration, and fewer cells in the beaded hyphae than untreated seedlings or those treated with benomyl. Both fungicides caused abnormalities in fungal ultrastructure. Hyphae treated with benomyl were often found to contain lomasomes, while those treated with prochloraz had thickened, fragmented walls, and disorganized cell contents.

Notes: Trimethylsilyl (TMS) derivatives of sucrose and TMS oxime derivatives of fructose and glucose were made directly from samples of freeze-dried fruit tissues without a preliminary extraction of sugars and quantified using gas chromtography. The sugars were identified by a combination of gas chromatography-mass spectrometry (GC-MS) and gas chromatographic retention times of authentic compounds. Results were quantitative and reproducible for all samples except tomatoes which had values for sucrose which were significantly more variable than those obtained for fructose and glucose. Hydrolysis of sucrose was minimized and extraction of free sugars was consistent when a 50: 1 ratio of oxime reagent (μL) per mg of dry tissue was used.

Notes: Supercritical carbon dioxide (SC-CO2) extraction temperature and pressure for oil removal from freeze-dried, fall Atlantic mackerel muscle were optimized. The effect of extraction conditions on pH and water-binding potential (WBP) of the protein residue was evaluated. For the temperature range (35–55°C) and pressure interval (20.7–34.5 MPa), 34.5 MPa/35°C gave highest oil yield and concentration of ω-3 fatty acids. SC-CO2 extraction at higher pressure levels caused slight decreases in protein residue pH. WBP of residual proteins was maximal at 1.49g H2O/g protein for 34.5 MPa/45°C. The high lipid removal and retention of protein functionality in the residue after oil extraction may make such processes useful for future food applications.

Notes: Acylglycerol lipids as total fatty acid methylesters (FAME) were rapidly determined by direct extraction derivatization from sample matrices utilizing 0.4N methanolic sodium methoxide in hexane solution and quantitated using gas chromatography. FAME values determined by the direct extraction derivatization (DED) method and standard AOAC ether extraction saponification method were similar for all samples. The DED method was reproducible and required less than 35 min total sample preparation and analysis time compared to a minimum of 6 hr needed for the standard AOAC method. The DED method yielded FAME derivatives of acylglycerol lipids which were free from interfering compounds when analyzed by gas chromatography. Identity and purity of isolated FAME were positively confirmed by mass spectrometry by comparison with authentic standards.

Notes: SUMMARY: A small fraction, containing evidence for the presence of pyroglutamyl dipeptides and an N-pyroglutamylhexosamine. was isolated from the edible, commercial mushroom. Agaricus campestris. Upon hydrolysis, this isolate liberated a copious amount of glutamic acid, together with smaller quantities of other amino acids and a hexosamine. Analyses of the unhydrolyzed and hydrolyzed portions of the fraction by an automatic amino acid analyzer revealed the identities and quantities of the compounds released. Additional chemical and physical methods of analysis gave supporting evidence for the presence in the mushroom in addition to proline and pyroglutamic acid of the pyroglutamyl dipeptides of threonine, aspartic acid, valine, leucine, citrulline, phenylalanine, glycine, alanine, glutamic acid and proline and also of the amino acid sugar, N-pyroglutamylglucosamine. Pyroglutamylcitrulline and N-pyroglutamylglucosamine were tentatively identified. The first 6 dipeptides are reported for the first time. A mechanism is proposed for the enzymic biosynthesis of the pyroglutamyl dipeptides in the mushroom. Results of the present work shed additional light on the complex nature of the higher basidiomycetes.