bluuebunny/crossref_metadata_2025 huggingface dataset:
Acrylic acid and sodium acrylate as additives for silage
Authors: Wilson R. F. , Woolford M. K. , Cook J. E. , Wilkinson J. M.
Published: March 2009

Perennial ryegrass, lucerne and maize were ensiled for 100 days in polythene-bag silos without additive or after the addition of aorylic acid at 0·125, 0·25 and 0·50% of fresh crop weight, sodium acrylate at 0·165, 0·33 and 0·66% of fresh crop weight and formic and propionic acid at 0·25% of fresh crop weight.

Both acrylic acid and sodium acrylate were effective in restricting fermentation and protein breakdown in the silo. At 0·25% acrylic acid and the corresponding rate of sodium acrylate (0·33%) they were more effective in restricting fermentation than formic or propionic acids at 0·25%. At all rates of application they were effective in preventing deterioration of maize silage exposed to air for 13 days but not with ryegrass. Lucerne silages made both with and without additives were stable when exposed to air.

It is suggested that because of its non-volatility and non-corrosive properties sodium acrylate has advantages over the additives at present available.
Competition for phosphate between establishing plants of Lolium perenne and Trifolium repens under differing cultivation treatments in an upland pasture
Authors: Buckeridge D. J. , Norrington-Davies J.
Published: March 2009

The relative uptake of phosphate, introduced as radioactive 32P into an Agrostis-Festuca hill land association in mid-Wales, was examined under two contrasting methods of cultivation: (i) complete cultivation, (ii) slot-seeding. Seedling plants of Lolium perenne S. 23 and Trifolium repens S. 184 were grown as pure stands and as binary mixtures with plants either 4 or 6 cm apart.

Relative uptake of phosphate was higher under complete cultivation and, in the binary mixtures, clover accounted for 26% of the uptake only. The percentage of phosphate removed by each of the species when grown in mixtures remained constant over cultivation treatments. The significance of the results to agronomic practice is discussed.
Genetical analysis of a barley mutant with reduced height and increased diastatic power
Authors: Ellis R. P. , Powell W. , Swanston J. S. , Thomas C. E.
Published: March 2009

The United Kingdom produces enough barley grain to meet its needs for animal feed and brewing. The Scottish grain whisky trade, however, imports large quantities of high-diastase barley from Canada (Hayter & Allison, 1975). The breeding of highdiastase cultivars which could be grown in Scotland and so replace these imports has been pursued at the Scottish Crop Research Institute (SCRI).
The effect of oestradiol-17 β implantation on the response in voluntary intake, live-weight gain and body composition, to fishmeal supplementation of silage offered to growing calves
Authors: Gill Margaret , Beever D. E. , Buttery P. J. , England P. , Gibb M. J. , Baker R. D.
Published: March 2009

The effect of oestradiol-17β on the response to fishmeal supplementation of grass silage was studied in young growing cattle. Voluntary intake and live-weight gain were recorded over 63 days with 36 British Friesian male castrates (initial live weight (LW) 119 kg) offered silage alone (C) or with 50 (FM1), 100 (FM2), or 150 (FM3) g fishmeal/kg silage dry matter. Twelve calves were allocated to each of treatments C and FM3 and six to treatments FM1 and FM2. Half of the calves on each treatment were ear-implanted with oestradiol-17β (Compudose 365) at the start of the experiment. The calves on treatments C and FM3 were slaughtered after 75 days and chemical analysis conducted on half of each carcass. The silage had an organic-matter digestibility in vivo of 0·794 and was well-fermented, with a pH of 3·7. Intake averaged 24·2±0·42 g D.M./kg LW over all the treatments and live-weight gain was 0·77 kg/day on the silage alone. There was a significant (P < 0·05) interaction between fishmeal and oestradiol-17β, such that response to the hormone was observed only in the presence of fishmeal at 100 or 150 g/kg silage D.M. A similar interaction was apparent between fishmeal at 150 g/kg silage D.M. and oestradiol-17β in the final weights of empty body and carcass. This level of fishmeal also increased protein gain from 96 to 147 g/day and this was further increased to 179 g/day in the implanted animals receiving fishmeal. However, the overall effect of oestradiol-17β on protein gain was not significant. Gross efficiency of energy utilization was significantly (P < 0·01) increased by fishmeal supplementation suggesting an improved balance of nutrients compared with the silage alone diet.
Interaction of blood supply to the porcine ovary and corpora lutea function
Authors: Pope W. F. , Lawyer Michelle S. , First N. L.
Published: March 2009

Forty-eight sows were partially hysterectomized on day 10 (day 0 = 1st day of oestrus) of the oestrous cycle such that the isolated-contralateral ovary received either an ovarian or an ovarian and uterine blood supply. These two treatments were examined for their ability to affect corpora lutea (CL) function when 10, 20, 40 and 80 cm (12 sows/group) of the ipsilateral uterine horn remained intact. Sows with only 10 cm of uterine tissue failed to return to oestrus when observed until day 40. When 80 cm of uterine tissue remained, all the sows recycled between days 20 and 24. As the length of uterine horn increased from 10 to 80 cm the contralateral ovary became susceptible to luteolysis. At these lengths (20–40 cm), increased blood supply to the contralateral ovary afforded the luteal cells resistance to luteolysis (uterine length × blood supply interaction, P < 0·05). An additional four sows received 125I-labelled microspheres for purposes of determining CL blood flow following these alterations of blood supply to the isolated ovary. Blood flow to the CL was increased in three of the four sows when the isolated ovary received an additional uterine blood supply. Results from these experiments support the concept of an involvement of blood flow in the regulation of CL function.
Tests of nitrification and of urease inhibitors, when applied with either solid or aqueous urea, on grass grown on a light sandy soil
Authors: Rodgers G. A. , Penny A. , Widdowson F. V. , Hewitt M. V.
Published: March 2009

In 1984 and 1985 a field experiment on a grass ley on a light sandy soil at Woburn Experimental Farm, Bedfordshire, tested injected aqueous urea and broadcast prilled urea, applied alone or with a nitrification or urease inhibitor. Aqueous urea, prilled urea and ‘Nitro-Chalk’ were applied as a single 375 kg N/ha dressing, and prilled urea and ‘Nitro-Chalk’ also as three 125 kg N/ha dressings. The nitrification inhibitor nitrapyrin or a mixture of sodium trithiocarbonate (STC) plus potassium ethyl xanthate (KEtX) was injected with aqueous urea. The nitrification inhibitor dicyandiamide (DCD) or the urease inhibitor phenyl-phosphorodiamidate (PPDA) was broadcast with prilled urea.

The nitrification inhibitors significantly retarded nitrification of both aqueous and prilled urea. PPDA reduced ammonia volatilization from 375 kg N/ha broadcast as urea, and hence losses to the atmosphere, which otherwise ranged from 13 to 33 kg N/ha.

Nitrapyrin or STC and KEtX increased yield and nitrogen uptake in both years when urea was injected in January. Nitrapyrin also increased yield and nitrogen uptake in 1985, but not in 1984, when urea was injected in March, whereas the STC and KEtX mixture was then either detrimental or ineffective. DCD increased yield and nitrogen uptake from a single dressing of broadoast urea only in 1985. PPDA increased yield and nitrogen uptake from a single broadcast dressing of urea in both years, but had little effect when applied with divided dressings.

In 1984 a divided broadcast dressing of ‘Nitro-Chalk’ gave the largest yield and nitrogen uptake, but in 1985 aqueous urea injected with nitrapyrin in January or without or with a nitrification inhibitor in Maroh and prilled urea broadcast as a divided dressing all gave a larger yield. Similarly, a single application was generally more effective as ‘Nitro-Chalk’ in 1984, but as urea in 1985.
An analysis of the effects of seed weight, seed rate and date of harvest on the yield and economic value of seed-potato crops
Authors: Allen E. J. , O'Brien Susan A.
Published: March 2009

Five experiments were carried out in two seasons which studied the effects of seed weight, seed rate and date of harvesting on yield of seed crops of Record (four experiments) and Maris Piper (one experiment) in Scotland. Small seed (35 g) produced more above-ground stems and tubers and higher seed yields at equal seed rates than large seed (105 g). Increasing seed rate with both seed weights increased yield of seed-size tubers. The value of the seed crop was measured as the number of ware hectares which could be replanted from the yield of 20–55 mm tubers and calculated using recommended seed rates (Ministry of Agriculture, Fisheries and Food, 1982). Small seed produced more replantable hectares than large seed at equal seed rates in all experiments with Record and increasing seed rate increased the number of replantable hectares. However, when seed retained for replanting at the same seed rate was taken into account, small seed produced more replantable hectares only when total yield reached approximately 40 t/ha. Seed yield was much higher in Maris Piper than in Record and effects of seed weight were small. Increasing seed rate increased the number of replantable ware hectares but the effect was much reduced after retention of seed for replanting.

The effect of pricing policy for seed and ware on returns to the seed grower was also established. The sale of seed (and ware tubers) at fixed prices per tonne produced lower returns than selling seed at varying prices per tonne in relation to tuber size and equivalent to a fixed ware cost per hectare planted especially where seed yields were high. Delaying harvesting increased sale value but crops reached 85–90% of the final value before many oversize tubers (> 55 mm) were found and large yields of such tubers from low seed rates produced lower returns than from increased seed rates.

The number of ware hectares produced per seed hectare (even net of seed retained for replanting) was high especially in Maris Piper. The results show that the area devoted to seed potato production in U.K. is much too high for the ware area and the significance for the future of seed production is discussed.
The production and management of Stylosanthes gracilis at Shika, Nigeria:II. In savanna grassland
Authors: Haggar R. J. , De Leeuw P. N. , Agishi E.
Published: March 2009

In an 80 acres (32·4 ha) grazing trial carried out over a 2-year period significant increases in cattle live-weight gains were achieved following the oversowing of savanna grassland by 4 lb/acre (1·8 kg/ha) of Stylosanthes gracilis (stylo) seed. The beneficial effects of the stylo was particularly apparent during the early part of the dry season. The early growth and subsequent survival of the stylo was not outstanding.

Better results were achieved in a second experiment where stylo was grown as a pure crop and ration-grazed in the dry season in association with unimproved savanna. The live-weight gain of cattle grazing the stylo only during the 12 h night period was the same as cattle receiving 1·8 lb (0·82 kg) whole cotton seed per day. In general, cattle live-weight gains were directly proportional to the time spent on the stylo.
Influence of cytoplasms on the fatty acid composition of two maize inbred lines
Authors: Gregory P. , Grogan C. O.
Published: March 2009

Gas liquid chromatography was used to investigate the influence of several T, S and unclassified cytoplasms on the fatty acid composition of oil from A632 and CrS4HLA maize seeds. The fatty acid compositions of the A632 and CrS4HLA seeds differed markedly from each other with respect to oleic and linoleic acids but were stable within each seed line with respect to all sixteen of the cytoplasms tested.
Response by sugar beet to superphosphate, particularly in relation to soils containing little available phosphorus
Authors: Draycott A. P. , Durrant M. J.
Published: March 2009

Twenty experiments between 1970 and 1974 tested the effect of five amounts of triple superphosphate (0–110 kg P/ha) on sugar-beet yield in fields where soil contained little sodium bicarbonate-soluble phosphorus. The average yield without phosphorus fertilizer was 6·69 t/ha sugar and the increase from the optimum dressing 0·46 t/ha; the average soil concentration was 12 mg P/l. The fertilizer increased yield by 0·77 t/ha sugar on fields with 0–9 mg/l soil phosphorus, by 0·31 t/ha when soil phosphorus was 10–15 mg/l and had little effect on soils containing larger amounts.

The concentration of phosphorus in plants harvested in mid-summer contained on average 0·29% P in dried tops and 0·13% in roots when given no phosphorus fertilizer, representing a total of 19·3 kg/ha P uptake. Giving superphosphate increased the phosphorus in both dried tops and roots by up to 0·03% and there was 3·7 and 1·7 kg/ha more phosphorus in tops and roots respectively. On the most responsive fields (0–9 mg/l soil P), the fertilizer increased the phosphorus in tops and roots by 0·05% and total uptake by 7 kg P/ha. The increase in uptake (or recovery) of fertilizer varied from 15% when 14 kg P/ha was given to less than 5% when 110 kg P/ha was used.

A dressing of 27 kg P/ha was adequate for maximum yield on 19 of the 20 fields. When fields were grouped, 0–9, 10–15, 16–25 and > 26 mg/l NaHCO3-soluble soil phosphorus, and taking into account the value of the increased sugar yield, the cost of the fertilizer and its residual value, 60, 30, 20 and 10 kg P/ha respectively were the most profitable dressings. These experiments provide evidence, however, that the fertilizer would be used more efficiently if fields containing 0–9 mg soil phosphorus were subdivided into those with 0–4·5 and those with 4·6–9·0 mg/l and the groups given 80 and 40 kg P/ha respectively. These recommendations are substantially less than those used at present; they are adequate for sugar beet but other crops in the rotation would need similar close examination to ensure maximum yield and maintain adequate soil reserves of phosphorus.
The influence of date of sowing on development and yield of maize in England
Authors: Bunting E. S.
Published: March 2009

Results are reported of twelve experiments—over a period of 11 years—on the effects of date of sowing on development and yield of maize at the Oxford University Field Station, Wytham. Information was obtained on 14 varieties, representative of the range of types likely to be considered for commercial cultivation in England, and sowing dates ranged from mid-March until the end of June.

All varieties gave excellent emergence from May and June sowings but, from sowings made in March or early in April, some American varieties (e.g. White Horsetooth, Wisconsin 255) were slower and poorer in emergence than varieties of northern European origin. For northern European varieties emergence exceeded 70% from March sowings and approached 90% from mid-April sowings. Sowing date markedly affected speed of emergence. More than 40 days elapsed from March sowings until mean date of emergence; about 25 days from mid-April sowings; 18 days from late April sowings and 8–9 days from late May or June sowings.

Plants from sowings made in March or early in April were not significantly earlier or more productive than plants from sowings made in late April. For grain production, however, any further delay in sowing time usually led to lower yields, even with the earliest varieties tested. In contrast, final production of dry material from the shoot was higher, on average, from mid-May sowings.

Provided growth was not arrested by autumn frosts before flowering was completed, plants from later sowings were taller and had more leaves than plants from earlier sowings. The causes of these changes in plant development following variations in sowing date are discussed in the light of published information on the effects of temperature and of length of day on growth of maize.

The practical conclusion drawn from the experiments is that the end of April is an appropriate time to sow maize in central and southern England. No further delay is warranted for grain production. The effect of sowing date on the value of fodder or silage maize requires further information.
Cultivation of quinoa (Chenopodium quinoa) under temperate climatic conditions in Denmark
Authors: Jacobsen S.-E. , Jørgensen I. , Stølen O.
Published: March 2009

Field experiments with the South American grain crop, quinoa, were carried out at two sites in Denmark in 1988–90 in order to study the effects of varying the nitrogen fertilization rate, seed rate, row spacing, harvesting method and harvest date. Although there was a significant yield increase when the amount of nitrogen fertilizer was increased from 40 to 160 kg N/ha, quinoa seems to be well adapted to poor soils. Yield decreased by 24–1% when the nitrogen supply was reduced from 160 to 40 kg N/ha, while the yield decrease was 120 and 2–7% when the nitrogen supply was reduced to 80 and 120 kg/ha, respectively.

A model expressing yield as a function of plant density, for three experiments analysed as one, showed an optimal plant density with respect to yield of 327 ± 220 plants/m2. This plant density was the top point of the curve relating yield to plant density. However, the large standard deviation indicates that apparently a rather wide range of plant densities would provide similar yields. When the row spacing was varied, it was shown that plots with a row spacing of 50 cm, which were hoed, gave a higher yield than plots with 25 or 12·5 cm row spacing, which were unhoed. There was an overall increase in yield when changing from combined harvesting to swathing; however, when comparing the yields from the optimal harvest dates for the two methods, no yield differences could be detected. The optimal harvest date for swathing was found to be the stage when the inflorescences start to turn brown, whereas for combining, the optimal harvest date was the stage when most of the inflorescences are already brown.
Effects of sowing date and sowing rate on plant development and grain yield of quinoa (Chenopodium quinoa) in a temperate environment
Authors: Risi J. , Galwey N. W.
Published: March 2009

Quinoa produces a cereal-like grain with a higher protein content and a better balanced amino acid composition than the major cereals. It is cultivated at high altitudes in the Andes, and is believed to have potential for temperate regions. In the development of quinoa as an arable break crop, sowing date, sowing rate and row spacing are identified as agronomic variables having a high priority for investigation. The variety Baer, from high latitudes at sea-level in Chile, and the variety Blanca de Junin, from the inter-Andean valleys of Peru, were sown on 25 March, 14 April and 7 May 1982 at spacings between rows of 0·8 and 0·4 m and sowing rates within rows of 0·2, 0·4 and 0·6 g/m, at Cambridge, England. These varieties were chosen for their strongly contrasting origins and plant types. In another experiment sown on 15 March 1984, Blanca de Junin was replaced by another valley variety, Amarilla de Marangani, somewhat better adapted for cultivation in England. Between-row spacings of 0·4 and 0·2 m, and sowing rates of 15, 20 and 30 kg seed/ha were used. Weed competition was more intense after later sowings, causing the plots sown in May to be abandoned. At the higher sowing rates, plants were shorter, a higher proportion were stunted, branching was reduced and maturity was earlier. These effects were more marked in the valley varieties, particularly Blanca de Junin. Increases in within-row density caused greater increases in competition effects than corresponding reductions in row width, except for the effect on the proportion of branched plants. The highest grain yield, 6·96 t/ha, was obtained with Baer sown in March in rows 0·2 m apart at 20 kg seed/ha. However, Amarilla de Marangani produced a higher yield at 30 kg seed/ha than at 20 kg seed/ha, which is surprising since valley varieties are normally sown with low target population densities or in intercrop, and Amarilla de Marangani was, in other respects, less tolerant of competition than Baer. The implications of these results for the cultivation of quinoa in mechanized farming systems, both in temperate and in highland tropical regions, are discussed.
A comparative assessment of water use efficiency in groundnut (Arachis hypogaea) grown in containers and in the field under water-limited conditions
Authors: Hebbar K. B. , Sashidhar V. R. , Udayakumar M. , Devendra R. , Nageswara Rao R. C.
Published: March 2009

Water use efficiency (WUE) was measured on fourteen genotypes of groundnut (Arachis hypogaea L.) grown in containers under adequately irrigated and water-limited conditions. The genotypes used similar amounts of water but produced different quantities of dry matter. WUE accounted for > 92% of the variation in dry matter production under both irrigated and water-limited conditions. There was a significant increase in WUE under water-limited conditions. Four genotypes selected from the container experiment as having either a high or a low WUE under non-limited or limited water input conditions were further tested under prolonged water deficit conditions in a field experiment. WUE varied significantly between genotypes and there was a positive correlation between WUE and the quantity of dry matter produced by the genotypes. The results suggested that, in three out of four genotypes, the WUE measured in the container experiment was positively correlated with the WUE estimated under field conditions.
SC-9880-progesterone applications in the induction of early breeding in sheep
Authors: Gordon I.
Published: March 2009

The mating response and lambing outcome was studied in 584 sheep in twentyeight farm flocks after treatment with progestagen impregnated intravaginal sponges and PMS during June/July (period of late anoestrus). Each pessary carried a dose of 30 mg ‘Cronolone’ (9α-fluoro-11β-hydroxy-17α-acetoxy-progesterone; SC-9880, G. D. Searle) in finely dispersed form; half the number of pessaries carried an additional dose of 400 mg progesterone. Intravaginal treatment was for 12 days; a single intramuscular injection of 500 i.u. PMS (Burrough's Wellcome) was made at pessary withdrawal. Breeding was by natural service, using 10% rams. The response was 98·8% bred in the 4 days after treatment, 61·2% conceptions in those served and an average of 1·65 lambs/conception. This resulted in the birth, within the period of about 1 week, of 100 ‘early’ lambs for every 100 ewes exposed to rams. The addition of 400 mg progesterone to pessaries or the injection of a dose of 5 mg progesterone at sponge withdrawal did not improve response beyond that found with ‘Cronolone’ alone.
A study of genotype × environment interaction in three chickpea triple test crosses
Authors: Singh S. , Pawar I. S. , Singh I. P.
Published: March 2009

The analysis of Perkins & Jinks (1971) was applied to 360 progeny families of three chickpea F2 triple test crosses, namely, F 378 × ICCC 1, P 1198–1 × ICCC 1 and US 613 × BG 203, to detect and measure the interaction of additive, dominance and epistatic gene effects with sowing dates. The families were grown in completely randomized blocks in three replications with two sowing dates, and data were recorded for plant height, number of branches per plant, number of days from sowing to flowering, number of days from sowing to maturity, number of pods per plant, number of grains per plant, 100-grain weight and grain yield per plant. The i type epistasis and additive genetic component were relatively more important than j and l type epistasis and dominance component, respectively. The j and l type epistasis and additive gene effects were more sensitive to environmental differences than the i type epistasis and dominance gene effects, respectively.
Fine-scale discrimination of forage quality by sheep offered a soyabean meal or barley supplement while grazing a nitrogen-fertilized heather (Calluna vulgaris) mosaic
Authors: Duncan A.J. , Hartley S. E. , Iason G. R.
Published: March 2009

The ability of 12 Scottish Blackface ewes to discriminate and concentrate grazing activity in nitrogenfertilized heather patches was determined. The nitrogen content of a stand of heather (Calluna vulgaris) was increased and the fibre content decreased by adding ammonium nitrate fertilizer (7·5 g N/m2) 3 months prior to grazing, in Scotland during August 1991, to selected areas within a patchwork array. The sheep were offered either a high protein (300 g soyabean meal) or low protein (285 g ground barley) supplement daily before being allowed to graze within the heather mosaic during November 1991. The proportion of time spent grazing in fertilized and control patches (patch selection) and the proportion of daylight hours spent grazing (proportion of time spent grazing) was estimated for individual sheep for 6 days. Rumen ammonia concentrations were determined at the end of the grazing period. All animals spent approximately twice as much time grazing in fertilized as in control patches. About half of the daylight hours were spent grazing. The nature of the supplement did not influence patch selection, the proportion of time spent grazing or rumen ammonia concentrations. It was concluded that sheep are able to discern differences in the chemical composition of heather on a fine scale and that their foraging behaviour is not influenced by the type of supplement offered.
Modelling Approaches to the Control of Agricultural Pollution
Authors: Audsley E.
Published: March 2009

The Agricultural and Related Industries Study Group of the Operational Research Society held a one-day meeting on ‘Modelling Approaches to the Control of Agricultural Pollution’ on 12 November 1991 at Silsoe Research Institute. The group promotes the use of the scientific method in solving management problems. The aim of the meeting was to look at different ways in which modelling could contribute to the understanding and hence control of different types of pollution. Contrasts were the order of the day, with the first talk being a complex mass of differential equations and the second talk describing an expert system with a few simple design equations. Model dimensions ranged from point sources for silage effluent to several farms for invertebrate populations. A common theme was the difficulty of validating models faced with the extremely variable and difficult-to-obtain experimental data.
Rotation and tillage effects on yield of pearl millet (Pennisetum glaucum) and cowpea (Vigna unguiculata), and aspects of crop water balance and soil fertility in a semi-arid tropical environment
Authors: Klaij M. C. , Ntare B. R.
Published: March 2009

A 4-year field experiment was conducted from 1986 to 1989 in Niger to determine the effects of pre- and post-harvest tillage and rotation of pearl millet (Pennisetum glaucum (L). R. Br.) and cowpea (Vigna unguiculata (L.) Walp.) on crop yield, crop water use and soil fertility on a sandy soil. Presowing tillage increased grain and crop residue yields over the traditional system of no tillage. Post-harvest tillage resulted in lower yields than pre-sowing tillage during the last 2 years of the experiment. Millet-cowpea rotation increased yield and there were no important tillage × rotation interactions. Crop water use was similar for a dry and a wet year, but less water was held in the profile after the harvest of cowpea. Compared to pre-sowing tillage and no tillage, post-harvest tillage increased the amount of water conserved until the next season. In all treatment combinations, soil organic matter and total N content both declined on average by 62%, and soil pH (KCI) decreased from 4·6 to 4·3.
Control of mean root weight in carrots (Daucus carota) by varying within- and between-row spacing
Authors: Benjamin L. R. , Sutherland R. A.
Published: March 2009

Results are reported from four carrot experiments (1987/88) to measure edge effects in crops of different ages grown in beds. A wide range of cultivars, densities and contrasting row-spacing systems was used to determine how effectively these edge effects could be eliminated by increasing the seeding rate in the outer rows relative to that in the inner ones.

Edge effects were first significant between 50 and 100 days after sowing. Where each row was sown with the same quantity of seed, carrots in the outer rows were 1·5 to 2·0 times heavier than those in the inner rows.

Increasing the seeding rate in the outer rows to between 1·5 to 3·0 times that in the inner rows, whilst holding the overall density constant, resulted in equal mean root weight in all rows. There was no evidence of alternate large and small plants in successive rows across the bed, as has been suggested in the literature.

A previously published spacing model gave large systematic deviations when fitted to these data, but this was rectified by a simple modification to the model, which did not entail the incorporation of more parameters.
Herbage yield and botanical composition over 20 years of a predominantly ryegrass sward treated frequently with phorate pesticide and three rates of nitrogen fertilizer
Authors: Clements R. O. , Murray P. J. , Bentley B. R. , Henderson I. F.
Published: March 2009

Plots at Hurley, UK, sown to perennial ryegrass (Lolium perenne) in 1968 were given 188, 376 or 752 kg N fertilizer/ha per year. Half of each plot at the lowest and highest rate of N fertilizer was given a severe pesticide (phorate) treatment at frequent intervals. Plots were cut and their herbage yield was assessed on five occasions during each of the following 20 years. There was no indication of a long-term decline in total annual herbage yield at any rate of N fertilizer use. The severe pesticide regime enhanced yield by an average of 14·6%/year during the first 11 years, but tended to have little effect or to reduce yields subseque7tly. Initially (1969) all treatment plots comprised at least 85% perennial ryegrass, but this proportion declined to between 67% (medium N) and 40% (high N) by 1989. Apart from ryegrass, the main sward components were species of the grasses Agrostis, Poa, and Elymus and traces of the broad-leaved species Stellaria media and Taraxacum officinale.
Effect of pollination on flower, pod and seed production in white lupin (Lupinus albus)
Authors: Williams I. H. , Martin A. P. , Ferguson A. W. , Clark S. J.
Published: March 2009

The pollination requirements of the white lupin cultivar Vladimir were investigated in a glasshouse. Five treatments were compared in which the flowers of each plant were (i) left to autopollinate, (ii) shaken, (iii) tripped, (iv) self pollinated or (v) cross pollinated. Pollination treatments had no effect on the numbers of flowers, pods or seeds or weight of seed produced by the plants but did slightly shorten the duration of flowering, the effect being greatest when flowers were tripped or cross pollinated and least when they were shaken or self pollinated.

The proportion of flowers that developed into pods differed with raceme, with secondaries producing more than tertiaries > primaries > quaternaries; the number of seeds per pod differed in the same order, but mean single-seed weight decreased on successive racemes. However, pollination treatments had no effect on the distribution of flowers, pods or seeds on the plant.

This crop species is clearly highly self fertile and self pollinating and likely to yield well without insect pollination.
Differences between twelve forage species in physical breakdown when eaten
Authors: Mtengeti E. J. , Wilman D. , Moseley G.
Published: March 2009

The effectiveness of chewing by sheep during eating in breaking a forage diet into particles was studied in twelve plant species over 2 years and related to the physical structure of the plants and their rate of intake. The twelve species were: Trifolium repens L., Medicago sativa L., Onobrychis viciifolia Scop., Desmodium intortum (Mill.) Urb., Brassica napus L., Spergula arvensis L., Lolium perenne L., Lolium multiflorum Lam., Festuca arundinacea Schreb., Chloris gayana Kunth, Cenchrus ciliaris L. and Zea mays L. In each case early harvesting was compared with later harvesting. The plants were grown in a heated glasshouse.

L. perenne and L. multiflorum were broken into a large number of particles per g dry matter; the particles were rather long and thin. F. arundinacea was broken into heavier, slightly shorter and slightly wider particles. C. gayana and C. ciliaris were broken into particles which were smaller, heavier and contained more vascular bundles than those of Lolium, reflecting the lower rate of intake, greater weight per unit area of leaf blade and greater proximity of bundles of the tropical grasses. Z. mays leaf blades broke into shorter, wider particles than the leaf blades of the other grasses, reflecting the much wider blades of Z. mays.

The leaflets of the four leguminous species and the leaf blades of B. napus were broken into particles with an average length:width ratio of c. 2:1, compared with an average ratio of c. 7:1 for particles derived from grass leaf blades other than those of Z. mays. The legume leaf petioles were broken into particles with an average length: width ratio of c. 13:1; many of the legume petioles were not split longitudinally during chewing. The stems of M. saliva and D. intortum were broken into particles similar in length and width to those from the stems of the tropical grasses, although the rate of intake of the legume diets was at least twice that of the tropical grass diets. The average length: width ratio of particles from B. napus petioles and stems was 5:1. A high proportion of particles from the B. napus and D. intortum diets had a rough surface. 5. arvensis was broken into more particles per g dry matter than the legumes and B. napus, despite its very high rate of intake. Many pieces of stem of S. arvensis were not split longitudinally during chewing.
15N-determined dinitrogen fixation capacity of common bean (Phaseolus vulgaris) cultivars under water stress
Authors: Castellanos J. Z. , Peña-Cabriales J. J. , Acosta-Gallegos J. A.
Published: March 2009

The effect of water stress on nitrogen fixation in seven common bean (Phaseolus vulgaris L.) genotypes was investigated in Celaya, Gto., Mexico, in 1991. Beans were grown under four moisture regimes: (1) well-irrigated, control, (2) with water stress during the vegetative stage, (3) with water stress during the reproductive stage and (4) with water stress during the whole growing cycle. Biological nitrogen fixation was measured by 15N-isotope dilution using sorghum as a reference crop. Nodulation and N2-fixation data showed genotypic differences in response to water stress. Under non-stressed conditions, cv. Bayocel fixed the most nitrogen (85 kg/ha) and cultivar Flor de Mayo Baji'o the least (33 kg/ha). Under water stress at the reproductive stage, these cultivars fixed 9 and 6 kg N/ha, respectively. Water stress during the reproductive stage reduced nodulation by an average of 43% with no recovery after rewatering. Water stress during the reproductive stage had a greater effect on N2-fixation than on grain yield; in comparison to the control, N2-fixation was reduced to one sixth while grain yield was only reduced by 50%.
Dry matter production, fibre composition and plant characteristics of cool-season grasses under two harvest systems
Authors: Kunelius H. T. K.
Published: March 2009

Cultivars of Phleum pratense, Festuca pratensis, Festuca arundinacea, Dactylis glomerata and Lolium × Festuca hybrids were exposed to 4- and 3-cut harvest systems in Prince Edward Island, Canada, in 1985–87. Lolium perenne × F. pratensis, Lolium multiflorum × F. pratensis and L. multiftorum × F. arundinacea hybrids and D. glomerata had more uniform growth among the harvests than other grasses during the growing season. L. perenne × F. pratensis and L. multiflorum × F. pratensis had lower contents of neutral and acid detergent fibre than other grass cultivars, particularly early in the growing season. P. pratense cv. Farol had the lowest and L. perenne × F. pratensis cv. Prior the highest tiller population density. The stem apex of all cultivars was above the cutting height of 5 cm in c. 50% of tillers of primary growth. Leaf area per tiller was largest for P. pratense cv. Farol in the primary growth stage but differences were small in subsequent cuts.
Traits associated with high yield in barley in low-rainfall environments
Authors: Acevedo E. , Craufurd P. Q. , Austin R. B. , Pérez-Marco P.
Published: March 2009

Results are reported from nine field trials carried out in 1985/86 and 1986/87 aimed at identifying plant traits which are associated with high yield in barley in low-rainfall Mediterranean areas. Thirtyseven two-rowed and 35 six-rowed genotypes, representing the known diversity in traits considered to be useful, were compared in trials at three sites differing in expected annual rainfall (212–328 mm) in northern Syria, and in droughted and irrigated trials at Cambridge, UK. Yield, its components and other morphological and developmental traits were measured and correlations calculated.

Grain yields of the two- and six-rowed groups of genotypes were similar at all sites except in the irrigated trial in Cambridge, where the six-rowed genotypes gave the highest yield. Aside from the known difference in number of ears and number of grains/ear between two- and six-rowed genotypes, the simple correlations between grain yield and measured traits suggested that important traits for high yield in two- and six-rowed genotypes in dry environments were prostrate habit, vigorous seedling growth, good ground cover, early ear emergence, many ears/m2 and large grains. In the two-rowed genotypes, short stature and a short grain-filling period were also important, while in the six-rowed genotypes, tall stature, high straw yield, many grains/ear and long peduncles were important. Correlations of these characters with an index of drought susceptibility and with yield adjusted for yield potential and date of ear emergence supported the conclusions based on the simple correlations.

The physiological basis of the correlated traits is discussed and the implications for breeding are considered.
Effect of altering the starch: fibre ratio in the concentrates on hay intake and milk production by Friesian cows
Authors: Sutton J. D. , Morant S. V. , Bines J. A. , Napper D. J. , Givens D. I.
Published: March 2009

Sixty-four multiparous Friesian cows were given one of eight diets from weeks 4–20 of lactation at the former National Institute for Research in Dairying, Shinfield, Reading in 1983–84. The diets consisted of 13·5 kg/day of experimental concentrates plus hay at 4·5 kg/day (fixed) or ad libitum. Concentrates were high-starch (S) based on cereal grains and cassava, high-fibre (F) based on highquality by-products, and two intermediate types containing 2:1 (SF) and 1:2 (FS) starch:fibre, all with a crude protein concentration of c. 180 g/kg DM. The diets were designed to provide similar intakes of digestible energy and crude protein at fixed hay intakes.

With ad libitum feeding, hay intake was lowest on S concentrates. With increasing fibre in the concentrates, the yields of milk, protein and lactose fell but fat concentration and yield were increased. These changes were linear and were unaffected by hay intake. Increasing hay intake to ad libitum had no effect on milk yield but increased the concentrations and yields of fat and protein. It also changed a net liveweight loss on fixed intakes to a gain on ad libitum intakes.

Diet digestibility was measured using sheep at about maintenance and cows at production intakes. Digestibility was higher in the sheep, probably because of the difference in level of intake. In the cows, increasing fibre in the concentrates reduced the digestibility of dry matter, organic matter, energy and nitrogen but increased the digestibility of fibre fractions and ether extract. Level of hay intake had variable effects on mean digestibility and on the relationship with concentrate type.

Increasing the fibre in the concentrates increased the molar proportions of acetate and n-butyrate in the rumen and reduced the proportions of propionate, n-valerate and n-caproate.

It is concluded that, with mixed diets of hay and relatively high proportions of concentrates, changes in the starch:fibre ratio of the concentrates by substitution of high quality by-products for starchy ingredients can induce linear changes in the yields of milk and the principal solids constituents and in milk fat concentration. Since changes in yields of fat and protein went in opposite directions, the optimal concentrate composition depends on the milk composition required by the market. These conclusions may not apply if poorer quality by-products are used.
Formation of biogenic amines in well fermented grass silages
Authors: van Os M. , van Wikselaar P. G. , Spoelstra S. F.
Published: March 2009

Biogenic amine formation was studied in silages made from perennial ryegrass. In 1991 two batches of grass from the same sward of the ID–DLO permanent pasture were wilted to either 250 or 450 g dry matter (DM)/kg, and ensiled in eight 1-litre laboratory silos for eachtreatment (Expt A). To induce differences in fermentation pattern, the grass was ensiled without additive (CON) or treated with formic acid (5 ml/kg; FA), cell wall degrading enzymes (2·1 ml/kg; ENZ), molasses (50 g/kg; MOL), or inoculated withLactobacillus plantarum(107colony forming units (CFU)/g; LP), a combination ofLactobacillus plantarumandStreptococcus faecium(105CFU/g; LPSF), orEnterobacter sakazakii(6×lO6CFU/g; EB). One silo for each treatment was opened after 1, 2, 4 and 7 days for pH determination and duplicate silos were opened after 10 and 90 days for pH determination and analysis of fermentation products. Two similar experiments (B and C) were performed using the CON, FA and LP treatments.

Total amine content of the grass was low (0·1–0·2 g/kg DM). The well preserved silages in each experiment contained considerable amounts of amines, ranging from 0·1 g/kg DM in the wilted LP and FA silages to 7·4 g/kg DM in a low DM CONsilage. Tyramine, cadaverine, putrescine and histamine were, in descending order, the principalbiogenic amines formed, representing together 90 (S.E. 9)% of the total biogenic amine contentof the silages. Formation of amines occurred mainly during the first 10 days of fermentation, and was highest in silages with a slow acidification rate. Ensiling at high DM content, with formic acid or inoculation with large numbers of lactic acid bacteria significantly (P< 0·01) reduced the amount of amines in the silage. Total and individual amine contents of the silages were significantly correlated with concentrations of ammonia and acetic acid. It was concluded that the formation of biogenic amines in grass silage is related to protein degradation, and that amine formation can be reduced by restriction of fermentation in the silage, or by achieving rapid acidification during the first phase of ensiling.
Classification of environmentally induced genetic male sterile lines of rice based on their fertility responses to photoperiod and temperature
Authors: Cheng S. H. , Si H. M. , Zhuo L. S. , Sun Z. X.
Published: March 2009

The use of environmentally induced genetic male sterile (EGMS) rice could alter the development of hybrid rice from a three-line system to a two-line system. It is critical for the utilization of EGMS rice to determine which are the main environmental factors influencing fertility changes. Fertility responses to photoperiod (P) and temperature (T) were studied in 101 EGMS rice lines under nine controlled regimes combining three photoperiods (15·0, 14·0 and 12·5 h)x three temperatures (30·1, 24·1 and 23·1 °C). According to the variance analysis of seed-setting data, 96% of the total EGMS lines studied could be divided into three types as follows: (1) photoperiod-sensitive genetic male sterility (PGMS) characterized statistically by significant (P < 0·05) P and P × T interaction effects but by a non-significant T effect on fertility, (2) thermosensitive genetic male sterility (TGMS) by a significant T effect, a non-significant P effect and by either a significant or a non-significant P × T interaction effect on fertility, and (3) photo-thermosensitive genetic male sterility (P-TGMS) by only a significant P × T interaction effect on fertility. Among the japonica EGMS lines studied, PGMS, TGMS and P-TGMS accounted for 32·3, 9·7 and 51·6%, respectively. However, among the indica EGMS lines, no PGMS lines were detected and most of them were TGMS or P-TGMS (61·4 and 35·7%, respectively). The results indicate that the selection of indica PGMS lines of rice might be very difficult. The availability of different types of EGMS rice in two-line system hybrid rice is evaluated and the selection of an ideal model of response to photoperiod and temperature for indica EGMS is discussed.
Nitrate leaching from sheep-grazed upland pastures in Wales
Authors: Cuttle S. P. , Hallard M. , Gill E. K. , Scurlock R. V.
Published: March 2009

Ceramic cup samplers were used to measure nitrate leaching from grass/clover pasture in Wales to which no N fertilizer had been applied and from a predominantly grass pasture receiving 100 kg fertilizer-N/ha annually. Annual leaching losses at individual sampling points, measured over a 3-year period between 1988 and 1991, ranged from the equivalent of < 0·1 to 226 kg N/ha. All data sets were positively skewed and in four out of six cases conformed to a log-normal distribution. The marked spatial heterogeneity was attributed to the uneven deposition of N in the excreta of grazing stock but variations in soil depth and hydrology may also have contributed. Particularly large losses occurred from those areas of the plots where sheep congregated. As a result of this heterogeneity, there were large standard errors associated with estimates of mean losses from the pastures as a whole. Overall losses ranged from 13 to 24 kg N/ha per year from grass/clover plots and from 10 to 13 kg/ha from fertilized grass plots. There was no consistent relationship between relative losses from the two types of pasture. The quantity of nitrate leached appeared to be independent of stocking rate, although there was a direct correspondence between the loss from grass/clover plots and the proportion of clover in the sward. Estimates of nitrate concentrations in drainage never exceeded 5·6 mg N/I for either sward.