摘要:

AbstractThe effect of level of nitrogen application upon the dynamics of herbage growth in a continuously grazed sward of tall fescue was investigated during two successive years. In order to obtain a large range of sward structural conditions, the experiments were carried out with two contrasting cultivars: cv. Clarìne and cv. Barcel, and, in Year 2, with two different sward heights or leaf area indices (LAIs). During each of five experimental periods (2‐3 weeks), swards received either optimum (N2) or deficient (N1) N applications, were maintained at their target LAI, and leaf growth was measured on labelled tillers. With continuously defoliated tillers, N‐shortage had only a small effect on the leaf elongation rate compared with tillers protected by cages. The leaf production per tiller was only slightly reduced by N shortage, and it was mainly by the means of a reduction in tiller density that the N deficiency resulted in reduced herbage growth per hectare. These results indicate that, in continuously grazed swards, in contrast with results previously found in intermittently defoliated swards, leaf elongation is not the only important component of difference in herbage growth and that the promotion of tillering rate is an additional pathway for N response in such management reg

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1994.tb01983.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractPerennial legume varieties and ecotypes belonging to the species sainfoin (Onobrychis viciifoliaScop.) and French honeysuckle (Hedysarum coronariumL.) were investigated under different management treatments (two regimes of irrigation, cutting and seeding densities) at the Forage Crops Institute in Foggia, Italy (which has a typical Mediterranean environment) for two seasons, 1990 and 1991. Dry‐matter production, seed production and seed yield components were affected more by harvest year and irrigation than by seeding density. Mean increases due to irrigation were 2·8% and 60·6% respectively for dry‐matter and seed yield in sainfoin and 35·3% and 32·5% respectively in French honeysuckle. Under both cutting regimes, the higher seeding density was more suitable for sainfoin, increasing stems m−2with irrigation and seed yield without irrigation. In French honeysuckle the lower seeding density was more suitable for production of inflorescences per tiller and for seed weight without irrigation. Higher seeding density positively influenced seed yield under irrigation. The seed yield components most influenced by irrigation were: 1000‐seed weight, seeds per inflorescence and inflorescence per stem. French honeysuckle genotypes were potentially more productive in dry matter and seed yield under both irrigation regimes than the sainfoin, which was more productive in seed yield when cut. The ecotypes of both legumes represent a genetic resource, particularly for seed yield after forage cutting, to be utilized in breeding programmes for developing varieties well adapted to Mediterranean e

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1994.tb01984.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe effect of adding rolled barley on the ensiling characteristics and nutritive value of lucerne and corn (Zea mays) forage was studied using 19‐1 plastic mini‐silos. Other factors evaluated with lucerne were the effect of wilting and added lactic acid bacteria. Rolled barley was added at rates of 0, 50, 100 and 150gkg−1(wet weight) to lucerne or corn forage. Lucerne was ensiled at 170–330 g kg−1dry matter (DM) and lactic acid bacteria were applied at 105g−1wet forage. Addition of rolled barley consistently improved the fermentation of lucerne by lowering the pH and decreasing the concentration of acetate and ammonia nitrogen. Wilting of lucerne had variable effects on fermentation in two experiments. The addition of lactic acid bacteria improved fermentation by decreasing the concentrations of acetate and ammonia nitrogen, improved the nutritive value by increasing thein vitrodry matter digestibility (IVDMD), and was associated with decreased amounts of lactic acid. Corn was ensiled at 250 g kg−1DM, and added rolled barley had little effect on the fermentation of corn silage. The digestibility of all silages determinedin vitrowas improved by the addition of

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1994.tb01985.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe effect of growth regulators on the yield and quality of red clover (Trifolium pratenseL.) was assessed in two growing seasons. An early‐flowering cultivar (Florex) and a late‐flowering one (Altaswede) were treated with the growth regulator, daminozide butanedioic acid [mono (2,2‐dimethylhydnizide)] or mefluidide [N‐(2,4‐dimethyl‐5{[(trifluoromethyl)sulphonyl]amino}phenyl) acetamide], either in early (mid‐May) or late (late May) season and at low rate [daminozide, 4kg active ingredient (a.i.) ha−1; or mefluidide, 0·13 kg a.i. ha−1] or twice the low rate (high rate), and compared with no treatment. Red clover yielded two‐ to three‐fold more dry mater (DM) in the first than in the second harvest, and growth regulator treatments did not redistribute yields more evenly between the two harvests. Growth regulator effects on the yield and composition of red clover were mainly confined to the first cut herbage. Daminozide increased first‐cut and annual yields of DM andin vitrodigestible DM (TVD); the latter was increased particularly for Altaswede, as compared with the untreated red clover. Mefluidide decreased first‐cut yields of DM and IVD for Florex only, but the annual yields for both cultivars were unchanged by this treatment. Changing the rate or time of growth regulator application did not affect DM or IVD yield in red clover. The treated red clover contained less water‐soluble carbohydrate in the first cut than did the untreated crop. The high rate of daminozide, when applied early, decreased neutral detergent fibre and increased IVD contents in the first‐cut red clover compared with the other combinations of rate and time. Altaswede produced as much DM annually and had a higher IVD content than Florex when these cultivars were cut on common dates, twice during the short gro

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1994.tb01986.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe effect of growth regulators on mineral composition of red clover (Trifolium pratenseL.) was assessed in two growing seasons, daminozide {butanedioic acid [mono(2,2‐dimethylhydrazide)]} or mefluidide [N‐(2,4‐dimethyl‐5{[(trifluoro‐methyl)sulphonyl]amino} phenyl) acetamide]]was applied early (mid‐May) or late (late May) at low rate [daminozide, 4 kg active ingredient (a.i.) ha−1; or mefluidide, 0·13 kg a.i. ha−1] or twice the low rate (high rate) to an early‐flowering cultivar, Florex, and a late‐flowering cultivar, Altaswede; the controls were the untreated cultivars. Red clover was deficient in S, but all other minerals were present in sufficient amounts for productive cattle. The first cutting showed increases in P and Zn contents after an early application of daminozide, Cu was increased when the high rate of daminozide was applied early, and Ca, Cu, K and Mg were increased when mefluidide was applied early or at the high rate. There were no interactions between daminozide and cultivar in terms of minerals, but mefluidide treatment increased Mg in Altaswede only. Altaswede showed a narrower N/S ratio in the first cutting, and contained more P, K and Mg in both cuttings than did Florex. This study indicated that growth regulator application, particularly the early application of daininozide at the high rate, improved the mineral p

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1994.tb01987.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe productivity and response to fertilizer nitrogen (N) was measured in herb‐rich wetland hay meadows within a Site of Special Scientific Interest (SSSI) in Somerset, UK. Output from hay cut after 1 July each year and from beef production at aftermath grazing was measured over a total of 4 years.Total utilized metabolizable energy (UME) output averaged from 40·6 GJ ha−1year−1without fertilizers to 61·7GJha−1at 200kgNha−1(N‐200), the highest rate used, with about two‐thirds of this output from hay. N response was markedly curvilinear above about 50kgN ha−1, but data from a concurrent experiment suggested that the comparatively low replacement rates of P and K applied were limiting at higher N rates. When hay cutting was delayed until early August in a wet year, yield response to N was lost because fertilized swards had passed a peak in yield several weeks before harvest.Compared with other published data, the results suggest that output and response to N is not constrained by the diversity of the flora or the damp conditions. The data will help to estimate the financial implications for farmers of restricted or zero fertilizer use within SSSIs and the wider Environmentall

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1994.tb01988.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe effects of fertilizer nitrogen (N), phosphorus (P) and potassium (K) on herbage production were investigated in herb‐rich hay meadows in Somerset, UK. Swards were cut after 1 July each year, followed by one or two aftermath cuts. Dry‐matter (DM) yield at cutting, metabolizable energy (ME) production and recovery of N, P and K were measured over 4 years.Total annual DM production increased from 4·7t ha−1without fertilizers to 10·5t ha−1with 200 kg N, 75 kg P and 200 kg K ha−1per year, and ME output from 38·8 GJ ha−1to 92·5 GJ ha−1. Applying moderate replacement rates of P and K without N increased annual DM and N yields by 43% and 36% respectively, but N response was modest unless high rates of P and K were used. Annual ME output and recovery of N, P and K were all significantly increased by taking an additional, earlier cut for silage, even though DM yield was unaffected.The results suggest that potential output of these meadows is similar to that of a wide range of less diverse permanent pastures. Data from this and a concurrent experiment will help to estimate the financial implications of fertilizer and cutting date restrictions within Sites of Special Scientific Interest and the wider Environmentall

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1994.tb01989.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractSupernatants derived from desiccated plant material gathered fromAgrostis/Festucavegetation had an inhibitory effect on the germination and early development of seedlings ofTrifolium repenscv. S184. Two compounds,o‐hydroxyphenylpropionic acid and benzoic acid, were identified chromatographically and their structures confirmed by mass spectrometry. Commercial preparations of the two compounds were effective inhibitors at a concentration of 10−2and 10−3mrespectively whenT. repenswas used as the phytometer species. Benzoic acid lost its inhibitory effect when the pH of the two solutions was adjusted to pH 5·5. The roots of seedlings of white clover were severely distorted byo‐hydroxyphenylpropionic add at 10−3m. It is likely that phenolic acids, produced from the surface trash created by slot seeding procedures, interfere with the establishment of white clover in uplan

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1994.tb01990.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe effects of transfusing cores of grass silage with mixtures of oxygen and nitrogen containing 0%, 0·2%, 2%, 5% and 20% oxygen were investigated. Changes in populations of yeasts, lactobacilli and streptococci were measured and the relationship between populations after 7 days' transfusion and oxygen concentration were tested against the predictions of two models, based on Monod and logistic growth functions. Yeasts were related to oxygen by the Monod model, while lactobacilli and streptococci were related by the logistic model. The differences were ascribed to yeasts initiating deterioration by growing aerobically, while lactobacilli and streptococci grew fermentatively once the environment had changed following yeast growth. Dry‐matter losses were related to oxygen by the Monod model. Changes in temperature were related to dry matter loss (through measurements of CO2evolution) using a simple heat balance mod

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1994.tb01991.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe effects of continuous stocking by sheep at sward surface heights (SSH) of 3, 5, 7 and 9 cm in grass/clover (GC) and nitrogen‐fertilized grass (GN) swards were examined in relation to herbage mass and quality, clover content, tiller density and rates of herbage production and senescence in two periods in each of three grazing seasons (1987‐89). The GN swards received a total of 300 kg N ha−1each year in six equal dressings from March; GC swards received a single dressing of 50 kg N ha−1in March each year.Herbage mass measured from ground level increased linearly with SSH with overall mean herbage masses of 0·89, 1·38, 1·78 and 2·12 t OM ha−1(s.e.m.0·024,P<0·001) at SSH of 3, 5, 7 and 9 cm respectively. GN and GC swards had mean herbage masses of 1·58 and 1·51 t OM ha−1(s.e.m. 0·051, NS) respectively. Mean N content of herbage on GN swards was greater than that on GC swards and declined with increasing SSH. Crude, fibre (CF) content of herbage was similar for both sward types and increased with increasing SSH.Clover content of GC swards remained low throughout the experiment, ranging from 0·002 to 0·074 of herbage mass. However, from tissue turnover rates it was estimated that its contribution to herbage production was in the range of 0·049–0·219 of net herbage growth.Total growth increased with increasing SSH in both sward types, with maximum growth rates in GN swards of 143 and 130 kg DM ha−1d−1and in GC swards of 88·2 and 85·4 kg DM ha−1d−1in Periods 1 (up to early July) and 2 (after July) respectively. Senescence rates ranged between 13·3 and 50·1 kg DM ha−1d−1and tended to be higher in Period 2 than in Period 1. Net production increased with increasing SSH in Period 1, while in Period 2 net production declined at SSH above 6·5 cm.The increased net herbage production in taller swards was not associated with greater utilized metabolizable en

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1994.tb01992.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY