摘要:

AbstractPerennial ryegrass/white clover mini‐swards were used lo determine whether sward responses to slurry were modified by subsequent simulated rainfall (SR). Combinations of two SR volume rates (6.5 and 13 mm), three SR timings (3, 24 and 48 h after slurry application) and two slurry types (cattle, pig) were compared with a fertilizer control (no SR). Scorch, smother and growth of marked stolons and tillers were monitored after slurry application, and yields of both species were recorded. Slurry coverage of plastic squares indicated that smother may be greater on horizontally orientated leaves (clover). Reduced grass leaf growth and numbers of clover growing points in the week following slurry application were attributed mainly to smother, and possibly other phytotoxic effects of slurry. Reasons for the superior clover growth with cattle slurry arc unknown, although its higher P and K content may have contributed. Timing of rainfall is important in influencing sward responses to slurry application. Results suggest that application of slurry may be most beneficial when it immediately precedes rainfall and that longer intervals between slurry application and rainfall reduce grass and clover growth through either greater ammonia loss or slurry negative effect

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1996.tb02067.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractField plots were established in autumn 1992 in which endophyte [Neotyphodium coenophialumGlenn. Bacon, Price and Hanlin (formerlyAcremonium coenophialum)]‐infected (E+) and endophyte‐free (E−) isolines of three tall fescue [Festuca arundinaceaSchreb.) genotypes were planted. Plants were subjected to three water‐withholding periods in 1993 and one in 1994, or were kept well watered throughout the experiment. There were no consistent endophyte effects for leaf elongation, tiller density or dry weight per tiller. There were genotype X endophyte interactions (P<001) for tiller density and shoot dry weight per area and genotype X water X endophyte interactions (P<005) for cumulative leaf elongation in 1993. These interactions indicated the highly specific effect of host genotype‐endophyte association on the expression of plant growth. Leaf rolling in the stressed treatments was more severe in E−than in E+plants in 1993, but there were no differences in 1994, and stomatal conductance tended to be lower in E−than in E+plants in 1993. Fractional water content of the lower 3 cm of the youngest fully developed leaf sheath was usually greater, and never less, in E+than in E−plants. The leaf rolling and stomatal conductance results suggest that E−plants were more severely stressed in the summer after planting. Thus, the endophyte may induce greater water retention in the leaf sheath and therefore better protect the internal growing zone from l

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1996.tb02068.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractA small‐plot experiment was carried out with grass‐lotus(Lotusspp.) swards on a lowland (185 m) clay‐soil site in S‐W England. Two species of lotus(Lotus corniculatuscv. Leo andL. pedunculatus, syn,L. uliginosus, cv. Maku) were each sown at 10 kg seed ha−1with lour grass species each at two grass‐seed rates:Festuca pratensisat 6 or 3 kg ha−1andPhleum pratense, Agrostis capillarisandPoa pratensisat 4 or 2 kg ha−1. Assessments were made over three harvest years (1992–94). during which no fertilizers were applied. Mean total herbage dry matter (DM) harvested from cv. Leo swards was 90 t ha−1in year 1, 8–9 t ha−1in year 2 and 4 0 t ha−1in year 3. and from cv. Maku swards 6–6 t ha−1in year 1. 8–9 t ha−1in year 2 and 3–9 t ha−1in year 3. Highest three‐year mean total yields were withF. pratensisas the companion grass (7–4 t ha−1year−1), followed byPhleum pratense(7–0 t ha−1),A. capillaris(6–9 t ha−1) andPoa pratensis(6–2 t ha−1). The lower grass‐seed rate resulted in a greater proportion of lotus in the total harvested DM in year I. The higher grass‐seed rate resulted in higher yields fromF. pratensisswards in year 1, but there were no significant effects for other species or in subsequent years. Lotus as a proportion of harvested DM declined from about 70% in year 1 to about 20% in year 3. The mean DM yield of lotus herbage in years 1, 2 and 3, respectively, was 5–5, 2–8 and 0–8 t ha−1from cv. Leo swards, and 4–0, 3–3 and 0–8 t ha−1from cv. Maku swards. Lotus herbage was of higher digestibility from cv. Leo [digestible organic matter (DOM) of 661 g kg−1of lotus DM] compared with cv. Maku (551 g kg−1DM). Mean N content of lotus herbage was 35 g N kg−1DM. Digestibility of companion grass herbage was highest forPhleum pratense(557 g kg−1DM) and lowest forA. capillaris(493 g kg−1DM). It is concluded that lotus may be an alternative legume to white clover for low‐input, low‐fertility situations. However, further research is needed to evaluate its performance on different sites and under different managem

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1996.tb02069.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractA factorial experiment was carried out to evaluate the effects of level of nitrogen (N) application to grassland and subsequent treatment of the herbage at ensiling with formic acid on the rate of silage fermentation, dry‐matter (DM) recovery, aerobic stability and effluent production. Herbage from the primary regrowth of predominantly perennial ryegrass swards received either 72 (LN), 126 (MN) or 180 (HN) kg N ha−1. The herbages were harvested and yield estimated after a 50‐day regrowth interval. After storage for 24 h in polythene bags, the herbages were ensiled, unwilled, in laboratory silos (6 kg capacity) either untreated (UT) or treated with formic acid (F) at 3 ml (kg herbage)−1. Three silos per treatment were opened and sampled on days 1, 3, 6, 15, 50 and 105 after ensiling. The mean herbage yields for the LN, MN and HN swards were 5.2, 6.3 and 6.2 (s.e. = 0.27) t DM ha−1and there was no carryover effect of nitrogen treatment on the yield of a subsequent 22‐day regrowth harvested on 2 September. As level of fertilizer N application increased, concentrations in the herbage at mowing of crude protein, nitrate and ash increased, DM decreased and water‐soluble carbohydrate andin vitroDM digestibility remained unchanged. Increasing the rate of N fertilizer to the sward resulted in higher silage pH (P<0.001) and ammonia N concentrations (P<0.001) at each time of sampling. Increasing the rate of fertilizer N increased effluent output (P<0.001) and DM recovery (P<0.001). Aerobic stability was improved (P<0.001) by use of high rates of N fertilizer application. Formic acid treatment restricted fermentation and increased effluent output (P0.05) on DM recovery. It is concluded that the rate and extent of pH decline was reduced with increasing N application, associated with increased buffering capacity and decreased DM concentrations of the herbage at ensiling. However, increasing the level of N fertilizer applied increased DM recovery and effluent output, and improved aerobic stability of the resu

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1996.tb02070.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractTwo experiments were carried out with grass silages cut at a leafy (Experiment 1) and a more mature (Experiment 2) stage of growth to evaluate the effect of wilting and chop length on silage intake and performance of store lambs. In each experiment, the herbage was cut with a rotary mower and was either ensiled within 24 h as unwilled silage (U) or wilted for 1–3 d (W). Each silage type was harvested with either a double‐chop harvester (D) or a precision‐chop harvester (P). All silages were treated with formic acid at 3 1 t−1and were well preserved. The silages were fedad libitumto Suffolk crossbred store lambs (twenty‐four lambs per treatment) without any supplement over a period of 8 or 9 weeks.Wilting of the silages had little effect on silage intake (797 vs. 809g dry matter (DM) d−1) or on lamb performance in Experiment 1. In Experiment 2, wilting of the D silage increased silage DM intake (589 vs. 534 g DM d−1; +10%) and reduced the extent of liveweight losses. Wilting of the P silage reduced silage intake (770 vs. 791g DM d−1; ‐3%) and reduced liveweight gains.In Experiment 1 intakes of the D silages were 650–667g DM d−1and just maintained lamb live weights. Intakes of the P silages were 39–49% higher than the D silages (927–968 g DM d−1) and increased liveweight gains. In Experiment 2 intakes of the D silages were 534–589 g DM d−1and resulted in a loss in lamb live weight. Precision‐chopping increased silage intakes by 31–48% (770–791 DM d−1)in Experiment 2 and improved lamb liveweight gains. Lamb performance was higher on the UP silage than on the WP silage.The rumen retention lime (RRT), estimated from the rumen contents of the lambs at slaughter and their silage intake before slaughter, was much shorter for the lambs fed on the P silages (12.6–20.6 h) than those fed on the D silages (21.4–29.3 h) in each experiment.Silage intake and liveweight gain were positively related to silagein vivoDM digestibility (DMD), whereas RRT was negatively related to DMD. However, there were distinct differences between the P and D silages in the elevation and, to a lesser extent, in the slope of the regression lines, indicating that intake of D silage was limited by factors other than the digestibility of the silageThe results of this study show that the chop length of grass silage had a far greater effect on intake and on lamb performance than silage digestibili

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1996.tb02071.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractA perennial ryegrass sward was cut at a leafy stage of growth and harvested with different harvesters to produce silages differing in chop length to evaluate the effect of silage chop length on silage intake and on the performance of store Iambs when silage was fed as the sole diet. The silage was harvested in late May either as long silage (L), single‐chopped (S). double‐chopped (D). long precision‐chopped (LP) or medium precision‐chopped (MP) silage with (he appropriate machinery. The silages were treated with formic acid at 2.5 1 t−1. were well preserved (pH 3.7–3.8) and were of high dry‐matter digestibility [749–810 g DMD kg−1dry‐matter (DM)]. The silages were fedad libitumas the sole diet to Suffolk crossbred store lambs over a period of 11 weeks.Silage intake and lamb performance progressively increased as silage chop length declined from 32.4 cm (L) to 6.8 cm (MP). Silage intakes were 572, 661, 750, 893 and 1129 (± 21) g DM d−1for silages L, S, D, LP and MP respectively. The corresponding daily liveweight gains were ‐3, 40, 53, 85 and 151 (± 7.6) g d−l. Similar increases in empty body weight gain and carcass weight gain were obtained as silage chop length declined.Rumen retention time (RRT), estimated from the rumen contents of the lambs at slaughter and their silage intake in the week before slaughter, was much shorter for silages LP and MP compared with silages L or S. Silage intake was negatively related to RRT(b= ‐24.5 ± 6.1 gDM h−lRRT).The results of this study showed that high intakes of grass silage and liveweight gains were achieved when grass was cut at a leafy stage of growth and harvested with a precision‐chop harvester set to produce a moderate chop length (7 cm). The feeding of long or flail‐chopped silages resulted in lowe

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1996.tb02072.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractAn experiment was carried out to study the effect of silage chop length and barley supplementation on silage intake and the performance of store lambs. The silages were cut from a perennial ryegrass regrowth at a relatively mature stage of growth in early July. Different types of harvester were used to produce a long silage (L), single‐chopped (S), double‐chopped (D), medium precision‐chopped (MP) or a short precision‐chopped (SP) silage. The chop length of the silages averaged 37.4, 12.4, 8.4, 7.0 and 2.9 cm respectively. All silages were treated with formic acid at 2.51 t−1grass. They were well preserved and of a good quality with a dry‐matter (DM) digestibility of 720–760 g kg−1DM. The silages were fedad libitumto Suffolk crossbred store lambs over a period of 10 weeks. Each silage was fed either alone or was supplemented with whole barley at 400 g lamb−1d−1.When offered silage alone, intakes were 738, 679, 773, 980 and 910 (± 30) g DM d−1for silages L, S, D, MP and SP respectively. Similar relative differences in intakes between the silages were evident when supplemented with barley. Liveweight gain on silage alone was higher on the precision‐chopped silages (85–93 g d−1) than the long or flail‐chopped silages (28–49 g d−1). Liveweight gain on the precision‐chopped silages was also better when supplemented with barley (150 vs. 90–112 (± 90) g d−1). Silage intake and lamb performance were similar for the MP and SP silages, despite the difference in chop length.Barley supplementation reduced silage intake to a similar extent for all silages (‐9%) and increased total DM intake (+ 30%) and metabolizable energy intake (+ 37%). The substitution rates of silage for barley were similar for all silages and averaged 0.24 g silage DM g−lbarley DM. The response in weight gain per 100g of barley fed was similar for all silages and averaged 20.0 g liveweight gain and 13.4 g carcass gain. Feed conversion efficiency of the total diet was similar for the Mail‐chopped and precision‐chopped silages but was less for the long silage.The results of this study show that the benefit in weight gain due to the higher intake of precision‐chopped silage was maintained when the silage was supplemented with a moderate level of barley. Such silage required supplementation with barley (400 g d

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1996.tb02073.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractTwo experiments were established in 1989 and 1990 to evaluate the performance of white clover (Trifolium repens) varieties under grazing, using sheep and cattle, and also under a ‘cutting‐only’ regime. The three potential medium/large‐leaved varieties (AberVantage, AberCrown and AberDai) were selected and evaluated in a breeding programme that emphasized improving yield and persistency under grazing.In Experiment 1, the potential varieties were sown with two different grass companions, and evaluated under a continuous cattle‐grazing system, representative of their future role in actual farm practice, i.e. a set stocking system. Clover yield of the potential varieties in the second harvest year averaged 1–5 t ha−1more than the control variety Olwen. Total sward production of AberVantage, AberCrown and AberDai was 2.0–1.4 t ha−1higher than that of Olwen.In Experiment 2, clover yields of the three potential varieties averaged 2.1 t more than Olwen in the second harvest year under continuous sheep grazing, but all three were lower yielding than Olwen in the cutting regime.Both experiments illustrate how the use of grazing treatments during breeding and evaluation can improve the role of white

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1996.tb02074.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractA laboratory‐scale study was conducted to evaluate various methods of removing surface moisture from grass during forage harvesting. This moisture originates from dew or rain deposits, and contributes directly to the production of silage effluent. Measurements were made to determine the quantity of surface moisture on unharvested grass and the removal efficiency that centrifuging, shaking, squeezing and blowing treatments might be expected to achieve. The absolute quantity of surface moisture on the samples, which included four varieties, was estimated by blotting. The results indicated that tall fescue retained 53% more surface moisture when left in swaths during prolonged wet weather compared with unmown crop. When the wet standing crop was mown, the brush mower conditioner removed 57% of its surface moisture.Centrifuging and blowing to achieve aerodynamic dispersion of surface moisture were found to be more effective than shaking and squeezing, but estimations of the likely complexity, size and cost of field equipment showed them to be unrealistic options at the farm scale. Italian ryegrass was found to release surface moisture slightly more readily than perennial ryegrass, tall fescue or Yorkshire fo

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1996.tb02075.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThe phenology and some aspects of the biology of the clover weevilSitona lepidusGyll. were studied in the field and the laboratory. Oviposition and hatching were temperature dependent. Most eggs were laid in September and October, although there was also an oviposition period in early summer. Hatching was largely confined to late spring and early summer. The relevance of this to control strategies is discussed.Most eggs were laid on the plant but(were very easily dislodged and probably usually hatch on the ground. In no‐choice tests, there were as many eggs laid on more cyanogenic as on less cyanogenic plants and cultivars. There was no evidence that the cyanogenic ability or any other cultivar characteristic would be useful in control strategie

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1996.tb02076.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY