bluuebunny/crossref_metadata_2025_split huggingface dataset:
Slot‐seeding investigations. 5 The effects of simulated delayed emergence and propyzamide on the spread and growth of white clover in permanent pasture
Authors: WILLIAMS E.D. , HAYES M. J. 
Published: April 2006

AbstractThe effects of delayed emergence of white clover (cv. Grasslands Huia) seedlings, following slot‐seeding during spring and early summer 1983, were simulated by sowing seeds at intervals into slots cut in turves of permanent grassland in soil‐filled tanks or in the field. The resulting spread and growth of the species were assessed during the following 15–18 months. The effects of propyzamide, a grass‐suppressing herbicide (at 0·2 kg ha‐1), were also investigated in the field.A delay of 10 or 18 days in the sowing of seeds in turves in the tanks reduced clover dry weight yield from 23 to 11 during 1983 and from 118 to 96 g (0·12 m)‐2 during 1984. Spread of stolons from the slots was also greatly delayed and effects persisted for at least a year. Increased clover growth on the earliest sown treatment more than compensated for a slightly smaller yield of grass.In the field, yields of clover from late summer 1983 until spring 1984 closely reflected the order of emergence. Afterwards, differences were less clear‐cut but the cumulative yield of clover until August 1984 of the earliest‐sown treatment was twice that of a treatment sown 20 d later. Effects of delayed sowing in summer 1983 were more pronounced on stolons than on foliage growth when measured in September 1984, with significant reductions in many stolon attributes even with 8 d delay in sowing. Application of propyzamide in autumn 1983 increased clover yield during 1984 from 1·7 to 3·0 and total herbage yield from 7·1 to 8·6 t ha‐1.The results demonstrated some of the benefits of rapid seedling emergence and of the use of a grass‐suppressing herbicide, but did not indicate any interaction between the two factors.
The invertebrate fauna of grassland and its influence on productivity. II. Factors affecting the abundance and composition of the fauna
Authors: CURRY J. p. 
Published: April 2006

AbstractThe main factors affecting the abundance and composition of the invertebrate fauna in grassland are reviewed. Old grasslands with species‐rich swards and complex structure support an abundant and diverse fauna compared with uniform leys with few species. Seasonal and successional changes in the sward are accompanied by equally marked changes in the invertebrate community. Climate and weather have a major influence, but their effects may be modified locally by the availability of shelter. Soil physical and chemical characteristics influence the soil fauna directly and the above ground fauna indirectly through the vegetation. Food quality as determined by physical and chemical plant characteristics strongly influences invertebrate growth, reproduction and mortality. The main biotic factors affecting abundance are natural enemies and disease; these, in combination with weather and food quality, are often the main agents in determining population density in natural communities.Management practices such as grazing, cutting, fertilizer application, burning, soil water control and pesticide use profoundly influence the sward and induce correspondingly great changes in the invertebrate community.
The effects of weather and nutrition on the yield of hay from Palace Leas meadow hay plots, at Cockle Park Experimental Farm, over the period from 1897 to 1980
Authors: COLEMAN S. Y. , SHIEL R. S. , EVANS D. A. 
Published: April 2006

AbstractThe yield of hay on the Palace Leas meadow hay plots has increased significantly with time on the higher yielding plots but has remained constant on the lower yielding plots. Yield on the higher yielding plots shows a relatively low fluctuation from year to year, and yields of plots treated with farmyard manure show high intercorrelations with each other, but lower correlations with the other plots. Yield is influenced by weather, but even the most successful climatic parameter– maximum soil moisture deficit—only accounts for 30% of the year on year variation in yield. There are highly significant autocorrelations between yields within each of the farmyard manure, treated plots indicating cyclic effects with periods of up to 6 years, but these are not related to the cyclic patterns of manure application.
The introduction of red or white clover into a perennial grass sward
Authors: CURLL M. L. , GLEESON A. C. 
Published: April 2006

AbstractSowing and post‐sowing management techniques were assessed for their effectiveness in introducing Trifolium repens and T. pratense into an established Phalaris aquatica sward in spring and autumn.Percentage emergence, seedling survival, seedling weight and final clover content were greater with T. pratense than with T. repens. Surface sowing gave 10% emergence compared to 62% for tilled treatments. Rotary sowing gave superior emergence in autumn, while tined sowing gave superior emergence in spring. However, seedling survival and weight, and therefore final clover content, were generally greater with rotary sowing than with tined sowing.The removal of competition from the resident grass by bandspraying with glyphosate prior to sowing, and repeated lenient defoliation postsowing, increased final seedling numbers by 19% and 46%, respectively, and their individual weight by 29% and 82%, respectively.The results showed that direct sowing in spring or autumn can be used to restore successfully a substantial population of clover plants to an existing perennial grass sward. They also demonstrated the importance of management to manipulate the environment of the developing clover plant.
Effect of commercial inoculant and formic acid± formalin silage additives on silage fermentation and intake and on liveweight change of young cattle
Authors: HAIGH P. M. , APPLETONT M. , CLENCH S. F. 
Published: April 2006

AbstractData from six experiments conducted at two Agricultural Development and Advisory Service Experimental Husbandry Farms during 1980–83 were used to compare low dry matter (DM, 160 g kg‐1), low water soluble carbohydrate (WSC, 15 g kg‐1), non‐additive treated silage with silage treated with commercial inoculants or formic acid with or without added formalin (formic acid ± formalin). Formic acid ± formalin significantly decreased silage pH and ammonia‐N and significantly increased silage residual WSC compared with inoculant or untreated silage. Formic acid ± formalin significantly increased oven DM and significantly reduced DM loss during ensiling compared with untreated silage. Formic acid ± formalin treatment significantly increased both silage DM and total DM intake compared with untreated silage. Daily liveweight gains of cattle offered formic acid ± formalin were significantly higher than those given inoculant or untreated silage.It is suggested from the results that formic acid ± formalin additives can be used successfully to prevent a clostridial fermentation developing when crops contain 15 g WSC kg‐1.
Grazing effects on shoot and root dynamics and above‐ and below‐ground non‐structural carbohydrate in Caucasian bluestem
Authors: CHRISTIANSEN S , SVEJCAR T. 
Published: April 2006

AbstractThe objective of this study was to characterize changes in morphology and shoot/root total nonstructural carbohydrate (TNC) relationships in Caucasian bluestem (Bothriochloa caucasica) under grazing. Pastures were continuously grazed by steers weighing about 225 kg from mid‐May to late September of 1983 and 1984. Heavily grazed (H) swards produced more tillers m−1 than lightly grazed (L) swards. Number of tillers declined in both treatments during the midsummer drought period; however, the reduction was much less in H than in L swards. Above normal precipitation in August 1983 allowed number of tillers to rapidly recover (by approximately 4000 and 8000 m−1 for L and H treatments, respectively) reaching 10 700 and 17 800 tillers m−1 respectively, in late September. After 2 years of grazing, H swards initiated twice as many roots on an area basis; however, ability to penetrate soil to lower depths may have been reduced. Heavily grazed Caucasian bluestem had lower concentrations of total non‐structural carbohydrate (TNC) in shoots (P < 0.04) in both years, but had higher (28% at the end of 1984) TNC concentration in roots compared to lightly grazed (P= 001) plants. Greater root mass was found in lightly grazed swards; therefore, we suggest that root growth and TNC concentration tend to be inversely related. Total amount of TNC was higher in L swards, but during the course of the study total above and below‐ground TNC in H swards remained stable. Total above‐ground TNC pools are subject to short‐term variation and dilution from senescent herbage, thus TNC pools in individual plant parts may be a better indication of plant response.
Effects of fertilizer application to grasslands in Greece
Authors: PAPANASTASIS V. P. , KOUKOULAKIS P. H. 
Published: April 2006

AbstractGrasslands in Greece are composed of a large variety of plant species, but they have relatively low productivity due to their misuse by domestic animals for thousands of years, and also to soil and climatic factors. Fertilizer application can improve productivity by affecting herbage yield, botanical composition, earliness of spring growth and quality. The application of N and P generally alters species composition and increases dry matter and crude protein yields, while the addition of K is often not effective. Also, NP fertilizer increases the in vitro digestibility while N often decreases P, Ca, Mg and Zn contents of herbage. It appears that Greek grasslands cannot utilize as much N as their temperate counterparts and that their soils are usually deficient in P. This indicates that NP fertilizer is necessary to secure increased yields with P being important in achieving a balanced grass‐legume composition in the plant cover.
1986 survey of upland grassland in England and Wales: changes in age structure and botanical composition since 1970–72 in relation to grassland management and physical features
Authors: HOPKINS A. , WAINWRIGHT JOANNE , MURRAY P. J. , BOWLING P. J. , WEBB MORAG 
Published: April 2006

AbstractA sample of 10000 ha of grassland in seven upland districts originally surveyed in 1970–72 was re‐surveyed in 1986. Forty percent of the area was above 240 m elevation, 38% had gradients above 81/2°, 29% had poor or bad drainage and 54% was classified as having difficult or severe limitations to management. Twelve percent had been reseeded within the previous 5 years and 39% within 20 years; 6% was classified as arable grassland (in rotation with crops). Thirty‐four percent was usually mown, two‐thirds of it for silage. In most years 72% of grassland received fertilizer N (average application 123 kg N ha−1) and 35% received organic manure; nearly 20% received neither. Older swards tended to receive lower rates of fertilizer N than reseeds, hay fields and grazed fields less than silage fields, and fields on beef/sheep farms less than those on dairy farms. The proportion of sown species in swards averaged 35%, of which Lolium perenne accounted for 23%. A good contribution of Trifolium repens was recorded in 15% of the grassland. Herb species were recorded in 30% of the grassland, mostly in situations with low fertilizer N under hay or grazing. Agrostis spp., Poa spp., Holcus lanatus and Festuca rubra were the main unsown grasses. The average contribution of L. perenne had increased since 1970–72; it was also present in two‐thirds of the area from which it was absent in 1970–72, whilst the contribution of T. repens had decreased. The incidence of Cirsium arvense and Ranunculus spp. had also decreased, whilst that of Pteridium aquilinum had increased.
The utilization of N fertilizer, applied to perennial ryegrass/white clover pasture growing on a humus iron podzol in N.E. Scotland
Authors: RANGELEY ANNE 
Published: April 2006

AbstractApplications of N fertilizer (0.40, 80, 120 and 240 kg N ha−1 year−1 in dressings of 40 or 80 kg N ha−1) were made to a perennial ryegrass/white clover (Lolium perenne L. Trifolium repens L.) pasture growing on a humus iron podzol reclaimed from heather (Calluna vulgaris L.) moor in 1982 and 1983. Where no N was applied, estimates of Ni fixation and mineralization were almost equal, being approximately 50 kg N ha−1 year−1 from each source. Apparent efficiencies of fertilizer use were generally low; for each dressing they ranged between –0·7 and 25·5 kg dry matter (DM)kgN−1. Also, responses to N fertilizer were affected by previous dressings. The net N recovery in harvested herbage from application of 120 kg N ha−1 year−1 was 30 kg N ha−1 year−1.
Photosynthetic potential of ryegrass pastures when released from continuous stocking management
Authors: KING J. , SIM E. M. , BARTHRAM G. T. , GRANT S. A. , TORVELL L. 
Published: April 2006

AbstractThe relationship between the rate of canopy gross photosynthesis and LAI was investigated for ryegrass swards released from grazing after a period of continuous stocking to maintain the pasture at LAI 2–3. The regrowing swards were allowed to increase to about LAI 5 over a period of about 2 weeks while the rate of photosynthesis was measured and compared with that for continuously stocked swards maintained at LAI values between 2 and 6. Gross photosynthesis was found to increase more rapidly than LAI on the regrowing swards than on the steady‐state control pastures. However, this response appeared to be influenced by seasonal factors. The potential increase in net COi uptake was estimated to range from 0 to 22%. The response was attributed to an increasing proportion of young photosynthetically‐efficient leaves near the top of the canopy, modified by seasonal changes in the rate of tillering. The agronomic implications of the results are iscussed.
Seasonal variation in white clover content and nitrogen fixing (acetylene reducing) activity in a cut upland sward
Authors: MARRIOTT C. A. 
Published: April 2006

AbstractThe seasonal variation in herbage mass and nitrogen fixing (acetylene reducing) activity of white clover in an upland sward, cut weekly to 3·5 cm from mid‐May until mid‐October, was measured. Acetylene reducing activity (ARA) was measured over a 24‐h period at 3‐weekiy intervals starting on 3 March 1983. Clover leaf and Stalon biomass was measured by harvest of the assay truces, and from mid‐May quadrat euts to 3·5 cm above the soil surface provided estimates of herbage accumulation.Little A RA was detected in March, but activity increased substantially after 10 cm soil temperatures reached > 3°C, and peak activity per unit of clover leaf dry weight occurred in June and July; standing clover leaf dry matter increased during the season to a maximum of 60·5 g m−1 in June. Acetylene reducing activity was positively correlated with the number of rooted nodes, and Stalon and leaf dry weights in early spring. Thereafter, except during a period of summer drought, ARA was positively correlated with the amount of clover leaf material.Clover population density increased during the season and maximum growing point numbers (5540 m−1) occurred in September; maximum leaf number per unit area (12 984 m−1) was found in October, prior to the final cutting of the site.Results suggest that higher levels of nitrogen fixation in upland swards should be obtained if sward management regimes, which encourage a high clover leaf area, are adopted.
Digestibility of energy and gross energy intake in fresh pastures
Authors: OSORO K. , CEBRIAN MERCEDES 
Published: April 2006

AbstractSeveral experiments were performed in spring summer over the period 1982–85 to study the relationships between digestibility of energy (DE), gross energy intake (GEI), acid detergent fibre (ADF) and dry matter (DM) content in pasture.Wether sheep in metabolism pens and fed ad libitum with daily‐cut fresh pasture were used. Two plots with different botanical composition were used to provide herbage; one dominated by Lolium perenne and the other by Holcus lanatus. A high correlation (r= ‐0·91) was observed between DE and ADF. The prediction used a second‐order degree polynomial.Gross energy intake and digestibility of energy were scarcely correlated (r= 0·50) when all cases as a whole were considered. Higher correlations between GEI and DE (r= 0·69) were obtained when only data from pastures where Holcus lanatus prevailed were considered, and still higher (r= 0·91) in those pastures dominated by sown species with DE values lower than 70%.Herbage DM content had a large effect on GEI(r= 0·83) in the pastures dominated by perennial ryegrass with DE higher than 70%, the correlation between DE and GEI being low and negative (r=‐0·36). It is possible, therefore, to predict apparent digestibility of pasture energy from ADF. However, DE is closely related to GEI only in those pastures in which DE is lower than 70%, DM content being an important factor limiting the intake of those fresh pastures dominated by Perennial ryegrass when DE is above 70%.
The suitability of plant tissue tests to indicate phosphorus deficiency in perennial ryegrass (Lolium perenne L.)
Authors: RANGELEY ANNE 
Published: April 2006

AbstractThe phosphorus (P) status of perennial ryegrass was measured using three tissue tests. The results were compared with dry matter (DM) production from ryegrass, and levels of extractable soil P, taken from a fertilized non‐calcareous gley in a field experiment. Large errors were associated with the test values but it was possible to separate P deficiency from luxury uptake with tissue tests for total P and inorganic P (Pi) in leaves. The latter test is simple and merits further investigation.
Variation in HCN potential among cultivars of white clover (Trifolium repens)
Authors: WHEELER J. L. , VICKERY P. J. 
Published: April 2006

AbstractThe hydrogen cyanide potential (HCNp) of 17 cultivars of white clover were compared. With inadequate phosphorus supply, HCNp ranged from 24 mg kg DM−1 for cv Lucky to approximately 640 mg kg DM−1 for cv Huia and from 6 to 322 mg kg DM−1 for the same cultivars, with adequate phosphorus. The four North American cultivars examined had notably lower HCNp than all European or Australasian cultivars except cv Clarence.
An evaluation through lactating cattle of a bacterial inoculant as an additive for grass silage
Authors: GORDON F. J. 
Published: April 2006

AbstractThree silages were prepared from herbage treated with either an inoculant (Ecosyl, Imperial Chemical Industries plc) at 3.21 t−1, formic acid (850 g kg−1, Add F BP Chemicals International Ltd) at 2·3 1 t−1, or no additive (control). The herbage used was the first regrowth from perennial ryegrass swards. It was ensiled unwilted, and had mean dry matter and water soluble carbohydrate concentrations at ensiling of 154 and 24·1 g kg−1 respectively. Time course studies showed only minor effects of additive treatment on fermentation patterns within the silo and all three silages had good fermentations. Over an 88 d feeding period, commencing on day 7 of lactation, forty‐eight British Friesian cows were used to evaluate the silages in a three‐treatment, randomized‐block design experiment. The animals were stalled individually, offered the silages ad libitum, and in addition received 5 kg d−1 of a supplement containing 196 g kg−1 crude protein. On the basis of the data recorded during the final 28 d on treatment the animals receiving the inoculant‐treated silage consumed 12 and 10% more silage dry matter and produced 2·1 and 2·3 kg d−1 more milk than those given the control and formic acid‐treated silages respectively. Over the total experimental period the milk yields were 1957, 1894 and 2094 (±41·3) kg for animals receiving the control, formic acid‐ and inoculant‐treated silages respectively. Animals offered the formic acid treated silage produced milk of significantly higher fat concentration than those given the other two silages. Total ration digestibility studies, conducted with three cows per treatment, indicated no significant differences in digestibility coefficients, nitrogen utilization or metabolizable energy concentrations of the three treatment diets. It is concluded that the higher milk yield recorded with the inoculant‐treated silage, and the higher milk fat concentration with the formic acid‐treated silage, over that obtained with the control silage, were due to the increases in ME intake of 5 and 16 MJ d−1 for the formic acid and inoculant‐treated silages respectively.
Effect of seed crop management on potential seed yield of contrasting white clover varieties
Authors: HOLLINGTON P. A. , MARSHALL A. H. , HIDES D. H. 
Published: April 2006

AbstractAn experiment is described in which the effects of different spring managements on the potential seed yield and seed yield components of three white clover cultivars of contrasting leaf types were assessed. Cv. S184, the small‐leaved variety, produced more but smaller inflorescences than CVS Olwen, a large‐leaved variety, or Menna, a medium‐leaved variety. However, cv. Olwen, produced inflorescences with more florets, seeds per inflorescence and a higher seed yield per ten inflorescences than the other cultivars. Both potential seed yield and the individual yield components were influenced by management. Cv. Olwen produced more inflorescences and a higher potential seed yield under a cutting system than under grazing systems, which reduced the number and size of the inflorescences. Cvs S184 and Menna were less influenced by management system and performed similarly under cutting and grazing. The highly significant relationship between the number of ripe inflorescences and potential seed yield showed clearly that high seed yields are only achieved if the crop is harvested when the number of ripe inflorescences is at a maximum. The relatively short duration of the period of maximum ripe inflorescences emphasized the importance of determining the correct harvesting date, although weather conditions also play an important part in deciding when to harvest. Florets per inflorescence, seed set and 1000 seed weight remained relatively constant over the harvest period, and were not influenced by harvest date. The results are discussed in relation to the management of white clover seed crops and the importance of climatic conditions during seed production.