bluuebunny/crossref_metadata_2025 huggingface dataset:
Distribution, transformations and recovery of urinary sulphur and sources of plant-available soil sulphur in irrigated pasture soil–plant systems treated with35sulphur-labelled urine
Authors: Nguyen M. L. , Goh K. M.
Published: March 2009

A field plot experiment of 271 days duration was conducted on New Zealand irrigated pastures, commencing in the summer (January) 1988, on a Templeton silt loam soil (Udic Ustochrept) by applying35sulphur (35S)-labelled urine (250 μCi/g S with 1300 μg S/ml) to field plots (600 × 600 mm) at a rate equivalent to that normally occurring in sheep urine patches (150 ml/0·03 m2) to investigate the distribution, transformations and recovery of urinary S in pasture soil–plant systems and sources of plant-available soil S as influenced by the available soil moisture at the time of urine application and varying amounts of applied irrigation water. Results obtained showed thatc.55–90% of35S-labelled urine was incorporated into soil sulphate (SO42−), ester SO42− and carbon (C)-bonded S fractions within the major plant rooting zone (0–300 mm), as early as 27 days after urine application. Hydriodic acid (Hl)-reducible and C-bonded soil S fractions showed no consistent trend of incorporation. On day 271, labelled-S was found in soil SO42−, Hl-reducible S and C-bonded S fractions to a soil depth of 500 mm, indicating that not only SO42− but also organic S fractions from soils and35S-labelled urine were leached beyond the major rooting zone. A large proportion (c.59–75%) of35S-labelled urine was not recovered in pasture soil–plant systems over a 271-day period, presumably due to leaching losses beyond the 0–300 mm soil depth. This estimated leaching loss was comparable to that (75%) predicted using the S model developed by the New Zealand Ministry of Agriculture. The recovery of urinary S in soil–plant systems over a 271-day period was not affected by different amounts of irrigation water applied 7 days after urine application to soil at either 50 or 75% available water holding capacity (AWHC). However, significantly lower S recovery occurred when urinary S was applied to the soil at 25% AWHC than at field capacity, suggesting that urinary S applied at field capacity might not have sufficient time to be adsorbed by soil particles, enter soil micropores or be immobilized by soil micro-organisms. Both soil ester SO42− and calcium phosphate-extractable soil S in urine-treated soils were found to be major S sources for pasture S uptake. Labelled S from35S-labelled urine accounted forc.12–47% of total S in pasture herbage.
The effects of seed size, autumn nitrogen and plant population density on the response to delayed sowing in winter oil-seed rape (Brassica napus)
Authors: Mendham N. J. , Shipway P. A. , Scott R. K.
Published: March 2009

The aim of the experiments reported here was to investigate the possibility of minimizing yield losses due to late sowing by increasing leaf area and radiation interception during the pre-flowering period. The use of large seed did increase leaf area, radiation interception and crop weight at flowering. Normally this would be expected to lead to increased yield of late sowings, but hot, dry conditions severely affected all crops during seed growth. Applying fertilizer nitrogen in the seed bed boosted pre-flowering growth of early but not late sowings, probably because low temperatures prevented a response in the latter. Increasing plant population density did improve leaf cover and radiation interception until just before flowering, but leaf canopies in late-sown, low density crops were then able to expand more and function for longer owing to less shading by flowers and pods. Seed retention was improved and, even with as few as 8 plants/m3 in 1973–4, a worthwhile yield was still obtained.
The pH and nutrient status of agricultural soils in England and Wales 1969–83
Authors: Church B. M. , Skinner R. J.
Published: March 2009

A representative soil sampling survey of arable and grassland fields in England and Wales between 1969 and 1983 is described.

The results show that of the rotationally cropped area 29% was below pH 6·5, and of the continuous grassland 46% was below pH 6·0. Levels of P and K were satisfactory except that 15% of grassland soils were low for P.

Data obtained by re-sampling the same fields at intervals of 5 years show that changes in the proportions of crops grown at different levels of pH and nutrients have been small. There has been some increase in the proportion of continuous grassland at lower pH, but the proportions of soils with low P and K have tended to decrease.
Oestrus detection by mounts received in Friesian × Bunaji and Bunaji heifers
Authors: Johnson A. O. , Oni O. O.
Published: March 2009

Behavioural oestrus was studied using 32 Friesian × Bunaji and 29 Bunaji heifers standing for mounts by either vasectomized bulls or heifer herdmates. The study was conducted from 06.00 to 12.00 h and from 13.00 to 18.00 h local time for 96 days. All the 61 heifers showedoestrus. The mounts received by the heifers ranged from 68 to 170, being few between the first 24 days but increasing later. A total of 171 oestrous cycles were recorded, 85·4% of which had a mean oestrous cycle length (± S.E.) of 22·6 ± 0·9 days, while the average duration of oestrus (± S.E.) was 5·9 ± 0·2 h. Results showed significant differences between the mounts made by the teasers as well as mounts received by the heifer groups (both P = 0·01), but the teaser x heifer group interaction was not significant (P > 0·05). As all the heifers showed oestrus at least once, observation for oestrus between 06.00 and 18.00 hwould be reliable for supporting an artificial insemination scheme in the Guinea Savannah of Nigeria.
The dynamics of nitrogen uptake and its remobilization during the growth of sugar beet
Authors: Armstrong M. J. , Milford G. F. J. , Pocock T. O. , Last P. J. , Day W.
Published: March 2009

The uptake and distribution of N were examined in a series of sugar-beet crops grown on different sites (Broom's Barn, Suffolk and Trefloyne, Dyfed) or with 0 (No) or 125 kg N/ha (N125) between 1978 and 1982. Depletion of soil N was followed in some years. Initial rates of N uptake in spring for the N125 crops at Broom's Barn ranged from 2·3 kg/ha per day in 1980 to 5·8 kg/ha per day in 1981 and 1982 and at Trefloyne from 4·7 kg/ha per day in 1980 to 5·4 kg/ha per day in 1979. The initial phase of N uptake in No crops was shorter and at Broom's Barn the rate ranged from 1·6 kg/ha per day in 1979 to 5·1 kg/ha per day in 1982. Crops with high initial uptake rates had somewhat greater shoot N concentrations. There was no relation between the initial uptake rates or the total N uptake and the amounts of mineral N in the soil at the start of rapid growth in June. Simulations of early crop growth coupled with analysis of changes in the total N in the crop-plus-soil system showed that the rate of N uptake by the N125 crops was regulated by crop demand for N as determined by growth rate in 4 of the years and by soil supply in the 5th. The analysis of the crop-plus-soil N also showed that substantial losses of N occurred when the crop was actively growing in June and July in 1979 and 1980 due to excessive rainfall following early irrigations. There were serious consequences for N uptake, N concentration in developing leaves and the overall growth of these crops.

N uptake rates in autumn ranged from no net uptake in 1979 and 1980 to 0·6 kg/ha per day in the other 3 years at Broom's Barn and 1·0 kg/ha per day at Trefloyne. Large amounts of N were remobilized from the shoot to sustain the growth of the storage root in years when uptakes from the soil in autumn were small. Remobilized N represented 80, 50 and 30% of the net increase in storage-root N between the end of August and harvest in 1979, 1980 and 1981 respectively. The amounts remobilized from shoots ranged from 8 to 18 kg N/ha and may therefore also represent a source of amino-N impurities in harvested beet. An analysis of N in individual leaves showed that remobilized N probably originated from leaf protein and that remobilization started at full expansion rather than at the onset of leaf senescence, which was often many weeks later.
Statistical analysis of two-dimensional variation in variety yield trials
Authors: Kempton R. A. , Seraphin J. C. , Sword A. M.
Published: March 2009

Methods of adjustment for two-dimensional spatial heterogeneity of grain yield were investigated for 224 UK cereal trials. The methods used row and column ‘block’ analysis of plot yields and neighbour analysis based on first differences of plot yields. In 36% of trial analyses for block models and 30% for neighbour models the average variance of variety differences was reduced by more than 10% compared with the better of the one-dimensional row or column models. Compared with complete blocks, 2-D block analysis had a mean efficiency of 153% whereas the conventional 1-D block analysis (by rows) had a mean efficiency of 127%. Similarly, 2-D neighbour analysis had a mean efficiency of 159% whereas the 1-D analysis had a mean efficiency of 137%. Recently, general statistical methods have been developed for two-dimensional design and analysis; their wider use should lead to major gains in the precision of variety trials.
The course of fertilizer nitrogen uptake by rainfed sugarcane in Mauritius
Authors: Kwong K. F. Ng Kee , Deville J.
Published: March 2009

The patterns of N uptake and dry matter synthesis by sugarcane (Saccharum hybrid spp.) were studied at four locations in Mauritius with 15N–labelled ammonium sulphate (100 kg N/ha) applied either in a single dressing in September or in two split applications in September and the following February. More than 80% of the total N recovered at harvest (100–120 kgN/ha) was absorbed by the sugarcane during an active uptake period from October to January. Split application prolonged this active N uptake until April only and had no effect on dry matter accumulation. While total Nabsorbed by above-ground sugarcane showed no decline over time, 10–20 kg N/ha of the 15N–labelled N was lost from the green tops even when the N was applied on two occasions. The fertilizer N losses from above-ground sugarcane were, however, not evident when fertilizer N recovery with time was studied by the difference method. In view of the observed losses of fertilizer N from the aerial parts of sugarcane, measurement of fertilizer N recovery at harvest by the N isotope dilution technique underestimates fertilizer N uptake by sugarcane and attributes too large a fraction of N loss to denitrification/volatilization of NH3.
Changes in soil properties of a newly-cleared Ultisol due to establishment of hedgerow species in alley cropping systems
Authors: Hulugalle N. R. , Ndi J. N.
Published: March 2009

This study was initiated to evaluate the short-term (< 3 years) ability of some selected acid-soil adapted hedgerow species when planted in alley cropping systems to improve soil properties in a newly-cleared Ultisol (Typic Kandiudult) of southern Cameroon, 1990–92. The hedgerow species selected were Senna (Senna spectabilis), Flemingia (Flemingia congesta)and Acioa (Acioa barterii). A non-alley-cropped control was also included in the trial. The greatest quantities of prunings, and hence, mulch were produced by Senna and Flemingia. Exchangeable Ca, effective CEC and water infiltration were greatly increased in the alleys of plots where either Flemingia or Senna had been planted within 2·5 years of hedgerow establishment. The large amounts of mulch produced by Senna and Flemingia did, however, result in soil temperatures greater than those of the control or Acioa plotsc.1 year after application of the prunings as mulch. Root growth of Senna in the subsoil was significantly greater than that of either Acioa of Flemingia, but that of cassava was reduced by alley cropping with all three hedgerow species. Compared to the control or alley cropping with Acioa, maize and cassava yields were greater when alley cropped with either Flemingia or Senna hedgerows.
Comparison of meal and pellets for growing pigs fed either in troughs or off the floor
Authors: Braude R. , Rowell J. G.
Published: March 2009

A co-ordinated trial has been carried out with fattening pigs at nineteen centres to compare the effects of the following methods of preparing and presenting the feed: (1) meal fed in the trough; (2) cubes fed in the trough; (3) meal fed off the floor; (4) cubes fed off the floor.

Pigs fed meal off the floor had substantially worse growth rate and feed conversion than pigs on any of the other three treatments, probably because of feed wastage. With trough feeding, pigs fed cubes had slightly better growth rate and feed conversion than pigs fed meal. When the feed was given as cubes, there was little to choose between trough feeding and feeding off the floor. Faster growing pigs were slightly fatter and had slightly smaller eye muscles.
Critical concentrations of potassium in cotton (Gossypium hirsutum)
Authors: Singh D. , Brar M. S. , Brar A. S.
Published: March 2009

Potassium concentrations in various plant parts of cotton (Gossypium hirsutum L.) at different growth stages were determined in field experiments in Punjab, India, in 1987, for plots fertilized at sowing and flowering, and these were compared with the final seed cotton yield. The optimum time of sampling for predicting relative yield depends on the time of K fertilizer application: if applied at sowing, plants should be sampled before the peak flowering stage (70 days after sowing, DAS); if applied at flowering (50 DAS), plants should be sampled 90–115 DAS. Critical K concentrations (% K. in dry matter) in the plant parts measured at different growth stages were 3·26 in the petioles of the third leaf from the top at flower initiation; 0·69 and 0·90 in blades and petioles of a lower leaf (first or second healthy leaf from the bottom of plant) respectively, and 2·60 in the petioles of the third leaf (young, fully mature leaf from the top of the plant) at peak flowering stage; 0·85 in blades of the third leaf, 0·53 and 0·50 in blades and petioles of a lower leaf, respectively, at the boll development stage; 0·70 and 2·85 in blades and petioles of the third leaf and 0·68 in petioles of a lower leaf at boll opening stage.
Maternal undernutrition during mid-pregnancy in sheep: variable effects on placental growth
Authors: McCrabb G. J. , Egan A. R. , Hosking B. J.
Published: March 2009

The effect of maternal undernutrition between the 30th and 96th day of pregnancy on placental growth in single-bearing ewes was determined separately in two experiments in consecutive years (1986 and 1987) at Mount Derrimut Field Station, Deer Park, Australia. In the first experiment, placental growth measured on the 96th day of pregnancy was reduced (473 v. 596 g) by maternal undernutrition, while in the second, placental growth was increased (600 v. 496 g). Foetal weight and its linear dimensions on the 96th day of pregnancy were not significantly affected by maternal u dernutrition in either experiment. The only significant difference in the animals and experimental conditions between the two studies was the liveweight of the ewes at mating, which wasc. 10 kg higher in the second experiment compared with the first (P< 0·01). Body condition score and the change in condition score during the respective nutritional treatments were not significantly different between the two experiments. The results suggest that maternal liveweight, possibly body reserves not quantifiable by condition score, protects and even enhances placental growth during a period of maternal undernutrition.
The evaluation of potassium metaphosphate as a source of potassium for potatoes with special references to foliar diagnosis, yield and quality of tubers
Authors: Lachover D. , Feldhay Helena
Published: March 2009

1. The availability of K in potassium metaphosphate was investigated in an experiment with large pots using a red sandy soil, low in exchangeable potassium. Potatoes were grown. The effects of potassium metaphosphate in three different granule sizes, applied at two rates, were compared with those of equivalent potassium chloride and potassium sulphate.

2. Characteristic deficiency symptoms appeared in plants receiving no K and the crop responded to K fertilizer in potassium concentration, yields of tubers, and dry matter, and starch concentrations.

3. Potassium metaphosphate, regardless of granule size and of application rate, was as effective as potassium chloride and potassium sulphate in giving normal development of potato plants, high potassium uptake in the foliage, and yield of tubers.
Venison production from farmed deer
Authors: Barry T. N. , Wilson P. R.
Published: March 2009

Deer farming commenced in New Zealand (NZ) in 1969, and since then the number of farmed deer has progressively increased, to reach 1·3 million in 1993 (Game Industry Board (GIB), personal communication). These comprise 85% European red deer (Cervus elaphus), with the remainder being composed of elk (Cervus elaphus canadensis), elk/red deer crossbreds, fallow deer (Dama dama) and small numbers of other species. Initially, deer were obtained from the capture of feral animals, introduced to NZ over 100 years ago, but in the last 10 years the increase has come from breeding on deer farms. The industry has a strategic marketing plan to coordinate all sectors in order to maintain profitability. This plan has been implemented and financed by the GIB, through the collection of compulsory levies on venison and velvet sales. With the formation of the GIB in 1984, the NZ Deer industry has been strongly export market-led, and thus differs from the NZ sheep and cattle industries, which developed with a production driven philosophy. Key aspects of the market-led approach have been to produce and market venison which is consistently tender and of low fat content, and at the carcass weight range and times required by the markets.
Differentiation of the effects of protein status and acid-base balance on the appetite of sheep for lucerne silage
Authors: Phillip L. E. , Simpson M. V.
Published: March 2009

Five cross-bred Suffolk lambs (liveweight 24–29 kg) were fed lucerne silage and made acidotic or offered supplemental protein with the objective of determining the effects of acidosis and amino acid undersupply on food intake from silage. In this study, at McGill University, Quebec, Canada in January 1989, lucerne silage (25% DM) was supplemented with equimolar amounts (450 mmol/kg DM) of ammonium chloride, ammonium bicarbonate and sodium bicarbonate; fishmeal was added at 100 g/kg silage DM. The lambs were fedad libitumaccording to a 5 × 5 Latin square with 21-day periods.

Digestibility of organic matter (OM) from silage ranged from 78 to 82% and was not significantly affected by diet (P> 0·05). Voluntary intake of digestible organic matter (DOM) from silage was. Fishmeal supplementation of lucerne silage improved nitrogen retention (P> 0·05) but not intake of DOM. The addition of ammonium chloride to silage reduced blood concentration (p< 0·05) and urinary output of HCO3, increased ammonia excretion in urine (P< 0·05), and depressed intake of DOM (P< 0·05). Ammonium bicarbonate also reduced voluntary intake of DOM (P< 0·05) but had no significant effect (P> 0·05) on the acid-base status of the lambs. Sodium bicarbonate depressed food intake but had no significant effect on measures of acid-base balance.

The results suggest that metabolic acidosis is not an underlying mechanism restricting food intake by sheep and that neither acid-base imbalance nor inadequate protein status is likely to explain the limitation in food intake from ensiled lucerne.
Studies on ewe's milk:V. The effect of high cereal diets on ewes and on the yield of milk and milk constituents
Authors: Poulton S. G. , Ashton W. M.
Published: March 2009

Milk yields determined by a lamb-suckling and an oxytocin technique were compared using a control group of four ewes. Both methods showed a similar linear decrease in yield with advancing lactation, but the oxytocin method gave 23% more milk presumably because residual milk was included.

When the diet of lactating ewes was changed so that the amounts of hay and commercial concentrates were reduced in favour of flaked maize, such severe acidosis developed when 39·5% of this food was introduced abruptly or 53% more gradually over one week, that the trials were discontinued.

Rolled barley, which probably ferments more slowly, was therefore used instead of flaked maize. Levels up to 62·9%, gradually introduced over a period of 3 weeks, also produced acidosis whose severity varied greatly in individual ewes.

Milk yield was also determined by the oxytocin technique for ewes receiving normal diets followed by those rich in rolled barley, and the milk was analysed for fat, protein and lactose. The composition of the milk was extremely variable during rolled barley feeding, but there was an indication of an increase in the percentage of crude protein and also fat, after a marked fall in the latter in the milk of two ewes with the change to the low-fibre diet.

Diet had little effect on yields of milk and its components but, on the rolled barley diets, the rate of decrease of these yields was arrested (or even reversed in the case of fat), with a high degree of significance (milk yieldP< 0·05, fat yieldP <0·01, protein yieldP< 0·01). These observations are discussed, in the light of knowledge on the effect of diet on molar proportions of volatile fatty acids in the rumen.
The effect of plant population and irrigation on sugar beet
Authors: Harris P. M.
Published: March 2009

Four experiments are described in which the response of sugar beet to irrigation was measured over a range of approximately 30000–150000 plants per hectare, and one experiment where the effects of plant population and spatial arrangement were studied. The experiments were carried out on a sandy soil in the south-east of England and extended from 1960 to 1965. The response of sugar beet to irrigation was affected by plant density. It is suggested that some explanation for the modified responses may be provided by considering effects of plant population on (i) the rate at which the soil surface is covered by leaves, and (ii) effects on the volume of soil exploited for water.
The residual effect of phosphate and potash fertilizers applied to cut or grazed grassland
Authors: Brockman J. S. , Shaw P. G. , Wolton K. M.
Published: March 2009

P and K fertilizers were applied over a 5-year period to plots that were either cut, individually grazed or communally grazed. Residual effects were assessed in the sixth year when the sward was ploughed and sown with Italian ryegrass. The residual study supported the earlier published inference that (a) P returned to the sward in sheep dung is not an effective P source under field conditions, (b) communal grazing can lead to appreciable transfer of K from one plot to another.
The transport of potassium to ryegrass roots in soils with and without added potassium
Authors: Addiscott T. M. , Talibudeen O.
Published: March 2009

The mechanisms responsible for moving K from soil to root were studied by growing perennial ryegrass in pots containing a flinty silt loam from Rothamsted and a sandy Woburn soil, with and without added K, at 0.75 water-holding capacity. More water was taken up from the Rothamsted soil than from the Woburn soil, and less was taken up when K was added without affecting dry-matter production. After 25, 52, 83, 122, 194 and 276 days, K uptake, water uptake and the K concentration in the soil solution were measured and the mass-flow contributionto K uptake calculated.

Without added K, mass-flow accounted for only about one-sixth of the K taken up from the Rothamsted soil and about one-third from the Woburn soil. Except at first, diffusion probably accounted for the remainder of uptake but was the rate-controlling step for uptake from the Woburn soil only. With added K, mass-flow became much more important relative to diffusion in both soils, and transported more than enough K to account for the measured K uptake. Root interception probably did not contribute to K uptake after the early part of the experiment, because the pots used were small.
Polysaccharide synthesis and degradation by rumen micro-organismsin vitro
Authors: Thompson J. K. , Hobson P. N.
Published: March 2009

Micro-organisms from the rumen of a hay-fed sheep rapidly synthesized an intracellular polysaccharide (starch) when growing or resting suspensions of cells were incubatedin vitrowith easily metabolized sugars.

In 30 min incubation periods the optimum pH for the synthesis of starch by resting cultures was about 6·0 when glucose or fructose were substrates. Relative to glucose (as 100%) in ability to form the polysaccharide were, fructose, 75%; sucrose, 80%; soluble starch, 18·6%; maltose, 6·9%; cellobiose, 4%; and xylose, 2·1%. No starch was formed from galacturonic, acetic, propionic, butyric, lactic or succinic acids. A bacterial fraction of the microbes was reponsible for about 80% of the starch formed from glucose, fructose or sucrose.

In incubations of 24 h, resting cultures formed more starch per unit of microbial protein than growing cultures. The utilization of microbial starch and lactic acid, formation of which often accompanied starch synthesis, gave rise to volatile fatty acids. Acid production was maintained from these substrates at rates similar to those obtained from the fermentation of glucose. The acids were in molar proportions of 65–70% acetic, 20–27% propionic and 8–15% butyric. The maximum starch calculated to be synthesized by the microbes from 100 ml of rumen liquor, in media containing excess sugar, amounted to over 250 mg from glucose, 200 mg from fructose, 200 mg from cellobiose and 50 mg from xylose. It is calculated that under optimum conditions for synthesis about 25 g of starch would pass daily from the rumen of a sheep.
The development of some digestive enzymes in the intestines of pigs reared artificially
Authors: Campbell Rosa M. , Brough Helen , Fell B. F.
Published: March 2009

A comparison was made of the development of acid and alkaline phosphatase, invertase, lactase and leucine aminopeptidase specific activities in the small intestines of two groups of neonatal pigs. The groups consisted of two litters of suckling pigs and two litters of pigs that were delivered by hysterectomy and reared in incubators on a diet based on cow's milk. In the unsuckled pigs there was retardation of the development of invertase and leucine aminopeptidase. The unsuckled animals grew slowly and were affected by diarrhoea, and it is possible that enteric disease may have affected the development of the brush border of the intestinal epithelial cells, or enzymes specifically associated with the microvilli.
Potassium in soils under different cropping systems:2. The effects of cropping systems on the retention by the soils of added K not used by crops
Authors: Addiscott T. M. , Johnston A. E.
Published: March 2009

The K balance, the difference between K added as fertilizer or farmyard manure (FYM) and K removed by the crops, was calculated for soils from the Classical and Ley-Arable experiments at Rothamsted and for the Woburn Ley-Arable experiment, for the duration of each experiment. Linear regressions on K balance accounted for 78% of the variation in exchangeable K (Ke) and for 83% in K uptake by ryegrass (KP) in the Classical experiments, for 56 and60% respectively in the Ley-Arable experiments at Rothamsted, and for 39 and 6% in the Woburn Ley-Arable experiment.

Regressions of Ke and Kp on K balance suggested that, in the Rothamsted Ley-Arable experiments, rather more than half of the K balance remained extractable by ryegrass from the plots with a rotation of crops, and apparently all of the K balance from those under continuous grass. About one-fifth of the K balance remained extractable by ryegrass from the soils in the Rothamsted Classical experiments and soils given FYM retained K slightly better than other soils. With all soils about half the K extractable by ryegrass was exchangeable to ammonium acetate.

The plots with FYM or under continuous grass contain more organic matter than other plots in the same experiments. The following possible effects of increasing the organic matter content of the soils were investigated by calculating the multiple regressions of K, and KB on K balance with either percentage of organic C, total CEC, or organic CEC:

(1) loss of K decreased by increasing the water retention and lessening leaching;

(2) improved K retention by increasing the total cation exchange capacity (CEC) available for K absorption;

(3) improved K retention by a mechanism arising from the different selectivities of clay and organic matter for K relative to Ca.

In the Classical experiments, where organic matter usually increases because of FYM additions, effect (2) seems the most probable, perhaps because the K given in the FYM was already absorbed by organic exchange sites. In the Ley–Arable experiments, where the K was given mainly as soluble K fertilizer and the organic matter develops mainly under grass, effects (1) or (3) seemed to operate, probably simultaneously.

The Woburn Ley-Arable experiment had no continuous grass plots, the soils differed little in organic matter content and no deductions could be made.
Field drainage experiments and design on former opencast coal mining land
Authors: Scullion J. , Mohammed A. R. A.
Published: March 2009

A series of drainage trials was set up to investigate various aspects of drainage design on former opencast coal mining land. The drainage problem was characterized. Subsoiling, subsoiling direction with respect to slope and drain spacing were assessed as factors affecting drainage performance. The persistence of subsoiling effectiveness was also monitored. Drainage performances were evaluated statistically (Scullion, Mohammed & Ramshaw, 1986).

Surface wetness was the predominant feature of drainage conditions on opencast land and the effectiveness of drainage treatments was limited to the control of this superficial water. Secondary drainage, in this case subsoiling, was found to be an essential feature of field drainage, reducing surface wetness and runoff. The effectiveness of subsoiling was dependent on there being sufficient gradient (4–5%) along channels for intercepted water to clear. For this reason, adoption of appropriate minimum reinstatement gradients and the arrangement of field drains to accommodate preferred directions of secondary treatments would assist drainage effectiveness.

There was a gradual deterioration in drainage performance as spacing increased. Spacings in the range 20–30 m appeared to offer a reasonable compromise between cost and benefit. The persistence of subsoiling treatments, which deteriorated markedly after 2–4 years, was not affected by drain spacing. Performance at the widest spacings tested was, however, generally poor regardless of time since subsoiling.

A basis for calculating design rates on individual sites and the implications for drainage theory of soil air-water interactions are briefly considered.
The effects of energy intake during pregnancy in doe rabbits on pup birth weight, milk output and maternal body composition change in the ensuing lactation
Authors: Partridge G. G. , Daniels Y. , Fordyce R. A.
Published: March 2009

A study was made in rabbits on the effects of energy intake during pregnanoy on pup birth weight and survival, and on doe body composition and milk output in the ensuing lactation. In addition the experiment examined the effects of varying crudeprotein intakes during lactation on the rate of fat loss of does and the resultant energetic efficiency of milk production.

Forty-seven multiparous cross-bred does were used. They were offered one of two diets in pregnancy, either diet HE (14·8 MJ digestible energy (DE)/kg D.M.) to appetite or diet LE (12·9 MJ DE/kg D.M.) at maintenance levels. After parturition seven does on each treatment were slaughtered and their body composition analysed (control groups). In lactation the remaining does were evenly allocated to receive either diet LE (195 g crude protein (CP)/kg D.M.) or diet HP (240 g CP/kg D.M.) to appetite. Litter sizes were standardized to six pups and litter growth rates were used as an indirect estimate of milk production. Does were then killed, at random, on day 9 or day 18 of lactation to give an estimate of changes in body composition as lactation progressed.

Does offered diet HE during pregnancy had higher carcass fat levels at parturition than their counterparts offered diet LE (496 cf. 370 g/kg carcass D.M. respectively). Litter size was unaffected by dietary treatment during pregnancy but litter weights at birth were significantly greater in HE does (442 cf. 398 g respectively). Pup mortality at birth, however, was also much higher in these animals (28 cf. 9% respectively). Voluntary food intake in early lactation (day 1—9) was depressed by feeding diet HE during pregnanoy. Milk composition was affected by pregnancy diet, with does offered diet HE producing milk containing significantly higher fat levels (HE 123 g fat/kg milk cf. LE 105 g fat/kg milk).

Doe carcass composition changes revealed that fat was usually mobilized in early lactation and gained as lactation progressed independent of dietary treatment. The protein content of the fat-free dry matter appeared to be relatively unaffected by the dietary treatments imposed. The data were used to derive an estimate of the partial efficiency of dietary energy utilization (fc) for milk output and maternal tissue gain. The line of best fit was described by the equation ER = 0·65 (±0·17) MEI-1–25, where ER = milk energy output + carcass energy change and MEI = metabolizable energy intake in MJ.
Temperature-induced changes in cold tolerance of Lolium perenne
Authors: Eagles C. F.
Published: March 2009

Responses of cultivars of Lolium perenne with contrasting winter hardiness to hardening and dehardening at different temperatures were studied in controlled-environment experiments in 1984/85. After hardening at 2 °C, the hardy cultivars Premo and S23 had faster initial rates of change of LT50 (lethal temperature at which 50% of plants were killed), measured on seedlings in an artificial freezing test, and achieved a greater degree of cold tolerance than the susceptible cultivar Grasslands Ruanui. When acclimated at higher temperatures (4–10 °C), the hardier cultivars were better able to develop increased cold tolerance than Grasslands Ruanui. Plants of Premo and S23, previously hardened at 2 °C, maintained their cold tolerance when transferred to warmer temperatures (4–12 °C) better than Grasslands Ruanui, which dehardened even at 4 °C.

The responses of the cultivars to hardening and dehardening temperatures under controlled-environment conditions were reflected in seasonal changes in hardiness, measured as cold tolerance of tillers sampled during fluctuating temperatures of a typical maritime winter (1977/78) at Aberystwyth, UK.
Nutritional availability of amino acids from the rumen anaerobic fungusNeocallimastixsp. LM1 in sheep
Authors: Gulati S. K. , Ashes J. R. , Gordon G. L. R. , Connell P. J. , Rogers P. L.
Published: March 2009

The rumen anaerobic fungusNeocallimastixsp. LM1 was specifically labelled in batch culture with either [14C]lysine, [14C]lysine + [3H] tyrosine, [14C] methionine, or [35S] sulphide. Fractionation of acid hydrolysates of fungal biomass on an amino acid analyser showed that the labelled amino acids were directly incorporated into fungal protein with little or no degradation. [35S] Sulphide was incorporated into cysteine and methionine.

Absorption of amino acids from the small intestine was measured in sheep with permanent fistulae in the abomasum and terminal ileum, by introducing radiolabelled fungal biomass into the abomasum together with Cr-EDTA as the marker for digesta flow. The proportions of [14C] lysine (Expt 1), [14C] lysine + [3H] tyrosine (Expt 2), [14C] methionine (Expt 3) and the sulphur amino acids from [35S] sulphide (Expt 4) which appeared unabsorbed at the terminal ileum averaged 0·13, 0·07 + 0·08, 0·13 and 0·02, respectively. These proportions reflect the high digestibility of certain essential amino acids and the sulphur amino acids of fungal proteins. The results indicate that the true fractional digestibility of fungal proteins isc. 0·9. Consequently, a large biomass of anaerobic fungi in rumen digesta would be expected to provide a valuable source of digestible amino acids to ruminants.
Determination of optimum tuber planting density for production of tubers in processing ware grades in the potato variety Record
Authors: Wurr D. C. E. , Fellows J. R. , Sutherland R. A. , Allen E. J.
Published: March 2009

A series of experiments examining the influences of size and spacing of planted potato tubers (‘seed’ tubers) on tuber yields was conducted at four sites in the UK in 1982–84. A new approach to data analysis was used to estimate the optimum tuber planting density for different ware grades. The optimum density, which maximized returns, decreased with increasing seed tuber weight and ratio of seed-tuber cost to ware value and with lower than average total tuber yields. Changing the required ware grade from 40–65 mm to 40–80 mm had a minimal effect on the optimum tuber planting density.

Optimum tuber planting densities were lower than in published recommendations but this disparity appeared to be accounted for by differences in the number of stems produced by each planted tuber. There was some evidence that, with lower seed-tuber weights, the optimum planting density differed with site and that at optimum economic densities small and medium seed tubers outyielded large seed tubers.
Effects of the infusion of amino acids into the abomasum of sheep, with emphasis on the relative value of methionine, cysteine and homocysteine for wool growth
Authors: Reis P. J. , Tunks D. A. , Munro S. G.
Published: March 2009

Merino sheep were given abomasal infusions of various amino acids or mixtures of amino acids. Effects on wool growth were measured using autoradiography or a clipping procedure and changes in the concentration of amino acids in plasma were measured in some experiments.

Mixtures of five (28 g/day) or ten (45 g/day) essential amino acids (both mixtures containing 3 g methionine) stimulated wool growth of sheep receiving a maintenance ration; on average, the volume of wool grown increased 48% and 86%, respectively. When cysteine completely replaced methionine in these mixtures, wool growth was markedly reduced, but two-thirds of the methionine could be replaced by cysteine without affecting wool growth. Homocysteine was partially effective in replacing methionine and, when supplemented with betaine, folic acid and vitamin B12, the mixture was still significantly inferior to that containing methionine. In contrast, abomasal supplements of methionine or homocysteine alone were equivalent as supplements for wool growth. The results indicated a specific role for methionine in the control of wool growth, other than the provision of cysteine. This role was postulated to be related to some function of S-adenosylmethionine.

Infusion often essential amino acids caused appreciable increases in the concentrations of cystine, methionine, cystathionine and taurine in plasma; total essential amino acids increased threefold whereas nonessential amino acids decreased in concentration. The replacement of methionine in the infusion by cysteine or homocysteine significantly altered the concentration of cystine, methionine and cystathionine in plasma.

Evidence was obtained that the adverse effects on wool growth of high abomasal doses of methionine (10g/day) could not be reduced or prevented by provision of additional glycine and were not related to the supposed toxic effects of 3-methylthiopropionic acid, a metabolite of the transamination pathway.
Response of Brassica juncea to chlorocholine chloride and ethrel sprays in association with nitrogen application
Authors: Grewal H. S. , Kolar J. S.
Published: March 2009

Field studies conducted in 1983/84–1985/86 at Ludhiana showed that the response of physiological and yield characters of Brassica juncea to foliar sprays of chlorocholine chloride as cycocel (CCC) at 250 and 500 p.p.m. and ethrel at 500, 1000 and 1500 p.p.m. differed at different doses of N (O, 50 and 100 kg/ha). The crop did not respond to CCC or ethrel in the absence of N, whereas a significant response was obtained with 250 p.p.m. CCC or 500 p.p.m. ethrel at 50 kg N/ha and 500 p.p.m. CCC or 1000 p.p.m. ethrel at 100 kg N/ha. Response to increasing doses of N increased in the presence of CCC or ethrel spray. The highest concentration of ethrel (1500 p.p.m.) proved detrimental at 0 and N/ha. CCC and ethrel reduced the crop canopy, enhanced the chlorophyll content of leaves, interception of photosynthetically active radiation and sink capacity (number of pods per plant and 1000-seed weight) at 50 and 100 kg N/ha. A higher leaf area index was obtained during the pod development phase with CCC and ethrel sprays. The oil content and germination potential of seeds from crops treated with CCC (250 and 500 p.p.m.) and ethrel (500 and 1000 p.p.m.) were as high as in the untreated crop, irrespective of N dose. However, 1500 p.p.m. of ethrel sprayed on a crop raised without N suppressed germination capacity.
Source–sink relations and effects of post-anthesis canopy defoliation in wheat at low latitudes
Authors: Aggarwal P. K. , Fischer R. A. , Liboon S. P.
Published: March 2009

Source–sink balance was studied by imposing different canopy defoliation treatments on wheat crops grown in Los Banos (Philippines) in 1985/86 and 1986/87, Sonora (Mexico) in 1972/73 and 1974/75 and New Delhi (India) in 1987/88. The crops were grown in replicated trials with optimum cultural management. Six defoliation treatments were imposed at anthesis on all shoots in the canopy in an area ranging between 1·65 and 3·0 m2. Defoliation reduced dry weight in proportion to the reduction in percentage light interception. The number of grains per unit land area was reduced slightly, and in most cases not significantly, except when all leaves were removed. Despite reduction of leaf lamina area index to as low as 0·5, the decrease in grain yield was small. In particular, flag leaf removal led to a remarkably small reduction in grain yield. Grain nitrogen content in defoliated crops decreased much less than expected from the amount of N removed by defoliation. The slope of the relation between reduction in grain yield with defoliation and reduction in post-anthesis dry matter accumulation was 0·56, indicating moderate source limitation for grain filling. The crops at the hottest site, in the Philippines, were less limited by source than the other crops. It is suggested that selection for smaller flag leaves may be worthwhile for high-input wheat crops.
The chemical buffer system in raw and digested animal slurry
Authors: Sommer S. G. , Husted S.
Published: March 2009

Slurry pH is of great importance for the regulation of ammonia volatilization from livestock slurry, and therefore more knowledge of the buffer system controlling pH is urgently needed for modelling ammonia losses from stored and surface-applied slurry. The composition of 17 different Danish cattle, pig and biogas plant-digested slurries was studied. The results were used to describe the main buffer components in the slurries, and to discover the most important chemical components necessary for modelling slurry pH. The results showed that the pH of slurry was mainly controlled by the species NH4+/NH3, CO2/HCO3-/CO32-and CH3COOH/CH3COO-, and that ion pair formation did not change the ionic balance significantly. There were only trace amounts of Ca2+, Mg2+and inorganic phosphates in solution due to precipitation of CaCO3(calcite) and MgNH4PO4.6H2O (struvite). Measured electrical conductivities were found to be strongly correlated with the calculated ionic strength.
Factors affecting faecal endogenous phosphorus loss in the sheep
Authors: Scott D. , Rajaratne A. A. J. , Buchan W.
Published: March 2009

Sheep fitted with a ruminal and a duodenal cannula were used to study the effect of dry matter intake and the physical form of the diet on salivary P secretion and faecal endogenous P loss. At constant low P intake, changing the form of the diet had no effect on either parameter and while increasing dry matter intake did produce small changes in the partitioning of P excretion between urine and faeces it had no effect on overall endogenous P loss (faecal endogenous P + urine P) which was largely determined by P intake.
Effects of strategic feed supplementation during pregnancy on birthweight and perinatal survival of West African Dwarf kids
Authors: Osuagwuh A. I. A.
Published: March 2009

Varied quantities of concentrate supplement were fed to three groups of pregnant West African Dwarf (WAD) goats at different gestational periods, while forage was provided ad libitum throughout pregnancy. One group (A) was fed on concentrate at the rate of 50 g/kg metabolic weight (W0·75) per day throughout pregnancy, a second group (B) was offered concentrate from Days 61 to 120, and 121 to term at the rate of 50 g and 25 g/kg metabolic weight per day, respectively, and a third group (C) was provided with concentrate from Days 61 to 120 and 121 to term at the rate of 25 g and 50 g/kg metabolic weight per day, respectively.

Results showed that there were no abortions, although two animals from group A had dystocia (difficult birth). There was no significant difference between the mean birthweight and neonatal growth rates of kids from groups A and B. The mean birthweight and neonatal growth rates of the kids from group C were significantly (P < 0·01) lower than those of groups A and B. There was no significant (P >0·05) difference between the mean udder circumference of animals in group C and those in groups A and B. All the neonatal deaths were recorded among the kids in group C. It is concluded that for economic animal production although it may not be necessary to feed pregnant WAD goats on high concentrate rations throughout the gestational period, they should not be underfed between Days 61 and 120 of pregnancy.
Effect of soil water stress on water economy and oil composition in sunflower (Helianthus annuus L.)
Authors: Talha M. , Osman F.
Published: March 2009

In a field experiment sunflower plants were subjected to soil water stress (SWS) at — 15 bar during stages of slow elongation, rapid elongation, flowering and ripening.

Significant decreases in yield, 100-seed weight and oil content were found as a result of SWS. The treatment resulted too in less evapotranspiration and a better water economy for production of seeds and oil.

The iodine value but not the acid or saponification values of the oil was affected by SWS. No qualitative differences in oil composition occurred at different treatments. However, percentage of oleic acid was higher than that of linoleic acid; SWS resulted in a clear tendency for an increase in the ratio of oleic/linoleic acids especially for plants subjected to SWS during elongation stage.

Sunflower plants were more sensitive to SWS during the elongation and flowering stages than during ripening stage
Changes in the biochemical composition of herbage upon freezing and thawing
Authors: Macrae J. C. , Campbell D. R. , Eadie J.
Published: March 2009

Six herbage samples (ranging from poor quality hill herbages to high quality ryegrass and clover) were analysed for soluble carbohydrate, total and soluble nitrogen (N), cell-wall carbohydrates andin vitrodigestibility. Changes during freezing and thawing processes were measured. Invertase activity occurred in all frozen and thawed samples. Although the total N content of all samples remained constant throughout, the soluble-N contents of the four better quality herbages were considerably reduced on freezing and thawing. Cell-wall carbohydrates andin vitrodigestibility measurements were unaffected by freezing and thawing.