An experiment to study the effect of row direction on the light interception, growth and yield of three wheat cultivars sown at three different dates was conducted at Punjab Agricultural University, Ludhiana during rabi seasons 1982–3 and 1983–4. The results showed that sowing in a north-south direction resulted in 0·20 and 0·22 t/ha higher yield than sowing east-west. Bi-directional sowing gave further increases of 0·30 and 0·18 t/ha over north-south direction during 1982–3 and 1983–4 respectively. Late sowing significantly reduced yield.

Experiments made under dryland conditions in the post-monsoon period for 3 years showed that deep placement of N and P fertilizers at 12 or 18 cm led to better utilization than their shallow placement at 6 cm. Grain yield was maximal when the fertilizer was placed at 18 cm depth. The yield increase by deep fertilizer placement resulted from higher tiller survival till harvest. In these treatments water use efficiency and mineralizable N content in soil were higher.

Of the two varieties tested the taller cultivar (C 306) yielded more in normal years but lodging due to a severe storm in one of the years reduced its yield considerably. While the yield of the tall variety was not much affected by variations in row distances, the dwarf (DL 153–2) responded to these variations and greatest yield was obtained at a row distance of 27·5 cm.

The recovery of autumn-applied labelled fertilizer N in winter wheat and in the soil and roots was measured in five experiments on three soil types in eastern England. In four of the experiments, crop recoveries of fertilizer N ranged from 11 to 34 % in years when drainage during winter and early spring was close to, or less than, the long-term average of about 200 mm. Crop recovery was higher (42 %) at a site where the soil was heavier and winter drainage was less. Total recoveries (in crop and soil, 0–50 cm) ranged from 22 to 61 %. Fertilizer N was at least risk to leaching when there was a large soil moisture deficit at the time of application. There was a linear relationship between fertilizer N lost and drainage (but not rainfall) between the time of N application and the end of March of the following year. Autumn-applied fertilizer N increased grain yield slightly in two of the experiments and decreased it in a third.

Incidences of pollination and fertilization were determined and the development of seeds was monitored in spring beans over 2 years. Plant density was varied in the 1st year and irrigation in the 2nd. The incidences of pollination, fertilization and seed development were all independent of plant density. The proportion of ovules that developed as seeds was slightly enhanced in irrigated plots as losses from abortion and from lack of fertilization within fertilized ovaries were both reduced. Autofertility, or spontaneous self-pollination leading to fertilization, led to an increase in the overall incidence of fertilization. Three autofertile stocks were up to 11% more pollinated and fertilized than two partly autofertile ones which, in turn, were up to 20% more than two non-autofertile, long-podded stocks. A closed-flower population was 30% less fertilized than the long pods and was insufficiently autofertile to allow an adequate number of pods to set on the lower flowering nodes. Three stocks, one autofertile, one with terminal inflorescences (ti) and the third with both characters, were subject to particularly high losses of fertilized ovules from abortion, 27–35%, while few ovules, 12% or less, aborted in closed flowers and long pods. Failure of seeds to mature in long pods was associated primarily with the low proportion of ovules fertilized within fertilized flowers, rather than with abortion of the fertilized ovules.

The performance of different stocks of Scottish Blackface sheep and their crosses was compared on a harsh Scottish hill experimental farm. The strains were the Stanhope farm stock (a control flock, closed for 30 years), stock from local Breeders, and first crosses and back-crosses of Stanhope stock with stocks represented by rams purchased at Lanark market. Some 3892 ewe records were available with 1837 lamb performance records. Estimated effects for the three types of stock and of heterosis in the Stanhope and Lanark cross were derived statistically. The local Breeders' stock had the heaviest lambs at weaning and the Stanhope stock the lightest. The local Breeders' stock also had the heaviest ewes and higher litter size but had lower fertility and lower lamb survival. Output expressed relative to ewe weight was highest for the cross-bred stock. Heterosis was positive for all traits studied except survival but was statistically significant only for ewe weight and lamb birth weight. If the Stanhope stock was representative of Scottish Blackface sheep of 30 years ago, breeding by Scottish Blackface breeders has led to an estimated improvement of 9% in the output per ewe exposed, and 5% in efficiency of production.

Field experiments made for 2 years under semi-arid unirrigated conditions of north India examined the physiological factors affecting the growth and yield of sorghum when intercropped with groundnut (Arachis hypogaea), mung (Vigna radiata) or cow pea (V. unguiculata). Dry-matter production and leaf area index of sorghum were increased when intercropped with any of the legumes. The mixture advantage was reflected in delaying the senescence of sorghum leaves. Maximum grain and stover yields of sorghum were obtained in a mixture with mung or cow pea. The higher seed yield resulted from more seeds per panicle and greater panicle and 1000-grain weight.

Two potato genotypes, Kufri Sindhuri (KS) and Kufri Chandramukhi (KC), were grown in association with sugarcane (cv. Co 1148) at 1:1 (SP) and 1:2 (SPP) sugarcane (S): potato (P)row arrangements. Growth behaviour and yield of both crops in companionship were compared with those of their sole cropping. Initially, KC accumulated more dry matter in tubers than KS. At harvest, the contribution of tubers to total dry matter was the same in both genotypes. However, KS produced significantly higher absolute tuber yields than KC. Potato row arrangements in sugarcane did not significantly affect the proportion of dry matter in different plant components. However, SPP gave significantly higher tuber yields than SP and was the same as with sole potatoes. Drymatter accumulation, canopy development and yield of sugarcane were not affected significantly by potato row arrangements in the companion cropping system. Sugarcane was unaffected by KC in companion cropping but KS exerted an adverse effect on all the growth characters and yield of sugarcane. Similarly, in sequential cropping, sugarcane yielded significantly less when planted after KS than after KC.

Energy budgets and estimates of forage intake requirements were developed for adult camels, cattle, sheep, and goats managed by nomads in the arid Turkana District of north-western Kenya. The estimates were developed by combining our field data on livestock activity patterns, diet quality, weight changes and milk yields with literature based estimates of the associated costs and efficiencies. On an annual basis, the average animal walked 17 km/day and had a total metabolizable energy (ME) allocation of 47% for basal metabolism, 16% for travel, 14% for other activities, and 23% for production. Season and species influenced patterns of energy demand and allocation. Average daily ME requirements ranged from 8·7 MJ (sheep) to 76·7 MJ (camels). ME demand for all species peaked during wet (April-May) or early-to mid-dry periods (June-October), and decreased considerably in the late-dry season (November-March). In the wet season the average sheep or goat allocated 45% of its ME budget to production of milk and gain, followed by cattle (36%) and camels (25%). All species were more similar in ME allocation for production during the late-dry season (7–13%; all to lactation), yet patterns of weight loss during this time indicated that camels experienced the lowest degree of negative energy balance. On an annual basis, camel budgets were the most deviant, as they allocated relatively more ME to activity and relatively less to basal metabolism or weight gain. Estimates of forage dry-matter intakes (per unit live weight per day) ranged from 3·8% (cattle, camels) to 4·6% (sheep, goats) throughout the year, and intakes declined for most species by an average of 50% from the wet to late-dry intervals. This approach has revealed ecological differences among livestock species that help explain the utility of multi-species holdings in this system.

Intercropped with legumes, sorghum removed more N from the growing medium than when grown alone. 16N data showed that out of the total N removed by sorghum in a sorghum + mung mixture 18·1% was derived from the fertilizer urea and 81·9% came from the soil pool; the latter included 21·9 % N derived from current fixation by the legumes. When grown alone sorghum plants derived 18·6 % N from urea and 81·4 % from the soil.

The yield of wheat grown in sequence was 5·13 t/ha after a previous sole crop of mung and 3·47 t/ha after sorghum. The yield of wheat after sole crops of legume was greater than after their mixture with sorghum. The latter was, however, greater than its yield after sole sorghum.

The economic optimum rate of N required after wheat, computed from an experiment with several rates of applied N on an adjacent plot, was 124 and 105 kg N/ha at expected yields of 5·2 and 4·5 t/ha of wheat respectively. By interpolation the relative yield advantage from sole legumes ranged between 28 and 68 kg N/ha in 1982–3 and was more than 90 kg N/ha in the next year. These advantages from legume + non-legume mixtures equalled 12–17 kg N/ha applied to wheat, in addition to 50 kg N/ha applied uniformly to the sequential crop of wheat.

Pedigree analyses were conducted of the Portland, Manx Loghtan and Hebridean sheep. These breeds are kept in small flocks, usually with only one ram active. Total population, and number of flocks have grown since registration started in 1975. Gene flow among flocks arisesfrom transfers of rams and of ewes: about 70% of breeding rams and 40% of breeding ewes have been transferred. Between half and three-quarters of the 1984 lamb crop were measurably inbred. More ram lambs are registered than would be expected in commercial practice.

About a third of flocks supplied rams to other flocks showing that these breeds do not have a very hierarchical structure. There is, however, a tendency towards hierarchical structure in the Manx Loghtan. A high proportion of the animals registered as foundation stocks in the earlyyears of the Combined Flock Book were represented in the pedigrees of recent lamb crops, i.e. genetic conservation has, on the whole, been achieved.

The ability of mepiquat chloride and chlormequat growth retardants to modify grain yield components and stem length in two contrasting spring barley cultivars was evaluated in 2 years of small scale field experiments in central southern England. Interactions with plant population density and sowing date were studied.

The mid-tall cv. Koru was more responsive than the shorter high tillering ‘erectoides’ cv. Goldmarker. Early treatments of mepiquat chloride (applied before the start of main shoot stem elongation) on Koru raised grain yield/plant in both years. Early treatments with chlormequat and later applications (during main shoot stem elongation) of either retardant were largely ineffective. Yield increases were achieved by raising the number of spikes/plant along with the number of grains/spike and the above-ground biomass in certain later-formed, lower ranking shoots.

A medium plant population density (250 plants/m2) allowed the best response to early treatment with mepiquat chloride, as did a normally-timed sowing in contrast to a late one. Retardant-induced improvements in yield components in Koru were positively correlated with plant height, the result of over-compensation in the length of upper internodes.

It appears that effective treatments reduced the dominance of the main shoot during tillering, allowing greater initiation and survival of florets (grain sites) in smaller shoots.

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.

Acremonium loliae is an endophytic fungus which infects plants of perennial ryegrass (Lolium perenne), an important pasture grass in New Zealand and much of Western Europe. In New Zealand the endophyte–ryegrass association was found recently to give rise to tremorgenic substances (lolitrem A and B), which are the cause of a serious disorder of grazing and domestic livestock there. The endophyte also confers resistance in ryegrass plants to certain insect pests in New Zealand and enhances plant growth even in the absence of pests. In the present work 61 swards at 52 widespread sites in the U.K. were checked for the presence of endophyte mycelium, and it was found in 14 swards, of which 12 were at least 15 years old. ELISA (enzyme-linked immunosorbent assay) tests confirmed that the fungus was A. loliae. Also, lolitrem B was detected in plants from most of the sites where the mycelium was found; this appears to be the first time this tremorgen has been reported in the U.K. or perhaps in Europe. In a small-plot experiment at two sites with newly sown perennial ryegrass the endophyte appeared to have no effect on infestation by frit fly larvae, a major pest of seedling ryegrass plants. Also, in the present work, the endophyte had no measurable effect on the growth or overwinter mortality of larvae.

Forty-nine and 58 Damascus goats were used in each of two trials, respectively. Goats were randomly allocated 2 days post-partum to twin-suckling (TS), singlesuckling (SS) and no-suckling (NS) kids treatments. In trial 1, artificially reared kids were divided into two groups fed either on ewe-milk (25·8% fat, 24·2% protein) or on calf-milk (15% fat, 22·5% protein) replacer. In trial 2, all artificially reared kids were fed on ewe-milk replacer. The ewe- and calf-milk replacers were reconstituted in the ratio of 1 part powder to 5 or 4 parts (by weight) of water, respectively.

Separation of kids from their dams reduced total milk yield (means of two trials) until weaning (TS 194, SS 176, NS 121 kg/goat) and from weaning to 90 days of lactation (TS 95, SS 89, NS 70 kg/goat). On the other hand, separation of kids increased marketable milk yield until weaning (TS 68, SS 99, NS 121 kg/goat). Marketable milk during the period 3–90 days post-partum was similar for NS and SS goats (TS 163, SS 188, NS 191 kg/goat). Goats suckling two kids suffered greater weight losses (TS 78, SS 44, NS 6 g/day). Goats suckling two males produced more milk until weaning than all other twin sets. Differences in concentrate intake between group means of TS and SS were smaller compared with the NS group (TS 2·26, SS 2·08, NS 1·86 kg/goat per day).

There were no differences in weaning weight and weight gain from birth to weaning between kids reared on milk replacers. However, four kids on the calf-milk replacer died and two more were excluded from the data because of severe scouring. Single suckling kids gained more weight until weaning than TS and those reared artificially (AR) on ewe-milk replacer (SS 11·1, TS 9·1, AR 9·3 kg/kid). Furthermore, males consumed more milk than females (males 74, females 64 kg/kid) and SS more than TS kids (SS 75, TS 63 kg/kid).

It is concluded that SS and NS treatments increase commercial milk yields compared with the TS goats, but NS should not be recommended because of an adverse effect on pre- and post-weaning lactation performance.

A field experiment on an acid soil of Shillong, in 1982 and 1983, investigated the comparative performance of Mussoorie rockphosphate (MRP), single superphosphate (SSP) and their combinations for potatoes. MRP, when applied alone, proved much inferior to SSP, on an equal P basis, in tuber characters, tuber yield and nutrients (N, P and K) uptake. Application of SSP together with MRP improved the efficiency of the latter. SSP and MRP combinations in 25:75, 50:50 and 75:25 proportions, on a P basis, were 79·3, 95·8 and 101·2% as effective as SSP in terms of tuber production. The response to P was optimum at 70 kg P/ha with SSP and was linear up to the highest rate (105 kg P/ha) with the combinations of SSP and MRP. Concentration of N in tubers declined with the increasing amounts of P, whereas P and K concentrations were little affected.

Eight forage rape cultivars were grown in replicated trials in 1980, 1981 and 1982; the plots were either inoculated to promote early infection with powdery mildew (Erysiphe cruciferarum) or they received one application of fiuotrimazole (in 1980) or triadimefon (in 1981 and 1982) to control mildew.

Mildew infections first appeared during August and increased rapidly during September to give highly significant differences between cultivars for the percentage leaf area infected in October; cv. Lair had the least mildew and cvs Samo, Early Giant, Bishop and Winfred were most severely infected. Regression analyses were used to investigate the increase in mildew over time in 1980 and 1981. No clear pattern of disease development was evident in 1980, but in 1981 the increase in mildew was predominantly linear and in untreated plots the greatest increase occurred in cvs Winfred, Samo and Bishop and the least in cv. Lair. Mildew was reduced in each year (P < 0·001) on fungicide treated plots and the mean fresh weight yield increase of 4·61 t/ha from treated plots was attributed mainly to the control of E. cruciferarum.

Fungicide treatment had little effect on % organic matter (OM), % digestible organic matter (DOMD) or concentration of thiocyanate ion (SCN-); both % nitrogen (N) and concentration of S-methyl cysteine sulphoxide (SMCO) were reduced in fungicide-treated plots in 1981, and N was also reduced in 1982. The mean concentration of SCN- from treated and untreated plots over 3 years was least in cv. Samo (14·90 mg/100 g D.M.) and greatest in cv. Lair (22·15 mg/100 g D.M.). The response in yield and quality factors to fungicide treatment is discussed in relation to the control of powdery mildew and other, possibly phytotonic, effects.

Winter wheat cv. Avalon was sown in autumn 1981, 1982 and 1983 on a clay loam soil following two cereal crops. Multifactorial experiments tested the effects of combinations of the following eight factors, each at two levels: rotation, sowing date, timing of nitrogen, amount of nitrogen, growth regulator, pesticide, spring fungicide and summer fungicide.

The best 16-plot mean grain yields in 1982–4 were respectively 8·7, 10·2 and 11·1 t/ha. Rotation had the largest effect on grain yield. Wheat following barley was severely infected with take-all and yielded, on average over 3 years, 2·2 t/ha less than wheat following oats. Take-all was more severe on wheat sown in mid-September than in mid-October; its effects on yield were lessened by early timing of N in 1982. Take-all decreased growth and N uptake mainly after anthesis, and also number of ears and dry weight per grain. Sowing in mid-September compared with mid-October decreased yield of wheat after barley by an average of 0·8 t/ha because take-all was more severe. Early sowing had negligible effects on grain yield of wheat after oats, but increased straw dry weight by 1·1 t/ha.

Spring fungioide increased yield by an average of 0·3 t/ha. Effects were larger after barley than after oats, associated with a greater incidence of eyespot after barley. Summer fungioide increased yield by an average of 0·3 t/ha. Foliar diseases were slight in all 3 years. Fusarium ear blight and sharp eyespot were prevalent in 1982 and were not well controlled by the fungioide treatments. Fungicide temporarily decreased the incidence of some components of the mioroflora on the ears. Pesticide increased grain yield of wheat after oats only in 1984, when aphids on the ears were numerous. Aphids were present on early-sown plots in all three autumns but there was little barley yellow dwarf virus infection even without pesticide. Pesticide always decreased the number of nematodes after harvest to fewer than present before sowing. Populations never approached levels expected to affect yield.

Early N application (main application early March) resulted in a larger grain yield in 1982 than N applied a month later. In 1983 and 1984 grain yield and N uptake by the grain were greater with the late application, especially when wheat was sown early. The soil contained more mineral N in the autumn of 1982 and 1983 than in 1981. Straw weight was always greater with early than with late application. Increasing the amount of N applied from 163 to 223 kg/ha increased N uptake by 40 kg/ha and grain yield by 0·5 t/ha after oats and by 0·6 t/ha after barley. N uptake in grain plus straw by the best yielding crops ranged from 205 kg/ha in 1982 to 246 kg/ha in 1984.

Chlormequat applied at the start of stem extension shortened the stems at maturity by 2 cm each year. In 1984 it inoreased yield of early-sown wheat by 0·3 t/ha and also decreased lodging, which did not occur in the first 2 years.

The utility of spraying some Na-fixing micro-organisms on rice (cv. Masuri and IR-26) and wheat (cv. Sonalika) leaves grown both in N2-less sand culture and under field conditions was examined. All the growth variables studied, including dry weight, chlorophyll content and N content of plants, were enhanced appreciably in N-less sand culture and under field conditions. The yield of rice cv. IR-26 per unit area was more than doubled or nearly so with Pseudomonas azotocolUgans, Ps. azotogensis, Klebsiella pneumoniae KUPBR2, K. pneumoniae KUP4, KUP6D, KUP7D, Azospirillum brasilense, Xanthobacter fiavus and K. rubiacearum. When rice cv. Masuri was used the grain weight was doubled by A. brasilense, Ps. azotocolUgans, Ps. azotogensis, KUPBR2, and KUP6D. Grain N content was increased appreciably in mostcases. The organisms also reduced acetylene to ethylene in the phyllosphere. In wheat cv. Sonalika grown in N-less sand culture, KUP4, KUPBR2, Ps. azotocolligans, A. brasilense, X. flavus, and KUP6D each doubled the N content of plants. Under field conditions Ps. azotocolligans gave the highest grain yield although grain yield was doubled by a large number of strains. N content of grains was also increased appreciably, the best result being given by KUP4.

From a mixed group of cross-bred steers slaughtered at the same age, up to 12 carcasses of similar weight from each of the five conformation classes were chosen using the European Economic Community (EEC) scale for the classification of carcasses of adult bovine animals. In the hindquarter of carcasses with better conformation the ratio of muscle to bone was higher with less internal fat and more subcutaneous fat, muscles were heavier and blockier, both the carcass and leg length were shorter. Short-thick muscles were associated with short-thick bones. The results indicate that the EEC scale is a useful method to discriminate between carcasses differing in composition. It is suggested that differences in muscle: bone ratio in cattle could reflect differences in the structure and shape of bones. The conclusions remain tentative until they are confirmed on a larger number of carcasses.

The recovery in the faeces of the n-alkanes of herbage (odd-chain, C27–C35) and of dosed artificial alkanes (even-chain, C28 and C32) was studied in twelve 4-month-old castrated male lambs. The lambs received three levels of cut, fresh perennial ryegrass or a mixed diet of perennial ryegrass (0·70) and a barley-based concentrate (0·30) (500–900 g D.M./day). C28 and C32 n-alkanes (130 mg each), absorbed onto shredded paper, were given once daily for 17 days to test whether the recoveries of herbage and dosed alkanes were similar to enable their use as markers for determining the herbage intake of grazing sheep. Stearic and palmitic acids (130 mg each) were given with the dosed alkanes to half of the animals with the objective of facilitating emulsification of the dosed alkanes within the digestive tract.

With the exception of C27 n-alkane, the faecal recoveries of all alkanes were unaffected by diet, feeding level or emulsifying agent. Faecal recovery of odd- chain herbage n-alkanes increased with increasing C-chain length. The recovery of the dosed C28 n-alkane was slightly greater than the recoveries of both C27, and C29 n-alkanes of herbage. The recoveries of the dosed C32 n-alkane and the herbage C33-alkane were the same.

The mean herbage intake estimated using C33 and C32 n-alkanes was identical to the actual herbage intake. Other alkane pairs gave slight underestimates of herbage intake ranging from 3·5% for the C28–C29 pair to 7·6% for the C27–C28 pair. No cyclical pattern of n-alkane excretion throughout the day was observed. Examination of daily variations in faecal alkane concentrations indicated that the start of alkane dosing should precede the sampling of faeces by at least 6 days.

These results suggest that accurate estimation of herbage intake in grazing sheep is possible from the simultaneous use of dosed C32 and herbage C33 n-alkanes as markers.

The method may be particularly useful in enabling unbiased estimates of herbage intake to be made in animals receiving supplementary feed.