Between 1980 and 1986, six field experiments were conducted to investigate the relations between planting density, total dry matter and pod yield of groundnut (Arachis hypogaea L. cv. TMV2) grown at different levels of irrigation and rainfall at two sites in central India. In general, the relationship between total dry matter and planting density for most treatments was well described by the function:

where W is the crop dry weight per unit ground area, wm is the maximum weight per plant, Wm is the maximum crop weight per unit ground area and P is the plant population. Because the harvest index, h, was constant for each treatment irrespective of plant population, a similar equation described the relationship between pod yield and planting density. When nine of the eleven treatments planted in a square (i.e. 1:1) arrangement were compared, the asymptotic value Wm varied between treatments depending on available soil water and atmospheric demand. To quantify the effects of plant and environmental factors on crop productivity, a ‘transpiration equivalent’ (ωw; (g/kg)/kPa), i.e. the product of the dry matter/water ratio and mean seasonal saturation deficit D, was used as a crop constant to calculate productivity at each site or season from a knowledge of seasonal rainfall and/or irrigation and soil water-holding capacity. Thus, total crop productivity, W'8, was calculated using the equation W'8 = ωwS/D where S (mm) is a soil supply term dependent on soil water-holding capacity and monthly values of rainfall and/or irrigation. When values for Wm and W'8 were plotted against each other, a linear regression was obtained with a slope = 1·02 (R2 = 0·78). The mean harvest index of 0·38 was used to predict pod yield from a knowledge of W'8. It was concluded that of all the climatic, soil and management factors that influence crop growth in semi-arid situations, it is the interaction between the supply of and demand for water that ultimately determines total productivity, pod yield and optimum plant population.

Dried spent hops possess a high absorptive capacity, and attention is drawn to its use as a “filler” to absorb such by-products as molasses and treacle.

The material possesses a high crude protein value and its ether extract is very high for a fibrous food, while the amount of crude fibre is the same as in good meadow hay. There is a high percentage of mineral matter present.

The digestibility of the material has been determined by feeding with hay chaff and linseed cake meal to three sheep. The spent hops were not readily eaten and could only be included in a ration in an amount equal to one-seventh of the dry weight of the total ration.

Its digestibility is low, a fifth of the crude protein and the nitrogenfree extractives, one-half of the ether extract, one-twentieth of the crude fibre and one-fifth of the total organic matter only being digestible. The production starch equivalent was 24.5.

1. A group of six lactating ewes, rotationally grazed a low-nitrogen treated plot (40 lb nitrogen applied in early March) and a similar group a highnitrogen treated plot (1001b nitrogen applied in early March and 60 lb at monthly intervals thereafter, all as Nitro-chalk) from mid-April to early July, and the concentrations of serum magnesium and calcium along with food intake and milk yields of the ewes were studied.

Diurnal variations in microbial protein nitrogen, total volatile fatty acids and ammonia were examined in two wethers fed once and twice daily with 0·4 kg of concentrateand 0·4 kg hay/day. The total protein nitrogen varied during the day from 76·9 to 130·2 mg/100 ml of rumen fluid. The greatest amount of protein nitrogen was noted immediately before feeding and the smallest 4 h after feeding. The protein nitrogen of rumen protozoa formed about 39·8–53·4% of total protein nitrogen in rumen fluid. Volatile fatty acids varied from 74·0 to 130·5 m-mol/1 of rumen fluid and ammonia from 187·0 to 305·6 mg/1. The higher concentration of total and protozoal protein nitrogen and of VFA was observed when animals were fed twice daily. The changing of feeding frequency from once to twice daily caused an increase of ammonia concentration in the rumen of only one wether. The results obtained are discussed.

Between March and August 1968 to 1970, Chlormadinone acetate (CAP), 10 mg/head/ day, was administered to 668 Zebu cows and heifers for oestrous cycle synchronization for 14, 12, or 9 days, the latter schedule supported by an injection of 5 mg estradiol valerate on day 2 to achieve luteolysis. Applied orally over a period of 14 days, CAP provided a reliable method for cycle synchronization. The severe anoestrous rate experienced in all herds reduced the overall percentage of synchronized animals. Fertility from insemination during the first synchronization period (day 2 to 10 after treatment) was slightly, yet insignificantly reduced, but was completely restored during the second synchronization period (day 20–30). Insemination only during this second synchronization period resulted in conception and pregnancy rates similar to those combined from the first and second synchronization period.

Of factors tested for influencing synchronization and fertility, presence or absence of penis-deviated teaser bulls (psycho-stimulation) had no effect on the percentage of animals synchronized, or on post-treatment fertility. In well-managed herds, the percentage of animals responding to treatment was predetermined by the number of animals already cycling, reflecting their phase of reproductive life. Levels of management had an important impact on the success of cycle synchronization combined with artificial insemination. Both methods are managerial tools for improvement of already good management. Their failure under insufficient management conditions has diagnostic value.

Possibilities and limits shown for oestrous cycle synchronization in Zebu cattle were similar to those reported in European cattle. Within these limits, CAP can be employed successfully as a means for cycle synchronization, providing sufficient synchronization and acceptable fertility and allowing economical use of artificial insemination.

Two calves (Aberdeen Angus and American Brahman) were used exposed to different combinations of wet- and dry-bulb temperatures in a psychromatric chamber at the Physiology Department of the University of Queensland. These animals were 7–8 months old when first exposed to heat.

Effect of various drugs affecting the sympathetic nervous system (adrenaline, noradrenaline, Dibenamine, Priscol, atropine and acetylcholine) on the rate of cutaneous evaporation in calves was tested. Cutaneous evaporation was measured by means of a capsule before and after the administration of these drugs.

Cutaneous evaporation increased with the introduction of adrenaline and was suppressed by the administration of Dibenamine. Noradrenaline and Priscol had no appreciable effect. Acetylcholine failed to stimulate sweating and atropine did not block the sweat glands.

Sweat glands of cattle were, therefore, found to be functional and their innervation adrenergic. Cattle use sweat to prevent body temperature from rising, yet the amount of sweat secreted is not large enough to allow cattle to maintain thermoneutrality at high air temperatures.

For straw incorporation, three crucial factors affect the soil microbial community and various enzyme activities: straw length, amount and burial depth. To analyse the individual and interactive effects of these three factors on the soil microbial community and various enzyme activities, 23 treatments with five levels of the three variables (straw length, amount and burial depth) were applied in a quadratic orthogonal rotation combination design. A comprehensive indicator was constructed that could represent soil microbial functional diversity and enzyme activity by determining the weights of measured indicators and using Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). The results indicated that the soil microbiological indicators have a higher criteria weight than soil enzyme activity indicators. The final weight orders of indicators were as follows: Shannon–Weaver > invertase > Shannon evenness > urease > catalase > McIntosh index > Simpson diversity > phosphatase. The soil comprehensive values constructed by the TOPSIS method are reliable. The optimal combination for the improvement of soil microbial functional diversity and enzyme activity was a straw length of 13–24 cm, burial depth of 10–17 cm and straw amount of 370–650 g/m2.

Growth and nutrient uptake by an upland rice variety, Agbede and a swamp rice variety, BG 79, were studied under four different soil moisture regimes (60, 80, 100% soil moisture saturation and flooding).

BG 79 (Swamp rice) ultimately attained greater mean total dry weight than Agbede (Upland rice), except in the flooding treatment, where the reverse applied. For both, 100% soil moisture saturation gave the greatest total dry weight increase, whereas the driest soil depressed dry-matter production: plants grown on soil maintained at 80% moisture saturation ultimately attained greater mean total dry weight than those grown on flooded soil. Flooded plants of the swamp rice outyielded plants grown on soil maintained at 80% moisture saturation, but the reverse applied to the upland rice.

Total leaf numbers were usually greater in BG 79 than in Agbede during the tillering and mid-vegetative stages. Increase in the soil moisture up to complete saturation increased the total leaf number in both varieties.

Mean leaf area was greater in Agbede than in BG 79 during the tillering and midvegetative stages. During these two periods of growth the 100% saturation treatment produced plants with the greatest leaf area, whereas 60% soil moisture saturation produced plants with the smallest leaf area in both varieties.

BG 79 had more shoots than Agbede. During tillering saturated and flooded soil encouraged the production of shoots in both varieties, but the driest soil prolonged the tillering period, especially in BG 79. Final shoot number tended to decrease with decreasing soil moisture. The percentage shoot mortality in Agbede was not significantly affected by soil moisture regimes, but BG 79 plants grown on the driest and saturated soil had significantly greater percentages of shoot mortality than flooded plants. In both varieties, plants grown on the driest soil had significantly greater percentage shoot mortality than those grown on soil maintained at 80% moisture saturation.

Mean Relative Leaf Growth Rate and Net Assimilation Rate were significantly faster in BG 79 than in Agbede variety, but the reverse applied with regard to Leaf Weight Ratio.

In both varieties flooded plants had the lowest concentration of manganese, especially during tillering. The small adsorption of Mn with flooding is attributed to a probable antagonism between iron and manganese.

In 1992 and 1993, eight rates of 15N-labelled fertilizer (0–245 kg ha−1) were applied to winter wheat growing on the Ropsley long term field trial where eight different N amounts had been applied annually since 1978. The fate of the labelled N in the crop and topsoil (0–23 cm) was determined at harvest in the year of 15N application and in the first and second residual years.

By harvest in the second residual year, 60–77% of the original labelled application had been recovered in the crop and topsoil with 23–40% lost. These losses virtually all occurred within the first two growing seasons; there was no significant loss during the second residual year. Significant changes in the 15N balance were observed at N applications in excess of the range 140–175 kg ha−1 which suggested a marked decrease in the efficiency of N use and an increase in residual labile N in the soil at harvest. At low N applications (<175 kg ha−1), a positive added nitrogen interaction (ANI) was observed: 40–50% of this was a residual ANI due to the short or long term effect of applying N fertilizer, and the remainder was probably an apparent ANI due to pool substitution in the immobilization process. At large N applications (>175 kg ha−1) a negative ANI was observed: large N applications resulted in a net suppression of soil N uptake due to substitution by fertilizer for a limited plant N demand.

In many nutritional experiments with cut pasture the voluntary intake and digestibility is determined with pen-fed sheep. However, the voluntary intakes of sheep are extremely variable, the between-animal coefficient of variation varying between 13·1% and 10·5% (Blaxter, Wainman & Wilson, 1961; Minson, Harris, Raymond & Milford, 1964). Thus each pasture cut must be fed to large numbers of animals if differences between pasture species and varieties are to be detected with significance. (Heaney, Pritchard & Pigden, 1968.)

Dry-matter intake (D.M.I.) from Panicum maximum(guinea grass) was studied in digestibility trials with Holstein and water buffalo bulls and in a feeding trial with lactating cows.

Differences in voluntary D.M.I. per unit body weight0·73 between the Holsteins and water buffaloes were not significant. Average D.M.I. for all bulls in all main trials was 2·16 kg per 100 kg B.W. Average D.M.I. by the lactating cows was 2·08 kg per 100 kg B.W., for all practical purposes the same as for the bulls.

D.M.I. was not related to stage of maturity or season of harvest of the guinea grass. Intakes of digestible protein, T.D.N., and digestible energy in different seasons and at different growth stages were related to the percentage of those nutrients in the grass.

Correlation coefficients were 0·68 between D.M.I. and B.W.0·73, 0·59 between D.M.I. and T.D.N. content, and 0·58 between D.M.I. and crude protein content, D.M.I. was not closely related to dry-matter content (r = 0·30) or crude fibre content (r= 0–01) of the guinea grass.

Water consumption in agriculture is impossible without considering relations between water, soil and plant. In this regard, there are various models and developed software in order to evaluate relation between soil, water and crop growth stages. These models can be used for irrigation planning if properly optimized and applied. AquaCrop is one of the known crop models, which was developed by the Food and Agriculture Organization of the United Nations. In order to optimize this model for crop production and irrigation management, an experiment was developed in a hydroponic cucumber greenhouse. Various parameters including water consumption volume, crop yield and leaf area index were measured during a season. A fuzzy control system was utilized for controlling temperature, relative humidity, planting bed moisture, light intensity and carbon dioxide values. The main purpose of designing a control system in the greenhouse is to achieve the desired values of temperature and relative humidity. In this model, evapotranspiration, irrigation requirements and crop yield were simulated. The results show that the AquaCrop model can estimate evapotranspiration with the least error in the greenhouse environment, which is controlled by a fuzzy controller. Also the system has estimated the crop yield and biomass of the product with a good degree of precision and it may support crop production in a greenhouse, including crop management and environmental control.

Nitroethane (NE), 2-nitroethanol (NEOH) and 2-nitro-1-propanol (NPOH) were investigated in order to determine their inhibitory effects on in vitro ruminal fermentation and methane (CH4) production of a hay-rich substrate (alfalfa hay: maize meal = 4:1, w/w). The rumen liquor collected from cannulated Holstein dairy cows was incubated at 39 °C for 72 h. The addition of NE, NEOH and NPOH slowed down the fermentation process and notably decreased molar CH4 proportion by 96.8, 96.4 and 35.0%, respectively. The abundance of total methanogen and methanogens from the order Methanobacteriales were all decreased with NE, NEOH and NPOH supplementation. Meanwhile, the nitrocompound addition reduced mcrA gene expression, coenzyme F420 and F430 contents. The correlation analysis showed that CH4 production was correlated positively with the population abundance of total methanogens, Methanobacteriales, mcrA gene expression, coenzyme contents of F420 and F430. The nitrocompound addition decreased acetate concentration and increased propionate and butyrate concentrations in the culture fluid. In summary, both NE and NEOH addition presented nearly the same inhibitory effectiveness on in vitro CH4 production; they were more effective than NPOH. The results of the current study provide evidence that NE, NEOH and NPOH can dramatically decrease methanogen population, mcrA gene expression and the coenzyme content of F420 and F430 in ruminal methanogenesis.

Whitefly (Bemisia tabaci Gennadius), leafhopper (Amrasca biguttula biguttula Ishida) and large yellow-banded blister beetle (Mylabris phalerata) cause considerable damage to okra, especially under organic farming. Thus, the present study was carried out to test the bioefficacy and environmental safety of six naturally derived components [indigenous water plant extracts, i.e. chilli (Capsicum annum), garlic (Allium sativum L.) and neem (Azadirachta indica A. Juss.) along with cow urine in three different combinations, one commercial botanical (azadirachtin 0.15%), and two formulated entomopathogenic fungi (Verticillium lecanii and Beauveria bassiana)] on aforesaid pests for two consecutive years at field scale. In addition to this, the eco-toxicological effect of naturally derived components was also studied on natural enemies’ populations, viz. spiders and coccinellids. Quaternary mixture application of chilli, garlic, neem leaf and cow urine (CGNC) at 10% w/v was found effective in reducing leafhoppers (94.6%), whiteflies (95.2%) and blister beetle (94.6%) over control. Okra treated with CGNC produced a higher marketable fruit yield (18.44 mg/ha) than those of other treatments. It was also observed that the application of CGNC had no phytotoxic symptoms on okra plants. Application of CGNC was found safer to the natural enemy's population (spiders and coccinellids). Thus, the study suggests that CGNC can be considered as a potential source for managing the population of whitefly, leafhopper and blister beetle without affecting the ecology of natural enemies and it could be a viable eco-friendly option in organic okra production for ensuring food safety and healthy environment.

1. A procedure is described for evaluating an “index of texture” (I.T.), based on determinations of moisture contents at the point of stickiness (P), and of sand contents (S) of soil samples.

2. The procedure is simple, and allows of a rapid laboratory examination of a great number of spot samples, so that detailed texture maps can readily be constructed.

3. Employed in conjunction with soil-reaction maps, the texture maps form a useful basis for detailed investigations of soil genesis and soil fertility.

From 1985 to 1987, 20 experiments were carried out on shallow chalk soils, in which soil N reserves were expected to be small, to assess seasonal variations in the response of winter cereals to applied fertilizer N, and to relate these responses to measurements of soil mineral N (SMN), temperature and soil moisture deficits (SMD).

Soil mineral N measured in autumn varied from 21 kg/ha (1986) to 73 kg/ha (1985), while SMN in spring ranged from 19 kg/ha (1987) to 91 kg/ha (1985), these values were typical of soils in long-term arable rotations. Estimates of apparent net N mineralization (AM) during the growing season were small at c. 26 kg/ha and suggested large seasonal variation. The small AM is considered to be due to the shallow topsoil drying out during the growing season. Whole crop N offtake without fertilizer N was only c. 40kg/ha. Crop N offtake, grain yield without fertilizer N and AFR (apparent recovery of fertilizer N) could not be reliably predicted by regression on SMN in autumn, SMN in spring or AM. Little or none of the variation in crop yield could be accounted for by regression on accumulated temperature over winter, maximum SMD in April to July or mean temperature in April to July.

Despite optimum grain yields being only moderate at 6·59 t/ha for winter wheat and 6·78 t/ha for winter barley, response to applied fertilizer N was large, between 3·77 and 5·38 t/ha. In consequence the requirement for fertilizer N (c. 240–250 kg/ha) was also large, but differed little between seasons. This large requirement is concluded to be a result of limited fertilizer recovery and mineralization of soil N during the growing season.

Two experiments (E1 and 2) were carried out in Northern Ireland in 1988/89 to examine the effects of a wide range of supplementary protein intakes given with grass silage-based diets on the performance and carcass composition of beef cattle, and to compare diets based on silage and dried forage. The five treatments used consisted of grass silage offered ad libitum and supplemented with 2·5 kg dry matter (DM) of barley-based concentrates containing (1) zero, (2) 0·2, (3) 0·4 and (4) 0·6 extracted soyabean meal and (5) artificially dried grass and hay supplemented with 3·3 kg concentrate DM. Experiments E3 and 4 were carried out in 1991/92 to examine the responses in ration digestibility, silage intake and animal performance to supplementary protein in relation to the requirements recommended by the United Kingdom Metabolizable Protein System. The two treatments consisted of grass silage offered ad libitum and supplemented with 3·2 kg DM of (1) barley and (2) 0·8 barley and 0·2 soyabean meal. The silages used were well preserved, containing on average 200 g DM/kg; 143 g crude protein (CP)/kg DM; 79 g ammonia-N/kg total N and 734 g digestible organic matter/kg DM. The cattle were castrated males of medium to late-maturing breed type and were initially 13 months old and 396 kg liveweight. Increasing protein intake did not affect ration digestibility, silage DM intake or animal performance in any of the four experiments, despite the fact that the effective rumen degradable protein (ERDP) intakes in the diets supplemented with barley alone were only 80–85% of ERDP requirements. However, increasing protein intake tended to increase carcass fatness in all experiments, the effect being significant (P < 0·05) for the lipid concentration in the M. longissimus dorsi muscle in E1 and 2. Offering the dried forage-based diet rather than an isonitrogenous silage-based diet did not affect carcass fatness. It is concluded that supplementing well preserved grass silages with mixtures of barley and soyabean meal, rather than with barley alone, did not affect ration digestibility, silage intake or animal performance but tended to increase carcass fatness, especially marbling fat, despite the fact that ERDP intakes for the diets with the lowest protein concentration were only 80–85% of requirements given by the United Kingdom Metabolizable Protein System.

A field experiment was made during the rainy seasons of 1968 and 1969 on a sandy loam soil to study the response of Sorghum hybrid CSH–1 to phosphorus in relation to content of water-soluble phosphate in fertilizers. Triple superphosphate, dicalcium phosphate, rock phosphate (200-mesh), nitrophosphate and mixtures of triple superphosphate with dicalcium phosphate and rock phosphate in 3:1, 2:2 and 1:3 ratios were studied. The amounts of phosphorus applied were 30 and 60 kg P2O5/ha. Phosphorus application significantly affected dry matterproduced, plant height, days to 50% bloom, number of grains per ear, thousand-grain weight, stover and grain yield. Triple superphosphate and 3:1 triple superphosphate/dicalcium phosphate mixture were the most effective while rock phosphate and 1:3 triple superphosphate/rock phosphate mixture the least. Differences among sources were more marked in 1968 and at the higher amount i.e. 60 kg P2O5/ha. The response of sorghum to phosphorus was considerably lowered when the water solubility waa below 50% in triple superphosphate/dicalcium phosphate mixtures and below 75% in triple superphosphate/rock phosphate mixtures. Relative effectiveness was assessed by calculating ‘superphosphate equivalents’ and ‘multiple regressions’. Using superphosphate equivalents dicalcium phosphate, nitrophosphate and rock phosphates were 47–53%, 35–56% and 3–25%, respectively, as effective as triple superphosphate.

In an attempt to determine the rôle of phosphates in tomato culture tomato plants have been analysed for potash, phosphoric acid and nitrogen.

In unmanured plants the fruit is of inferior quality but the weight as picked is 2·6 times that of the foliage and stems of the same plants. In manured plants this ratio is 1·6. The relative efficiency of the plants under the two sets of conditions is discussed.

Manured plants have a higher ash content than unmanured plants.

The interrelationship in metabolism between dietary selenium (Se) and copper (Cu) was investigated in sheep receiving a diet with or without sodium bicarbonate (NaHCO3). A sheep finishing diet, containing 0·3 mg Se/kg DM and 7·4 mg Cu/kg DM, and supplemented with 1·0 mg Se (as Na2SeO3) and/or 15·0 mg Cu (as CuSO4) and/or 40 g NaHCO3 per kg feed, was fed to young ewes for a period of 64 days. Hepatic Cu concentration and net accumulation were not affected by NaHCO3 supplementation. Furthermore, no evidence was found in blood, tissues or faeces to show that NaHCO3 influenced Se metabolism. However, hepatic Cu concentration was raised from 354 to 422 mg/kg DM (P<0·05) when the diet was supplemented with 1 mg Se/kg DM, independent of the level of dietary Cu. Furthermore, hepatic Cu retention was significantly (P<0·05) influenced by a Se × Cu interaction, namely when the diet was supplemented with 15·0 mg CuSO4 or 1·0 mg Na2SeO3 /kg DM or both, 0·084, 0·081 and 0·088 of the dietary Cu respectively was retained in the liver, compared to 0·047 in the sheep on the basal diet. In addition, supplementation with Se and Cu together increased hepatic Se concentration to a greater extent (P<0·001) than when Se alone was added to the feed (3·65 v. 5·17 mg Se/kg DM respectively). The concentration of Se in both muscle tissue and in rumen bacteria was raised (P<0·001) by Se supplementation, but more so (P<0·05) in both cases when Cu was not added to the diet. Interactions between Se and Cu were not influenced by NaHCO3 supplementation in the conditions of this study.