During three growing seasons (1980–3) the influence of sowing date (early September to mid-November) on the yield of winter barley (cv. Igri) was assessed. Delaying sowing resulted in a linear decrease in maximum grain yield at a rate of 0·43 % for every day sowing was delayed. Advancing the date of sowing increased the duration of preanthesis development, increased the level of tillering and hence ear density at harvest. Yield was linearly related to the resultant higher number of grains.

The object of this study was to investigate the vegetative growth in six barley varieties grown in southern Spain (Granada) during 1979, 1980 and 1981. The results showed that crop dry weight (CDW) was dependent on environmental factors (mean temperature, rain, and radiation) which were the determinants of the two CDW components, leaf area index (LAI) and leaf area ratio (LAR). However, the effects of these climatic factors on crop growth rate (CGR) and on its components, mean leaf area index () and net assimilation rate (NAR), were partially obscured by ontogenetic drift. In addition, a highly significant relationship was demonstrated between CDW (when the LAI reaches its maximum value) and grain yield. This suggests that the pre-anthesis period has a great influence in the determination of grain yield variation in hot, dry areas, where photosynthesis is very limited after ear emergence.

In view of the increase in micronutrient deficiencies in crop plants, ans attempt is made to group 57 Benchmark Indian soils into different micronutrient availability classes (clusters) vis-à-vis some soil characteristics. Since most of the soil characters are expressed in proportions or percentages (a usual practice in soil studies), the data matrix was transformed into log10 values to bring it nearer to normality. The transformed data matrix was used for cluster analysis and subsequently also for discriminant analysis. By following the method of Euclidean cluster analysis, the 57 Benchmark soils could be subdivided into three clusters. The distinctness of clusters was proven by distance-matrix as well as discriminant analysis. All the soils of cluster I and II originated from arid and semi-arid climates and these were alkaline in reaction, low in organic carbon (OC) and high in total lime. On the contrary, cluster III comprised all but a few soils from humid-subhumid regions. These soils were acidic in reaction and relatively high in OC and total lime. The soils of cluster I and II were poorer in diethylene triamine penta-acetic acid (DTPA) extractable micronutrient cations than those of cluster III. This study thus reveals that it is possible to classify diverse soils by statistical means into distinct clusters based upon micronutrient availability and associated soil properties. Furthermore, it suggests that soils of arid and semi-arid climates as a group, because of their low micronutrient availability, are expected to be more prone to deficiencies than those of humid and subhumid zones.

A field experiment, made during the rainy seasons oof 1982 and 1983 at the Indian Agricultural Research Institute, New Delhi, studied the effects of blending urea with dicyandiamide (DCD) on the yield and yield components of rice. DCD-blended urea was as effective as neem-cake-coated urea in respect of yield components as well as grain and straw yield of rice and when all the nitrogen was applied 10 days after transplanting both the materials produced significantly more grain and straw than prilled urea. Urea super granules (USG) were superior to DCD-blended, as well as neem-coated, urea.

Field and laboratory studies were carried out in 1981 and 1982 to investigate the relationship of stalk morphology and chemical composition to lodging resistance in maize in the rainforest zone of Nigeria.

Morphological characters correlated with lodging were plant height, diameter and length of basal internode, thickness of rind and weight of 5 cm basal section. Lodging was negatively correlated with grain yield, and with the percentages of total nonstructural carbohydrate, protein and potassium in the stalks. Premature stalk senescence and rot were common in varieties susceptible to lodging. Lodging had no relationship with leaf area and number of days from sowing to flowering.

Two groups of six sheep were fed either dried-grass or ground maize-based diets for at least 4 weeks before slaughter. Samples of the small intestinal mucosa and spancreatic tissue were assayed for a-amylase, glucoamylase, maltase and oligo-l,6-glucosidase.

The pancreatic tissue contained high activities of α-amylase and much lower activities of glucoamylase, maltase and oligo-1,6-glucosidase. There was no effect of diet on the specific activities of any of these enzymes in the pancreatic tissue.

The activity of α-amylase adsorbed on to the mucosa of the small intestine was greatest in the proximal region of the small intestine, the activity generally declining with increasing distance away from the pylorus. There was no diet effect on the absorbed α-amylase activity.

Similar patterns of distribution along the small intestine were observed for maltase, glucoamylase and oligo-1,6-glucosidase with the highest activities in t he jejunum. There was no overall effect of diet on glucoamylase or maltase specific activities and glucoamylase total activity, although the total activities of maltase and oligo-1,6-glucosidase were significantly greater for the sheep fed the ground maize-based diet (P < 0·05).

It is suggested that ruminant animals may be capable of digesting large amounts of starch in the small intestine through an adaptation in the activity of the host carbohydrases.

Pollen grains of oil-seed rape, Brassica napus, were germinated in vitro in conditions in which water activity could be closely controlled. Germination success depended on the humidity experienced by the grains before contact with the germination medium, as well as on the osmolarity of that medium. On contact with the germination medium the grains swelled and then shrank. Each suffered one of three fates: it burst, or it germinated without bursting, or it did neither, remaining unchanged. Grains that were to remain unchanged swelled least. Those that were to burst swelled most. Those that were to germinate were intermediate.

Some implications for in vitro germination studies are discussed.

Effects of seven levels of N application and three seeds mixtures were studied on two sites for 4 years. One seeds mixture comprised perennial ryegrass (Lolium perenne L.) and two comprised perennial ryegrass with white clover (Trifolium repens L.). One site (Trefloyne) was 24 m above sea level on deep soil and the other (Pwllpeiran) was 328 m above sea level on relatively shallow soil. The plots were cut seven times per year.

White clover grew very strongly at Trefloyne in the first 2 years, fixing 350 kg N/ha/year where no N was applied; the clover declined very markedly during the 3rd year and there was very little in the sward in the 4th year; quite large quantities of clover were harvested in the 1st year even where 600 kg N/ha were applied. At Pwllpeiran the yields of clover were never high, but the clover persisted well where no N was applied. At Trefloyne the indirect contribution of the clover (in increasing the yield of grass) was greater in the first than in the second half of the year; clover was later than grass to grow strongly in the spring, but the extra grass growth compensated for this, so that the seasonal distribution of total herbage yield was similar on a grass-clover sward receiving no fertilizer N to that on a grass sward receiving six applications of N per year. At Pwllpeiran, on the other hand, the indirect contribution of the clover tended to be greater in the second than in the first half of the year where no N was applied.

The olover was similar to grass in phosphorus and potassium content and higher than grass in calcium and nitrogen. The clover was higher in nitrate-N content than grass grown without clover, at low levels of applied N, and increased the nitrate-N content of the grass growing with it.

Water consumption at Trefloyne was greatest on swards which contained olover and on the swards without clover which received at least 400 kg N/ha/year. The effect of clover on soil water was apparent particularly in the lower horizons of the soil.

Several laboratories are currently using the rapid excreta collection assay desoribed by Sibbald (1979), or a modification thereof, to measure digestibility of amino acids (AA) in feedingstuffs for poultry. The use of faecal or excreta collection assays to measure utilization of dietary AA has been frequently questioned because of the unknown effects of gut micro-organisms on AA excretion. These effects may be large with swine (Holmes et al. 1974) and thus many researchers have used ileal digesta collection to measure AA digestibility with pigs (Zebrowska, 1978). The question on significance of microbial effects is less clear with poultry. Some studies with germ-free chicks suggested that influence of the hindgut microflora on digestibility of protein and AA was significant (Salter & Coates, 1971; Elwell & Soares, 1975), whereas others indicated that these effects were small and probably negligible (Salter, Coates & Hewitt, 1974; Salter & Fulford, 1974). More recently, Parsons, Potter, Brown, Wilkins & Bliss (1982) concluded that microbial fermentation in the hindgut may have a significant effect on AA excretion by poultry, but to a much lesser extent than swine.

Water buffaloes (Bubalus bubalis) are reared in many tropical and subtropical countries for meat and milk production and to serve as draught animals. The improvement of milk yield in water buffaloes has been handicapped by the absence of physiological data that may provide means of rapid genetic improvement. Endocrine function is known to vary with lactation intensity. Thyroid hormones seem to have a stimulatory effect on the metabolic rate and, consequently, on the productivity of dairy animals (Lenon & Mixner, 1957; Picha, Pichova & Karasek, 1970; Swanson, 1972). Anderson (1969) also reported an increase in thyroid activity in lactating cows and rats, although other investigators (Johnson & Vanjonack, 1976; Hart et al. 1978; Hart, Bines & Morant, 1979) reported that lactation induced a decline in plasma thyroid hormones. None of these studies performed measurement of plasma thyroid stimulating hormone.

Java citronella (Cymbopogon winterianus Jowitt) is an important perennial aromatic grass cultivated in different parts of India. The steam-volatile essential oil from the citronella herb is widely used in perfumery, in manufacture of deodorants and mosquito repellent creams and in flavouring beverages. Systematic cultivation of this crop is being taken up and application of large quantities of N fertilizers was found to increase yield (Narayana et al. 1975; Bommegowda, 1978; Singh, Pathak & Bodoloi, 1980; Prakasa Rao et al. 1983). However, the efficiency of N utilization by this crop was found to be quite poor (Prakasa Rao et al. 1983). No systematic data are available in India on the effect of harvest season and N fertilizers on the principal constituents of citronella oil. Therefore the present experiment was made with two objectives: (i) to determine the effect of harvest season and N fertilizers on the essential oil concentration and the principal constituents of the oil which determine the oil quality, and (ii) to determine the effect of neem cake, an indigenous cheap material which is reported to have nitrification inhibitory properties, on the herb and essential oil yields of citronella.