Results obtained previously on distribution and behaviour of phosphate between organic and inorganic forms in pig slurries are extended to slurries from wastes of hens, cows and calves. Organic P in the slurries varied from about 1 to 15% of total P, with slurries from veal calves having the lowest content of organic P. In all slurries roughly half of organic P in solution had a high molecular weight (50000 and higher) and is therefore potentially mobile in soils.

A total of 140 British Friesian cows in their second or later lactation and with a mean calving date of 27 October (s.D. 18 days) were used in a randomized-block experiment over a 3-year period. The experiment was designed to examine the effects of level of concentrate given during the winter period, in addition to ad libitum access to grass silage, on total lactation performance. The silage had a mean dry-matter content and digestible organic matter in the dry matter of 206 and 698 g/kg respectively and the mean inputs of concentrates on the five treatments were 0–64, 0–89, 1–14, 1–38 and 1·59 t/cow (treatments 1–5 respectively). Sixteen replicates per treatment were housed in individual stalls during the winter period in order to facilitate the measurement of silage intake and the remaining animals in each year were maintained as a single group.

All animals in each year grazed together as a single group at pasture at a mean stocking rate of 6–0 cows/ha and without supplementary concentrates.

Level of concentrate supplementation had a significant linear effect on the intake of silage dry matter with the relationship between total intake of silage dry matter over the winter period (kg, y) and concentrate dry matter input (kg, x) being described by equation (1)

Effects of controlled tillage and soil-water conditions at the time of cultivation on emergence and grain yield were measured for a spring barley crop grown on a silty clay loam soil. A range of soil densities was achieved using conventional implements (tine-cultivator and roller) in combination with three levels of soil wetness. Concrete tracks supported both tractor and implements to prevent compaction due to wheelings, and rain-activated mobile shelters excluded precipitation from the field site.

Tillage treatments had large and significant effects on plant establishment. Both rate of emergence and final emergence were lowest where the soil was rolled at a high moisture content, and greatest where it was cultivated dry. Time for 50% plant emergence, rate of emergence and final plant population density all tended to be linearly correlated with the bulk density of the prepared seed bed. Despite large differences in plant establishment, later compensatory growth caused final yields of grain to show no significant response to tillage treatment.

The incidence of lantana poisoning and its effect on mortality, growth rate and fertility were recorded from 1975 to 1982 in seven lines of Bos taurus and Bos indicus cattle and their crosses.

Two Bos taurus Hereford × Shorthorn (HS) lines had higher incidences of poisoning and higher mortalities after poisoning than the Bos indicus based breeds.

During the period of poisoning, live–weight gains of affected animals of all breeds were reduced but subsequent recovery was rapid. Lantana poisoning had no detectable effect on the fertility of animals affected at least 10 months prior to their first mating, irrespective of breed.

Parasite control influenced the incidence of poisoning and mortality in genetically similar groups of HS cattle. This observation, when combined with the between-breed relationships between the incidence of lantana poisoning and susceptibility to environmental stresses suggests that the marked breed differences in susceptibility to lantana poisoning stem from differences in resistance to other environmental stresses, including cattle ticks. This offers little scope for selection of animals that are resistant to lantana poisoning per se but has practical significance in lantanainfested regions.

Most commercial cultivars of Cucurbita pepo L. reacted by producing severe leaf symptoms when infected with either of two British strains of cucumber mosaic virus. Resistance was identified in some pumpkin-types of C. pepo, with the highest level in cv. Cinderella. Studies with selfed populations produced from selected resistant plants demonstrated that resistance in cv. Cinderella is heritable.

The development of statistically sound methods of summarizing the results from germination tests appears to have been neglected. This paper reviews the literature critically, proposes the use of maximum likelihood techniques to summarize such data and develops an appropriate routine, available as a computer program ‘DISTGERM’.

Changes in soil fertility status brought about by the application of P and K fertilizers and farmyard manure (FYM) to a fixed wheat-maize rotation for 10 years in a calcic ustochrept are reported. The treatments comprised three rates of P (0, 30 and 60 kg P2O5/ha), two rates of K (0 and 30 kg K2O/ha) and two rates of FYM (0 and 15 t/ha) applied to maize or wheat alone or to both the crops. Organic carbon and available P and K contents of the soil increased significantly with the addition of FYM. P application at 60 kg P2O5/ha nearly maintained the original level of available P even after 10 years of continuous cropping. However, a considerable and highly significant increase in available P was obtained with the combined application of P and FYM. Available K status of the soil remained more or less unaffected by K application. Organic carbon content, and available P and K contents were significantly higher in the plots that received fertilizers and manure for both the crops than in those where the application was to maize or wheat alone.

Twelve factorial experiments made from 1977 to 1981 compared the effects of 0, 4 and 8 t CaCO3/ha, 0 and 360 kg N/ha/year as urea and 0 and 60 kg P/ha/year as either superphosphate or ground rock phosphate on the yield and mineral composition of established grassland on soils of pH 4·7–5·6 in Northern Ireland.

Lime did not increase yield whether urea was applied or not. It substantially reduced herbage Mn and, to a lesser extent, herbage P, Mg and Zn.

With lime, ground rock phosphate was almost completely ineffective in raising yield and herbage P content. Without lime, it had some value but was less effective than superphosphate.

Soil P extracted either by ammonium acetate at pH 4·2 or Olsen sodium bicarbonate reagent did not predict response to superphosphate. When the soil test values were adjusted for field bulk density, soil P extracted by ammonium acetate, but not by Olsen reagent, was significantly correlated with response.

Herbage P in the first cut in 1978 was highly correlated with response to superphosphate; only sites with herbage P < 0·27% responded to P.

One hundred and twelve indigenous gilts and sows were used in two trials to study the effects of strepcillin (a mixture of streptomycin and penicillin) at 0, 25, 50, 75 and 100 g/t feed in a basal 15% protein diet and strepcillin at 0, 25, and 50g/t feed in rations containing 12, 15 and 18% protein, on the reproductive performance of pigs.

Reproductive performance in terms of sow net gain in weight through the reproductive cycle, average birth weight of live pigs per litter and number of pigs weaned per litter were significantly affected by antibiotic levels. The dietary level of 50 g antibiotic/t feed gave the highest reproductive performance though at higher levels no adverse effects on reproductive performance were obtained.

Reproductive performance of pigs was significantly influenced by protein and antibiotic levels. A significant interaction between antibiotic and protein levels was obtained for weight loss in sows at parturition and lactation, net gain in weight through the reproductive cycle, total and live pigs farrowed per litter.

There have been a number of reports on the frozen storage of ram semen, and artificial insemination with frozen semen has been performed on an experimental basis in several countries. Intensive laboratory studies led to considerable progress regarding the freezing and thawing procedures (Salamon & Visser, 1972; Colas, 1975). However, fertility following insemination tends to be considerably lower than for fresh or chilled semen (Maxwell et al. 1980).

Underground irrigation water, particularly saline, when in arid and semi-arid regions of India may contain toxic amounts of B, from a trace up to 10 mg B/l (Anon. 1981–82). Continuous use of such water for irrigation may lead to the accumulation of salts and B in soil and this creates toxicity problems. Kanwar & Mehta (1970) have reported that water containing 2 mg B/l is hazardous if used on heavy soils. For sandy loam soils of semi-arid tracts in India, Chauhan & Powar (1978) have reported reductions in the grain yield of wheat and pea at 4 and 6 mg B/l respectively, while under similar conditions grain yield of lentil and barley was reduced at 3 and 6 mg B/l respectively (Chauhan & Asthana, 1981). So far, few attempts have been made to evaluate the effect of boronated saline water on soil and crops, under different agroclimatic conditions. A study of the effect of boronated saline water on an important oil-seed crop, linseed, on alkaline sandy loam soil in the semi-arid region of Agra, India was therefore undertaken.

The nutritional importance of a foodstuff in a diet depends on the composition of the raw foodstuff, the amount that is usually consumed and the extent to which nutrients are destroyed or lost during preparation of the diet.

Most Nigerian foods have to be prepared and cooked before they can be eaten. A lot of food preparation in Nigeria involves soaking, steeping, boiling, frying and roasting; at each stage of the preparation, some of the nutrients may be discarded or destroyed, while in some cases toxic substances may be discarded (Oke, 1968)

The formation of effective nodules by rhizobial strains is influenced by both the host and the environment (Gibson, 1977). The interaction between host genotype and strains of Rhizobium sp. has already been established for some species (Gasser et al. 1972; Rai & Singh, 1979). The present study presents data for the contribution of different rhizobial strains to nodulation character and quality of green gram.

A great portion of south-western Colorado and the other western states of the U.S.A. is covered with gambel oak (Quercus gambelii). Gambel oak was determined by Brown (1958) to be an important component of the mountain brush type in Colorado. It occurs in pure stands as well as in association with pinyon pine, juniper, ponderosa pine, aspen, and spruce on several million hectares. Ranges covered with gambel oak have relatively low grazing capacity and low availability of the understory vegetation for grazing animals. Jeffries (1965), studying the effect of gambel oak on range forage production, indicated that herbage yield under the oak canopy was less than that of grasses growing in the open. The restriction in forage growth under the oak is attributed to the shading effect rather than the competition for moisture. Therefore, removal of gambel oak would be likely to improve the ranges.

The management of non-leguminous annual forage crops can affect dry matter (D.M.) yields, chemical composition, and nutritive (feeding) values largely because of the stage of maturity at which the crop is harvested. After studies for selecting high-yield forage oat varieties for a highaltitude tropical climate (Haile, 1976), it was considered necessary to look into the management of forage oats so that the time of harvesting for maximum forage and crude protein yield could be established.

Green gram is one of the most important kharif pulse crops of India. It is of short duration, can fit well in crop rotation and, therefore, can be grown throughout the year. Information has been accumulating concerning the role of potassium and zinc in cereal crops but very little information is available regarding the nutrition of potassium and its interaction with zinc on the yield and quality of pulses. However, Malewar, Budhewar & Jadhav (1980) and Ghildiyal, Saini & Sirohi (1975) have reported significant positive effect of zinc treatment on growth attributes in green gram. The present investigations were, therefore, planned to study individual and interaction effects of potassium and zinc on growth, dry-matter and grain yield and quality of green gram.