The seedling emergence from fluid-drilled germinating and natural onion seeds was compared at five sowing dates between 10 February and 18 May on irrigated and unirrigated plots in two experiments. In the second experiment fluid-drilled seeds selected for uniform germination were also included. There were few significant differences between the emergence of seedlings from germinating and natural seeds in the field sowings of Expt 1. However, a reduction in mean emergence time at the earliest sowing led to an increase in bulb weight while a reduction in the spread of emergence at sowing 3 led to a reduced coefficient of variation of bulb diameter at harvest. Under the less variable conditions on the irrigated plots of Expt 2 germinating seeds reduced mean emergence time and increased percentage emergence compared with natural seed at some sowings. Fluid-drilled selected germinated seeds, however, reduced mean emergence time and increased percentage emergence at every sowing and reduced the spread of emergence at all but the first sowing compared with natural seed.

Low soil moisture content made seedling emergence more unpredictable and reduced the benefits gained by sowing germinated seeds. The results presented suggest that techniques to increase the proportion of germinated seeds at the point of sowing and economical methods of applying water during periods of low soil moisture following sowing are needed if the full benefits of fluid drilling are to be realized.

Three composite populations of oats were grown at contrasting sites in the north, east and west of Scotland for four successive generations from F3 to F6. Analyses of variance and canonical analysis both showed that the genetic constitution of the composites was responsible for a greater proportion of the variation than locations (sites). This suggests that either natural selection was not operating to any great extent or the effect of natural selection was very similar at the three sites. These findings were supported when selections were taken from one of the populations and subjected to canonical analysis. The implications for oat breeding in Scotland are discussed.

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.

A field experiment was conducted for 3 years to study the effect of Rhizobium inoculation, mulch and N and P fertilizers on soya bean. The application of wheat straw mulch helped greatly in lowering the maximum soil temperature but failed to increase the yield, particularly on the fields where soya bean was raised for the first time. Seed inoculation gave significantly greater yield than control (no inoculation and no mulching). The combination of mulch and seed inoculation, on average, produced 0·76, 0·43 and 0·84 t/ha more grain than inoculation alone in 1976, 1977 and 1978 respectively. A basal dose of 15 kg N/ha increased the yield when seed was inoculated but no mulch applied whereas the dressing of N did not prove beneficial when mulching was combined with inoculation. The grain yield, however, increased up to 180 kg N/ha in the case of mulch alone and control treatments. The response of soya bean to phosphorus application was inconsistent.

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).

Apparent digestibility of forage kale (cv. Maris Kestrel) was compared with that of mixed perennial ryegrass (0·85) and clover (0·15) herbage in two experiments. In a third experiment measurements were made of the partition of digestion between the reticulo-rumen and post-ruminal regions of the digestive tract in sheep fed kale, using intra-ruminal infusion of inert ruthenium phenanthroline and chromium-EDTA markers and time sequence sampling from the duodenum. Results in Expt 3 were compared with predicted values for a range of ruminant diets, including digestion of fresh perennial ryegrass and white clover.

In Expts 1 and 2 the ratio of readily fermentable to structural carbohydrate (CHO) was much higher in kale (2·6–3·2) than in mixed ryegrass and clover herbage (0·6), and showed little difference between kale leaf and stem components. Apparent digestibilities of organic matter (OM), cellulose and hemicellulose were 80–90% for kale diets, varied little with changes in leaf/stem ratio, and were generally slightly higher than for mixed ryegrass and clover herbage. Calculated metabolizable energy (ME) concentrations were 12·0 and 11·7 MJ ME/kg D.M. for kale and mixed ryegrass and clover respectively.

Despite large intakes of water-soluble CHO and pectins in kale-fed sheep in Expt 3, duodenal flows were small and respectively 92 and 98% of the total amounts digested were digested in the rumen. Ruminal cellulose digestion (95% total digested) was as predicted for normal ruminant diets, but less hemicellulose was digested in the rumen (71% total digested) than predicted. Total N flow at the duodenum was 5 g/day less than N intake, and respectively 27 and 66% of the N apparently digested was accounted for as total N absorption from the rumen and post-ruminal absorption of NAN. Calculated absorption of amino acids from the small intestine was less for the kale diet (14% ME intake) than for diets of fresh perennial ryegrass and white clover (20% ME intake). Possible reasons are that 10% more of the OM ingested was digested in the rumens of sheep fed kale than was predicted, that the ratio of dietary total N/100 g digestible OM was much less for kale (3·7) than for perennial ryegrass and white clover (5·6) diets, and that protein formed a lower proportion of the total N in kale diets (75%) than in diets of ryegrass and clover (90%). Despite 3·3 g of S-methyl-L-cysteine sulphoxide (SMCO) being consumed per day, none was detected in either rumen or duodenal contents or in faeces.

In was concluded that complete conversion of SMCO to dimethyl disulphide occurred in the rumen, that dimethyl disulphide may have caused the depression in ruminal digestion of hemicellulose, and that the digestion products of kale are deficient in absorbed amino acids relative to other forms of energy, thus explaining responses to essential amino acid supplementation in lambs grazing kale.

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.

Variation in infestation of S. avenae on plots of wheat was assessed by combining techniques of enhancing field infestations with scoring individual shoots according to the number of aphids on them, using a logarithmic scale with base 2. The mean score appeared the most useful way of describing the aphid infestation on each plot.

In 1982, the sampling effort required for assessment of S. avenae on many plots was considerably reduced by this approach. The artificial increase in numbers of aphids avoided problems associated with sampling small populations, and the logarithmic classification of shoots reduced the time needed to assess large numbers. Scoring plots as a whole, although much quicker, gave results that differed from the assessments based on shoot sampling, and should be used with caution. The differences observed among cultivars in infestation of adult plants in the field in 1982 were not always the same as those observed on younger plants in the glasshouse.

Geranium (Geraniaceae) is an important aromatic plant grown for its light yellow to light brown or green coloured volatile essential oil obtained bysteam distillation of the green overground biomass. Geranium oil is extensively used in many perfumery formulations. The crop is generally raised from rooted cuttings whose initial slow growth leaves a large portion of land uncovered. Under identical situations in many other crops, it has been observed that growing grain or fodder legumes as intercrops resulted in monetary or yield advantages (Willey, 1979a,b; Mead & Willey, 1980; Rajeswara Rao & Singh, 1982, 1983; Rajeswara Rao & Sadaphal, 1983). The objective of the present investigation was to study the feasibility of growing a short-duration leguminous intercrop during the initial lag phase of geranium in such a way as not to affect the yield of geranium.

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)

A number of factors affect predictions of rumen degradability of feedingstuffs when using the in sacco technique (Lindberg, 1983). One factor which exerts a great influence is the bag cloth aperture (Lindberg & Knutson, 1981; Lindberg & Varvikko, 1982). Without doubt part of the difference in degradation between pore sizes can be explained by differences in particulate matter losses (Lindberg & Knutsson, 1981; Lindberg & Varvikko, 1982). It has, however, also been suggested that the differences between pore sizes are due to the combined effect of differences in liquid exchange between the bags and the rumen contents and on the selection of microbes entering the bags (Lindberg & Varvikko, 1982).

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.

Groundnuts are mostly grown during the rainy season (kharif) in India. Most of the cultivation is without irrigation. Consequently the crop experiences water deficits of different intensities and durations, depending upon the rainfall distribution. Yields are poor under such conditions. In other leguminous species irrigation at flowering usually improves yield, if the pod development period coincides with a break in rainfall or water deficit (Khanna-Chopra, Koundal & Sinha, 1980). Thus, an understanding of reproductive behaviour and reproductive efficiency could be helpful in adjusting planting to coincide with favourable agroclimatic conditions. Alternatively, this understanding could help in scheduling irrigation.

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.

Fruit curvature is a trait which has been little investigated by botanists and horticulturists. The degree to which a fruit is curved can be accounted for intuitively in cases where there are no physical barriers to normal fruit growth, such as obstruction by plant parts or the soil surface. The curvature of pendant, unobstructed fruit, as in the Solanaceae, has received limited discussion in the literature.

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.