The effect of infrequent drinking on nitrogen metabolism was studied in Bedouin goats, a breed herded in the extreme deserts of the Middle East. The goats were given water either daily or only once every 4 days, while being maintained on roughages of different quality: lucerne hay (19% protein), Rhodes grass (10% protein) or wheat straw (3·7%). On lucerne hay and Rhodes grass the goats kept their body mass constant, whether given water daily or only once every 4 days. When on wheat straw the body mass was maintained constant only when given water once every 4 days. Infrequent drinking was found to hamper considerably the food intake of the goats when fed on high quality roughage. When on the wheat straw, the nitrogen intake of the goats (only 12% of that recorded when fed lucerne hay and given water daily) was, however, not affected by the drinking regime. Infrequent drinking improved nitrogen digestibility on all the diets, but more so on those of low quality than on the lucerne hay.

When tested on the low quality feeds, urea excretion was low and urea retention and recycling were maintained at high rates. Infrequent drinking had no adverse effect on these capacities.

In field experiments with potato conducted from 1981 to 1983 on acid hill soils of Simla, a technique was developed to work out the relative contribution of soil and fertilizer nutrients to potato production. The locations accounted for more variation in tuber yield than the fertilizer effects. The value of soil tests in explaining the variation due to locations was modified by years. On average, nitrate, organic carbon and available K explained 59, 25 and 41% of the variation. The response to fertilizer N was significant in all yea s and to K was significant in 1982 only, but that to fertilizer P was not significant in any year. The fertilizer doses of N and K were calculated both from the soil test based regression equations and the fertilizer response equations. The dose of N varied from 129 to 133 kg/ ha in different years but the response per kg N at the economic dose varied from 0·05 to 0·13 t/ha.

The effect of artificially applied urine on clover performance in a perennial ryegrasswhite clover sward grazed by sheep was examined during summer. Sheep urine or deionized water (51/m2) was applied to areas (2·70 × 1·25 m) which were protected from subsequent excretal return by graze-through cages. Grass and clover populations, nitrogen-fixing activity, soil nitrogen and soil pH were monitored over the following 90-day period.

Urine reduced clover population density, stolon length and dry weight but had little effect on number of grass tillers. Nitrogen-fixing activity of clover was reduced initially to less than 30% of control values, perhaps owing to high levels of soil inorganic nitrogen inhibiting fixation, although osmotic effects due to the high salt concentration in urine cannot be discounted. The lower levels of activity at later dates were due largely to reduced clover in urine-treated areas. Soil pH (0–5 cm) was increased by about 0–5 units 3 days after urine application, with a smaller increase in the 5–10 cm horizon. Recovery of urine nitrogen in the soil mineral N pool was at best 27% of the added nitrogen.

The results are discussed in terms of the significance of urine-affected areas in determining a patchy distribution of clover in grazed swards; the role of animals in the transfer of fixed N from clover to grass is considered.

Jute (Corchorus capsularis L.) is grown in the tropics. It is next only to cotton in importance as a fibre crop. Adequate supplies of plant nutrients, especially N, are essential for its vegetative growth. Response to applied N varies from region to region. In a light-textured soil with low cation exchange capacity (CEC), part of the applied N is generally lost mostly under rainfall (Engelsted & Russel, 1975) and the rest is manifested in the form of residual effect (McEwen, 1970). Such losses can be reduced by using slow-release N fertilizers or by coating the urea granules by paraffin wax, resin, gum, lac, or with a nitrification inhibitor (Prasad, Raj ale & Lakhdive, 1971). There is little information on the use of these products on jute. Mondal, Dohary & Pal (1977) reported that coated urea is better than uncoated ones. The current programme was designed to give a better picture.

There has been considerable research on techniques for artificial insemination of sheep with frozen ram semen (Maxwell, 1984). Acceptable pregnancy rates were reported following ‘two-step’ dilution and freezing of semen in P.V.C. ‘ministraws’ (Colas, 1975; Colas & Guerin, 1981); however, other workers have obtained poor fertility following cervical insemination with semen frozen in straws (Maxwell, etal. 1980; Tervit elal. 1984).

Bollworms (Heliothis zea Boddie and H. virescens F.) are serious cotton pests. During 1980, the cotton crop in U.S.A. suffered an 8·73% loss due to insect pests; 3·07% of this loss was due to the damage caused by bollworms. This 8·73% loss in cotton production occurred despite control measures adopted by cotton growers at an average cost of $36.27 per acre (Anon. 1981). Four plant characteristics impart varying degrees of host-plant resistance against bollworms in cotton (Maxwell, 1977). The bollworm moths exhibit an oviposition nonpreference towards glabrous and nectarless cottons. Presence of high gossypol and ‘X-factors’ in plant parts detrimentally affects the growth and survival of bollworm larvae. The ‘X-factors’ are unknown chemical substances that impart host-plant resistance against bollworms in cotton. This resistance was shown to be heritable by Lukefahr et al. (1974).

Australian feral goats have recently been found to produce commercially viable quantities of the luxury fibre cashmere (Smith, Clarke & Turner, 1973). Cashmere is the fine down produced by secondary follicles as an undercoat during winter. Fibre diameter ranges from 8 to 24 μm with a mean diameter of 16 μm. Unlike modern breeds of sheep such as the Merino which exhibit almost continuous wool growth, cashmere growth is distinctly seasonal with fibre growth commencing in summer (long daylength) and reaching a maximum length in early winter (short daylength) (McDonald, 1985). The cashmere is cast in spring with growth recommencing again in summer.

Although over 90% of small ruminant production in Nigeria is done under native husbandry or semiintensive management, relatively little information on their reproductive performance is available. However, information on the reproductive performance of Nigerian small ruminants under intensive management conducted at Research Centres or Institutes is readily available (Adu, Buvanendran & Lakpini, 1979; Adu, Brinckman & Kuteyi, 1979; Molokwu & Umunna, 1980; Osinowo & Ekpe, 1985). Such reproductive information includes age at first lambing or kidding, birth weight, lambing or kidding intervals, seasonal effects and conception rates. Although the latter findings are meant for dissemination through Extension Services to rural producers for application, records of the effects of such application are scanty.

Agronomic experiments have shown that nitrogen applied in organic manures gives variable responses in grass growth (van Dijk & Sturm, 1983; Smith, Unwin & Williams, 1985). In a series of field trials in southern England, the average apparent recovery in herbage of the nitrogen from cow slurry was only 13% (Unwin, Pain & Whinham, 1986). The volatilization of ammonia from spread slurry is one possible mechanism for the nitrogen inefficiency (Freney, Simpson & Denmead, 1983; Ryden, 1984). Direct measurements of ammonia loss from land surfaces can be made by micrometeorological methods (Denmead, 1983) and, using the micrometeorological mass balance technique, high rates of ammonia loss were recorded after the land spreading of liquid dairy cattle manure in Canada (Beauchamp, Kidd & Thurtell, 1982). The micrometeorological mass balance method has been used in England to measure ammonia loss from a grazed sward (Ryden & McNeill, 1984). This paper presents the results of an experiment where the same method was used to measure the ammonia loss after land-spreading cattle slurry in Northern Ireland.