Herbage intake by grazing dairy cows can be estimated by measurements on the pasture ('t Mannetje, 1978) or by measurements on the animal (Raymond, 1969; Corbett, 1978). Of the sward sampling techniques, the difference method, based on pre- and post-grazing sampling, has the greatest potential for providing valid estimates of herbage intake, but only when grazing periods are short and stocking densities are relatively high (Pigden & Minson, 1969). Estimates of intake by measurements on the animal are made by the faecal output-indigestibility ratio technique (Raymond, 1969; Corbett, 1978). The most widely used marker for the determination of faecal output is chromic oxide (Cr2O3).

Maize yield was increased by the application of organic mulch (6 t/ha). Mulched plots treated with any of the antitranspirants (kaolin or alachlor) and receiving two or four irrigations yielded as much as untreated plots receiving four or six irrigations. Cob length, number of grains and grain weight of maize were increased by mulching and by the transpiration suppressants. Irrigation water-use efficiency was improved by evapotranspiration control treatments.

The factorial approach to the determination of the dietary requirements of macroelements is a two-stage process; in the first the net requirements are estimated and in the second, the fractional absorption of the dietary mineral is used to convert net to dietary requirements (Agricultural Research Council, 1965). At the first stage the maintenance component is allotted a fixed value, so that estimated dietary requirements are directly proportional to absorbability of the element.

Field studies were carried out to determine the sources of photosynthate for developing pods and to assess the effect of defoliation and flower removal at different stages on the performance of lentil. The leaves of flowering nodes were the primary source of assimilate to pods. Removal of 25–75% of leaves reduced seed yield by varying degrees depending on crop growth stage. The plants compensated for the loss of foliage to some extent, possibly through increased efficiency of the remaining leaves. One complete or 50% defoliation reduced seed yield to different extents at the vegetative, flowering, early pod formation and late pod formation stages, the greatest effect being seen at flowering and early pod formation. Plants compensated considerably by production of new leaves when defoliated at the vegetative phase. Increased moisture supply greatly enhanced the compensation ability of the lentil plants.

Removal of all flowers up to 1–2 weeks after an thesis under unirrigated conditions and up to 3 weeks after anthesis in irrigated conditions did not adversely affect the seed yield. Flower removal beyond this period resulted in a significant reduction in seed yield. Little seed yield was obtained when flower removal was continued for either 6 or 8 weeks under unirrigated conditions. The plants compensated for the loss of earlier-formed flowers by setting pods from later-formed flowers. Compensation was greatly enhanced when the crop was irrigated during the reproductive phase. There was relatively little or no effect of the deflowering treatments on the number of seeds per pod or weight per seed. The flowering period of the deflowered plants was extended and their senescence was delayed. When 25% of the flowers were removed at different intervals during the reproductive phase, seed yield was not adversely affected. An increased intensity of flower removal decreased yield but the decrease was not proportional to the degree of flower removal. The plants apparently compensated by setting new pods.

Early investigations into the effects of the growth retardant chlormequat on wheat and barley showed that in the absence of lodging the number of ears was frequently increased following treatment at the beginning of stem elongation (Humphries, Welbank & Witts, 1965; Alcock, Morgan & Jessop, 1967; Barrett, Meens & Mees, 1967). More recently, earlier applications, at the three-leaf stage, to barley have been shown to be more effective in increasing the number of ears (Koranteng & Matthews, 1982). However, there appears to be little information on the effects on number of ears of early application of chlormequat to winter wheat. Therefore, in 1982 three field experiments were carried out to investigate the effects of early application of chlormequat on the numbers of tillers and ears and grain yield of winter wheat.

Barley (Hordeum vulgare L.), an important cereal crop in India, is grown mostly under rainfed conditions on about 3 million hectares. Vigorous and rapid development of roots of cereals contribute considerably to drought resistance (Genkel, 1961; May, Milthorpe & Milthorpe, 1962; Abdel Rahman, Batanouny & Ezzat, 1967; Bhan, Singh & Singh, 1973; Chang & De Datta, 1975). Many workers (e.g. Abdou & El-Kobbia, 1976; Basu & Gupta, 1974; May et al. 1962; Bozhenko, 1965; Woodruff, 1969; Salim & Todd, 1968; Hussain, May & Aspinall, 1968; Shkolnik & Bozhenko, 1974) have reported that pre-sowing seed treatments increase plant vigour and grain production. The production of barley under rainfed conditions in winter (November–February) depends greatly on the extent to which it can exploit the stored soil moisture after the harvest of the previous crop grown with monsoon rains in India during June–October. The main objective of the study was to dermine to what extent the increase in seedling vigour caused by pre-sowing treatments of seeds can be exploited for increasing the production of barley which has to depend mainly on the continuously depleting soil moisture, after the cessation of monsoon rains, and to investigate the possible reasons for such variations.

Little reliable information is available on the range and variability of the copper content of the wool of sheep (Underwood, 1977), although the effect of Cu deficiency on keratinization and pigmentation of wool is well known (Ryder & Stephenson, 1968) and the Cu content of hair has been suggested as a possible aid in diagnosis of hypocuprosis. Results from Kellaway, Sitorus & Leibholz (1978) showed that, in cattle, Cu in hair and plasma decreased in animals when the concentration of Cu in the liver fell below 20 mg/kg D.M. An experiment carried out jointly by the Animal Breeding Research Organisation and the Animal Diseases Research Association to investigate breed differences in the long-term accumulation of Cu in sheep gave an opportunity to investigate both the range of Cu concentrations in wool and the relationship between the Cu content of the liver and wool Cu.

The ‘conventional’ method of measuring the area of a wool sample patch involves the direct in situ measurement of the patch dimensions while in the field using callipers (Turner et al. 1953). This procedure is time consuming and expensive in terms of labour required. In an attempt to reduce the cost and increase the speed of the procedure in the field a new method was devised and tested.

Since Monteith (1977) proposed that growth can be analysed in terms of the amount of energy intercepted by the leaf surface and the efficiency of its use, there has been much interest in the measurement of light interception in potato crops (Scott & Wilcockson, 1978; Milford et al. 1980; Allen & Scott, 1980). This can be measured directly using tube solarimeters placed horizontally above and below the canopy. However, this method suffers from three major drawbacks: (a) in an experiment with many plots it becomes expensive in terms of equipment, (b) a single solarimeter samples only a very small part of the plot canopy, and (c) the solarimeter cannot distinguish between living leaves and other material. Thus, when the crop lodges and/or starts to senesce, visual observations suggest that the area over the solarimeter may not be representative of the plot as a whole.

Pyrethrum is a small bushy perennial crop cultivated for its flowers which have insecticidal properties. Pyrethrins, the active principles in the flowers, are contact insecticides causing nervous breakdown leading to paralysis and death of insects. Kroll (1963) and Parlevliet, Muturi & Brewer (1968) have shown that the flower yields of pyrethrum could be improved by applying P fertilizer whereas N and K fertilizers did not increase the yields. On the other hand, Mwakha (1979a, b) showed that pyrethrum responds to N fertilizer on soils deficient in N. The present investigation was carried out to study the response of pyrethrum to various rates of application of N, P and K and sources of phosphorus.

Nutritional problems for cultivated plants related to phosphorus (P) and zinc (Zn), among other elements, are common in recent alluvial calcareous soils of Greece. The negative interaction which exists between these two elements aggravates these problems.

As part of their normal behaviour, buffaloes need to wallow in water or mud for a period of the day and, in general, show a greater affinity for water than other domestic ruminants. It has been reported (McFarlane, 1971) that buffaloes turn over more water than other domestic ruminants. This, in turn, should make them more susceptible to deprivation of water, even for short periods. Requirements for water are also known to change with the physiological state of animals. The experiment described in this paper was carried out to compare the effects on the daily turnover of body water in growing, pregnant and lactating buffaloes, under normal management, when denied wallowing and when drinking water was restricted.

The objective of this study was to examine the effect of the chemical growth regulator Terpal (a mixture of mepiquat chloride and ethephon or 2 chloroethyl phosphonic acid) on the pattern of branching, plant height and yield components of winter oil-seed rape (cv. Jet Neuf). Mepiquat chloride (a quaternary ammonium compound with similar antigibberellin properties to cycocel) was developed as a morphoregulator for cotton where it has been shown to reduce plant height, shorten internodes and increase boll retention (Willard et al. 1977). The activity of ethephon has been attributed to its release of ethylene which influences a wide range of developmental processes, for example fruit abscission and ripening (Chatterjee, 1977; Gvozdenovic, Dulic & Slavic, 1978), growth retardation (Van Andel & Verkerke, 1978) and also the extent of lodging in cereals (Hill, Joice & Squires, 1982).

During the last decade, a calcium (Ca) deficiency syndrome, nutritional secondary hyperparathyroidism (NSH), has caused lameness and bone lesions in horses grazing certain tropical grasses in Australia. These grasses contain over 0·5% total oxalate (Walthall & McKenzie, 1976; Blaney, Gartner & McKenzie, 1981a). Blaney et al. (1981a) and McKenzie, Blaney & Gartner (1981) carried out mineral balance experiments with horses fed tropical grass hays or diets with added soluble potassium oxalate. Their results suggested that NSH was caused by the oxalate in the grasses preventing the absorption of Ca. They also suggested that the Ca in the grasses may already be in the form of the insoluble calcium oxalate (Ca(COO)2) salt and thus unavailable to grazing horses. Blaney, Gartner & McKenzie (1981b) subsequently demonstrated that horses could not absorb significant amounts of Ca from Ca(COO)2 crystals added to their diet.

Supermarkets in the U.K. want uniform heads of crisp lettuce weighing at least 450 g and preferably 600 g but it is difficult to meet these requirements consistently throughout the season because there can be considerable variation in head weight both between and within sowings. In the butterhead lettuce crop the synchronization of seedling emergence, which was responsible for a large proportion of the variation in head weight at maturity (Gray, 1976), was improved by fluid sowing pre-germinated seed (Gray, 1978a, 6). Finch-Savage & Cox (1983) have also shown with butterhead lettuce that pre-germinated seed emerged earlier and produced earlier-maturing, heavier heads than dry seed and that the addition of sodium phosphate to the gel further advanced maturity and increased head weight. Therefore, fluid sowing pre-germinated seed of crisp lettuce in a gel containing phosphate might be expected to reduce variation in seedling emergence and to improve head weight and the uniformity of head weight at maturity.

Coriander is an important aromatic plant of India. On steam distillation, the seeds yield a colourless or pale yellow volatile essential oil, which is used for flavouring food products, liqueurs, alcoholic beverages and perfumes. Coriander is also used in the synthesis of vitamin A (Bedoukian, 1967). The Central Institute of Medicinal and Aromatic Plants introduced several Bulgarian selections of coriander and evolved a superior variety, CIMPO S-33. This variety contains more essential oil (about 1·5%) than the local varieties available in India (0·2–0·3%) (Dimri, Khan & Narayana, 1976). Earlier work on coriander has shown that application of N (Bhupinder Singh et al. 1979) and N, P and K (Vagujfalvi, 1964) increases seed and oil yields of coriander. Information on nutrient uptake by coriander and on the effect of fertilizers on coriander oil quality is not available in India. The present experiment was designed to study the effect of different rates of nitrogen, phosphorus and potassium application on seed yield, yield and quality of essential oil and N, P and K uptake by coriander (cv. CIMPO S-33).

Rape (Brassica campestris L.) is well adapted to the Bangladesh climate and is an important oil crop of the northern part of Bangladesh. It requires a shorter growing season than any other crop of this kind but is less resistant to drought, which causes considerable damage to the crop by reducing total green area during late December and January and results in a poor yield. Considerable increase of rape-seed production will be possible through the elimination of drought by irrigation, the right supply of nutrients and application of proper cultural practices. We report here on studies of the effect of fertilizer under irrigated and non-irrigated conditions on the seed yield, oil content and some seed yield associated characters of rape and the importance of irrigation in rape cultivation in Bangladesh.