One of the most widely used methods of root study involves obtaining soil cores and washing the roots contained free of soil (Wellbank & Williams, 1968; Ellis & Barnes, 1971; Kolesnikov, 1971; Schuurman & Geodewaagen, 1971; Bohm, Maduakor & Taylor, 1977). However, the process of root washing is time consuming and laborious. Some of the washing assemblies elsewhere (Peyev, 1952; Schuurman & Goedewaagen, 1971; Wellbank et al. 1974) have not gained popularity with researchers in developing countries because of the high costs involved or the sophisticated facilities needed. There is therefore a need for a low-cost root washing apparatus which can be fabricated with locally available materials. This note reports the development of such an apparatus.

Corolla colour in chickpea (Cicer arietinum L.) is white or various shades of pink or blue (Smithson, Thompson & Summerfield, 1985). Normally, a leaf axil subtends a single peduncle bearing a single flower but ‘double-flowered’ types, where a pro-portion of the peduncles subtends two flowers, are not uncommon and produce 6–11 % more seed yield than the normal single-flowered type (Sheldrake, Saxena & Krishnamurthy, 1978)

Effects of mepiquat chloride on gradients of shoot growth within spring barley plants (cv. Koru) were determined in two small-scale field experiments. Mepiquat chloride was applied at either the lemma primordium stage or the late carpel primordium stage of spike development in the main shoot. The shoot dry weight, stem length, spike length, number and size of florets and floret developmental score were measured for all shoots, over the period from the lemma primordium stage of main shoot spike development to the late milk stage of grain development.

Lemma primordium mepiquat chloride increased the size and developmental score of later-formed shorter shoots pre-anthesis while delaying the spike development of the main shoot and other longer shoots by up to 4 days. The overall effect was to produce plants with a reduced range of shoot and spike sizes from the end of floret initiation in the main shoot until maturity. In addition, there was a slight increase in the number of shoots per plant in both experiments. Gradients of carpel development and carpel width along the spike were reduced in all treated spikes by the time of floret abortion in the main shoot but the effects were more noticeable in shorter shoots. The number of florets initiated per plant was increased by 21–22%. All shoots contributed to the larger number of florets but again the major additions came from the shorter shoots. The few extra florets initiated in longer shoots were lost during abortion of distal florets while the 2–5 extra florets on shorter shoots were retained to give extra grains at maturity.

Application of mepiquat chloride at the late carpel primordium stage had little effect on gradients of spike size or on number, size and development of florets.

The Agricultural Research Council (1980) has recently published revised estimates of the phosphorus requirements for ruminants. These new estimates are considerably lower than those formerly recommended (Agricultural Research Council, 1965) and some concern has been expressed as to whether or not they are adequate (Cooke, 1982; Todd, 1983).

The salt tolerance of five muskmelon (Cucumis melo L.) cultivars Hara Madhu, Punjab Sunhari, Punjab Hybrid, Pusa Madhuras and Durgapur Madhu was assessed in field plots artificially salinized with NaCl and CaCl2. Percentage germination and melon yield of all the cultivars decreased linearly with increasing soil salinity. Decline in percentage germination with increasing salinity differed with cultivar. If soil salinity exceeded 1·11 dS/m, mean germination of muskmelon decreased at a rate of 9% per unit increase in soil salinity. Similarly melon yield decreased at a rate of 8·73% for each unit of EC exceeding 103 dS/m. Hara Madhu had the highest rate of yield drop per unit salinity increase. The salt tolerance limit of muskmelon was found to be associated with soil ECe value of about 5·20–6·32 dS/m.

Japanese mint, an important essential-oil-bearing crop, is cultivated for menthol used in cosmetic and pharmaceutical industries. It requires a high level of nitrogen fertilizer, between 150 and 250 kg N/ha depending on the agro-climatic conditions (Ghosh & Chatterjee, 1976; Yadav, Mohan & Ram, 1983). During the crop cycle (January–August), frequent irrigations and high intensive rains result in poor N recovery especially on light-textured soils. With a view to reduce losses of N and improve N recoveries, the relative efficiency of neem-cake-coated urea, laccoated urea and urea supergranules has been investigated in comparison with prilled urea in Japanese mint.

Studies on productivity of pigeonpea-wheat cropping systems at the Indian Agricultural Research Institute, New Delhi during 1984–6 revealed that wheat following summer pigeonpea and given 120 kg N/ha produced 4–93, as compared with 451 t grain/ha when it succeeded kharif pigeonpea. Intercropping of preceding pigeonpea with dhaincha for green manure, fodder cowpea and greengram (grain) gave higher yields of 4·35, 397 and 3·68 t/ha respectively than the wheat following pigeonpea alone (3·20 t/ha). Similar effects on wheat straw were also recorded. Summer-sown pigeonpea produced 2·38 t grain/ha without any adverse effect of intercrops. However, kharif pigeonpea produced grain yield half of that obtained in the summer-sown crop. Further, the reductions in grain yield of kharif pigeonpea due to dhaincha, cowpea and greengram were 0·60, 0·52 and 030 t/ha, respectively. Summer pigeonpea + dhaincha-wheat and summer pigeonpea+greengram-wheat proved their superiority over other cropping systems.

Improved management compared with traditional practices common in northern Syria for growing field bean (Vicia faba L.), chickpea (Cicer arietinum), lentil (Lens culinaris), peas (Pisum sativum) and vetch (Vicia sativa) was shown to increase significantly (P < 0·001) the crop nitrogen (N) uptake and subsequent protein yields in either hay, grain or straw. This intervention more than doubled N uptake in 1982–3 when averaged over crops and locations increasing from 31·8 kg N/ha under traditional management to 68·7 kg N/ha under improved management. Improved management also increased the proportion of nitrogen uptake that was derived from symbiotic nitrogen fixation by the crop from 55 to 69%. The treatments which gave improved crop N uptake were application of phosphate fertilizer, reduced row spacing and control of weeds. Seed inoculation with rhizobia had little or no effect on N uptake or on the proportion of N that was fixed biologically by the crop. Environmental effects on productivity, as expressed by seasonal and locational differences, were as, or more, important than management-imposed effects.

Differences in N uptake by barley, following either a legume crop or barley, indicated that the residual effects of the legume crop amounted to approximately 10 kg N/ha. This represents a substantial contribution to the N nutrition of a barley crop in the dry areas of northern Syria.

Pearl millet is the choice crop in the semi-arid tropics. Strong winds, intense storms, high solar radiation and extreme temperatures are characteristics of these zones. Germination and seedling establishment are the major problems and are commonly associated with low moisture availability, high temperature of the soil and soil crusting. Water stress can affect germination by delaying initiation of germination, slowing rate of germination or by decreasing final germination percentage.

The treatment of straw using ammonia released by the hydrolysis of urea and subsequent improvements obtained in digestibility of straws have been reported (Jayasuriya & Pearce, 1983; Williams, Innes & Brewer, 1984). Benefits achieved by this method compare well with those obtained by sodium hydroxide (Verma, 1983). Urea is widely and cheaply available in many developing countries; this favours its use in improving nutritive values of low quality roughages. In addition, this method is relatively safe, uncomplicated and inexpensive compared with some other chemical treatments. Considerable attention has been paid to the treatment conditions for treating cereal straws with liquid or anhydrous ammonia which lead to the optimum effects (Waagepetersen & Vestergaard Thomsen, 1977; Solaiman, Horn & Owen, 1979; Borhami & Sundstøl, 1982), but equivalent studies on the ammoniation of crop residues through urea are limited (Cloete & Kritzinger, 1984; Singh & Negi, 1985). No report is available on the changes in in sacco dry-matter digestibility (DMD) of urea ammoniated straw during treatment at different temperatures. This paper describes our observations on the changes in in sacco DMD of urea ammoniated wheat straw at different treatment times and temperatures.

Weaned cross-bred lambs either grazed mature pasture or were confined to yards where they were offered material cut from ungrazed areas of the same pasture. A 1:2 mixture (on an air-dry basis) of sunflower meal and oat grain was offered for 81 days at 0, 200, 400 or 600 g/head or ad libitum. Individual estimates of intake of pasture and supplement by grazing sheep at four levels of supplementation were made on four adjacent plots.

Weight gain increased from –30 to 178 g/day in the grazing animals as supplement intake increased up to 1030 g D.M./day and from –25 to 142 g/day in the yarded animals as supplement intake increased to 1076 g D.M./day. Growth of greasy wool increased from 4·5 to 11·7 g/day for grazing animals and from 4·5 to 10·2 g/day for those kept in yards.

At levels of supplement intake below 400 g D.M./day, the intake of grazed pasture increased by up to 58% compared with unsupplemented animals. However, when the intake of supplement was increased to about 650 g D.M./day, pasture intake fell, with an estimated substitution rate of 1·1 g D.M. pasture per g D.M. supplement. At all levels of supplementation, the intake of hay by the yarded lambs was less than half the intake of herbage in the field. However, at levels of supplement intake between 300 and 500 g D.M./day, the substitution rate was similar to that measured in the grazing animals, suggesting that this is an attribute of roughage quality, rather than differential eating behaviour between grazing and yarded animals.

The wastage, w (g D.M./day), of supplement was linearly related to the amount offered, s (g D.M./day), by the equation

w = 0·263s − 38·8; R2 = 0·89

Variability in supplement intake between individual grazing lambs was not affected by the level of supplementation but the coefficient of variation of supplement intake was considerably greater than that of the intake of unsupplemented pasture. Variability in the intake of pasture increased with the level of supplementation but variability in the total intake of food was similar at each level of supplement, indicating some degree of individual compensation in the intake of the two components.

A central issue in the husbandry of seed crops of perennial tropical grasses is the disposal of residues from previous crops. Flowering of these grasses is usually poorly synchronized, and the sudden removal of all shoot material by burning, mechanical removal or stock concentration is necessary to create a population of tillers of similar age (Humphreys & Riveros, 1986). There has been little critical study of alternative systems of residue disposal and their effects on the ways in which seed yield is realized. Questions requiring attention are whether cutting differs from burning in its effects, and whether the fuel load, determined by the size of the previous crop, influences the potentially damaging effect of fire on crown buds.

There is considerable evidence that stress causes an increase in plasma cortisol concentrations in sheep (Stephens, 1980). Stress had deleterious effects on female reproductive efficiency (Christian, Lloyd & Davies, 1965) possibly, in part, by suppression of gonadotrophin release by increased pituitaryadrenal activity (Wagner & Li, 1982; Moberg, 1984). Previous experiments from our laboratory (Dobson, Essawy & Alam, 1988) have shown that administration of synthetic adrenocorticotrophin hormone (ACTH 1–24) results both in increased cortisol release and suppression of the luteinizing hormone (LH) response to gonadotrophin releasing hormone (GnRH). The purpose of the present experiment was to investigate whether LH release is suppressed in ewes subjected to an environmental stressor.

Grain yield of blackgram or urdbean, a popular and highly proteinaceous pulse crop of India, is very low. This is possibly because of its cultivation on marginal and submarginal lands of low soil fertility where little attention is paid to adequate fertilizer, especially phosphorus and nitrogen. Although large achievements have undoubtedly been made in plant nutrition in cereals like wheat and rice, much less attention has been devoted to the development of suitable agro-techniques for production of pulses, especially blackgram. Inoculation with efficient Rhizobium strains and fertility management are important in the production technology of this crop. Though blackgram is regarded as excellent in symbiotic nitrogen fixation, many workers (Pate & Dart, 1961; Shanthakumari & Sinha, 1974) have opined that actual nitrogen fixation starts about 3 weeks after sowing and the senescence of nodules after profuse flowering. This results in nitrogen hunger at initial stages of crop growth as well as in the reproductive stage. Beneficial effects of starter nitrogen in blackgram have been reported by some workers (Singh et al. 1975). However, symbiotic nitrogen fixation may not be adequate to satisfy the N need of developing pods. Since no information is available on the effect of top dressing of nitrogen in the reproductive phase, the present investigations were planned to study the effect of Rhizobium. inoculation and phosphorus as well as time and method of N application on growth and yield of blackgram and its residual effect on fodder sorghum.