In two experiments, carried out on non-irrigated fields in the Northern Negev region of Israel, inoculation of Sorghum bicolor with bacteria of the genus Azospirillum resulted in significant increases over controls of 17% in grain yield of cv. 610 and of 19% in the forage yield of cv. 6078. In addition, significant increases over controls in plant dry weight, mineral content (N, P and K) and panicle number were obtained by inoculation of cv. 610.

Ramie (Boehmeria nivea Gaud.), which can provide fodder in addition to bast fibre, was supplied with nitrogen in three different forms: as neem cake coated urea (NCU), lac coated urea (LCU) and standard urea, at rates of 60, 120, 180, 240 and 300 kg N ha−1 annually in four equal applications. The ramie was cut four times a year for two years. NCU increased fresh weight, leaf dry matter yield and leaf protein at almost every cutting compared with the other forms of nitrogen, and there was an indication of increased residual nitrogen in the soil. Leaf dry matter and protein content increased with increasing levels of nitrogen up to 180 kg ha−1. It is suggested that coating urea with neem cake makes it a better source of nitrogen for ramie leaf production.

The effects of irrigation and spraying of transpiration suppressants on growth and nutrient uptake by spring sorghum (CSH 6) have been investigated. Crop growth, measured by plant-height, leaf area index and dry matter production, and uptake of N, P and K increased with more frequent irrigation and in response to the spraying of transpiration suppressants. Foliar applications of atrazine at 200 g ha−1 and CCC at 300 ml ha−1 proved to be the best in this NW Indian location.

A field technique to screen large numbers of pearl millet and sorghum lines for seedling emergence through soil crusts is described. Seeds were sown on raised broad beds in an Alfisol field. The beds were smoothed after sowing with a bed shaper. Thirty five mm of water was applied from two parallel lines of sprinklers at a rate of 14 mm per hour. A crust of relatively constant strength in different tests developed as the surface dried out. The crust was broken in the control treatment with a crust breaker. The ratio of emergence under crust to that under control (c/u ratio) was used to classify the test materials.

The Land Equivalent Ratio (LER) has been generally accepted as an agronomically sound index for assessing yield advantages derived from an intercropping practice. However, LER takes no account of the fact that, in subsistance agriculture, it is usually important to maintain a certain minimum percentage of the pure stand yield of the staple crop component in an intercropping system. A new measure ‘Staple Land Equivalent Ratio’ (SLER) is proposed in this paper which takes account of this requirement. Yield data from intercropping experiments are used to show how SLER can be effective in comparing the yield advantages of intercrop treatments in agronomic experiments.

Cassava (Manihot esculenta Crantz) has generally been reported to possess hypostomatal leaves. Several cultivars have now been found to possess clusters of functional stomata around the veins on the upper leaf surface and two cultivars (M Col 88 and M Col 90) have significant numbers of stomata (83–140 mm−2) dispersed over the entire upper leaf surface. Stomatal density on the lower leaf surface ranged from 322–553 mm−2 among cultivars, with a relative stomatal area of 3.4–6.1%. The CO2 uptake by the upper leaf surface (27% of total) and the transpiration loss (32% of total) corresponded closely to the ratio of relative stomatal areas on the upper and lower leaf surface of cv. M Col 88.

Six intercropping systems and four levels of nitrogen were compared at the Indian Agricultural Research Institute, New Delhi, in the summer rainy seasons (July-October) of 1978 and 1979. The maximum increase in sorghum yield was obtained when it was associated with fodder cowpea, followed by association with grain cowpea and greengram. The application of 40, 80 and 120 kg N ha−1 increased sorghum yield by 8.6, 16.1 and 18.2% in 1978 and by 2.9, 8.1 and 14.1% in 1979, respectively, compared with unfertilized sorghum. The nitrogen uptake by sorghum, and by the total system, was greater in sorghum-legume intercropping systems than in sole sorghum. Nitrogen application also increased the nitrogen uptake by sorghum and by the whole system.

The results of a two year field study to determine the effect of iron on the yield of maize in the forest and savanna zones of Nigeria have indicated that new and old fields in the savanna, and old fields in the forest zone, require additional iron. The optimum iron requirement for maize in both zones is 3 kg ha−1.

Plants of two genotypes of chickpea (Cicer arietinum), classified as early or late-maturing in the field, and relying either on dinitrogen fixation by nodules or on nitrate-N, were grown in various simulated tropical environments in growth cabinets. Plants were transferred between cabinets at various times so that they experienced either warm (30°C) or hot (35°C) days (both in combination with a typical night temperature of 10°C) for different durations of reproductive growth, after growing in average (30°C day - 10°C night) or warmer than average (30° - 18°C) temperatures for the first 28 days from sowing and then average temperatures until transferred into the hot regime. Diurnal vapour pressure deficits were adjusted so that plants experienced a constant atmospheric relative himidity (70%) in all thermal regimes. The greater the proportion of the reproductive period spent in hot days the smaller the seed yields produced; plants transferred at 50% flowering were almost barren. The implications of these data for breeding chickpeas well adapted to hot environments are discussed.

Wheat yield was increased significantly when grown after sorghum intercropped with cowpeas (both for fodder and grain) or with groundnut compared with sole sorghum in the previous season. The nitrogen requirement for the target wheat yield of 4.0 t ha−1 was 108 kg ha−1 after sole sorghum and this was reduced by 87, 61, 83 and 38 kg ha−1 after intercrops of sorghum with fodder and grain cowpeas, groundnut and greengram, respectively. The different levels of nitrogen applied to the sorghum-legume intercropping systems also allowed savings of between 18 and 55 kg ha−1 of fertilizer nitrogen on wheat in the following season.

Bush area, shoot number and yield were all strongly and positively correlated in 100 young seedling tea bushes. Clones derived from the bushes exhibited characteristics which were correlated with those of the mother bushes, indicating the usefulness of these observations in the selection of clones for improved performance.