The effect of sowing time and variety were tested for three consecutive years under irrigated conditions. The relation between yield and planting time was quadratic, best described by y=a+bx-ex2 where y is grain yield and x is planting time. The results showed that, irrespective of variety, the optimum sowing date is around mid-November. Varietal differences are related to number of ears per unit area, with a stronger association of yield with grain weight than with any other yield components.

The response of cassava to CCC was investigated by applying concentrations of 0, 500, 1000, 1500 and 2000 ppm twice or four times as a foliar spray, which resulted in a significantly greater tuber yield than the control with most marked effects at the final harvest. CCC at 1500 ppm, applied four times at various growth stages, gave the best increase in tuber yield. Application of CCC tended to cause greater RGR and dry matter content (percentage) of tubers.

Smallholders in south-east Tanzania grow the groundnut Red Mwitunde (Arachis hypogaea ssp. hypogaea), a long-season variety with seed dormancy, although earlier maturing varieties with no seed dormancy (ssp. hypogaea and fastigiata) usually yielded better in trials, particularly when late sown. Small-seeded, short-season varieties established better in the field than Red Mwitunde and other large-seeded varieties, especially under moisture stress. Trials with selective fungicides to estimate yield losses from leafspots (mainly Cercosporidium personatum) and rust (Puccinia arachidis), jointly and separately, showed no consistent varietal differences.

The use of tropical grass–legume mixtures containing the grasses Brachiaria decumbens or Andropogon gayanus associated with a mixture of several herbaceous legumes was tested on farms in the rainforest area of Pucallpa, Peru. Pastures were established by farmers using manual labour and without fertilizer in previously deforested areas covered with secondary growth. The pastures, together with their grass-alone control, were incorporated by farmers into the normal paddock rotation, and were grazed by dual-purpose cattle of mixed breeding. Cows were milked once daily by hand and with their calves at foot. Following a training period, farmers kept records of milk yields. Frequent and unannounced visits at milking time by the research team were used to verify milk yields and to annotate events such as calving, drying out, sales and others. Across farms and years, grass–legume mixtures significantly outyielded grass-alone pastures by 9%. Milk yields on the mixed pastures were examined further by stepwise regression. A positive and significant effect of the proportion of crossbred cows in the herd was established, whereas soil quality (evaluated by the percentage of aluminium saturation) had a negative impact on milk yields. Two of the farms, which for different circumstances had poorer than average animal and pasture management, also had a significantly negative effect on milk yield. The interactions between animal and pasture management, and regional infrastructure are discussed. It is concluded that grass–legume mixtures increased milk yields on farms. Nevertheless, it is also hypothesized that they may have a more restricted niche than anticipated and that their adoption may be highly sensitive to the overall economic context of the region.

Castor beans grew well in sandy soils in U.A.R. where field crops had previously failed to produce good yields. Calcium nitrate up to 300 kg. per feddan resulted in increased yields of seeds and oil in a two-year experiment. Better yields were obtained by increasing the number of plants up to 3 per hill at distances of 45 cm. apart. The oil percentage and other properties were not influenced by nitrogen fertilizers or plant density.

Four trials are described on the effects of spraying and cultural practices on pests and yields of seed cotton. Precropping with sorghum or beans after opening from a ley did not reduce yields of cotton compared to the recommended practice of ploughing a ley 6 weeks before sowing, but late ploughing and late sowing reduced yields. Nitrogenous fertilizer after a successful ley did not increase yields, but multiple sprays (up to twelve) significantly increased them over the recommended standard four spray regime, and reduced the percentage of stained seed cotton. In general cultural practices did not affect the level of pest attack, but DDT spraying gave excellent control of Heliothis armigera, while dimethoate prevented the build up of red mite (Tetranychus telarius) and gave excellent control of tea mite (Polyphagotarsonemus latus) in the multiple spray regimes.