This paper describes the design of six data-recording forms which have been found to be acceptable by both field workers and data-processing staff. The reasons for the choice of design and hints on how to present the data are also given.

Future research in agronomy will doubtless lay stress on the efficient use of inputs by applying them during the most appropriate development phases of the plant, and by modifying those phases, which in some cases can now be well defined. The plant can often be influenced or stimulated well before the effect commences, storing the stimulus for the future, and the terms ‘Receptive Phase’ and ‘Responsive Phase’ are proposed to describe these stages. To apply research most effectively, receptive phases should be delimited and linked with responsive phases in a way convenient for the agronomist. Schematic diagrams can be prepared relating growth phases to field appearance, as is illustrated by examples based on cotton, rice, maize and apple.

Two field experiments were conducted to evaluate the effectiveness of several pelleting materials in increasing the yields of cowpea (Vigna unguiculata (L.) Walp.) and soyabean (Glycine max (L.) Merr.) on acid soils in Sierra Leone. The results demonstrated the beneficial effect of molybdenum, applied either alone or in combination with rock phosphate, in improving growth and yield of cowpea. The beneficial effect of molybdenum was comparable (Exp. 1) or greater (Exp. 2) than the effect of liming with 3 t/ha basic slag. However, none of the coating materials had any effect on soyabean growth and yield, although molybdenum significantly increased nodules/plant. Calcium carbonate and basic slag pelletings were ineffective in both crops.

Cotton is widely grown as a cash crop by subsistence farmers of Northern Nigeria, although it is invariably sown too late to produce yields that would allow economic use of insecticides to control insect pests. This late sowing is because subsistence farmers always emphasize the production of food crops, delaying sowing of cotton until these are established. Experiments are described in which cotton was sown early within the cereal, without affecting cereal yields yet producing significantly greater cash returns than sole cereal.

Alternate row mixtures of millet, maize and sorghum were compared with equivalent areas of sole crops. Yield of mixtures were rarely reduced but there was a gain when components differed by a certain margin in height or age at maturity, or both. Approximately 75% of variation in yield gain from mixing was attributable to these two factors. Subsistence farmers who mix a fast-growing early-maturing cereal with a slower-growing, later-maturing one thus reduce interference between neighbouring plants during the reproductive phase of growth, and obtain grain harvest spread in time and heavier than from equivalent areas of the component sole crops.

In contrast to earlier results, a clear advantage from mixed cropping of maize and beans (Phaseolus vulgaris) was found in the long-rain seasons (March to September) of 1976 and 1977. Pure stand yields were low due to drought in 1976 and excessive rainfall in 1977. These and other results for long-rain seasons in Kenya suggest that mixtures are more efficient where pure stand yield levels are low, but there is little difference between cropping systems where levels are high. Light interception by maize leaves was quite small until late in the life of the bean crop.

The effect of soil salinity on growth and yield of broad bean was investigated, using correlation analysis. The salinity level at which 50% reduction in bean yield occurred was 9 mmho/cm. The negative correlation between dry matter production and yield and ECe, together with the field observations, indicated that soil salinity may be responsible for the different growth and yield of broad bean fields in the salt-affected areas of northern Sudan.

Oil content (percentage) was determined by pulsed nuclear magnetic spectrometry to study its variability in rai (Brassica juncea) and yellow sarson (B. campestris). Wide inter-varietal and intra-varietal variability was observed in both crops. Genetic aspects of oil content were also worked out, and single-plant and bulk selection methods used for 3 years to exploit the intra-varietal variability. A positive trend in the improvement of oil percentage was observed in 27 out of 30 varieties, some of which showed significant improvements over their respective unselected stocks. A maximum increment of 7% was observed in variety BR 40 of rai and 6% in variety YSM of yellow sarson.

Maize was grown from three batches of seed, with mean 1000-grain weights of 225, 432 and 649 g. Initial plant size was larger when grown from large seed, but development rates were similar for all three sizes and relative growth rates were similar during the early stages. Relative differences in plant size became smaller as the crop matured. Crop growth rates during the linear phase of dry matter production were the same, and there were no significant yield differences. Comparisons of leaf and spikelet initiation, and individual leaf size are also reported.

Seed dormancy was found in the Mexican sesame cultivar Cola de Borrego but it disappeared about 6 months after harvest. Dormancy was completely broken by soaking the seeds in GA3 solutions of 100 and 500 ppm for 48 h; soaking in 1000 ppm GA3 concentration was helpful but not as good as the 100 and 500 ppm treatments. GA3 treatments also hastened emergence.

This study examined the economic, technical, and social feasibility of an improved groundnut production technology at the farmer's level vis-à-vis traditional practices. Improved practices are shown to be superior, but several economic and technical issues are raised.

Pigeonpeas (Cajanus cajan) are normally sown in June or July in India, at the beginning of the monsoon, but trials were carried out at Hyderabad by sowing in October or November as a winter crop. The duration of the crop, especially of the ‘medium’ and ‘late’ cultivars, was much reduced. In 1975–76, October-sown pigeonpeas gave yields comparable to those of the normal season but much lower yields were produced by planting in November 1975. ‘Medium’ and ‘late’ cultivars significantly outyielded early ones. Optimum plant populations for winter crops were 3–5 times higher than are normally used in the monsoon. Pigeonpeas at relatively high population densities could have considerable potential as a winter crop in peninsular India.

An aqueous solution of a morphactin (chlorflurenol) was applied at 100–1000 ppm to plants of corn (Zea mays L.) variety White Ganga-2 to examine its influence on growth, sex expression, yield and carbohydrates in the grain. At concentrations up to 600 ppm morphactin decreased height, weakened apical dominance, increased the number of tillers and thickness of stem, and caused an appreciable increase in female sex expression, yield and carbohydrates in the grain but reduced them at 800 and 1000 ppm.

The effects of nitrogen fertilization and cutting intervals on extractable protein have been studied in three arid zone grasses, viz. Cenchrus setigerus, C. ciliaris and Lasiurus sindicus. Depending on the number of cuts and soil fertility status, maximum protein could be harvested from C. ciliaris followed by C. setigerus and L. sindicus. It is concluded that the maximum yield of leaf protein per unit area of land can be achieved with short intervals of cutting coupled with the application of nitrogenous fertilizer.

Three field experiments were conducted at Guneid, Sudan, in which N was applied to sugarcane (A) in one dose, (B) in split doses at 2 and 4 months, and (C) as a single dose 4 months from planting. Nitrogen application generally increased the yields of both cane and sugar but did not significantly affect sucrose recovery. Correlation coefficients for yields of cane and sugar suggested that the application of 88–176 kg N/ha 2 months after planting was economic.