Simple methods are described for the analysis of daily rainfall measurements. The distinctive feature is that each year provides one number for any event or characteristic of interest. The resulting observations are then analysed, assuming that they are a simple random sample from a single distribution. An estimate of the probability of an event can be made directly from its relative frequency of occurrence, or alternatively a distribution (such as the normal) can be fitted. The methods are applied to agronomic questions on dry spells, the start, end and length of the growing season, and the distribution of amounts of rainfall through the year. Examples are given from Nigeria and India.

A probabilistic model of daily rainfall can be used to derive results of potential value to agriculture. A simple example shows how this model works, but more realistic models are also fitted, using standard statistical computer packages, and examples of the results are presented graphically. The modelling approach is compared and contrasted with direct methods of analysing daily rainfall.

The integration of a microcomputer-based data-capture and data-processing system into an existing mainframe computing environment in a crop research institute is described. The system includes hand-held data terminals and electronic balances. Some computing terms are explained in an appendix.

We describe the insertion and reinstatement of a simple lined access pit that allows for the permanent installation of tensiometers, piezometers, etc. in soil that is cultivated annually. The presence of the access pit did not affect the hydrology of the soil in its vicinity. We give an example of the application of results from tensiometers permanently installed in this way.

A series of experiments was designed to evaluate a wide range of possible cropping systems for deep Vertisols of the Indian semi-arid tropics. The introduction of a rainy season maize crop, compared with traditional fallowing, had little effect on the yields of post-rainy season crops of sorghum, chickpea and pigeonpea. Introducing a rainy season sorghum crop caused severe yield reductions of post-rainy season crops in one year but only slight reductions in two subsequent years. Intercrop systems of maize/pigeonpea or sorghum/pigeonpea, and a three-crop system of maize/pigeonpea/chickpea, appeared very promising. Gross returns were usually much higher for the improved systems that utilized both the rainy and post-rainy seasons, though differences in net returns were not quite so great because of the extra costs of growing the additional rainy season crops.

Significant differences were found between 20 chickpea cultivars and four locations in respect of the concentration of protein in the seeds. Cultivar x location interactions were also significant. The average protein concentration among cultivars varied from 18.5 to 23.2% and among locations from 18.3 to 22.7%. Correlations between seed protein concentration and seed yield and seed size were very small. Protein concentration was influenced by available nitrogen in the soil.

In maximizing productivity levels in oilseed sesame (Sesamum indicum) one of the major constraints is the large-scale shedding of buds, flowers and capsules. The present study examines the reproductive behaviour of five sesame genotypes with a view to ascertaining the extent of production, shedding and retention of different reproductive organs. Sesame genotypes produce 250–350 flower buds per plant but shed most of them at different stages of development. Shedding is thus excessive, and 86–91% of the reproductive potential was not realized in this study, thus limiting yield. Improvement in yield through increased fruit retention is essential.

COCA (highland), TZPB (lowland) and COCA x TZPB maize varieties were tested at Bambui Plain (1330 m) and Ekona (550 m). Leaf blight and rust were controlled chemically with Dithane-M45 and Benlate, and their use significantly increased the yields of COCA when grown in lowland environments, where it does not possess resistance to lowland leaf blight (H. maydis) and rust (P. polysora); yields of TZPB were similarly increased in highland areas, where it is susceptible to highland leaf blight (H. turcicum) and rust (P. sorghi). COCA x TZPB was intermediate in resistance to both diseases at the two locations.

Papaver bracteatum Lindl., a potential source for codeine production, is a perennial species which is known to flower from the second year of growth. Through selection and early planting date, a high flowering rate (96%) was achieved during the first growing season. The flowering response and yield of capsules were very sensitive to planting date and seedling type. Delaying planting markedly decreased both flowering rate and yield of capsules in the first year. Direct sowing was more advantageous than transplanting. A yield of 36 g/m2 of dry de-seeded capsules was obtained during the first growing season by direct sowing in late summer.

Time of planting was found to significantly influence insect damage, quality of harvest and yield of cowpea in southern Nigeria. The greatest insect damage occurred on the August planting. Maruca testulalis was the most serious pest on cowpea whilst thrips were the least. Dry grain yield was higher in the early season plantings but quality of harvested crop was better in the late season plantings. These observations were also influenced by cultivar differences.

In trials conducted over five years, data on pest (insect, disease, bird) attack and yield of sorghum cultivar 65D were accumulated. A modified analytical method of damage assessment is described, which includes consideration of all pest occurrences and different levels and timing of pest attack. There was a positive correlation between crop yield and rainfall. The selective infestation of stronger plants, or the ability of those plants to support pest populations, is shown; thus, in most cases, yield reductions are masked. The importance of the tillering habit of 65D on yield, and its ability to compensate for pest damage by further tillering, are shown. A cultivar which does not normally tiller was tested in the final year. Effects on yield of all the pests encountered in the five years are discussed.