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.

In nine breeding trials with cocoa in Ghana the experimental trees were interplanted with temporary trees of a standard variety as ‘calibrators’. The calibrators were removed after 2–2½ years before there was strong competition with the permanent trees. Trunk diameters of the calibrators were used as covariates in analyses of trunk size and yield of dry cocoa up to 7 years after planting, giving reductions in standard errors of differences between progenies of up to 25% in analyses of size and 15% in analyses of yield.

There is wide variation in the morphological characteristics of sweet potato leaf tips which are acceptable as a vegetable for human consumption. Thus many cultivars are available from which further selections can be made for yield, palatability, tenderness, flavour, and nutritional quality. A list is given of some cultivars which combine a number of desirable traits.

Many of the papers submitted to this Journal fall far short of the standard of presentation that editors are entitled to expect. This tends to sour the all-important relation between editor and author, making unnecessary work for the former and perhaps even prejudicing acceptance of the latter's paper. The author, typist, editor and copy-editor have specific roles to play in preparing copy for the compositor and this article explains those roles, in the hope that the explanation may help authors to present their papers in the correct form.

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.

Yields of sweet potato tips varied from 10 to 16 t/ha in weight and 61 to 352/m2 in number, whilst yields of marketable roots varied from 1 to 16 t/ha. Cultivar differences in dry matter, fibre, ash, vitamin B2 and oxalate were also observed. The tips appeared to provide an excellent source of vitamin B2 which is important for Asian diets deficient in this vitamin. Application of 120 kg N/ha gave higher tip yields than no nitrogen, primarily due to increases in their number and size. Among the leaf types evaluated, Kinangkong (a fine leaf cultivar) produced the highest yield, and had the highest amount of protein, lowest oxalate, and fairly high dry matter, which makes it a very desirable leafy vegetable.

Uptake of nitrogen, phosphorus and potassium was measured for irrigated and unirrigated crops of pearl millet grown at Hyderabad, India. Irrigation slightly increased the concentration of nutrients in the crop and this, together with a higher dry weight, resulted in the nutrient content at harvest (day 82) being approximately twice that of the dry crop. Nutrient uptake by the latter ceased at about day 40 whereas the irrigated crop continued to take up nutrients for a further 7–21 days. However, both crops showed the importance of redistribution of nutrients from leaves and stems during the grain filling. The mean rate of nutrient uptake per metre of root per day (inflow) fell throughout growth in contrast with the rate of nutrient uptake per plant, which reached a maximum at about days 26 to 33. These findings are discussed in relation to possible strategies for fertilizer placement.

In trials of seedling cocoa in Ghana, biases in the estimates of yield and tree size arising on the perimeters of experiments and on the interfaces of unguarded plots were strongly correlated, characteristic of progenies and stable across environments, but were inconsistent for black pod losses. No variate showed progeny × site interactions, but those of Caribbean yield data were interpreted by principal components analysis. The results show that 25-tree plots may be used for initial tests of new varieties and, as long as the environmental variation does not exceed that of the Ghanaian trials, at single sites.

An experiment was conducted during the minor season in Sierra Leone to determine the optimum planting date for a photo-insensitive cowpea cultivar and study the relations between total rainfall and soil moisture available at different growth stages. Cowpeas planted in early September produced the tallest plants and higher grain yields than from other planting dates, since they benefited from 90% of the season's rainfall and made use of stored soil moisture. Average weekly rainfall or soil moisture in the top 15 cm of soil, recorded from planting to 50% flowering, can be used to predict cowpea grain yield.

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.

Blanched leaf tips of ten sweet potato cultivars were evaluated for eating qualities such as tenderness, flavour, stem and leaf colour, and hairiness to determine selection criteria. Some cultivars compared favourably with the control in most quality attributes, with a general agreement on the acceptability ranking of three cultivars. Stepwise multiple regression analysis suggested that all the quality attributes studied are important in predicting general acceptability of blanched tips, but the use of stem colour and hairiness for initial selection should be sufficient to reduce the number of lines prior to further evaluation.

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.

Reducing the leaf areas of different maize hybrids at the time of female flowering resulted in a reduction of up to 70–90 g/plant of grain yield, with a parallel deterioration in the health of the stalk pith (due to infection by Fusarium sp.) and an increase in lodging. However, beyond a certain limit defoliation caused a loss in fertilization and a further decline in grain yield, which was accompanied by an improvement in the health of the pith and less lodging. There were considerable differences in the reactions of six genotypes to the defoliation treatments.

Field measurements with a pressure chamber showed that the water potential of tea shoots was more closely related to the atmospheric saturation deficit than to the amount of water in the soil. Records for shoot growth and weather then revealed that, within a narrow range of mean temperature, the weekly rate of shoot extension was inversely related to mean saturation deficit measured at 1400 h. During periods when saturation deficit did not rise above 20 mbar, the rate of shoot extension varied linearly with mean temperature above a base temperature of 12.5–13.0°C. These correlations suggested that seasonality of shoot growth in tea can be explained largely by the independent effects of temperature and humidity. The effect of mean air temperature on the rate of shoot extension was confirmed in a glasshouse built over an established crop.

In dryland areas, where rains recede much earlier than the time of sowing of crops, moisture in the seed zone becomes limiting for stand establishment. Mulches are known to conserve moisture in the upper soil layers, so we studied the effect of mulching a standing maize or fallow on the yield of the maize and on following wheat. Mulching maize with green twigs of ‘basooti’ a few weeks before harvest increased its yield by 16%. Both in maize and on fallow mulching increased water storage, particularly in the upper soil layers, and increased wheat yields from 19.0 to 22.5 q/ha after maize and 29.1 to 33.3 q/ha after fallow. It also led to increased water use and water use efficiency of wheat.

The potential was demonstrated of using sodium chloride and sodium metabisulphite as chemical preservatives during pre-drying storage of wet cassava chips, and during slow sun-drying under adverse weather conditions. Both chemicals permitted chips to maintain a good colour and texture and prevented gross microbial deterioration.

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.

Two experiments were conducted on timing the application of N to maize on Njala upland soils in Sierra Leone. Application of all the N (urea) at planting or thinning gave lower leaf N values and relatively poor yields compared to split applications. Lower grain yields in the minor season might have been due to poor and inadequate rainfall. Basal application of SCU does not seem to release enough N for maximum grain yield of maize. Total N (urea) in the major and minor seasons may be phased in two splits, viz. ½ N 30 DAP + ½ N 50 DAP or ⅓ N at planting + ⅔ N 25 DAP, respectively.

Ethephon (ethrel) sprayed once on to pineapple inflorescences at the onset of flowering, at rates of 400, 800 and 1200 ppm, suppressed anthesis, with the highest suppression from the latter concentration. Suppression was associated with failure of flowers to open; where flowers did open they were usually short, shrivelled and devoid of nectar. One application was sufficient to affect anthesis for the following 16 days. Ethephon-treated plots had a significantly lower incidence of ‘fruit collapse’ (a disease caused by Erwinia chrysanthemi entering via the open flowers). Highest control (2·3% incidence) was achieved with ethephon at 1200 ppm compared with 7·0% in the control (P < 0·01). A highly significant correlation was established between disease incidence and the mean number of open flowers.