The potential of pigeonpea (Cajanus cajan (L.) Millsp.) as a simultaneous fallow component in cropping systems is unique in that, being a shrubby grain legume, it combines food production with ease of establishment, fast growth and high biomass productivity. A study was carried out under on-farm conditions at three different sites in southern Bénin, West Africa over two years to evaluate the biomass productivity and recycled nutrients of a local pigeonpea cultivar, managed as annual hedgerows. Pigeonpea was sown between a standard cassava–maize intercrop and compared with two other agroforestry systems and annual intercrops with and without mineral fertilizer. The number of cuts taken at a height of 1 m was doubled from two in 1991–92 to four in the 1992–93 season, leading to an increase in total cut dry matter by a factor of eight (1908 g m−2) and cut leaf dry matter by a factor of fourteen (1317 g m−2) in 1992–93. There were no trade-offs in subsequent dry grain (9.5 g m−2) and firewood yields (96.2 g m−2) for cutting hedges earlier and more often during the second year, despite much lower precipitation. In pigeonpea recycled nutrients, N, P, Ca, Mg and K, increased proportionally to cut dry matter yields. Yield increases over two years with pigeonpea were highest among all evaluated cropping systems for maize (+150%) and significant for cassava (+66%). Pigeonpea as a simultaneous fallow component in cassava–maize intercropping, can help to sustain moderate yields of maize and cassava, provided that insects, nematodes and diseases do not lower its high biomass productivity with continued cropping after two years.

Mechanically dehydrated potato pulp containing up to 50% dry matter was stored, without visible deterioration, for up to 25 weeks after treatment with at least 0·3% of propionic acid. Wetter pulps required more acid for satisfactory preservation. Thorough mixing was important if maximum storage periods were to be achieved. Ammonia was less satisfactory as a preservative. No visible deterioration occurred while ammonia vapour was present, but bacterial growth was still found even after the addition of about 0·7% ammonia to pulp containing 40–45% dry matter.

The seed of American Cotton, Var. 134, was stressed at 50, 60, 70, 80 and 90°C for 24 or 48 hours before seeding. Stresses at 50 to 70°C had a stimulatory effect on seedling emergence and subsequent performance of the cotton plants, but higher temperatures caused thermal injury or killed the seed.

Urban and peri-urban (UPA) cultivation supplies fresh vegetables and employment for the increasing number of urban inhabitants. It is characterized by the use of large nutrient inputs to increase productivity and often associated with negative environmental risks. For these reasons, this study quantified nutrient (nitrogen, N; phosphorus, P; and potassium, K) flows and economic performance of UPA gardening of the three West African cities of Kano, Nigeria; Bobo Dioulasso, Burkina Faso; Sikasso, Mali, during a 2-year period using the Monitoring for Quality Improvement (MonQI) toolbox considering inflows and outflows sources. Average annual N, P and K balances were positive for all gardens in the three cities with N balances of 279, 1127 and 74 kg N ha−1 in Kano, Bobo Dioulasso and Sikasso, respectively, except for annual K deficits of 222 and 187 kg K ha−1 in Kano and Sikasso, respectively. Nitrogen use efficiencies were 63%, 51% and 87% in Kano, Bobo Dioulasso and Sikasso, respectively, with poor P use efficiencies due to excess application in all three cities. However, a high K efficiency was observed in Bobo Dioulasso (87%) while applications of K were lower than required in Kano and Sikasso with efficiencies of 121% and 110%, indicating possible K mining. The average annual gross margins from gardening indicated a statistically higher (p < 0.05) return of US$3.83 m−2 in Bobo Dioulasso than returns obtained in Kano (US$0.92 m−2) and Sikasso (US$1.37 m−2). Although an economically vibrant activity, intensive UPA vegetable production needs to be reviewed for strategic planning towards improving N and P use efficiencies in order to maintain its productivity as well as safeguard the environment. Appropriate K fertilization is necessary to avoid long term K depletion in Kano and Sikasso UPA gardening.

Lusala (Dioscorea hirtiflora Benth. subsp. pedicellata Milne-Redh) is an important wild edible tuber foraged widely from natural forests in Southern Zambia, but at risk from overharvesting and deforestation. Its propagation was investigated in glasshouse studies to explore potential domestication and future in situ and ex situ genetic resources conservation. Almost all tubers planted with visible shoot buds produced vines, with no effect of tuber size on vine emergence or tuber yield. Few tubers without visible shoot buds at planting produced vines, but those that did not re-tuberized. The progeny provided good vine emergence and similar tuber yield, with vines from tubers produced by re-tuberization being more vigorous. Re-tuberization in the absence of vine emergence also occurred in other experiments. Minisetts cut from the proximal end of tubers provided better vine emergence (with more from 20-mm than 10-mm-long sections) and greater tuber yield than mid- or distal minisetts. Nodal stem cuttings rooted well, vined, and provided small tubers. This study shows that lusala can be propagated successfully from tubers, minisetts, nodal vine cuttings, or mini-tubers from nodal vine cuttings, for genetic resources conservation and/or domestication. Domestication is likely to be hampered by the long period required for vines to emerge and establish. More sustainable foraging, including re-planting in natural forests, is recommended to balance consumption of lusala in the region and promote its long-term conservation.

Equal volumes of irrigation water, applied in different ways to a crop of haricot beans in two seasons, showed that the best practice was 60 mm. irrigation every ten days.

The aim of the study was to analyze the role of small-scale dairy farms in central Mexico in combating rural poverty from a gender perspective. Specifically, it was determined whether these production systems generated sufficient income for alleviating poverty and purchasing the basic food basket. Two hundred and twelve farmers were selected through snowball sampling. To maintain a gender perspective, female-headed farms were considered as an independent group, and male-headed farms were grouped according to multivariate statistics. Two official indicators of poverty were considered in the economic analysis: income and the extreme poverty line. Factor analysis identified four factors that explained 66.10% of accumulated variance. The cluster analysis identified five groups of farms headed by males. Then, a comparative analysis was carried out for the six groups, including the female-headed group (FG). The economic analysis revealed that, if 52% of income are production costs, groups 1, 2, 3, and 4 generated sufficient gross income to purchase the basic food basket to the household of the area. However, the FG and group 5 did not generate sufficient gross income to purchase the food basket. In contrast, if 70% of income are productions costs, only groups 1 and 4 generated sufficient gross income. It can be concluded that small-scale dairy farms generate sufficient daily income under certain conditions for the purchase of the basic food basket and, therefore, help to fight poverty in rural families, especially in groups 1 and 4. In the case of the FG and groups 2, 3, and 5, dairy production along with the diversification of productive activities and backyard activities supports the livelihoods of rural families. It is recommended that existing gender norms be further explored because these could directly influence the motivation of farmers, particularly female producers, to adopt or reject agricultural and livestock technologies.

In Ghanaian cocoa progeny trials plot values were adjusted by covariance on neighbouring plots. Standard errors of differences between progenies were usually reduced by 10% and often by over 20% when covariates were formed from the residuals of neighbouring plots and analyses were iterated using successive improved estimates of treatment effects to derive fresh residuals. The method gave larger reductions in error and was effective over a wider range of variates than adjusting on early growth data from interplanted temporary trees of a standard variety.

To evaluate the potential efficacy of fungicides for the control of birds' eye spot in rubber nurseries, 49 formulations were tested in the laboratory by the paper disc diffusion and liquid culture methods. After discarding phytotoxic fungicides, only certain of the carbamate compounds, especially thiram, and those containing manganese and difolatan showed mazked activity in both series of tests. The results were compazed with field experience, and for the most part good correlations were found between laboratory and field results, a marked exception being the poor in vitro inhibition shown by zineb. A bimodal growth response was shown by the fungus to some of the carbamate formulations.

Groundnut (Arachis hypogaea) has very great economic importance in Cameroon. In pot experiments, groundnut yields on highly acidified but limed soil were 50% greater than those on unlimed soil. These results demonstrate that severely acidified soils of the western highlands of Cameroon should be limed at moderate rates to sustain crop productivity.

The influence of planting mixtures of two potato cultivars on the incidence of leafminer fly (Liriomyza huidobrensis (Blanchard)) and on damage to potato foliage, and the effect on growth and yield, was studied in two field experiments in coastal Peru. Climatic differences between the two years of the experiments (1983 and 1984) had a greater effect than did cultivar mixtures on adult fly populations and on the numbers of feeding punctures and pupae per leaflet. Mixtures reduced the number of pupae in the tolerant cultivar, but increased it in the susceptible cultivar; in contrast, mixed planting tended to decrease the adult populations and feeding punctures in the susceptible cultivar of each mixture. In neither year did mixture yields or intercepted radiation exceed those of the highest-yielding sole crop, although land equivalent ratios (LER) reached 1.19. Considering the cultivars' different maturity rates and their tuber growth curves, it is probable that the later maturing cultivar of each mixture was able to exploit available light after, and perhaps even before, senescence of the earlier cultivar. Mixed planting of potato could be beneficial but only to farmers who plant both early and late cultivars, under conditions where the early harvest commands a premium price.

Studies of the effects of age on yield components and nutrients status of Celosia argentea cultivars showed the highest crude protein content, total vitamin C and leaf/stem ratio in leaves harvested 5 to 7 weeks after sowing, but the highest total marketable and edible yields, as well as total crude protein, 15 weeks after sowing. The narrow-leaved local cultivar gave higher crude protein per cent and vitamin C than the broad-leaved one, but its yield of edible leaf was lower. Breeding potentials of the cultivars were highlighted.

Field experiments were conducted on very alkaline calcareous soils to investigate the effects of two proprietary foliar micronutrient fertilizers, Wuxal Suspension Polymicro and Bayfolan 11-8-6, containing iron, zinc, manganese and boron, on the seed cotton yield of Gossypium barbadense and G. hirsutum. Two applications of foliar fertilizer, one at flowering and one three weeks after flowering, increased yield by 40–68%. The foliar fertilizers enhanced earliness and minimized nutrient depletion from the leaves, and thus increased reproductive efficiency.

Seeds of wheat (Triticum aestivum L.) were coated with a range of vegetable oils before sowing, in an effort to provide a hydrophobic coating that would only dissolve or wash away in the presence of sufficient water to maintain continued seedling growth. Germination of oil-treated seeds was reduced by 20–50% and time to 50% emergence was increased by two to five days. Treating pesticide-coated seeds with vegetable oil further decreased germination and extended time to emergence. Oil treatment did not decrease water uptake or affect seed respiration. Degree of saturation and linoleic acid:oleic acid ratio were not correlated with the effects of the various oils. The decreased germination and delayed emergence associated with the oil treatment were probably due to physiological rather than physical factors.

New productive variants (PV) with physiological and morphological characters distinctly different from their original counterparts (OR) were isolated under disruptive selection in Brassica campestris cv Brown Sarson. Two new breeding approaches were tested—mating (PV × OR) F1 lines with selected cultivars, and mating disruptive with two-directional selection lines. The resulting superior three- and two-way hybrid populations, when advanced through large-scale inter-mating, produced double the yield potential of the existing controls. The genetic principles behind these breeding approaches are discussed.

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.

Effects of plant population on mean yield and yield components of 2-year sole cassava crops were studied on Njala upland soils of Sierra Leone in two experiments. Increasing plant population of multi-shoot Cocoa cassava over 7000/ha decreased all the parameters studied except top/root weight ratio, which increased. The observed effects were attributed to competition for environmental resources, since area of land/plant unit decreased as plant population increased. The relations between plant populations and yields of fresh root and cortex dry matter were asymptotic, indicating that the respective yields were products of the vegetative phase of cropping.

Checker-board field layouts are used to screen sorghum genotypes for resistance to Striga. A systematic check entry is used to monitor crop growth conditions and methods to analyse the results are assessed.