Effects of hedgerow species on surface soil physical properties were studied in an on-going trial established since 1981 on an Oxic Paleustalf in southwestern Nigeria. The experimental treatments were Leucaena leucocephala, Gliricidia sepium, Alchornea cordifolia and Acioa barterii hedgerows planted at 4 m interhedgerow spacings and a control (no hedgerows). Plots were sequentia-ly cropped with maize (Zea mays) and cowpea (Vigna unguiculata). Soil physical properties, i.e. particle size distribution, ...

The effect of no-tillage and mulch on soil properties and tuber yield of cassava was studied over a five year period on an infertile, acid Ultisol in south-eastern Nigeria. Mulch was applied at a rate of 12 t ha−1 as a split application once at planting and once six months after planting. No chemical fertilizers were used during the trial. Bulk density and proportion of micropores (pore radius, r, <1.4 µm) were greater, and proportion of macropores (r>14.4 µm) lower, with no-tillage. Water ...

A laboratory screening method was developed for evaluating resistance of cowpea, Vigna unguiculata (L.) Walp, to Clavigralla tomentosicollis Stål. The technique uses dry cowpea seeds, which were judged better than fresh seeds or fresh pods, to identify protracted nymphal development and high cohort mortality. Two wild cowpea relatives, TVNu 72 and TVNu 73, were highly resistant to C. tomentosicollis. Insect mortalities were >85% on the resistant lines as compared to <25% on the susceptible lines. ...

Reports the findings of a mission carried out by the International Institute of Tropical Agriculture in Zimbabwe to gather genetic resources of cowpea, rice, bambarra groundnut and their wild relatives. 461 samples of 365 species were collected. Sampling was made over 140 sites of both natural vegetation and cultivated habitats. The team was able to gather samples from farmers' stores (43%), markets (6%) and from standing crops 39%. 12% of the samples collected were from wild vegetation.

Farmer-managed trials in developing countries often show great variability in yield and treatment effects. The use of statistical techniques is demonstrated to explain this variability in a maize + cassava intercropping trial in southwestern Nigeria. Concomitant variables, measured in the trial fields, are used as covariates in the ANOVA and as regressors in the analysis of mean site yield. It was found that a new maize variety (TZSR-W) performed better than the lcoal irrespective of farmers' yield ...

Cassava is traditionally grown on tilled soils. Interest in reduced-tillage systems is increasing in the humid tropics due to erosion problems. A field study was conducted on a sandy clay loam Ultisol to compare cassava performance in three tillage systems effects on soil water and organic carbon content. Tillage treatments were: (1) ploughing, harrowing and ridging (conventional); (2) digger-made holes (minimum); (3) pushing the sharpened end of cassavs cuttigs directly into the soil (no-till). ...

The spatial and temporal development of leaf spots on alfalfa(Medicago sativa ‘Are’ and Ladino-type white clover (Trifolium repens ‘Regal’) caused by Leptosphaerulina trifolii were mentioned during spring 1987, fall 1987, and spring 1988. In spring 1987, diseases gradients developed from diseased alfalfa to both white clover, little diseases developed on either host in plot with diseases clover at the focus. In fall 1987 and spring 1988, disease developed from alfalfa or clover on both hosts. ...

Fatty acid composition of extracted oils from 58 lines of cowpea (Vigna unguicuiata (L) Walp) was investigated by gas‐liquid chromatography (GLC). Considerable variability was observed in the fatty acid profile, though palmitic (16:0), linoleic (18:2) and linolenic (18:3) acids were the dominant components in each line. Correlation analysis shows that seed oil composition differs according to response to Callosobruchus maculatus (F). In fact, besides a group of correlations common to all lines, ...