This paper describes a study into the influences of spacing on the early performance and biomass production of Gliricidia sepium in an alley cropping system in southern SierraLeone. Four between-row spacings of 2, 4, 6 and 8 m were combined with three within-row spacings (0.25, 0.50 and 1.00 m) in a split plot experimental design.Survival, tree height and leaf nitrogen content were not affected by between-or within-row spacings. For the other parameters measured, namely root-collar diameter, branch production, total biomass and nitrogen yields per hectare, it was found that for equivalent tree densities, the lower the rectangularity of planting, the better the performance of the individual trees, and consequently the greater the yields per hectare.Total biomass production per unit area was, expectedly, greatest where the spacings between hedgerows were closest, while production per plant decreased with closer within-row spacings. The total fresh and dry weights of leaves and stems, as well as leaf nitrogen yields per unit area were strongly influenced by between-row spacing and less so by within-row spacing.

The effect of cutting height and cutting interval on dry matter production of Leucaena leucocephala (Lain) De Wit was investigated at Njala, Sierra Leone using three year old Leucaena trees. Four cutting heights, (25, 50, 75 and 100 cm), and two cutting intervals (one and three months), were adopted.Dry matter yields were highest at the 75 and 100 cm cutting heights, especially at the longer, three-monthly, cutting interval. They were significantly reduced by more frequent cutting, probably due to the increased number of recovery phases.Leaf nitrogen yields per tree for trees cut at three-monthly intervals were over twice as high as the total yields obtained from monthly cutting over the same period.

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An investigation was undertaken at Senehun --Kamajei, a high rainfall region inSierra Leone, to assess the effects of Leucaena leucocephala, on the growth and productivity of maize, cowpea and sweet potato. The experiment was laid out in a completely randomised design with four replicates of each treatment. The treatments and controls were: (i) pure crops of maize, cowpea, sweet potato, Leucaena clean weeded and unweeded and (ii) intercrops of Leucaena with the food crops, both (iii) with and without applied fertilizers after the first year.The growth of Leucaena was slow but nevertheless tended to reduce grain yields of maize, and tuber and vine yields of sweet potato in the rows in the immediate vicinity of the trees, especially in the nitrogen-treated plots. The maize, in particular, caused an improvement in the early height growth of the trees.

Competition is one of the most important factors that influence productivity of component crops in intercropping systems. Thus, an experiment was conducted in order to evaluate the competitive interactions between the component crops in a cassava-legume based intercropping system. The experiment was a factorial randomized complete block design with three replications. The treatments consisted of seven cropping associations and two spatial arrangements. The results show that the root yield for cassava was higher for the cassava-soybean system with Segbwema recording the highest root yield. For the grain legumes, yields were higher for the sole legumes compared to the intercropped. In addition, both root and grain yields were on average higher when the grain legumes were intercropped with cassava using the 2 m x 0.5 m spatial arrangement for cassava. The result further shows that land equivalent ratio was greater than one and was higher for the cassava-soybean system compared to the other cropping systems. Furthermore, the result shows a higher monetary advantage index for all cropping systems indicating that all cropping systems were feasible and profitable. In conclusion, it was shown that cassava-legume intercropping systems were more advantageous in terms of productivity and monetary advantage for smallholder farmers across the three agro-climatic zones.