To date, the site-specific, mixed reports of the influence of hedgerows on crap yields provide little predictive insight into which type of tree/crop combination is most appropriate for a specific location. The Alley Farming Network for Tropical Africa was established in 1989. The objectives of that network include the identification of the best hedgerow species and management practices for tropical Africa. The results of the first 3 years of network activities were assembled into a statistical database as a means of cross-site comparison of aIIey farming research. Based on tree height the performance of Senna siamea was best in humid environments and Acacia auriculiformis did well in subhumid regimes. Several species nor regularly associated with semi-arid environments (e.g., Albizialebbeck, Senna spectabilis) out performed those that are so associated (e.g., Faidherbia albida, and A tortilis). When compared to monocrop controls, maize (Zea mays) performed well as a hedgerow intercrop, but cassava (Manihol esculenta) and cotton (Gossypium spp.) performed poorly. Dimensionless indices are proposed as a means of comparing alley farming systems between sites. The ratio of hedgerow intercrop to monocrop productivity values (FYI) of the maize intercrops ranged from 1.72 to 4.06 and those of cassava from 0.13 to 0.80. The FYI indices 01 the maize/Leucaena system covaried significantly with total soil N (r = - 0.66), extractable P (r = 0.84) and other site characteristics. The RETURN index represents the change in intercrop performance with each increment of hedgerow pruning inputs. The sensitivity of the RETURN index to the amount of foliage pruned is proposed as a tool in optimizing alley cropping systems.

Farming Systems; Land Use

Alley Farming; Tree Crop; Hedgerow; Site

Africa; West Africa

Nigeria