Alley cropping, or hedgerow intercropping, is an agroforestry technique in which fast growing leguminous trees are planted in dense hedgerows, and annual crops are planted in the "alleys" between the hedges. Before planting crops, the hedges are pruned, and the leaves are added to soil as mulch. This study compared soil nutrients and crop yields of sorghum planted under four nutrient enrichment regimes including root pruned and root intact alley cropping with Albizia julibrissin, leguminous winter cover cropping with Trifolium incarnatum, and inorganic fertilizer addition. During a drought year alley cropping provided greater nitrogen additions than the other treatments and similar phosphorus additions to the cover crop treatment. Sorghum yields were highest in the fertilizer treatment and lowest in the cover crop treatment. There appeared to be root competition between the hedgerows for nutrients and moisture, but root pruning the hedgerows reduced competition.
