Hedgerow Pruning Management Effects on Maize Yield and Nitrogen Uptake in an Alley Cropping System in Haiti

Abstract

Hedgerow management is crucial to successful alley cropping. Leucaena [Leucaena leucocephala (Lam.) de Wit] hedgerow management practices were assessed over four seasons for effect on maize (Zea mays L.) yield and N recovery in alley cropping. Maize was planted between leucaena hedgerows spaced 4 m apart on a Lithic Eutropepts. Pruning application and regime factors were arranged in 3 × 3 factorial augmented with a control (stone walls) in randomized complete block design with three replicates. Hedgerows were pruned at 0.50 m height at (a) maize planting and at 30 d after planting (DAP), (b) planting and 40 DAP, or (c) planting, 30 and 60 DAP. Prunings were (a) removed from plots, (b) applied as mulch or (c) incorporated into the soil at planting. A hedgerow + fertilizer treatment in an adjacent trial was included for comparison. Soil application of leucaena prunings increased average maize yield and grain N uptake by 157 and 163%, respectively, compared to when prunings were removed. Addition of inorganic fertilizer further increased maize yield and N recovery. Pruning three times per season gave higher maize yield, N uptake and N recovery than pruning twice, but reduced leucaena biomass and N yield. Pruning twice per season, with the second pruning at 40 rather than at 30 DAP, increased biomass N yield but reduced N recovery over the seasons. Alley cropping with soil application of three prunings per season averaged 31% higher maize yield and 48% higher N uptake than control. N recovery was enhanced by soil application of three prunings per crop and by fertilization.