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Pruning management of Leucaena leucocephala alleycropped with maize and cassava

University of British Columbia

An experiment was carried out to determine suitable pruning intervals for Leucaena leucocephala in an alley cropping system with maize and cassava in Southwestern Nigeria. I considered light and soil moisture limitations to crops in the system, in addition to nutrient contributions by Leucaena prunings to both crops and the soil. Pruning labour was also taken into account to provide an economic perspective. Marked reductions in maize yield were recorded when hedgerow pruning was delayed beyond 10 weeks after crop planting while cassava economic yield was not affected. I observed a general trend of taller plants with thinner stems when Leucaena hedgerows were not pruned or pruned at intervals of 8 weeks or less. Plants adjacent to the hedgerows were usually shorter than those in the middle of the alleys. I attributed the yield declines and growth effects to light limitations rather than soil moisture depletion by the hedgerows, although the potential for the latter could exist in drought. While productivity was affected by light reductions, there was no clear indication that Leucaena prunings contributed to crop growth. Differences in leaf nutrient content were obvious between treatments where hedgerows were pruned at least once a season and where they were not. Maize nutrition was likely satisfied by inorganic fertilizer and initial application of Leucaena pruning, but the same could not be established for cassava where nutrient concentrations were low. I suggest that prunings applied at or just after planting could contribute to crop nutrition, while subsequent prunings are instrumental in maintaining soil fertility. When costs of different pruning intervals were calculated, it was clear that pruning at least once during the maize growing season was advantageous. I briefly discuss some possible economic advantages and disadvantages of pruning every 4 and 8 weeks, or mid-season and at harvest. Upon integrating the biophysical and economic data gathered in the study, it is clear that hedgerow pruning can be delayed up to 10 weeks after planting for maize. For cassava, further studies are necessary in order to recommend pruning intervals for a maize/cassava intercrop in an alley cropping system.

Thesis/Dissertation

application/pdf

2009-02-25

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http://hdl.handle.net/2429/5024

Soil Science

University of British Columbia

UBCV

DSpace