Moisture relations in agroforestry with maize: leucaena leacocephala ally cropping in a semi arid environment at Chalimbana in Zambia

Alley cropping offers great potential for increased and sustained crop production. However, there is currently limited understanding of the effects of maize/leucaena interactions on water distribution. A field trial was conducted to investigate the distribution of soil water and performance of maize grown in three year leucaena alleys. Maize was planted in plots with and without leucaena alleys, and was either fertilized (177 kg N/ha plus 92 kg P205/ha) or not fertilized. The treatments were laid out in a factorial design with a split plot arrangement with alley or no alley in the main plots and fertilizer treatments in subplots. The experiment was replicated three times. Soil water was measured weekly in maize and leucaena rows to a depth of 90 cm. Maize parameters measured include leaf area, plant height, position of secondary cob from ground level, number of harvested plants, days to tasseling and silking and dry matter, empty cob and grain yields. Leucaena alleys had more soil water than no-leucaena alleys by 8%. Leucaena hedge had 16% more water (p < 0.01) than maize rows. Row water content reduced with increasing distance from the hedge. Seasonal water use in the hedge and maize rows were different (p < 0.01). No water competition existed between maize and
leucaena. Fertilization of alley maize boosted dry matter production from 7.47 to 15.86 t/ha exceeding fertilized sole maize by 4.57 t/ha. With inorganic nitrogen supplementation, alley cropping can function as a system of sustainable crop production. These observations need be investigated further over several seasons in order to obtain tangible conclusions.