WATER-BALANCE AND WATER-USE OF PEARL-MILLET COWPEA INTERCROPS IN NORTH-EAST NIGERIA

An experiment was conducted in North East Nigeria to examine the water balance and water use of intercrops of pearl millet and two cowpea varieties as well as sole crops of the same cultivars. The crops were grown on a sandy loam soil in a spatial arrangement typical of husbandry practices of the region. The soil is characterised by rapid drainage and low water-holding capacity. Results indicate that intercropping cowpea with millet did not increase the water use rate over sole millet as transpiration by cowpea may be substituting for soil evaporation. Root zone water storage after the millet harvest was sufficient to maintain a long duration cowpea cultivar that was able to make use of water that otherwise would have been lost to drainage during the dry season. As there was no evidence of water stress up to millet harvest, intercropping cowpea with millet increased the efficiency of utilisation of rainfall. It is concluded that water supply may not be the most limiting constraint on agricultural production in such conditions. The implications of these findings for agriculture in the region are discussed.