Water extraction patterns and water use efficiency of chickpea (Cicer arietinum L) cultivars in Canterbury

The response of two Canadian Kabuli chickpea (Cicer arietinum L.) cultivars to four different irrigation treatments was studied on a Wakanui silt loam soil in Canterbury, during 1999/2000. This study aimed to quantify yield potential under irrigation at different crop growth stages. Irrigation applied during or post flowering gave significant seed yield increases and there were indications of greater water use efficiency. In both cultivars, full irrigation (105 and 109 mm) increased seed yield (> 4 t/ha) by 76 - 124 % over the unirrigated chickpeas. Soil water depletion was generally confined to a soil depth of 80 cm. While this indicated the effective rooting depth, most of the water used came from the top 0 - 30 cm of the soil profile. Evapotranspiration (i.e., crop water use) was measured using a neutron moisture meter and water use efficiency (WUE) was examined at crop maturity for all treatments. The pattern of water use is an important parameter determining seed yield in chickpea and there was a significant correlation (p < 0.001) between water use and seed yield (r(2) = 0.73). There were also highly significant (p < 0.001) interactive effects of irrigation, sowing date and cultivar on WUE and the trend was similar to that for seed yield. The estimated WUE ranged from 5.8 to 11.7 kg of seed/ha per mm of water used.