The effect of irrigation and sowing date on crop yield and yield components of Kabuli chickpea (Cicer arietinum L.) in a cool-temperate subhumid climate

The canopy development, radiation absorption and its utilization for biomass production in response to irrigation at different growth stages of three Kabuli chickpea (Cicer arietinum L.) cultivars was studied on a Wakanui silt loath soil in Canterbury, New Zealand (43degrees38S, 172degrees30E). The study also aimed at quantifying the yield potential of the crop under varying irrigation regimes and sowing dates. Green area duration (GAD), intercepted radiation (F-i), radiation use efficiency (U) and total intercepted PAR were significantly (P<0.001) increased by irrigation. Total dry matter (TDM) yield seas more strongly correlated (R-2=0.69-0.83) with GAD than seed yield (R-2=0.60-0.69). Accumulation of TDM was highly related to intercepted PAR. Folly irrigated November-sown crops had a final U of 1.46 g DM/MJ PAR. The unirrigated crop had a U of only 0.92 g DM/MJ PAR. The U tended to decrease with delayed sowing. Averaged over the 2 years, irrigation increased seed yield by 74-124% and trends were similar for TDM yield. Seed yield was doubled in November-sown chickpeas (4.6 t/ha) and cv. Sanford produced 14 and 16% more seed than cvs Dwelley and B-90 respectively. Full irrigation from emergence to physiological maturity always gave the highest seed yield (>4.7 t/ha), and there was no indication of a critical period of sensitivity to water stress. Based on results collected in the first growing season a simple model relating seed yield to radiation interception, U and HI was made. Results froth the second growing season were then used as a simple verification to test the accuracy of predictions. The results suggest that these varieties have the potential to yield more than 4.5 t/ha of seed in Canterbury.