Effect of irrigation on growth and yield of Kabuli chickpea (Cicer arietinum L.) and narrow-leafed lupin (Lupinus angustifolius L.).

The response in growth and yield of Kabuli chickpea (Cicer arietinum L.) cv. Princepe and narrow-leafed lupin (Lupinus angustifolius L.) cv. Fest to different irrigation levels when unirrigated (water stressed), given half irrigation, full irrigation and double irrigation (waterlogged) and full irrigation with 150 kg N ha (optimum, control plots) was investigated on a Templeton silt loam soil at Lincoln University in 2007/08. Irrigation had a marked effect on growth and yield. There was a 51 % increase in the weighed mean absolute growth rate (WMAGR) with full irrigation over no irrigation. In Kabuli chickpea, WMAGR with full irrigation was 18.6 g m day and in narrowleafed lupin it was 23.0 g m day. Seed yields of fully-irrigated crops were treble the unirrigated treatment. With full irrigation, seed yield of chickpea was 326 and that of lupin 581 g m. Seed yield of the two legumes fell 45 % with double irrigation compared with full irrigation. Nitrogen (N) fertilizer did not increase seed yield in either legume. The increased seed yield resulted from increased radiation interception. With full irrigation, total intercepted photosynthetically active radiation (PAR) increased by 28 % and 33 % over that in nonirrigated plants in Kabuli chickpea and narrow-leafed lupin, respectively. The results of this study suggest that to achieve their yield potential, crops should be irrigated to replace water deficit over the whole of crop growth.