Effect of planting methods and irrigation levels on water productivity of onion (Allium cepa L.)

To investigate the effect of planting methods and irrigation levels on irrigation water productivity and onion (Allium cepa L.) yield, a field experiment was conducted on sandy loam soil at the Research Farm of Department of Soil Science, Punjab Agricultural University, Ludhiana during rabi 2011-12. Three planting methods tested include drip irrigated beds, furrow irrigated beds and flat flood irrigation. In drip irrigated beds and furrow irrigated beds three onion rows were planted on 55 cm wide beds at a spacing of 15 cm from row to row. Three levels of irrigation water were tested i.e. IW/PAN-E ratio of 0.3, 0.4 and 0.5 in drip irrigated onions and 1.2, 1.6 and 2.0 in both bed furrow and flat flood methods of irrigation. The results of the experiment indicated that in drip irrigated beds by applying same quantity and 50 per cent of water as of flat flood irrigation, the yield was increased by 43 and 25 per cent, respectively. Irrespective of irrigation levels, highest onion yield (32.5 t ha-1) was recorded under drip irrigated beds followed by furrow irrigated beds (28.5 t ha-1) and least under flat flood irrigation method (25.0 t ha-1). The onion yield increases with the increase in irrigation level in all the planting methods. The highest irrigation water productivity was observed under drip irrigated beds (1.26 t ha-1 cm) followed by furrow irrigated beds (0.84 t ha-1 cm) and least under flat flood irrigation (0.48 t ha-1 cm) with equivalent IW/PAN-E ratios. Bigger size onions (40 mm and 50 mm) were observed under drip irrigated beds followed by furrow irrigated beds and smallest size bulbs under flat flood method of irrigation. The results revealed that drip irrigation could successfully be used for onion production with significant water saving and higher production.