Influence of drip fertigation on yield and water use efficiency of aggregatum onion in western zone of Tamil Nadu

A field experiment was carried out at the Agricultural Research Station, Bhavanisagar, Tamil Nadu during kharif season of 2015-16 to 2016-17 to evaluate and optimize the drip fertigation on water use efficiency, yield attributes and yield and economics of aggregatum onion under different fertigation levels. The research was carried out in randomized block design with four replications. The treatments comprised nine fertigation levels combination with basal application compared to absolute control. Drip fertigation with 100 per cent N, P and K through fertigation (T₃) registered higher water use efficiency (60.46 and 78.44 kg/ha mm) and water productivity (6.046 and 7.841 kg/m³) followed by 75 per cent N, P and K through fertigation (T₇). Lower water use efficiency (44.75 and 58.05 kg/ha mm) and water productivity (4.475 and 5.803 kg/m³ ) were recorded in 75 per cent N through fertigation with75 per cent P and K applied as basal (T₅). Significantly higher yield attributes like bulb weight and bulb number/clump were registered in T₃ which was on par with T₇. Perceptively higher yield was also recorded in T₃ (23.82 and 22.99 tonnes/ ha) that was at par with T₇ (23.31 and 22.49 tonnes/ha). Strikingly lower yield was recorded in T₅ (17.63 and 17.01 tonnes/ha) except absolute control (T₁₀). However T₇ registered higher net return of Rs 1,76,302/ha and B-C ratio of 2.84 followed by 100 per cent N and K through fertigation with 100 per cent P applied as basal (T₂) with net return of Rs 1,54,139/ha and B-C ratio of 2.80.