Bitter Gourd Response to Surface and Subsurface Drip Irrigation under Different Fertigation Levels

A 2-year field experiment was conducted to investigate bitter gourd response to surface drip irrigation (DI, D0) and subsurface drip irrigation (SDI) at 5, 10 and 15 cm (D05, D10 and D15 respectively) in interaction with four fertigation levels (F1 50: 30: 30; F2 100: 60: 60; F3 120: 90: 90 and F4 150: 120: 120 kg NPK ha−1). It was observed that SDI having D10 and D15 treatments maintained a relatively drier soil surface and maintained higher soil water content in the crop root zone, providing more favourable conditions for plant growth. Vine length and fruit weight were less responsive to differences in lateral depth than marketable yield. Bitter gourd yield was significantly higher (21.9 and 21.2 t ha−1) under D10 and D15. At all fertigation levels, SDI recorded higher irrigation water productivity (IWP) over DI. Highest IWP (5.98 and 6.33 t ha−1 mm−1 in 2010–2011 and 2011–2012) was obtained under D10 treatments at the F4 level of fertigation. SDI fertigation level (F4) increased yields by increasing the mean weight of the fruits, and also by increasing fruit number. SDI with 10 cm depth of lateral placement and F4 level of fertigation is recommended as an optimum practice for improving yield and IWP of bitter gourd. Copyright © 2017 John Wiley & Sons, Ltd.