Irrigation Requirement of Winter Maize under Shallow Water Table Condition in Damodar Valley Irrigation Command Area

Field experiments were conducted to determine the water requirement of winter maize (NLD composite) under shallow water-table condition (1.20 m) on a sandy loam soil (Typic Fluvaquent) in rabi seasons of 1989–90 and 1990–91. Three irrigation scheduling based on IW/CPE ratios, viz. 1.2 (I₁), 0.9 (I₂) and 0.6 (I₃) were followed. Capillary contribution from ground water increased from 0.38 x 10⁻² to 1.4 X 10.² m under IW/CPE = 1.2 over 0.6. Relatively drier soil water regimes induced maize plant to develop more extensive root systems at 0.60 to 0.90 m depth with 0.08 to 0.11 x 10⁻⁵ m m⁻³ more root length density values than wetter soil regime. Significantly higher yields were obtained with five post-sowing irrigations applied at IW/CPE = 1.2. Total actual evapotranspiration was maximum under IW/CPE of 1.2 followed by 0.9 and then 0.6. The yields under three water regimes were 2.22, 1.85 and 1.77 Mg ha⁻¹ and the values of water use efficiency were 7.23, 6.41 and 6.32 Mg ha⁻¹ m⁻¹, respectively.