Evaluating deficit water management techniques on water efficiency, consumptive use, and economics of rabi Maize (Zea mays L.)

A field experiment was conducted on sandy loam soils of Agricultural College Farm, Bapatla during rabi, 2017-18 to analyze the effect of deficit irrigation on yield and water use efficiency of maize. Results of the experiment were statistically analyzed using a split-plot design and revealed that the maximum water use efficiency (16.4 kg ha mm^-1) was recorded from the alternate furrow method of irrigation (I₁) when compared to fixed alternate furrow (I₂) and conventional furrow irrigations (I₃). Irrigating the crop at 30 mm depth (D₁) resulted in higher water use efficiency (15.4 kg ha mm^-1) compared to irrigating the crop at 45 mm (D₂) and 60 mm depths (D₃). Consumptive use of water (422.4 mm) and soil moisture use rate (3.8 mm day^-1) was found maximum under conventional furrow irrigation followed by alternate furrow irrigation and minimum under fixed alternate furrow irrigation. Irrigation at 60 mm depth resulted in higher consumptive use of water (492.9 mm) and 30 mm depth of irrigation recorded lower consumptive use of water (302.5 mm). Among different irrigation practices, maximum gross returns (87521 Rs ha^-1), net returns (44562 Rs ha^-1) and BC ratio (1.03:1) were recorded with alternate furrow irrigation and minimum with fixed alternate furrow irrigation. 60 mm depth of irrigation recorded maximum gross returns (90377 Rs ha^-1), net returns (45731 Rs ha^-1) and BC ratio (1.02:1) over 45 mm and 30 mm.