Estimation of Evapotranspiration and Water-use Efficiency of Sesame Crop (Sesamum indicum L.)

Abstract

The evapotranspiration rates of sesame crop (Sesamum indicum L. cv. RT-127) were quantified using gravimetric lysimeters at Jodhpur during 2009 and 2010 kharif season, maintaining the crop at two levels of irrigation (100% and 50% evapotranspiration, ET) and under rainfed condition. The mean evapotranspiration rates of sesame (100% ET rate irrigated) were 2.5-3.9 mm day-1 during early growth, 6.9-13.5 mm day-1 at vegetative stage, 9.2-9.7 mm day-1 at flowering stage and 5.5-8.5 mm day-1 at seed setting stage. The crop coefficients were 0.3-0.7 at early growth stage, 0.8-1.5 at vegetative stage, 1.6- 1.9 at flowering stage and 0.3-1.2 at seed setting stage with an average value of 0.9 for the season. The mean seasonal evapotranspiration, seed yield and water-use efficiency of sesame were 581 mm, 1479 kg ha-1 and 2.54 kg ha-1 mm-1 for 100%ET irrigated crop, 495 mm, 997 kg ha-1 and 2.12 kg ha-1 mm-1 for 50%ET irrigated crop and 362 mm, 635 kg ha-1 and 1.76 kg ha-1 mm-1 for rainfed crop. Relationships between leaf appearance and branch initiation with growing degree days and advection at vegetative stage of crop were also quantified. Key words: Sesame, arid region, evapotranspiration rates, crop coefficients, water-use efficiency, growing degree days.