Irrigation requirement of cotton (Gossypium spp.) under shallow water table conditions.

摘要

A field experiment was conducted during the rainy seasons of 2003-2005 for three consecutive years at Khetawali Distributary, Hanumangarh, Rajasthan to study the yield, benefit:cost ratio and water use efficiency of cotton cultivars under high water table conditions. Among the varieties, RS 2013 gave significantly the highest seed cotton yield (25.91 q/ha), water use efficiency (7.50 kg/ha-mm) and benefit:cost ratio (3.74) compared to RS 810, RST 9 and RG 8. Between the two irrigation levels, three irrigations at 45 days after sowing (DAS)+flowering+boll development stages recorded significantly higher seed cotton yield (24.57 q/ha) and benefit:cost ratio (3.45). However, water use efficiency (6.92 kg/ha-mm) was higher with two irrigations at 45 DAS+flowering stages. Water table depth was the lowest (100 to 125 cm in different years) at sowing in all the years, thereafter water table went down upto 1st week of July and then came up progressively till harvest. Electrical conductivity (EC) of soils at harvest was higher (1.9 to 2.2 dS/m) with two irrigations at 45 DAS+flowering stages over 45 DAS+flowering+boll development stages (1.5 to 1.8 dS/m).