Effect of soil covers on growth and yield of irrigated wheat planted at two dates

Abstract

A field study was conducted to evaluate the effect of soil covers, viz. control (C), transparent polyethylene (TP), black polyethylene (BP) and rice straw (RS), on growth and yield of irrigated wheat planted on 30 November (S 1 ) and 6 January (S 2 ) during 1978–1979, and 19 November (S 1 ) and 24 December (S 2 ) during 1979–1980. The TP cover expedited seedling emergence, caused a higher rate of dry matter accumulation, advanced inflorescence emergence and lengthened the grain filling period, resulting in a greater number of fertile tillers and grains per head and higher grain yield. These favourable effects on growth and yield of wheat relative to the control were associated with significant increases in 14.30 h soil temperature at 0–15 cm depth during the first 6 weeks after planting. Consistent with the smaller increase in soil temperature under BP, growth and yield advantage were less. With the decrease in soil temperature under RS, growth and yield were significantly less. The positive or negative effect of a soil cover on grain yield was of greater magnitude for S 2 than for S 1 since temperatures were lower during early growth. The results indicated the possibility of increasing the grain yield of late planted wheat by covering soil with TP sheet during early growth.