Productivity and economics of cotton (Gossypium hirsutum)-wheat (Triticum aestivum) and pearl millet (Pennisetum typhoides)-wheat cropping sequences under different plant geometry and irrigation options in cotton under semi-arid India

An on farm study was conducted during summer season of 2004-5 and 2005-6 on cotton in semi arid region of Agra with three levels of supplementary irrigation (I₁: irrigation at 21 DAS; I₂: irrigation at 42 DAS and I₃:I₁ + I₂) and plant geometry (S₁: 60 x 30; S₂: 60 x 45 and S₃: 60 x 60 cm) in split plot design in cotton-wheat cropping sequence. Residual effect of irrigation and plant density in cotton was evaluated on succeeding wheat. The yield performance of cotton-wheat system was compared with pearl millet-wheat raised on nearby farmer's fields in terms of pearl millet equivalent. Results showed that I₁ recorded significantly higher mean seed cotton yield (1546 kg ha⁻¹), total biomass yield (3791 kg ha⁻¹), net return (Rs 32265 ha⁻¹) and benefit cost ratio (1.87) than I₁ and I₃ in cotton-wheat system. Although, I₂ recorded significantly higher mean cotton stalk yield (2319 kg ha⁻¹), wheat grain (3791 kg ha⁻¹) and straw (4898 kg ha⁻¹) yield but mean seed cotton yield (1389 kg ha⁻¹) and monetary returns (net return: Rs 28984 ha⁻¹ and benefit cost ratio: 1.79) was minimum among different irrigation treatments tested in cotton-wheat system. S₃ recorded significantly higher mean seed cotton yield (1615 kg ha⁻¹), total biomass yield (3859 kg ha⁻¹), main branches plant⁻¹ (15.9), balls plant⁻¹ (36.2) and wheat grain yield (3810 kg ha⁻¹) due to lower competition on behalf of more space plant⁻¹. S₃ also recorded significantly higher mean net return (Rs 40011 ha⁻¹) and benefit cost ratio (1.92) than other plant geometry treatments in cotton-wheat system. Among interactions, I₂S₃ recorded significantly higher seed cotton yield (1694 kg ha⁻¹) and benefit cost ratio (1.96) but variations in wheat grain yield and net returns under different interactions of irrigation and plant geometry were not significant. Cotton-wheat produced higher wheat yield (3786.5 kg ha⁻¹) than pearl millet-wheat (3416 kg ha⁻¹) system. Cotton-wheat also produced higher mean pearl millet equivalent (8270 kg ha⁻¹) than pearl millet-wheat (2394 kg ha⁻¹) in the kharif season.