Influence of deficit irrigation on growth, yield and yield parameters of cotton–maize cropping sequence

• Cotton and maize crops are amenable for deficit irrigation implemented through drip system.
• Alternate deficit irrigation (ADI) resulted higher seed cotton yield and grain yield of maize.
• No. of bolls and sympodial branches per plant are highly correlated to seed cotton yield.
• No. of grain per cob and cob weight are the highly correlated to maize grain yield.

Field experiments were conducted at Agricultural College and Research Institute, Coimbatore, India during 2007–2009 to study the effect of deficit irrigation practices implemented through drip irrigation system on cotton–maize cropping sequence. Creation of soil moisture gradient is essential to explore the beneficial effects of partial root zone drying (PRD) irrigation; and it could be possible through ADI (alternate deficit irrigation) practice in paired row system of drip layout, commonly practiced in India. In the present study, PRD and deficit irrigation (DI) concepts (creation of soil moisture gradient) were implemented through ADI at two levels of irrigation using drip irrigation system. Experimental treatments comprised of seven irrigation levels (full and deficit) through drip system with surface irrigation for comparison. Maize was sown after cotton under no till condition without disturbing the raised bed and drip layout. Response of the crops to water stress indicated growth, yield parameters and crop yield were highest in mild water deficit (ADI at 100% ETc once in three days) among different deficit irrigation treatments. Alternate deficit irrigation (ADI100-50 and ADI80-40) resulted in higher values in plant height, LAI (leaf area index) and DMP (dry matter production). Among the deficit irrigation practices, mild deficit (ADI at 100% ETc once in three days) registered higher values for seed cotton yield (3670–3760 kg ha−1), grain yield of maize (7420–7590 kg ha−1). The same treatment registered higher values for net income and benefit cost ratio (BCR) in both the crops. Number of bolls per plant and sympodial branches per plant were the highly correlated parameters to seed cotton yield. In the case of maize, the number of grain per cob and cob weight were the highly correlated parameters to grain yield.