Sub-surface drip fertigation enhances seed cotton yield and economic returns in semi-arid environments

Surface flood (SF) method to irrigate cotton in India results in huge wastage and necessitates adopting efficient water management strategies. Therefore, a field experiment was conducted during 2019 at 2 different agro-climatic locations (Faridkot and Abohar) to investigate the effect of sub-surface drip fertigation (SSDF) on seed cotton yield (SCY), and productivity indices in comparison with SF and surface-drip fertigation (SDF). The field experiment had 8 treatments arranged in a complete randomized block design, wherein 3 levels of sub-surface drip irrigation-SSDI (i.e. 0.6, 0.8 and 1.0 ETc-crop evapotranspiration) and 2 nitrogen levels [75% RDN (recommended dose of nitrogen) and 100% RDN (112.5 kg N ha⁻¹)] were applied in 6 combinations, while SF (Control 1) and SDF of 0.8 ETc (Control 2), both with 100% RDN served as controls. SSDI levels of 0.8 and 1.0 ETc showed 27% and 29% better SCY as compared to SF (2626 kg ha⁻¹). Quantity of applied water under SF was 56% and 110% higher as compared to highest level SSDI of 1.0 ETc, for Faridkot and Abohar, respectively. A SSDF of 0.8ETc along with 100% RDN recorded improved SCY by 33% besides higher NUE by 24% over SF. Net returns under SF remained lesser by 35% and 37% compared to SSDI of 0.8 ETc and SSDI of 1.0 ETc, respectively. These findings clearly elucidated the advantage of SSDF applied at 0.8 ETc along with 100% RDN in enhancing cotton yield and monetary benefits as compared to surface flood.