Use of wheat residue and manures to enhance nutrient availability and rice-wheat yields in sodic soil under sodic water irrigation

A field experiment was conducted during 2001–02 and 2002–03 at Bhaini Majra experimental farm of Central Soil Salinity Research Institute, Karnal (Haryana) to evaluate the effect of management of wheat residue with Sesbania green manuring and sulphitation pressmud (SPM) on soil properties and yield of rice and wheat crops irrigated with sodic water [residual sodium carbonate (RSC) 8.5 m.e. L⁻¹, and sodium absorption ratio (SAR) 8.8 mmol/L^1/2)]. The increase in grain yields due to the application of recommended dose of fertilizer N₁₂₀P₂₆ kg ha⁻¹ with wheat residue burning (WRB) or wheat residue ploughing (WRP) or WRP + green manure (GM) or WRP + sulphitation pressmud (SPM) were 6.2, 24.6, 25.6 and 27.4% for rice and 1.0, 9.5, 16.9 and 16.2% for wheat, respectively over that recommended dose of fertilizer N₁₂₀P₂₆ kg ha⁻¹. The yield trends for both crops followed the sequence: WRP + SPM > WRP + GM > WRP > WRB. The integrated use of fertilizer and organic materials also improved the organic carbon, P, K, Zn status and decreased the soil pH. The results suggest that incorporation of wheat residue 50 days before rice transplanting with green manuring or with sulphitation pressmud along with the recommended dose of fertilizer is necessary to improve and sustain the productivity of rice-wheat system in areas having sodic water. The commonly adopted practice of burning of WR proved to be the least beneficial.