Economics of Residues Incorporation and Phosphorus Application for Direct Seeded Rice and Wheat under Saline Soil

摘要

Two-year long field study was conducted using a permanent layout to investigate the economics of crop residues incorporation (2 t·ha-1) and P application (0, 40, 80 and 120 kg P2O5 ha-1) to directly sowing of rice and wheat crops gown under naturally salt-affected calcareous soil (ECe = 4.59 dS m-1;pHs = 8.38;SAR = 6.57 (mmolc L-1)1/2;CaCO3 = 3.21%;Extractable P = 4.07 mg·kg-1;sandy clay loam) at farmers field in district Hafizabad during the year 2012-13. Split plot design (crop residues in main plots and P application in sub plots) was followed with three replications. Agronomic data on growth and yield were collected at the time of each crop maturity. Maximum growth and yield of both the crops were harvested from the plots where P2O5 was applied @ 80 kg·ha-1 along with crop residues incorporation. On an average of two years, maximum paddy (3.26 t·ha-1) and wheat grain (3.56 t·ha-1) yield were produced with P application @ 80 kg P2O5 ha-1 along with crop residues incorporation. Although, the yield harvested with this treatment (80 kg P2O5 ha-1 + crop residues) performed statistically equal to 120 kg P2O5 ha-1 without crop residues incorporation during both the years, however, on an average of two years, grain yield of directly sowing rice and subsequent wheat was significantly superior (22% and 24% respectively) than that of higher P rate (120 kg·ha-1) without crop residues. Overall, continuous two-year crop residues incorporation further increased (17%) paddy yields during the follow up year of crop harvest. Economic analyses of both the crops were carried out to choose the best treatment with adequate economic benefits as compared to those without crop residue incorporation. Maximum net benefit of Rs = 108,680/- for direct seeded rice and Rs = 99,362/- for wheat grown with 80 kg P2O5 ha-1 application under crop residues incorporation was determined. Among P application treatments without crop residues incorporation, the maximum net benefit (Rs = 75,874/- and Rs = 65,725/-) and highest residual values (49,809 and 39,160) for direct seeded rice and wheat respectively, were obtained with extended P application rate (120 kg P2O5 ha-1) which was not again as much as that of 80 kg P2O5 ha-1 application with crop residues incorporation.