Wheat Yield and Chemical Composition as Influenced by Integrated Use of Gypsum, Pressmud and FYM in Saline-Sodic Soil

Crop yields are limited under salt-affected soils receiving saline irrigation water. A field experiment was conducted on silty clay loam saline sodic soil [fine loamy, mixed, hyperthermic Typic Haplustepts, ECe = 8.03-11.76 dS m(-1), SAR=15.8-17.9] to investigate the effect of gypsum (G), pressmud (PM), and farmyard manure (FYM) applied alone or in various combinations on soil reclamation and mitigating the adverse effects of saline tube-well waters (EC(iw) = 5.5 dSm(-1), SAR = 10.0). Treatments included the amendments (AM);G (6.0 Mg ha(-1)), PM (7.0 Mg ha(-1)), G+PM (3.0 + 3.5 Mg ha(-1)) equivalent to 100% gypsum requirement (GR) applied alone or with 4.0 Mg ha(-1) FYM in two factorial [4 AM x 2 FYM] RCB design with three replications. Sole application of G, PM, and G+PM significantly increased wheat plant height, grain and biomass yield by 24-28%, 27-36%, and 37-39% over control which further increased to 42-46%, 68-87% and 61-73%, respectively, when these AM were applied in combination with 4.0 Mg FYM ha(-1). Wheat leaf K and Ca+Mg concentrations increased while Na was depressed by G and PM but was highest in FYM treated plants. Due to increases in tissue [K], the K:Na ratio was higher in G and PM treated plots and lowest in control and FYM alone. The K:Na ratio in tissue was positively correlated to Ca+Mg:Na ratio (r(2) = 0.53) and K:Na ratio (r(2) = 0.43) in the soil solution. The post harvest soil SAR significantly (P < 0.01) decreased from 13.03 in control to 5.40, 7.73 and 6.27 with G, PM and G+PM treated plots, respectively. Water soluble K increased by 2-3 times with sole AM and 4-5 times with AM+FYM applications. In spite of saline irrigation the lower SAR values and high K values revealed the significant role of AM application for better management of these soils. The comparable increases in wheat grain yield and decreases in post harvest soil SAR and EC suggest that PM could be as effective as gypsum in these saline-sodic soils. The combined use of PM+G equivalent to 100% GR along with FYM is advised for the reclamation and mitigating the adverse effect of saline irrigation in these areas and for obtaining economical yields on sustainable basis.