Amelioration of a calcareous saline‐sodic soil by gypsum and forage plants

Abstract A field experiment was carried out at the University of Agriculture, Faisalabad (Pakistan) during 1988–90 to evaluate the comparative efficiency of chemical and biological methods for the reclamation of a calcareous saline‐sodic soil (pHs pHs = pH of saturated soil paste = 8.2–8.6; ECe ECe = Electrical conductivity of the saturation extract = 7.4–9.0 dS m−1; SAR SAR = Sodium adsorption ratio = 55.6–73.0 for upper 30 cm layer). Five treatments were assessed, three involved cropping: sesbania (Sesbania aculeata), sordan (Sorghum bicolor x Sorghum sudanese), and kallar grass (Leptochola fusca) and two were non‐cropped (control and gypsum at 100.0 per cent GR‐15·0 cm) were employed. Water of low electrolyte concentration (EC = 0.27 dS m−1) was used for irrigation and leaching. Sesbania and kallar grass were found to be effective biotic materials for soil reclamation. These plant species produced substantial biomass and also improved the soil environment by lowering the EC and SAR of the soil. Sordan was relatively less‐effective due to its sensitivity to high temperature and sodicity during germination and early seedling stages. After two cropping seasons, wheat (cultivar LU 26S) was sown as a test crop. Efficiency of treatments as indicated by wheat grain yield was in the order: sesbania = gypsum > kallar grass > sordan > control.