Importance of gypsum in crop production under sodic water use in light textured soils of Haryana

A long-term experiment was carried out to evaluate the effect of sodic waters (RSC 2.8, 12 and 16 me L⁻¹) and amendments (gypsum applied @ 100% neutralization of RSC above 2.8 me L⁻¹ and FYM applied at @ 15 t ha⁻¹ year⁻¹) on the productivity of various cropping systems and physico-chemical characteristics of the light textured soil (loamy sand, Typic Haplustepts). The crop rotations were fallow-wheat, pearlmillet-wheat, fallow-mustard, chillies-wheat, desi cotton-mustard and American cotton-wheat, each rotation continued for three years. Progressive buildup of sodicity (ESP) and soil pH with low infiltration rate was observed with water of higher alkalinity (RSC 12 and 16 me L⁻¹). The gypsum maintained the ESP and pH of soil and increased the infiltration rate. The FYM was found to be more beneficial with irrigation water of RSC 2.8 me L⁻¹. Crops yields decreased significantly with increasing sodicity of the irrigation water. Sodic water of RSC 12 me L⁻¹ with gypsum produced statistically equal yields to that of irrigation water of RSC 2.8 me L⁻¹ in pearlmillet, wheat, mustard and desi cotton whereas the yields were significantly less in chillies and American cotton. Sodic water of RSC 16 me L⁻¹ with both amendments was not found suitable. FYM as an amendment increased the crop yields but was inferior to gypsum under high sodic water condition (RSC 12 and 16 me L⁻¹). In general, sodic water of RSC 12 me L⁻¹ alongwith gypsum can be successfully used in fallow-wheat, pearlmillet-wheat, fallow-mustard and desi cotton-mustard crop rotations in light textured soils.