Effect of deficit saline irrigation, tillage and rice straw mulch in wheat‐sorghum cropping system on yield and nutritive value of rainfed forage sorghum in salt‐affected soils

Abstract

Soil and groundwater salinity associated with limited rainfall are the challenges for checking salinity build‐up in semi‐arid regions. This field experiment was conducted to test the impact of deficit saline irrigation (DSI) (in winter) with mulching and tillage on salinity build‐up, yield and nutritive value of rainfed‐forage sorghum. Tillage (reduced, conventional and zero), saline water (8.0 dS m⁻¹) irrigation (100%, 80% and 60% of water requirement [WR] in wheat) and mulch were allocated following split factorial layout. DSI with mulching produced at par wheat and sorghum yield compared with 100WR irrigation with harvested rainwater. Mulching improved wheat grain yield and the soil water content by ~13% throughout the cropping season. Forage sorghum yield was increased by DSI and mulching in the previous season compared with irrigation with 100WR saline water. Reduced tillage declined the neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL) with an increase in cell soluble constituents. DSI and mulching also increased the digestible nutrient, crude protein (CP), ash and reduced ADF of sorghum. Soil salinity showed a negative correlation with CP, positive correlation with ADF, ADL and cellulose. Therefore, it is recommended that DSI and reduced tillage with mulching can be a reliable option for productive use of saline soils and water by cropping system intensification. These results also showed the potential for achieving 2030 agenda for sustainable development goals as well as targets of land degradation neutrality in salt‐affected soils by savings irrigation, doubling cropping intensity and preventing salinity build‐up.