Soil salinity indicators and salinity build-up on saline water irrigation in seed spices

Context Soil salinity is a major constraint in crop production in arid and semiarid regions where saline water is the main irrigation source affecting soil quality and crop productivity. Aims A pot experiment was conducted to study the impact of alternate application of saline water (electrical conductivity (EC): 6.0 dS m−1) and fresh water on soil salinity indicators and salinity build-up under four seed spices (Anethum graveolens L., Nigella sativa L., Pimpinella anisum L. and Trachyspermum ammi L.). Methods Soil samples were collected from a pot experiment (0–15 cm depth) conducted at ICAR-Central Soil Salinity Research Institute, Karnal, Haryana, and analysed for different physicochemical properties (pH and EC), cationic (Ca2+, Mg2+, Na+ and K+) and anionic (CO32−, HCO3−, Cl−, SO42−) concentration and their contribution to salinity build-up in soil. Key results Soil EC varied between 0.45 and 8.27 dS m−1 (EC1:2) and between 1.20 and 24.90 dS m−1 (ECe) irrespective of the seed spice species. The application of saline water in the early stages of growth followed by fresh-water irrigation resulted in a comparatively low ECe, and cation and anion concentrations over continuous saline-water irrigation irrespective of the seed spice crop. ECe, sodium adsorption ratio, potassium and pHs are the important indicators identified by principal component analysis and better explained soil salinity under this situation. Conclusions Keeping these in view, there is a need for cyclic use of saline and fresh water in growing seed spice crops to prevent soil degradation. Study recommends that these four seed spice crops should be irrigated with fresh water during crop establishment and flowering stage, whereas, in between, saline water can be applied. Implications Such management of saline water irrigation could help to reduce salinity and maintain soil health for sustaining crop productivity, specifically for seed spices, in arid and semiarid regions.