Green Manuring and Irrigation Strategies Positively Influence the Soil Characteristics and Yield of Coriander (Coriandrum sativum L.) Crop under Salinity Stress

Abstract

This study shows the influence of soil salinity and irrigation dose on biomass production and its impact on some edaphic indicators and functions. For this purpose, an experiment was carried out in two representative soils from Murcia (SE Spain), one slightly saline (LS) and the other saline (S), where an oat–vetch green manure was intercalated between a spinach cycle and a coriander cycle; the latter being subjected to three different irrigation doses (deficient, optimum and surplus). Rapid response indicators (ECext, cations and anions in the soil solution, etc.) were monitored, as well as the material balances, in particular C and salts. Green manure and crop residues increased soil OC by 12.5% and reduced Na+ and NO3− concentrations. Total biomass production was also affected by salinity, both in oat–vetch, 35.9 and 31. 9 tm ha−1 in LS and S, respectively, and in the coriander crop, where the irrigation dose was decisive, obtaining around 29 tm ha−1 with the optimum and surplus doses and significantly lower amounts with the deficit dose: 20.4 tm ha−1 in LSD and 14. 0 in SD. Therefore, it is necessary to adjust the irrigation doses, since deficit irrigation significantly reduces production and the surplus does not lead to an increase with respect to the optimum, while also causing ions to leach to depth horizons, as is the case for NO3−, Cl− and Na+, with the consequent risk of contaminating the water table.