Nutrients availability in salt-affected soils varies with the ionic composition of solid and solution phases of inland and coastal agroecosystems of India

Understanding the ionic composition and physicochemical properties of salt-affected soils (SAS) is vital for their rehabilitation. The sodium adsorption ratio (ESR), exchangeable sodium ratio (SAR), exchangeable sodium percent (ESP), ESR-SAR relationship, and Gapon's selectivity coefficient (K-G) were determined for inland and coastal soils. The inland SAS had greater alkalinity and lower soluble salts than coastal agroecosystems. The coastal SAS had greater clay, organic C content, exchangeable Ca2+ to Mg2+ ratio, and low ESR and ESP compared with the inland. The Na+, Ca2+, Mg2+, K+, SO42-, and Cl- concentrations were greater in soil water saturation paste extract of coastal SAS. The inland SAS were deficient in KMnO4-N, while available P and NH4OAc extractable K were in the sufficient range for crop nutrition. The ESP, pH(s), alkalinity, clay, and K-G explained similar to 66.2 and 59.4% variability in the available nitrogen, phosphorous, potassium, calcium, and magnesium content in the inland and coastal SAS, respectively. The organic C, Na+, and SO42 significantly affected the KMnO4-N and available P for inland and organic C, alkalinity, and clay, K-G and ESP significantly affected the N and P for coastal SAS. These findings suggest that SAS in different agroecosystems need specific management approaches for successful rehabilitation.