Sub-soil sodicity in the central Indo-Gangetic Plains (IGPs) is characterized by high levels of exchangeable sodium, elevated pH, poor soil structure, and low permeability. These physico-chemical properties lead to soil dispersion and swelling, which in turn cause crusting and compaction of the sub-soil layers. As a result, the soil becomes dense and less porous, creating a physical barrier that restricts root penetration. This limitation hampers the ability of major crops to explore deeper soil layers for water and nutrients.

The high sodium concentration in sodic soils also adversely affects nutrient availability and uptake. Excess sodium competes with essential nutrients such as potassium, calcium, and magnesium on the soil cation exchange sites, reducing their availability to plants. Nutrient imbalances and poor root growth together compromise the efficiency of nutrient absorption in crops like wheat, rice, and maize. Consequently, sub-soil sodicity results in stunted growth, lower crop yields, and compromised soil health if not managed appropriately.

Overall, managing sub-soil sodicity is critical in the central IGPs to ensure healthy root development and optimal nutrient uptake, which are vital for sustaining productive agriculture in the region. Amendments such as gypsum application, organic matter incorporation, and appropriate irrigation management can improve the physico-chemical properties, facilitating better root growth and nutrient acquisition.