Enhancing Soil Health and Cotton Productivity in Sodic Soils Using Treated Alkaline Water and Soil Amendments

ABSTRACT

A field experiment evaluated the effects of ameliorated alkaline drip irrigation water and soil amendments on soil restoration and productivity of hybrid cotton (RCH‐20). The study adopted a strip‐plot design, where main plots consisted of alkali irrigation water treated with a gypsum bed or distillery spent wash (DSW), while subplots included soil reclamation treatments using gypsum (5.2 t ha ⁻¹ ) and DSW (500 m ³  ha ⁻¹ ), along with untreated controls. The integrated use of treated irrigation water and reclaimed sodic soil significantly reduced post‐harvest soil pH and exchangeable sodium percentage (ESP), while enhancing organic carbon, nutrient availability and microbial activity. The highest cotton yield (3015 kg ha ⁻¹ ) was recorded in treatments receiving gypsum‐treated alkali water combined with DSW‐amended soil, followed by treatments involving DSW‐treated water with DSW‐amended soil (2881 kg ha ⁻¹ ) and gypsum‐treated water with gypsum‐amended soil (2778 kg ha ⁻¹ ). In contrast, the lowest yield (1410 kg ha ⁻¹ ) was observed in untreated control, highlighting the severity of sodic stress. A Principal Component Analysis (PCA)‐based Soil Quality Index (SQI) identified pH, EC, ESP, dehydrogenase activity, phosphatase activity, and available nitrogen as key indicators of sodic soil recovery, with 91.12% of the variance explained by the first three components. SQI results demonstrated the superiority of ameliorated irrigation water and soil amendments over untreated systems. SQI strongly correlated with yield ( R ²  = 0.91), confirming that improved soil health enhanced productivity. These findings highlight integrated water–soil amelioration as a potential strategy for improving soil quality and cotton productivity in sodicity‐affected regions, aligned with bioeconomy principles.