Sub-surface drainage: A win-win technology for achieving carbon neutrality and land amelioration in salt-affected Vertisols of India

This study aims to investigate the long-term impact of subsurface drainage (SSD) in restoring the soil quality and sugarcane productivity of waterlogged saline Vertisols. A combination of methodologies including analytical techniques, collection of soil and water samples and field survey with farmers was applied to collect the data, and drawing the inferences. The results indicated that successful long-term operation of SSD improved soil quality. A significant reduction in soil salinity (ECe) (Kavathesar site: 13.27 to 2.61, Shedshal site: 33.21 to 13.72 dS m−1) was observed. An appreciable improvement in soil bio-physico-chemical properties including organic carbon (OC%) (Kavathesar site: 0.48 to 0.63, Shedshal site: 0.22 to 0.44%) and dehydrogenase activity (DHA) (Kavathesar site:10.22 to 13.87, Shedshal site: 4.01 to 17.16 μg g−1 24 h−1), alkaline phosphatase (ALPA) (Kavathesar site:74.00 to 93.00, Shedshal site: 34.00 to 61.00 μg P-NP g−1 h−1), bulk density (BD) (Kavathesar site: 1.17 to 1.13, Shedshal site: 1.19 to 1.07 Mg m−3), saturated hydraulic conductivity (SHC) (Kavathesar site: 2.38 to 3.20, Shedshal site: 1.70 to 2.95 cm day−1) was found on surface (0–30 cm) layer comparing to their control sites (without SSD). The principal component analysis (PCA) showed that % OC, ECe, BD, and available K content were the most contributing factor for soil quality index (SQI). The improved soil quality has resulted in increasing the sugarcane yield by 226.8 and 585.5% at Kavathesar and Shedshal sites, respectively. The farmers' perception revealed that SSD technology (adopted on community scale) could play substantial role in improving the soil condition, and thereby enhancement in the yield of sugarcane crop. Thus, SSD technology was observed to have great potential in improving soil quality, crop (sugarcane) productivity, farmers' income and ensuring land degradation neutrality goal under saline Vertisols of India. Therefore, the large-scale adoption of SSD, managed with regional planning and strong cooperation among the stakeholders, may fulfil the promise of Sustainable Development Goals (SDGs) including Life on Land, No Poverty and Zero Hunger in degraded black saline soils.