Soil Degradation and Remediation: Strategies for Restoring Soil Quality

To ensure an adequate food supply for the growing global population, which was approximately 7.3 billion in 2015 and is projected to reach 9.5 billion by 2050, a substantial increase of approximately 70% in agricultural production is necessary between 2005 and 2050. However, this required increase in agricultural output is hindered by soil degradation, which manifests as a decline in quality and a reduction in ecosystem goods and services. Soil, being a finite/non-renewable resource within human timescales, is susceptible to degradation due to intricate interactions among processes, factors, and causes that occur at various spatial and temporal scales. Accelerated erosion, depletion of the SOC pool, loss of biodiversity, diminished soil fertility, elemental imbalances, acidification, and salinization are among the prominent soil degradation processes. To counteract soil degradation trends, it is crucial to transition to restorative land use practices and adopt recommended management techniques. The overarching approach is centred on minimizing soil erosion, establishing positive balances of SOC and nitrogen, enhancing the activity and diversity of soil organisms across various scales (micro, meso, and macro), and improving the stability of soil structure and pore geometry. Enhancing soil quality, including increasing the SOC pool, enhancing soil structure, and promoting soil fertility, can mitigate the risks associated with physical, chemical, biological, and ecological soil degradation, while simultaneously benefiting the environment. A critical step towards initiating the restoration process is to raise the SOC pool above the critical threshold of 10 to 15 g kg-1. Site-specific methods for restoring soil quality encompass conservation agriculture, integrated nutrient management, the adoption of continuous vegetative covers like residue mulch and cover cropping, and implementing controlled grazing at appropriate stocking rates. The overarching strategy is to maximize productivity by minimizing losses and optimizing the efficiency of soil, water, and nutrient utilization. In conclusion, restorative land use and site-specific approaches are vital for addressing soil degradation, meeting food demands, enhancing soil quality, and ensuring sustainable agriculture amid population growth. This chapter aims to provide an overview of soil degradation in India and identify potential strategies for improving soil quality to mitigate risks of soil degradation