Influence of Sewage Sludge and Heavy Fertilization on Nitrate Leaching in Soils: An Overview

Sewage sludge is now widely used for production of crops throughout the world. Utilizing the sewage sludge for crop production has various advantages such as nutrient recycling, reducing the need for mineral fertilizer, increasing organic matter amount in soils, and improving physical properties of soil. A large amount of sludge is generated during the sewage treatment process, and it is disposed off on land in the form of fertilizer or soil conditioner. In this, heavy metals are usually in greater concentration than in soil, which is one of the main problems which restricts its utilization as a fertilizer. Nitrate leaching and heavy fertilization cause serious problems for the groundwater and this issue of nitrate leaching is usually neglected. Continuous used of swage sludge cause contamination of soil and water and affects plant growth and soil microorganisms. In this chapter, we have focused on i) various factors which affects nitrate leaching in soil, it includes soil texture, rate of fertilization, season and climate, ii) strategies to reduce nitrate leaching and iii) nitrogen conversion mechanism in sewage sludge