Nitrate Sequestration and Sorption Capacity in Soil Under Varying Organic Loading Conditions

Organic nitrogen occurs generally as a part of soil organic matter and has multiple sources and pathways in soil based on the prevailing bio-geo-ecosystems. Since their mobility defines sequestration capacity and adsorption kinetics, it is necessary to understand the fate and transport of nitrogen species in organic amended agricultural soils. The present study investigates the distribution of nitrogen species in a monocultured field in Alathukombai, Erode District, Tamil Nadu. Adsorption and mass transfer parameters were estimated by batch and column experiments by varying the proportions of organic amendments to assess source zone influence. Statistical analysis showed that labile fraction of organic matter has the least influence on nitrogen species sequestration in soil compared to the inert fraction derived from compost amendments. The batch experiments resulted in maximum adsorption capacity of 34% for nitrate-nitrogen onto the sugarcane-monoculture soil. When the soil is mixed with compost, the maximum available total nitrogen (TN) was found to be 86.71 ppm. The leaching trends in the sugarcane field were simulated by a continuous column experiment where the redistribution of organic nitrogen was found to be dependent on the prevailing soil conditions. The results might be quite helpful in identifying the suitable fertigation strategy for monocultured soils.