POTENTIAL NUTRIENT STOCK AND EMISSION OF GREENHOUSE GASES FROM SOIL DUE TO APPLICATION OF ORGANIC AMENDMENTS IN INDIA.

In India, large quantities of organic amendments such as crop residues (550 mt yr^-1), municipal solid waste (48 mt yr^-1), animal manures (182 mt yr^-1) and other sources are produced. Recycling these organic amendments in agriculture has several beneficial effects such as improving plant growth, yield, soil carbon content, and microbial biomass and activity. Nevertheless, organic amendment applications have some disadvantages such as nutrient eutrophication and greenhouse gas (GHG) emission. Agriculture sector emits substantial quantities of GHGs (carbon dioxide-CO₂, methane-CH₄, and nitrous oxide-N₂O). Though quantity wise CH₄ and N₂O emissions are less than CO₂, they have higher global warming potential. Although there have been studies on the role of chemical fertilizer application on GHG emission, there have been very few studies on the effect of organic amendments application on GHG emission in agricultural soils. We reviewed quantification of various organic amendments used in agriculture that include manures, municipal solid waste, green manuring, crop residues and other miscellaneous organic amendments, major processes for GHG emission, and impact of organic amendment application on GHG emission from soil. The article aims to highlight the management practices to mitigate the emission and the future research needs in relation to nitrogen and carbon dynamics in soil for judicious use of organic amendments in agriculture to maintain soil health with minimum impact on GHG emission from agriculture. [ABSTRACT FROM AUTHOR]