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Determination of nitrogen balance in agroecosystems

Sainju, Upendra M.
MethodsX 2017 v.4 pp. 199-208
agricultural productivity, agroecosystems, air quality, ammonium, atmospheric deposition, biomass, crop yield, denitrification, fertilizer rates, gas emissions, greenhouse gases, irrigation water, leaching, mineralization, nitrogen, nitrogen balance, nitrogen fertilizers, nitrogen fixation, nitrous oxide, runoff, soil, soil nutrient balance, volatilization
Nitrogen balance in agroecosystems provides a quantitative framework of N inputs and outputs and retention in the soil that examines the sustainability of agricultural productivity and soil and environmental quality. Nitrogen inputs include N additions from manures and fertilizers, atmospheric depositions including wet and dry depositions, irrigation water, and biological N fixation. Nitrogen outputs include N removal in crop grain and biomass and N losses through leaching, denitrification, volatilization, surface runoff, erosion, gas emissions, and plant senescence. Nitrogen balance, which is the difference between N inputs and outputs, can be reflected in changes in soil total (organic + inorganic) N during the course of the experiment duration due to N immobilization and mineralization. While increased soil N retention and mineralization can enhance crop yields and decrease N fertilization rate, reduced N losses through N leaching and gas emissions (primarily NH4 and NOx emissions, out of which N2O is a potent greenhouse gas) can improve water and air quality.