In conservation tillage systems, at least 30% of the soil surface remains covered by crop residue which generally contains significant amounts of nitrogen. Crop residues are important resources involved in nutrient cycling in agro-ecosystems.
Residue return in combination with synthetic N fertilizer is considered to be beneficial to soil fertility and crop yield, but also influences gaseous emissions.
However, few studies regarding the effects of application of residue on the emissions of both NH3 and N2O are not clear.
Dr. Li Jie, a researcher of Institute of Applied Ecology, Chinese Academy of Sciences, conducted a field experiment to investigate the effects of crop residual return on NH3 volatilization and N2O emissions over a growing season on a maize land.
This study is valuable to assess how management will affect nutrient loss and greenhouse gas emissions in agricultural land and could be helpful to minimize the N2O fluxes from agriculture ecosystems in practice.
They found that different residue return rates showed a significant effect on NH3 and N2O emissions from the maize system. NH3 volatilization loss rate from the full residue return treatment was lower than those in N fertilizer application only and half residue return plots.
Meanwhile, compared to the fertilizer-only treatment,half residue return increased N2O emission and full residue return decreased N2O emissions.
Overall, this study indicated that the combined application of maize residue and synthetic N fertilizer could minimize both NH3 and N2O losses.
The study entitled "Effects of maize residue return rate on nitrogen transformations and gaseous losses in an arable soil" has been accepted in Agricultural Water Management.
This research is financially supported by the National Key Research and Development Program of China and the National Natural Science Foundation of China.