Greenhouse Gas Emissions in Red Soil as Influenced by Different C/N Residues Under Nitrogen Applications

WU Yu-peng;LIU Tian;PENG Qi-an;Muhammad Shaaban;HU Rong-gui;College of Resources and Environment, Huazhong Agricultural University;Key Laboratory of Arable Land Conservation(Middle and Lower Reaches of Yangtze River),Ministry of Agriculture;

residue returning;;greenhouse gas emission;;C/N;;nitrogen fertilizer application;;red soil

Nitrogen(N)fertilizer application can accelerate decomposition of incorporated residues in soils. However, the effect of N applications on greenhouse gas(GHG)emissions following incorporation of different C/N residues is still not well understood. In this study, an incubation study was carried out to examine GHG emissions from red soil incorporated with rape cake(C/N:4), maize stalk(C/N:28), rice straw(C/N:41)and wheat straw(C/N:71)under three N addition rates(zero, low and high levels). Nitrogen applications increased CO2 emission, but significant difference was observed only in wheat straw treatment. The cumulative CO2 emission in wheat straw treatment was1 271.44 mg·kg-1at low N and 1 212.83 mg·kg-1at high N application, significantly higher than that of no N application(883.40 mg·kg-1). The cumulative N2 O emission was highest in rape cake treatment(5 550. 42 μg·kg- 1)at low N application while relatively lower N2 O emission(3 752.84 μg·kg-1)at high N addition. However, nitrogen application did not show significant influence on the cumulative N2 O emissions in soils incorporated with maize and wheat residues. Over the entire incubation period, all treatments tended to be a sink of CH4. Overall, nitrogen effects on GHG emissions depend on residue C/N ratios.