EFFECT OF CH4 EMISSION REDUCTION OF WATER, FERTILIZER AND BIOCHAR REGULATION METHOD ON A RICE FIELD IN THE NORTHEASTERN COLD AREA OF CHINA

The objective of this study was to analyse the black soil rice fields of the northeastern cold region of China, D311 optimal design scheme with three factors secondary saturation was adopted and static opaque chamber - gas chromatographic method was utilized to analyze the effect of irrigation amount, nitrogen fertilizer and straw biochar on the emission of the greenhouse gas CH4 from rice fields, the study determined the optimal application scheme of water and fertilizer for emission control. The results show that the order of influence for these factors from the highest to the lowest is: biochar > nitrogen fertilizer > water; effect of irrigation amount on CH4 emission is increased at first, followed by a decrease. Increase of nitrogen fertilizer and biochar can significantly reduce CH4 emission loads; interaction between two factors has an inhibitory effect on CH4 emissions and it is shown as below: nitrogen fertilizer + biochar > water + biochar > water + nitrogen fertilizer; in combination with the yield, when emission reduction target of rice field CH4 is controlled at 20 similar to 40% of normal emission, the optimized application scheme in combination of water, fertilizer and biochar is the following: irrigation amount 4,930-5,310 m(3)/hm(2), nitrogen application amount 96.93-107.74 kg/hill' and biochar application amount 19.71-24.12 t/hm(2).