Effects of Reduced Nitrogen Fertilization and Biochar Application on CO_2 and N_2O Emissions from a Summer Maize-Winter Wheat Rotation Field in North China

This experiment was conducted in Xinxiang, Henan from June 2013 to June 2014. Total four treatments were designed including farmers ’ common practice （F, 250 kg/hm^2）, 80% F （LF, 200 kg/hm^2）, 80% F＋biochar （LFC） and no fertilizer （CK） to measure the dynamic emissions of CO2 and N2O from a summer maize-winter wheat field by static chamber-gas chromatography method. The results showed that the soil CO2 emission was 21.8-1 022.7 mg/（m^2·h）, and was mainly influenced by soil temperature and moisture content. During the growth of summer maize, the soil CO2 emission was more significantly affected by soil moisture con-tent; and in winter wheat growing season, it was more significantly affected by soil temperature in the top 5 cm. The LF and LFC treatments significantly reduced the soil cumulative CO2 emission, especial y during the growth of winter wheat. Fertiliza-tion and irrigation were the main factors influencing the soil N2O emission. The soil N2O emission during the fertilization period accounted for 73.9%-74.5% and 40.5%-43.6% of the soil cumulative N2O emission during the summer maize-and winter wheat-growing season, respectively. The peak of emission fluxes was determined by fertilization amount, while the occurrence time of emission peak and emission re-duction effect were influenced by irrigation. The LF treatment reduced the soil cu-mulative N2O emission by 15.7%-16.8% and 18.1%-18.5% during the growth period of summer maize and winter wheat, respectively. Reduced nitrogen fertilization is an effective way for reducing N2O emission in intensive high-yielding farmland. Under a suitable nitrogen level （200 kg/hm^2）, the application of biochar showed no significant effect on the soil N2O emission in a short term. The N2O emission factors of the L and LF treatments were 0.60% and 0.56%, respectively. ln the intensive high-yield-ing farmland of North China, reducing the nitrogen application amount is an appro-priate measure to mitigate greenhouse gas emissions without crop yield loss.

Impact of Silicon,Zinc,Boron Combined with Reduced Nitrogen Fertilization on Rice Growth

Under the condition of reduced application of nitrogen fertilizer, the impact of silicor）, zinc and boron on rice growth was investigated by field experiment. The results showed that when the application amount of nitrogen fertilizer was reduced by 20%, the application of silicon, zinc and boron did not reduce the yield of rice, but reduced the incidence of panicle blast in rice and optimized the structure of rice production.

Application of Aisi Si/TE Compound Bacterial Fertilizer in Rice

[Objectives]To investigate the application effect of compound microbial fertilizer on crops.[Methods]Livestock and poultry breeding waste,rapeseed cake and peanut straw were fully decomposed,and then added with compound functional microbial inoculum to produce Aisi Si/TE(active chelated silicon/trace element)compound microbial fertilizer,which was used to conduct 10%nitrogen reduction alternative fertilization experiment on rice.[Results]The yield of rice applied with 225 kg/ha Aisi Si/TE compound bacterial fertilizer was 7203 kg/ha,increased by 5.4%,6.9%and 46.9%,respectively compared to those of rice applied with 225 kg/ha inactivated Aisi Si/TE compound microbial fertilizer,conventional fertilization and blank control(P<0.01).Application of Aisi Si/TE compound microbial fertilizer to rice improved soil organic matter and effective nutrient content and showed obvious effect of saving nitrogen and increasing yield and income.In addition,it provided a good micro-ecological environment,passivated and solidified heavy metals,effectively reduced the biological mobility of heavy metals,and greatly reduced the cadmium content in rice.[Conclusions]Application of Aisi Si/TE compound microbial fertilizer is beneficial to improving the quality of agricultural products.