Effects Of Biochar On Calcareous Soil Green House Gas Emissions On The Loess Plateau

The research about the impact of biochar on soil greenhouse gas emission is the key thatsolving the doubt whether organic waste resources could be returned into the field as biochar.The soil laboratory incubation was conducted to determine the effect of different biochar typeand addition amount on the soil CO₂, CH₄, N₂O emissions and research the changes ofdifferent properties （including bulk density, field capacity, pH, EC, CEC, organic carbon, totalnitrogen, ammonium and nitrate nitrogen index） before and after the incubation. This aim ofthis paper is to make a scientific clear answer for the question whether the biochar additioninto the typical calcareous soil in loess plateau could decrease the soil greenhouse gasemission, based on the full understand about the effect of biochar addition on the soil carbonand nitrogen cycles and the soil physical and chemical properties.The results are as follows:（1）Soil bulk density could be significantly reduced after biochar addition to soil. BothField capacities and pH of three soils could be increased, while soil EC could be reducedbecause of biochar addition. Effects of biochar on aeolian sandy soil in bulk density, fieldcapacity and CEC is the most largest, the increase in lou soil pH is the most largest, thereduction of biochar on loessal soil and lou soil is bigger than that of aeolian sandy soil.Compared to sawdust biochar, reduction of apple tree branch biochar on soil bulk density,increase in field capacity and CEC is larger than that of sawdust biochar, while increase ofapple tree branch biochar on soil pH is less than that of sawdust biochar.（2）Biochar can increase soil organic matter and total nitrogen, the increase of biocharon soil organic matter and total nitrogen of aeolian sandy soil is bigger than that of lou soiland loessal soil. the increase of apple tree branch biochar on soil organic matter and totalnitrogen is about twice of that of sawdust biochar. Both soil organic matter and total nitrogencan increase with the biochar addition amount.（3）The CO₂cumulative emission of three soils could be obviously increased bybiochar addition. The CO₂cumulative emission in the treatments added with sawdust biocharwas higher than that of treatments added with apple branch biochar. Effects of biocharaddition amount on the soil CO₂cumulative emission depended on the biochar type. For applebranch biochar, the CO₂cumulative emission in the treatment added with lower addition amount was bigger than that of the treatment added with higher biochar addition amount.While the CO₂cumulative emission in the treatments added with sawdust biochar couldincrease as the biochar addition amount increased.（4）The CH₄cumulative emission of three soils could be decreased by11.32%for lousoil,7.30%for loessal soil,6.25%for aeolian sandy soil. The reduction of apple branchbiochar on the soil CH₄cumulative emission was bigger than that of sawdust biochar. The soilCH₄cumulative emission could decrease with the biochar addition amount.（5）The N₂O cumulative emission could be reduced by9.19%for lou soil and9.18%for aeolian sandy soil because of biochar addition, while biochar had no obvious effect on theN₂O emission in the loessal soil. The reduction of apple branch biochar on the soil N₂Ocumulative emission was higher than that of sawdust biochar. The soil N₂O cumulativeemission could decrease as the biochar addition amount increased.