Effects Of Biochar Amendment On Soil Enzyme Activity And Greenhouse Gas Emissions In Farmland

Biochar is widely uesd in agricultural production,for example,improving soil,carrying out soil carbon sequestration and so on.This is of great significance to improve soil enzyme activity and promote greenhouse gas emissions reduction in farmland.Because the use of biochar is conducive to the achievement of current agricultural development goals.Therefore,in recent years,the research of converting straw and other farmland wastes into biochar has developed rapidly as an effective measure to increase agricultural sinks and reduce emissions.The effects of one-time application of biochar and slow application of biochar on soil enzyme activity and greenhouse gas emissions from farmland are the innovation points of this study.This study took dryland of Xuji Village in Xiangshan district,Huaibei city,Anhui province from 2018 to 2019 as the research object,and carried out the corn-wheat rotation system.The following treatments were designed:total amount of straw returned to the field+NPK?CS?,750 kg/ha carbon base fertilizer?BF?,20t/ha biochar+NPK?B20?,7t/ha biochar slow application+NPK?B5?,and single applied chemical fertilizer?CK?as the control.The effects of biomass carbon under different treatments on soil enzyme activity?urease,invertase,catalase,alkaline phosphatase?and greenhouse gas?CO₂,CH₄ and N₂O?emissions in Huaibei dry land were investigated.The process was divided into maize and wheat seasons,and each season was measured soil urease,sucrose enzyme,catalase,alkaline phosphatase activity,soil N₂O emissions flux and N₂O cumulative emissions,soil CO₂ emissions flux and CO₂ cumulative emissions.The results are as follows:1.Effect of biochar amendment on soil enzyme activity in Huaibei dryland?1?Soil urease enzyme activity:There was no significant difference in urease enzyme activity in corn season.The urease enzyme activity of the other four treatments were decreased compared with the control,with a decrease of 1.0%,4.5%,5.7%and 5.0%,respectively.In wheat season,the BF,B5 and B20 treatments were decreased compared with the control,with a decrease of 4.8%,5.2%and 5.4%,respectively.CS was significantly higher than control at 31.1%;?2?Soil invertase enzyme activity:There was no significant difference in invertase enzyme activity in corn season.The treatment of CS,BF,B5 and B20 decreased by2.1%,0.5%,4.3%and 8.1%,respectively.In wheat season,the difference between CS,BF treatment and control was not significant,and there was a decrease.decreased by 2.0%and14.5%,respectively.The treatment of B5 and B20 was significantly lower than that of control,with a decrease of 22.8%and 18.0%,respectively;?3?Soil catalase enzyme activity:There was no significant difference in catalase enzyme activity in corn season.The treatment of CS,BF and B5 decreased by 0.6%,0.2%and 0.6%,respectively.The B20 treatment increased to 0.3%compared with the control.There was no significant difference in catalase enzyme activity in wheat season.The treatment of CS,B5 and B20 increased by 0.2%,0.6%and 0.7%,respectively.BF treatment decreased to 0.4%compared with control;?4?Soil alkaline phosphatase enzyme activity:There was no significant difference in alkaline phosphatase enzyme activity in corn season.CS,BF,B5 treatment were higher than control,4.8%,8.0%,13.5%,respectively.The B20 treatment was lower than control at4.0%.There was no significant difference in alkaline phosphatase enzyme activity in wheat season.CS treatment was improved to 1.2%compared with control.BF,B5 and B20decreased by 8.0%,4.9%and 7.3%,respectively.2.Effects of biochar amendment on CO₂ emission from dryland in Huaibei?1?In corn season:the average emission flux of CO₂-C in farmland soil,there was no significant difference between CS,B5,B20,BF treatment and control.Compared with control,the emission of CO₂ in farmland soil increased by 4.51%,and the treatment of B5,B20 and BF decreased by 8.04%,12.79%and 20.39%,respectively;In terms of cumulative CO₂ efflux from farmland soils,there was no significant difference between BF,B20,B5 treatment,CK and BF,and CS and BF,B20.the cumulative emissions of CO₂ under cs treatment alone were higher than control treatment at 4.48%.The cumulative CO₂ efflux in wheat season under the treatment of B5,B20 and BF were lower than those under the control treatment,which were 7.58%,11.78%and18.56%,respectively.?2?In wheat season:the average emission flux of CO₂-C in farmland soil was not significantly different between CS,B5,B20,BF treatment and control.Compared with control,the emissions of CO₂ in farmland soil were increased by 7.31%,3.30%,0.72%and1.93%,respectively;There was no significant difference in cumulative CO₂ efflux in the wheat season.The cumulative CO₂ efflux under cs treatment alone were higher than control at 4.95%,the same as in corn season.The cumulative emissions of CO₂ in the wheat season under the treatment of B5,B20 and BF were lower than those under the control treatment of0.18%,1.42%and 0.71%respectively.3.Effect of biochar amendment on N₂O emission in dryland in Huaibei?1?In corn season:There was no significant difference in the average emission flux between CS,B5,B20,BF treatment and control in farmland soil N₂O-N.Compared with control treatment,CS,B5,B20 and BF treatment decreased by27.53%,14.13%,35.90%,24.91%,respectively;There was no significant difference in the cumulative N₂O efflux in corn season.The cumulative N₂O efflux in corn season under CS,B5,B20 and BF treatment were lower than those in control,and the cumulative N₂O efflux decreased by26.40%,12.94%,35.51%,27.12%,respectively.?2?In wheat season:the average emission flux of N₂O-N in farmland soil.There was no significant difference between CS,B5,B20 and BF treatment and control.Compared with control,CS,B5,B20 and BF increased by 52.76%,130.71%,100.98%,99.41%,respectively.In terms of cumulative N₂O efflux,the cumulative N₂O efflux in wheat season under CS,B5,B20 and BF treatment were all higher than those under control,and the cumulative N₂O efflux increased by 6.67%,26.67%,30.00%,26.67%,respectively.