施用生物炭对农田土壤N_2O的减排效应

Effect of biochar on N2O emissions from agricultural soil

生物炭作为一种土壤改良剂,在农田土壤氮素转化和温室气体减排等方面发挥着重要作用。本实验对不同施氮量的农田土壤添加生物炭,研究了其对N2O的减排潜力,为生物炭的固氮减排提供理论依据。于2015年6月18日至9月25日,利用盆栽实验研究了施用生物炭对农田土壤在不同氮肥用量下N2O排放的影响,实验共设4个处理:对照(CK)为不施氮处理、N1(200 kg·hm-2)、N2(400 kg·hm-2)和N3(600 kg·hm-2),各处理均施用土壤质量15%(W/W)的等量生物炭。结果表明,随着施氮量的增加,土壤N2O的累积排放量逐渐增加,N2和N3处理差异不显著,N2O排放系数逐渐降低,N1、N2、N3的排放系数分别为1.33%、1.27%、0.90%。Pearson相关分析表明,土壤孔隙含水量(WFPS)、土壤pH、土壤NO-3-N和土壤微生物量氮(MBN)含量是影响N2O排放最主要的因素,其中土壤WFPS、土壤NO-3-N和MBN含量与N2O排放通量之间呈极显著的正相关关系,土壤pH与N2O排放通量之间呈极显著负相关关系。生物炭的施用对农田土壤N2O具有巨大的减排潜力,并且生物炭与氮肥配施对土壤氮素有很好的固持作用。

As a soil amendment,biochar plays an important role in soil N transformation and reducing greenhouse gas emissions.The purpose of the experiment is to study the N2O emission reduction potential under different N rates with biochar addition,and to provide a theoretical basis for the reduction potential of biochar.A pot experiment was conducted from June18to September25in year2015,and the effects of biochar on N2O emissions under different N levels in farmland soil were studied.The experiment consisted of four treatments with three replicates.The treatments were CK(non-N application),N1(200kg·hm^-2),N2(400kg·hm^-2),and N3(600kg·hm^-2).A biochar amount of15%(W/W)of the pot soil was applied to each treatment.The results showed that the cumulative N2O emissions increased with N rates.There was no significant difference between N2and N3.The emission factors(EFs)of N1,N2,and N3were1.33%,1.27%,and0.90%,respectively,and the EFs decreased with increasing N rate.The correlation analysis showed that N2O fluxes were significantly positively correlated with soil water-filled porosity(WFPS),soil NO-3-N content,and soil microbial biomass nitrogen(MBN)(P<0.01),and that N2O fluxes were significantly negatively correlated with soil pH(P<0.01).The addition of biochar has great potential to reduce N gas loss.The combined application of biochar and N fertilizer has a good retention effect on soil N.