生物炭添加对半干旱地区土壤温室气体排放的影响

为确定生物炭添加对半干旱地区农田土壤温室气体释放的影响,采用小区定位试验,利用锯末(J)和槐树皮(H)及3种添加比例(1%、3%、5%,质量百分比),研究了生物炭添加6个月内表层土壤CO2、CH4和N2O等3种温室气体排放的动态变化.结果表明,与对照相比,各处理土壤CO2排放通量随生物炭的添加呈现增加的趋势,锯末和槐树皮等两种生物炭处理的土壤CO2平均排放通量分别增加了1.89%和3.34%,但差异不显著.CH4排放随着生物炭添加量的增加而降低,各生物炭处理的土壤表层CH4排放量平均降幅分别为:J1:1.17%、J3:2.55%、J5:4.32%、H1:2.35%、H3:5.83%、H5:7.32%.其中,锯末生物炭仅在5%添加量时较对照差异显著(P0.05),而槐树皮生物炭处理在3%和5%的添加量与对照差异均达显著水平(P0.05).生物炭对N2O的排放影响没有明显规律性.研究表明,生物炭在短期内对半干旱地区农田土壤CO2和N2O的排放没有显著影响,而对CH4排放则影响显著(P0.05).就生物炭类型而言,槐树皮生物炭在抑制CH4排放方面优于锯末生物炭,差异显著(P=0.048).

Effect of Biochar on Soil Greenhouse Gas Emissions in Semi-arid Region

This study aimed to investigate the effects of biochar addition on the emission of greenhouse gases from farmland soil in semi-arid region. Through an in-situ experiments, the influence of sawdust biochar(J) and locust tree skin biochar(H) at three doses (1%, 3%, and 5% of quality percentage) on CO₂, CH₄ and N₂O emissions were studied within the six months in the south of Ningxia province. The results indicated that soil CO₂ emission flux was slightly increased with the addition doses for both biochars, and the averaged CO₂ emission flux for sawdust and locust tree skin biochar was enhanced by 1.89% and 3.34% compared to the control, but the difference between treatments was not statistically significant. The soil CH₄ emission was decreased with the increasing of biochar doses, by 1.17%, 2.55%, 4.32% for J1, J3, J5 and 2.35%, 5.83%, 7.32% for H1, H3, H5, respectively. However, the difference was statistically significant only for J5, H3 and H5 treatments (P<0.05). Across addition doses, there was no apparent effect on soil N₂O emission. Our study indicated that the biochar has no significant influence on soil CO₂ and N₂O emissions within six months in semi-arid region and can significantly influence soil CH₄ emissions(P<0.05). As for biochar type, the locust tree skin biochar is significantly better than the sawdust biochar in terms of restraining CH₄ emission(P=0.048).