不同施肥措施对稻田土壤温室气体排放的影响

选取江西红壤性双季稻水稻土为研究对象,采用盆栽模拟试验研究了4种不同施肥措施即当地农民习惯施肥(FP)、较FP减施20%化肥氮且有机肥替代20%化肥氮(T1)、在T1基础上加施Si、Zn、S三种微肥(T2)和在T2基础上采用20%缓释氮肥替代普通化肥氮(T3)对稻田主要温室气体CO2、CH4和N2O排放的影响,并对土壤微生物量碳(SMBC)、土壤微生物量氮(SMBN)、水稻产量的影响进行了分析。结果表明:4种处理稻田土壤CO2的总排放通量均无显著性差异;稻田土壤N2O的总排放量与FP处理相比,T1、T2和T3处理均有显著性减少(P<0.05),分别减少了31.72%、27.17%和43.65%,T3较T2处理显著减少22.83%(P<0.05);稻田土壤CH4的总排放量与FP处理相比,T1、T2、T3处理分别高了13.06%、13.90%、21.97%,其中T3处理差异达到显著水平(P<0.05)。与FP处理相比,T1、T2、T3处理显著提高了SMBC和SMBN的含量(P<0.05),分别提高了18.91%、19.30%、20.07%和28.95%、31.66%、29.96%;T1、T2、T3处理对水稻产量均无显著性影响。稻田土壤CH4和N2O的排放与SMBC和SMBN存在显著的相关性(P<0.01)。总体看,T3处理在降低N2O的总排放量的同时对提升土壤SMBC和SMBN含量具有明显作用。

Effects of Different Fertilization Practices on Greenhouse Gas Emissions from Paddy Soil

Paddy soil is an important source of greenhouse gases. Different fertilization methods may impact greenhouse gas emissions. In a pot experiment, a paddy soil of red soil under double cropping in Jiangxi Province was used to examine the emissions of greenhouse gases under local farmer fertilization practice(FP), organic nitrogen substitution for 20% of chemical nitrogen in FP(T1), Si, Zn and S additions to T1(T2), and slow release nitrogen substitution for 40% of chemical nitrogen in T2(T3). Soil microbial biomass carbon(SMBC), soil microbial biomass nitrogen(SMBN) and rice yield were also investigated. The results showed that total emission fluxes of CO₂ were not significantly different between treatments. However, the total emission fluxes of N₂O in T1, T2 and T3 treatments were significantly reduced(P<0.05) by 31.72%, 27.17%, and 43.65%, respectively, compare to that in FP. In the T1, T2, and T3 treatments, the total emission fluxes of CH₄ were respectively 13.06%, 13.9% and 21.97% higher than in the FP treatment. Compared with FP, the SMBC and SMBN contents were increased by 18.91%, 19.30%, and 20.07%, and 28.95%, 31.66%, and 29.96%, respectively, for T1, T2 and T3. The rice yields did not show significant difference in T1, T2 and T3 treatments. The emission fluxes of CH₄ and N₂O in paddy soil had a significant correlation with SMBC and SMBN (P<0.01). Totally, T3 could significantly reduce the total emission fluxes of N₂O and improve the soil SMBC and SMBN contents.