保护性耕作对黄土旱塬箭筈豌豆地土壤呼吸的影响

目的]揭示保护性耕作对土壤呼吸的影响,为旱区保护性农业的发展提供理论依据。方法]采用多通道土壤碳通量系统监测传统耕作(T)、传统耕作+秸秆覆盖(TS)、免耕(NT)和免耕+秸秆覆盖(NTS)下箭筈豌豆(Vicia sativa)地的土壤呼吸速率。结果]各措施下花期呼吸速率比收获期高10.45%~45.09%,NTS处理下土壤呼吸速率最低别比TS,NT和T处理显著减少39.17%,21.37%和30.25%(p0.01)。耕作处理(T,TS)下日均土壤呼吸速率高于免耕处理(NT,NTS)(p0.05)。晴天土壤呼吸变化呈单峰曲线,最大值出现在14:00。耕作下土壤呼吸速率与气温显著线性相关,免耕下(NT,NTS)与气温呈指数关系(p0.01)。不同耕作措施间气温敏感性Q10值大小依次为:T(1.97)NT(1.62)TS(1.58)NTS(1.52)。结论]免耕加秸秆还田处理对减少温室气体排放有一定的贡献。

Effects of Conservation Tillage on Soil Respiration in Vetch Field in Rain-fed Loessial Tablelands

Objective] The effects of conservation tillage on soil respiration were researched to provide a theoretical basis for the development of conservation agriculture in arid area.Methods] Soil respiration rate was carried out using multi-channel soil carbon flux measurement system instrument. Tillage treatments were:conventional tillage(T), conventional tillage with stubble retention(TS), no tillage(NT) and no tillage with stubble retention(NTS).Results] Respiration rate in flowering period was 10.45%~45.09% higher than that in harvest period for all tillage measures. In comparison with TS, NT and T treatment, NTS treatment significantly reduced soil C emission with the percentages of 39.17%, 21.37% and 30.25%, respectively(p<0.01). Soil respiration at sunny day presented an stubble unimodal curve with the peak value at 14:00. The averaged daily soil respiration rates under the two tillage treatments were high but not insignificant than that under the two no-tillage treatments. Under tillage treatments(T, TS), a significant linear correlation was found between soil respiration rate and air temperature; under the no-tillage treatment(NT, NTS), they had a significant exponential relationship(p<0.01). Q₁₀ values, namely the atmospheric temperature sensitivity under the four tillage treatments had a rank of T(1.97) >NT(1.62) >TS(1.58) >NTS(1.52).Conclusion] Conservation tillage as the no tillage with stubble retention(NTS) has its contribution to the reduction of greenhouse gas emissions.