不同培肥措施下土壤CO2释放及其动力学研究

实验室恒温密闭培养法研究了 4种培肥措施连续培肥 23年后农田土壤的CO2释放状况及其动力学特征。结果表明 ,含水量 12%至 24%范围内 ,土壤CO2释放过程完全可以用一级反应动力学方程 y =A0(1-e-kt)进行定量描述 (r2=0.9812～0.995 9,P 0.01) ;土壤CO2释放量和潜在可释放C量A0 随含水量增加呈线性增加 (r2=0.9728～0.9987,P0.01) ,速率常数k则随含水量增加呈线性降低 (r2=0.9356～0.9939,P0.01)。不同培肥措施明显影响土壤CO2释放状况及其动力学特征参数 ;NP化肥和厩肥 +NP化肥 2种培肥措施较不施肥对照明显增加了土壤CO2释放量、潜在可释放C量A0和速率常数k ;秸秆 +NP化肥培肥措施较不施肥对照显著增加了土壤CO2释放量、潜在可释放C量A0,但却显著降低了释放速率常数k ;有机无机肥料配合措施 (秸秆 +NP、厩肥 +NP)与单施NP化肥措施比较 ,明显降低了释放速率常数k。

Study on CO2 emissions and its kinetics of soils with different fertilization systems

CO₂ emission and its kinetics of farmland soils with different fertilization systems were studied by incubation method. The results showed that CO₂ emission of farmland soils is a first-order reaction in the condition of water content between 12% and 24%. CO₂ emission of soils can be described quantitatively by kinetic equation y=A₀(1-e^-kt) of first-order reaction (r²=0.9812～0.9959). Kinetic coefficient A₀(potential respiration C)was increased linearly with the increasing of water content (r²=0.9728～0.9987). Rate constant k was decreased linearly with the increasing of water content (r²=0.9356～0.9939). The kinetics and its coefficient of CO₂ emission of farmland soils were affected significantly by fertilizations. Contrasted to CK (no fertilizer) soil, the potential respiration C(A₀) and rate constant (k) of soils with NP fertilizer or manure +NP fertilizer were increased significantly, and A₀ of soil with straw +NP fertilizer was also increased significantly, but k of soil with straw +NP fertilizer was decreased significantly. Contrasted to soil with NP chemical fertilizers, the rate constant (k) of soils fertilized with organic and inorganic fertilizer ( straw +NP, manure +NP ) was decreased significantly.