不同培肥措施下土壤CO_2释放及其动力学研究

Study on CO_2 emissions and its kinetics of soils with different fertilization systems

实验室恒温密闭培养法研究了 4种培肥措施连续培肥 2 3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 2 4%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 0 1) ;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 =0 972 8～ 0 9987,P <0 0 1) ,速率常数k则随含水量增加呈线性降低 (r2 =0 935 6～ 0 9939,P <0 0 1)。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。

CO 2 emission and its kinetics of farmland soils with different fertilization systems were studied by incubation method. The results showed that CO 2 emission of farmland soils is a first-order reaction in the condition of water content between 12% and 24%. CO 2 emission of soils can be described quantitatively by kinetic equation y=A 0(1-e -kt) of first-order reaction (r\+2=0.9812～0.9959). Kinetic coefficient A\-0(potential respiration C)was increased linearly with the increasing of water content (r\+2=0.9728～0.9987). Rate constant k was decreased linearly with the increasing of water content (r\+2=0.9356～0.9939). The kinetics and its coefficient of CO 2 emission of farmland soils were affected significantly by fertilizations. Contrasted to CK (no fertilizer) soil, the potential respiration C (A\-0) and rate constant (k) of soils with NP fertilizer or manure +NP fertilizer were increased significantly, and A 0 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.