不同施肥处理红壤生物活性有机碳变化及与有机碳组分的关系

采用物理分组方法对长期不同施肥处理的旱地红壤有机碳组分进行了区分,布置室内培育试验观测了培养过程中土壤有机碳的矿化动态,通过拟合一级动力学方程计算土壤生物活性有机碳库量.研究结果表明,不同施肥处理的土壤中,轻组有机碳(LF-C)、团聚体包裹的粗颗粒有机碳(iPOMc-C)及细颗粒有机碳(iPOMf-C)、矿物结合态有机碳(mSOC)分别占总有机碳的7%～10%、0.5%～1.5%、4%～7%、76%～85%,并与总有机碳(TOC)含量显著相关;厩肥处理显著增加了各组分含量,其作用优于绿肥处理和单施无机肥处理(CK);培养过程中土壤有机碳矿化动态符合一级反应动力学方程;有机无机肥配施处理的土壤生物活性有机碳库(C0)显著提高;和绿肥相比,厩肥处理中生物活性有效碳库(C0)增加幅度更大,但其周转速率常数k更小;各组分有机碳含量与C0含量均达到极显著(p＜0.01)相关,但除LF-C外其余有机碳组分占TOC的百分率均与C0达到极显著水平.

Relationship Between Biologically Active Organic Carbon Pool and Carbon Fractions in Upland Soils Different in Fertilization

Fractions of organic carbon in upland soils different in fertilization were determined with a physical fractionation technique, and samples of the soils were incubated in lab to observe dynamics of mineralization of organic carbon in the soil. Calculation of the biologically active organic carbon pool was fitted with a first-order kinetic model. Results indicated that in soils different in fertilization, the content of organic carbon in light fraction (LF-C), coarse intra-aggregate particulate organic matter (iPOMc-C), fine intra-aggregate particulate organic matter (iPOMf-C) and mineral associated organic carbon (mSOC) accounted for 7% ~ 10%, 0.5% ~ 1.5%, 4% ~ 7% and 76% ~ 85%, respectively, of the total organic carbon (TOC) in soils, and was significantly correlated with TOC. Barnyard manure (manure NPK) increased the contents of carbon in all fractions, more significantly than green manure (green manure NPK) and CK (NPK). The dynamic of soil organic carbon mineralization under incubation consisted with the first-order kinetic model. Both green manure and barnyard manure significantly increased the size of biologically active organic carbon pool (C0), and the latter showed a better effect, than the former, but had a lower turnover rate (k). The contents of organic carbon in all fractions were significantly related to C0 at the 0.01 level, and so were the percentages of all the fractions to TOC, except LF-C .