水土保持耕作下陇东玉米-小麦-大豆轮作系统产量、土壤易氧化有机碳动态

在陇东黄土高原定位研究了玉米－冬小麦－大豆轮作系统中4种耕作处理：传统耕作（T1）、耕作覆草（T2）、免耕（T3）和免耕覆草（T4）对作物产量和表层土壤有机碳的影响。结果表明，2001年至2004年，经过2个轮作周期后，4个处理下作物产量无显著差异；免耕＋秸秆还田下土壤易氧化有机碳比传统耕作处理下显著增加2.44g／kg，易氧化有机碳与土壤全氮和水稳性团粒结构有显著的正相关关系，说职水土保持耕作对改善土壤理化性质有积极促进作用。易氧化有机碳组分可指示轻壤质地土壤对耕作措施的响应，水土保持耕作对产量增加的效应滞后于其对土壤理化性质产生的良好效应。

Dynamics of Crop Yield and Soil Oxdizible Organic Carbon Fraction Within a Maize-Winter Wheat-Soy Rotation Under Different Tillage Treatment in Longdong Loess Plateau

A field trail was conducted to determine the effects of conventional tillage(T1), conventional tillage with stubble retention(T2), no tillage(T3) and no tillage with stubble retention(T4)treatment on crop yield and soil oxdizible organic carbon within maize-wheat-soy rotation system in the western Loess Plateau. The results indicated that there was no significant tillage effect on crop yield for each six harvesting during the year 2001 to 2004. The easily oxdizied organic carbon in the 0~5 cm soil layer under no-till with stubble retention treatment increased by 2.44 g/kg significantly compared with that under conventional treatment. The most oxdizible organic carbon had significant positive correlation to soil total nitrogen and water stable aggregates. We concluded that effect of conservation tillage on crop yield was delayed to that on soil fertility change,soil oxdizible organic carbon is a one of sensitive indicator to indicate soil organic carbon change to the tillage practice.