耕作方式对黑土有机碳及有机无机复合状况的影响

目的]研究耕作方式对黑土有机碳数量的变化、有机无机复合度及腐殖质结合形态的影响。方法]采用设置休闲、玉米连作和玉米—大豆轮作3种耕作方式进行长期定位试验。结果]不同耕作方式对黑土有机无机复合状况有明显的影响。休闲、连作及轮作均能增加土壤有机碳及其各组分、重组有机碳含量以及原土复合量,提高土壤活性有机碳含量,降低土壤有机碳的氧化稳定性及原土复合度。连作和轮作增加黑土土壤追加复合量和追加复合度,以轮作效果最好。不同耕作方式中各种结合形态的腐殖质在绝对含量上均有明显提高,以松结合态腐殖质增加较多。结论]轮作更有利于提高土壤HA/FA比值、HA的E4/E6比值、土壤松结合态腐殖质含量及土壤重组腐殖质碳的松/稳和松/紧比值。

Effect of Cultivation Patterns on the Organic Carbon and the Organo-mineral Complexation in Black Soil

Objective] The aim was to study the effect of cultivation patterns on the change of organic carbon amount,the degree of organo-mineral complexation and forms of combined humus in black soil.Method] The long-term located experiments were carried out by using 3 kinds of cultivation patterns including fallow,continuous cropping of maize and maize-soybean rotation cropping.Result] The different cultivation patterns had obvious effects on organo-mineral complexation in black soil.The fallow,continuous cropping and rotation cropping all could increase the organic carbon content and its components in soil,the recombination organic carbon content and soil complex amount,enhance the active organic carbon content in soil and reduce the oxidation stability of soil organic carbon and soil complex degree.The continuous cropping and rotation cropping could increase the additional quantity and additional degree of organo-mineral complexation,with the effect of rotation cropping being best.The absolute contents of various combined humus forms in different cultivation patterns were increased greatly and the increasing contents of loosely combined humus were more than the others.Conclusion] The corn-soybean rotation were propitious to increase soil HA / FA ratio and E4/E6 ratio of HA,the contents of loosely combined humus and the ratio of loosely to stably combined humus and that of loosely to tightly combined humus in soil.