黑土开垦后水稳性团聚体与土壤养分的关系

研究了黑土开垦后水稳性团聚体变化规律及其与土壤养分状况的关系．结果表明，黑土开垦初期，水稳性团聚体的含量迅速下降．在开垦的第一个10年，水稳性团聚体下降约10％；随着开垦时间的延长，其下降幅度趋缓，第10年～第50年，水稳性团聚体仅下降10％，之后下降幅度更加缓慢，接近一个稳定的水平．黑土中>0．25mm水稳性团聚体与土壤的有机碳、全氮、全磷和CEC具有良好的相关性，相关系数分别为0．7625、0．6794、0．6084和0．8134，均达到极显著水平；与交换性钙、交换性镁、交换性钾和交换性钠的相关性也达到极显著水平；在回归关系中，与有机碳和CEC之间的关系更密切，与全钾、速效磷、速效K和缓效K没有明显的相关性．要保持黑土良好的结构状况，土壤有机碳变化应处于平衡状态。

Relationships between water-stable aggregates and nutrient status in black soil after reclamation

The study on the dynamics of water-stable aggregates in black soil after reclamation and its relation to soil nutrient status showed that the contents of soil water-stable aggregates decreased significantly at initial reclamation stage,but the declining became small with time. >0.25 mm water-stable aggregates had a significant correlation with soil organic C,total N,total P and CEC,the correlation coefficients being 0.7625,0.6794,0.6084 and 0.8134,respectively,and also had a significant correlation with soil exchangeable Ca,Mg,K and Na.A closer relationship of the aggregates was found with soil organic C and CEC than with other fertility properties,while no evident correlation was existed between the aggregates and soil total K,available P,available K and slow-release K.In order to maintain a good aggregate structure of black soil,it is of most importance to concern a proper balance of soil organic C.