大豆连作土壤障碍因素研究──Ⅰ、连作对土壤腐殖质组分性质的影响

STUDIES ON SOIL OBSTRUCTIVE FACTORS SOYBEAN (Glycine max) CONTINUOUS CROPPING ──ⅠEffects of Succesive Soybean Planting on Characters of Soil Humus Composition

由于大豆连作造成根系分泌有机酸类物质的残留和积累，使土壤根际ｐＨ值下降，引起根系范围土壤中生化它感现象产生，导致反映土壤有机肥力核心指标的土壤腐殖质总量、胡敏酸（ＨＡ）、ＨＡ／ＦＡ（富里酸）比值随连作延长而呈现下降趋势。其中活性胡敏酸含量、胡敏酸在波长为４６５ｎｍ和６６５ｎｍ的消光度比值（Ｅ４／Ｅ６）在连作第二年变化明显，此时是大豆连作实施有机培肥的最佳时期。

This paper reports that the remains and accumulation of organic acids secreted from the net work of roots in successive soybean planting cause pH value around soil rhizosphere to decrease and other biochemistry phenomenons occur around the network of roots, so that total content of soil humus,HA , ratio of HA to FA which are the index of soil organic fertility shows decreasing trend with successive soybean planting.The content of the active humic acid and the ratio of E4 to E6 changed significally in successive soybean planting in the second year,which offers the valuble reference to fertilize organic fertilizer for soybean following soybean at the best period.