杨树刺槐混交林下沙质土壤腐殖物质特性

研究了沙质土壤种植杨树、刺槐纯林和混交林后土壤腐殖物质特性变化的状况。研究结果表明：与无林地相比，沙地土壤种植树、刺槐纯林和混交林后土壤有机C和腐殖质C增加，土壤胡敏酸的光密度值增大，胡敏酸／富啡酸比值上升，E4和Ec值提高，色调系数（△logK）降低和相对色度（RF）升高，土壤松结合态腐殖物质（Ⅰ）和紧结合态腐殖物质（Ⅲ）以及松／紧（Ⅰ／Ⅲ）比值均有不同程度的增加，土壤稳结合态腐殖质（Ⅱ）的含C量占土壤全C的比例有不同程度的下降，表明土壤腐殖物质的聚合程度提高，腐殖物质的芳香核原子团增多，芳化度和芳化分子复杂程度以及腐殖化程度均得到提高，腐殖物质的品质变佳，土壤熟化度增大，土壤供肥保肥的能力增强，土壤肥力得以提高。培肥土壤的效果以种植杨树枣槐混交林为,其次为刺槐纯林，再次为杨树纯林。

HUMIC SUBSTANCES CHARACTERISTICS OF THE MIXED PLANTATION OF POPLAR AND BLACK LOCUST IN SANDY SOIL

The humic substances characteristics of the mixed and pure plantation of poplar and black locust in sandy soil were studied,the results were as follows:Compared with soil without forest,after the mixed and pure plantation of poplar and black locust being planted in sandy soil,soil organic C and humic C increased,the light density value of humic acid,HA/FA ratio,E4,EC,and RF values raised,Δlog K decreased,soil loose (Ⅰ) and tight (Ⅲ) combined form humus contents and the ratio of Ⅰ/Ⅲ went up,the ratio of organic C content in soil stable combined form humus (Ⅱ) to that in soil declined,indicating that the polymeric degree of soil humic substances raised,the atomic groups of aromatic nucleus increased,the aromaticity,complex degree of aromatized molecules and humification degree all went up,the quality of humic substances became better,soil maturity raised,soil nutrient\|providing and nutrient\|holding capacities increased and the soil fertility promoted after the mixed and pure plantation of poplar and black locust being planted in sandy soil.The increase in sandy soil fertility degrees followed the order:mixed plantation>black locust plantation>poplar plantation.