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采集棕壤长期肥料定位试验站不施肥和施用不同用量有机肥的土壤,通过超声波分散—离心分离得到细黏粒(<0.2μm)、粗黏粒(0.2～2μm)、粉粒(2～53μm)、细砂粒(53～250μm)和粗砂粒(250～2000μm)5个颗粒级别后,分析全土及不同粒级中土壤有机碳和氮并进行含量与分布的比较。结果表明,有机质主要分布于黏粒级中,其含量占全土有机碳的42.8%、全氮的58.3%,碳氮比随着粒级的增加而逐渐增大,表明氮易于在小粒级中富集。长期施用有机肥后,全土及各粒级有机碳和氮含量均有显著增加;砂粒级中有机碳和氮的富集系数升高,黏粒级中富集系数降低,粉粒级和砂粒级中的碳氮比降低。增加有机肥的用量加强了全土和各粒级对有机碳和氮的积累,同时加强了粉粒级和砂粒级碳氮比降低的程度。
The long-term fertilization experiment station of brown soil was collected and fertilized and applied with different organic manure soils. Fine clay (<0.2μm), coarse clay (0.2μm ~ 2μm), granule (2 ~ 53μm) were obtained by ultrasonic dispersion- ), Fine sand (53 ~ 250μm) and coarse sand (250 ~ 2000μm), the content and distribution of soil organic carbon and nitrogen in the whole soil and different fractions were analyzed. The results showed that the organic matter mainly distributed in the clay fraction, which accounted for 42.8% of the total organic carbon and 58.3% of the total nitrogen. The ratio of carbon to nitrogen increased with the increase of grain size, set. After long-term application of organic manure, organic carbon and nitrogen contents of all soil and grain fractions increased significantly. The enrichment coefficient of organic carbon and nitrogen in sand grains increased, the enrichment coefficient of clay fractions decreased, In the carbon to nitrogen ratio decreased. Increasing the amount of organic fertilizer enhanced the accumulation of organic carbon and nitrogen in the whole soil and each grain size, and at the same time strengthened the degree of reduction of grain-size and grain-size carbon-nitrogen ratio.