【摘要】 在江西省鹰潭市余江县孙家红壤小流域的典型红壤区随机选取了具有代表性的林地(F)、花生旱地(PU)、新稻田(NP,<30 a)和老稻田(OP,> 200 a),在0～40 cm深度每隔5 cm采集分层土样,分析了土壤全磷(TP)、有效磷(Bray P)、磷素活化系数(PAC)及有机磷(Po)、无机磷(Pi)与各组分磷的深度变化,探讨了土壤pH与土壤有机质(SOM)对红壤磷素有效性的影响。研究结果表明:孙家小流域不同利用方式红壤TP含量大小依次为:老稻田>新稻田>林地>花生旱地;除林地外,花生旱地与稻田土壤TP、Bray P、Pi和Po含量随着土壤深度的增加呈显著降低趋势,且稻田土壤Po含量及其占全磷的比例显著高于林地和花生旱地。花生旱地与稻田0～20 cm土壤中极有效磷(EAP)、中等有效磷(MAP)及EAP、MAP中的无机磷与有机磷的比值均显著高于林地土壤。林地转为旱地和稻田,尤其是长期植稻可以促进土壤非有效磷(NAP)向利于作物吸收的EAP与MAP转化,因而提高土壤磷素有效性。相关分析表明,随着SOM累积量的增加,四种利用方式红壤中EAP、MAP含量均显著提高。更多还原

【Abstract】 Soil samples were collected from the 0-40 cm depth of red soils under the land use types of forest, peanut upland, new paddy field(< 30 yr.) and old paddy field( > 200 yr.) at the Sunjia Watershed, Jiangxi Province of China.The vertical variation of soil total phosphorus(TP), available P(Bray P), P activation coefficient(PAC), organic P(Po),inorganic P(Pi) and various fractions of soil P were analyzed, and the relationships between soil pH, soil organic matter(SOM) and soil P availability were also discussed. Results showed that soil TP content in the red soil under different land use types was in the order of old paddy field > new paddy field > forest > peanut upland. Soil TP, Bray P, Pi and Po significantly decreased with the soil depths, except in the forest soil. The Po content and its proportion in TP in the paddy field were all significantly higher than those in the forest soil and peanut upland soil. In the surface soil(0-20 cm) of peanut upland and paddy field, the contents of easily-available P(EAP), moderately-available P(MAP) and the ratios of EAPi/EAPo and MAPi/MAPo were all significantly higher compared with the forest soil.The change in land use types from forest to the peanut upland and paddy, especially the long-term cultivated paddy system, significantly promoted the transformation of non-available P(NAP) to EAP and MAP in the soil, and then the availability of soil P was increased. Correlation analysis showed that the contents of EAP and MAP in the forest,peanut upland and paddy soils increased significantly with the increase of SOM content.更多还原