【摘要】 研究结果表明红壤坡地固体径流中80%以上土壤颗粒为粉粒和粘粒。与其相应的表层土壤相比,固体径流中砂粒含量比其低24.3%~30.8%,粉粒含量比其高11.4%~15.9%,粘粒含量则基本一致。2001年与1993年相比,坡地2种不同经营方式固体径流,砂粒含量下降30.0%~53.8%,粉粒、粘粒含量分别增加18.0%~21.2%与3.8%~9.4%,其中油菜-玉米/甘薯复种制的粉粒化过程明显,乔-灌-草复层植被结构的粉粒化和粘粒化过程显著。2种经营方式固体径流的养分富集率均为水解性氮>有效钾>速效磷≥全N>全K≥全P>有机质,且养分富集率随土壤肥力的提高而显著增加。固体径流中有机质主要富集在0.05~0.001mm土粒中,N主要富集在<0.01mm土粒中,K主要富集在<0.005mm土粒中,其数量占该养分在固体径流中富集总量的73.5%以上;P在固体径流各粒径中均有分布。更多还原

【Abstract】 The results show that 80% of the soil particles in the runoff solid is silt and clay in the sloping field of red soil.Compared with the particles in surface soil,the amount of sand in runoff solid decreases by 24.3%～30.8%,while the amount of silt increases by 11.4%～15.9% and the amount of clay is similar.The changes of particle components respond to various managing patterns during 1993～2001.In runoff solid,the amount of sand in 2001 is 30.0%～53.8% lower than that in 1993,while the amounts of silt and clay are 18.0%～21.2% and 3.8%～9.4% higher than those in 1993,respectively.The silt-increasing in runoff solid is significant in the multiple cropping system of rape-maize/sweet-potato,while silt-increasing and clay-increasing in runoff solid are significant in the vegetative cover structure of arbor-shrub-grass.The nutrient enrichment rates in both managing patterns show that water extractable N>available K>available P≥total N>total K≥total P>organic matter.Moreover,all the enrichment rates decrease significantly with the improvement of soil fertility.In runoff solid,most of the organic carbon enriches in the soil particle whose diameter is 0.05～0.001mm,N in the particle whose diameter is <0.01mm,K in the particle whose diameter is <0.005mm.Each nutrient enrichment amount accounts for over 73.5% of the relevant enrichment amount in runoff solid.P is distributed in various particles.更多还原