钙、铁、铝形态对岩溶石灰土磷有效性的影响

为揭示钙、铁、铝形态与岩溶地区土壤磷有效性关系，通过改进的BCR元素形态连续提取法获取石灰土不同发育阶段土壤矿质元素赋存形态，并分析与总磷及速效磷含量之间的相关关系。初步研究表明:石灰土壤中全磷和速效磷在石灰土发育过程呈降低趋势，从黑色石灰土到黄色石灰土，总磷降低了76.7%，速效磷减少了84.7%。石灰土总磷与速效磷同酸溶态、可还原态及残渣态钙，可氧化态铁、铝和可还原态铝显著正相关，而同总铁、总铝以及残渣态铝显著负相关，相关系数绝对值均达到0.9以上。随着石灰土发育进行，钙总量及其形态均降低，而铝、铁总量和形态呈增加趋势，可能导致岩溶地区石灰土磷及其有效性缺乏越发突出。 

Effects of calcium, iron and aluminum fractions on the phosphorus bioavailability in limestone soil of karst region

In this paper, the effective relationships between phosphorus (P) in the soil of the karst region and the fractions of calcium, iron and aluminum have been studied to provide theoretical basis for stabilization of karst bio-system and lime soil fertility. The fractions of mineral elements in limestone soil at different stages of development were detected by improved BCR sequence extraction method and the relationship between total phosphorus and available phosphorus was analyzed. The results revealed that the concentration of total soil phosphorus and readily available phosphorus decreased with the development of limestone soil. The concentration of total P decreased to 76.7% and readily bioavailable P decreased to 84.7%. The positive corrections occurred between total and readily bioavailable P with the acid extractable, reducible and residual fractions of calcium, oxidable iron and aluminum, reducible aluminum. Total iron, aluminum and residual aluminum had negative corrections with total and readily bioavailable P. The absolute correlation coefficients were higher than 0.9 With the development of limestone soil, the lack of total P and readily bioavailable P was more and more prominent for the limestone soil quality and fertility.