石灰性菜园土壤中各形态磷素的富集与变异特征

由于长期种植蔬菜，石灰性菜园土壤中的磷素在剖面中发生了分异，直接影响到其它营养元素的吸收和蔬菜的产量及品质。通过对不同植菜年限石灰性菜园土壤剖面磷素形态分级及其变异规律的研究，探讨了全磷、有效磷和无机磷不同形态的变异特征以及其磷素形态分布与其它土壤性质的关系。研究结果表明，石灰性菜园土壤耕层全磷、有效磷、无机磷与有机磷均比粮田富集强烈，有效磷源的无机磷形态含量与植菜年限呈明显的正相关，各形态无机磷含量的垂直分布与粮田存在显著关系，Ca2-P、Ca8-P、Fe-P含量为表层强烈富集，向下骤减的垂直分布特征。溶度较高的Ca2-P、Ca8-P与有机质等养分呈极显著的正相关，而与CaCO3含量和pH值的降低呈显著的负相关，随植菜年限的延长，有机质及其它养分含量的提高以及CaCO3含量和pH值的降低也促进了难溶杰礁的有始化．

Enrichment and Variation of Various Forms of Phosphorus in Calcareous Vegetable Cultivated Soils

Differentiation of phosphorus in calcareous vegetable cultivated soil profiles with long-term vegetable cultivation influenced the uptake of other nutrient elements and also output and quality of vetetables. The objective of this study was to illustrate the variational characteristics of total phosphorus, available phosphorus, different forms of inorganic phorphous, and the relationships between the distribution of different phosphorus forms and other soil properties. The results showed that the enrichments of total phosphorus, available phosphorus, inorganic and organic phosphorus in vegetable cultivated soil profiles were more intensive than that of the grain crop cultivated soils. The significant positive correlations between the available inorganic forms of phosphorus and the vegetable cultivated time was found. The difference of the vertical distribution of various inorganic phosphorus fractions between vegetable cultivated soil profile and grain crop cultivated soil profile was also significant. The content of Ca2-P, Ca8-P, Fe-P enriched intensively in surface soil and reduced sharply downwards from the surface horizon. Significant correlations between the content of various phosphorus forms and other soil properties such as the content of organic matter and the changes of CaCO3 content and soil pH. As the vegetable cultivated time prolonged, the changes of these soil properties accelerated the transformation of available phosphorus from insoluble phosphate minerals.