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以珠江三角洲平原由三角洲沉积物、河流沉积物和滨海沉积物发育形成的水耕人为土(水稻土)为对象,研究了水田、果园、菜地3种利用方式下不同发生层土壤全磷(TP)、有机磷(Po)、有效磷(AP)、无机磷(Pi)组分的含量和剖面分布特征,并利用液相31P核磁共振(NMR)技术测定了耕层土壤中磷形态分布。结果表明,珠江三角洲平原农田土壤全磷、有机磷、有效磷和各形态无机磷含量随土层深度增加呈减小的趋势,耕层土壤中全磷、有效磷、Al-P和Fe-P明显富集;菜地和果园耕层土壤中全磷、有效磷、Al-P、Fe-P、Ca-P和O-P含量均高于水田。土壤磷素以无机磷形态为主,无机磷、有机磷占全磷比例平均值分别为71.3%和28.7%。土壤无机磷组分以O-P和Fe-P为主,Al-P最低。Al-P、Fe-P、Ca-P、O-P与全磷呈极显著或显著正相关,有效磷与Al-P、Fe-P、O-P、全磷呈极显著正相关;Fe-P和Al-P是土壤有效磷的主要贡献者。31P-NMR结果表明,耕层土壤磷形态均以正磷酸盐为主;土地利用方式影响土壤磷组分,菜地耕层土壤中磷形态包括正磷酸盐、磷酸单酯和焦磷酸盐,水田和果园包括正磷酸盐、磷酸单酯、磷酸二酯和焦磷酸盐;水田土壤中正磷酸盐所占比例最低,磷酸单酯和磷酸二酯所占比例最高;成土母质对水田耕层土壤各形态磷所占比例影响很小。
Taking Pearl River Delta Plain as an example, the hydroponic artificial soil (paddy soil) developed from delta sediments, river sediments and coastal sediments was used to study the effects of paddy fields, orchards and vegetable fields on the total phosphorus TP, Po, AP and Pi, and the distribution of phosphorus species in the topsoil was determined by liquid phase 31P nuclear magnetic resonance (NMR) technique. The results showed that total phosphorus, organic phosphorus, available phosphorus and inorganic phosphorus contents of farmland in the Pearl River Delta decreased with the increase of soil depth. Total phosphorus, available phosphorus, Al-P and Fe-P in topsoil Obviously enriched. The contents of total phosphorus, available phosphorus, Al-P, Fe-P, Ca-P and OP in topsoil and orchard topsoil were all higher than those in paddy field. Inorganic phosphorus was the main form of soil phosphorus. The ratios of inorganic phosphorus and organic phosphorus to total phosphorus were 71.3% and 28.7% respectively. The content of inorganic phosphorus in soil was mainly composed of O-P and Fe-P, and lowest in Al-P. Al-P, Fe-P, Ca-P and OP had a significant or significant positive correlation with total phosphorus. There was a significant positive correlation between available phosphorus and total phosphorus, Fe-P, -P is a major contributor to soil available phosphorus. The results of 31P-NMR showed that the forms of phosphorus in the topsoil were dominated by orthophosphates, and the land use types affected the phosphorus fractions in the soils. The phosphorus forms in the topsoil of the vegetable fields included orthophosphate, phosphate monoester and pyrophosphate, And orchards include orthophosphates, monophosphates, phosphodiesters and pyrophosphates; the proportion of orthophosphates in paddy soil is the lowest, and the proportion of phosphate monoesters and phosphodiesters is the highest; The proportion of form phosphorus has little effect.