杨凌地区大棚土壤无机磷形态及有效性研究

Study on Forms of Inorganic Phosphates and Its Validity in Yangling Area

为了研究杨凌地区不同年限大棚土壤磷素的有效性及无机磷的空间分布状况,采用蒋-顾石灰性土壤无机磷形态分级方法,对大棚土壤磷素形态、空间分布特性以及无机磷形态的生物有效性进行了研究。结果表明：大棚土壤各形态无机磷呈现出在表层（0-10 cm）强烈富集,向下剧减的垂直分布特征,大棚土壤的磷素以无机磷为主,Ca-P含量占无机磷含量的73.61%~77.11%,平均74.99%,大棚土壤0-40 cm土层中各形态无机磷含量大体也表现Ca-P含量（Ca10-P、Ca8-P）高于其他形态的磷;大棚土壤无机磷含量高于露天菜地,但无机磷占全磷的比例有所下降,随着大棚土壤栽培年限的延长,Ca-P在无机磷组分中始终占主导地位,Ca10-P、Ca8-P、Ca2-P等无机磷组分的含量顺序及比例在一定范围内基本不变,保持耕层各形态磷的平衡,无机磷组分的形态分布及比例分配并没有随棚龄的变化而发生改变;与露天土壤相比,大棚种植的环境提高了Ca8-P、Ca2-P在无机磷所占的比例,从而提高了土壤中磷素的生物有效性。

This paper was studied the content of available phosphorus and distribution of inorganic phosphorus. The results showed that different forms of inorganic P were rich in the surface of 0--10 cm green-house soil, inorganic P decrease evidently as the soil depth increased, most P form is inorganic P, 73. 61%-77.11% Ca--P of total P content of inorganic P, 74.99% on average. Ca--P （Cal0--P,Ca8--P）was the most form in 0--40 cm depths green-house soil. As the year increased Ca--P still remain the dominant degree of forms of inorganic P , Ca10--P and Ca8--P come out top. The sequence and proportion of Ca2--P and other forms kept the same as a balance with other P form. The distributing and proportion of inorganic P is nothing to do with the years when green-house was used. The condition of green-house increased the proportion of Ca8--P and Ca2 --P content in inorganic P, thereby improve the biologic effectiveness of P components in soil.