塑料大棚内长期施肥对菜田土壤磷素组成及其含量影响

对塑料大棚内自1988年开始的蔬菜施肥长期定位试验田土壤磷索组分和含量进行了研究.结果表明,除了长期单独施用氮肥引起耕层土壤全P、有效P降低外.其他施肥处理均能提高土壤中全P和有效P含量.长期施用有机肥土壤闭蓄态P(O-P)含量最高.占无机P总置的35%～47%;不施有机肥土壤磷酸钙(Ca-P)含量最高,占无机P总量的29%～39%.施用有机肥可以显著提高土壤有机P总量,有机肥组各处理土壤活性有机P和中等活性有机P含量均显著高于不施有机肥组各对应处理,而稳定性有机P和高稳定性有机P含量则低于不施有机肥组.长期施用磷肥会增加土壤中无机P积累,且有效性较高的Ca-P、磷酸铝(Al-P)积累程度高于较稳定的O-P、磷酸铁(Fe-P),土壤有效P含量与各组分无机P及其总量、活性有机P、中等活性有机P及有机P总量呈显著正相关.而与稳定性有机P、高稳定性有机P和全P含量的相关性不明显.因此,长期施用有机肥和磷肥能够改变土壤磷索组成.提高磷素有效性.

Long-term Fertilization Effect on Fraction and Content of Phosphorus in Vegetable Soil in Plastic Film House

The fractionation and contents of soil P are conducted in a plastic film house after continuous application of organic manure and chemical fertilizers since 1988. Results show that long-term application of manure and chemical P fertilizers resulted in increase of total and plant available P contents except for the treatment of N applied solely. Long-term fertilization of organic manure gave the highest O-P content ranged from 35% to 47% of total inorganic P. Whereas, Ca-P contents were the highest in the treatments of commercial fertilizers applied only, which ranged from 29% to 39% of total inorganic P. Long-term fertilization of organic manure can also increase the organic P content. The contents of labile organic P (LOP) and moderately labile organic P (MLOP) in group A were more than those of group B, however, the contents of stable organic P (SOP) and highly stable organic P (HSOP) were lower than those of group B. The accumulation of inorganic P was increased by long-term fertilization of P fertilizers, and the easily available Ca—P and Al—P can accumulate more than difficultly available O-P and Fe - P. There was significant positive relationship between soil available P and the contents of total inorganic P and various forms of inorganic P, LOP, MLOP and total organic P. And there was little relationship between soil available P and SOP, HSOP and total P. These results indicated that long-term application of manure and chemical P fertilizer may lead to transformate among various forms of soil P and increase soil P availability.