长期施肥对旱地土壤有机磷及其组分的影响

通过15年长期定位试验,采用Bowman和Cole提出的土壤有机磷分级方法,研究了不同耕作施肥措施对旱地耕层土壤有机磷及其组分的影响。结果显示旱地土壤各个处理的活性有机磷含量低,占有机磷总量的比例低于3.6%,中活性有机磷为有机磷的主体,约占有机磷总量的73.37%-91.54%。休闲、撂荒及磷肥与其它肥料配合使用,均增加了耕层土壤的中活性有机磷含量,增加了中稳性有机磷含量及其比重;休闲、撂荒及磷钾提高了高稳性有机磷含量及比重,而氮磷钾及其与有机肥配合处理则降低了高稳性有机磷的含量。尽管不同耕作施肥管理均影响旱地土壤有机磷含量,但是施用有机肥对有机磷的增加贡献最大;撂荒与休闲相比,前者更有利于土壤有机磷的积累。

Effects of Long-term Fertilization on Organic Phosphorus and Its Components in Rain-fed Soil

The effects of different fertilizer treatments on organic phosphorus and its components in rain-fed soil were studied with the method of the Bowman-Cole. The results of long-term located experiment showed that applying fertilizers could increase soil organic phosphorus content of rain-fed soil obviously. Moreover,organic fertilizers could increase soil organic phosphorus content more significantly. The content of organic phosphorus components and ratio of each components to total organic phosphorus in rain-fed soil were as follows: Moderately labile organic P > Moderately stable organic P > Labile organic P > Highly stable organic P. Chemical fertilizers could promote the transformation of other forms of soil phosphorus to the moderately stable organic P. While applying organic fertilizers in rain-fed soil,the content of labile organic P declined. Balanced fertilization could promote the transformation of highly stable organic P to other forms of soil phosphorus those availability were relatively high,therefore balanced fertilization was benefit for crop utilizing phosphorus. A combined application of organic and chemical fertilizers could increase significantly available P content in rain-fed soil.