我国南方不同地带性水稻土有机氮组分变化

Soil Organic Nitrogen Composition in Paddy Fields Varied with Latitude in Southern China

采集我国南方不同地带性水稻土,运用封管水解Brerrmer法测定了土壤中氨基酸氮、氨基糖氮、铵态氮、未知氮等酸解性有机氮组分,以探究区域条件对土壤有机氮结构组成的影响。结果表明,从区域地带性来看,水稻土中全氮及有机氮各组分含量无明显规律,这可能与区域性的施肥等管理措施和气候因素综合作用相关。然而,土壤有机氮各组分占全氮比例除氨基酸氮外均与区域纬度呈线性相关,其中酸解总氮、未酸解氮、氨基糖氮、酸解未知氮以及铵态氮线性相关的决定系数R^2分别为0.556 6、0.729 3、0.803 6、0.897 5和0.411 3。可见,人为耕作管理对土壤全氮含量影响很大,而自然环境则对土壤有机氮结构组成起决定作用。

In this study, paddy soil samples in latitude sequence were collected from southem China. Soil organic nitrogen composition was identified by using the modified Bremner method. Various soil organic nitrogen forms including amino-acid N, amino-sugar N, ammonium N and unknown hydrolysable N were determined. Results showed that the contents of soil total N and various N forms in paddy soils were not related to the latitude which were considered to be attributed to the interactions of field management and environment. However, the proportions of various N to total N were linear to the latitude, the determination coefficient values were 0.556 6, 0.729 3, 0.803 6, 0.897 5 and 0.411 3 for hydrolysable N, non-hydrolysable N, amino-sugar N, unknown hydrolysable N and ammonium N, respectively. Overall, the field management exerted a great influence on the contents of soil total nitrogen and its components. The environmental condition played a key role in soil nitrogen composition