水成土壤演化中有机质含量变化的研究

STUDY ON CHANGES IN ORGANIC MATTER CONTENT IN THE SUCCESSION OF HYDRO-MORPHJC SOILS

Changes in organic matter content of surface and gleying horizon soils in the succession of wetland ecosystems were studied, which are from senile lake to swamp and rice fields in Four Lake region and Lixiahe region of China. In addition, the relation between organic matter content and reduction potential was also studied with incubation experiment. The results are as follows:The organic matter content of soil increased sharply in the succession from senile lake to swamp, and decreased significantly in the succession from swamp to rice fields, developsment with of soil deswamping, the degree of reduction was more remarkable.The organic matter content in surface horizon increased from 3.80% to 10.1% in Four Lake region, and from 4.32% to 14.4% in Lixiahe regoin after senile lake became swamp, but declined by 35 per cent in younger deswamping soil, by 47 per cent in deswamped soil in Four Lake region, and by 58 per cent in deswamped soil in Lixiahe region. The changes in organic matter content in gleying horizon were similar to surface horizon,but the degree of decrease was greater than surface horizon in deswamped soil, and slighter than surface horizon in younger deswamping soil.The date from incubation experiment indicated that the reduction potential was in a close relation to content of organic matter. Organic matter content was negative correlation with Eh value,and positive correlation with reductive substances.