浙北嘉湖平原沉积环境与土壤发育的探讨

APPROACH ON SEDIMENTARY ENVIRONMENTS AND SOIL DEVELOPMENT IN JIA HU PLAIN OF THE NORTHERN ZHEJIANG PROVINCE

Jia hu plain is looted at the lower Yan}tse River Delta. paddy soils occupy about 88% of the cultivated lands. Historically, most of the paddy soils were used for rice-wheat rotation. At the present time, laree areas have been adopted for rice-rice-barley (or rape) rotation.The present article deals with the interelation between Soil development and sedimentary environments in Holocene period. In order to study the sedimentary substances, We chose four kinds of representative paddy soils (lacustrine loamy albic paddy soil, silt-clayey yellow motrled paddy soil, silt. paddy soil, submgergic clayey paddy soil) as testing samples, dating of ¹⁴C, distribution of ancient ruins, particle parameter analysis, combination of microfossil and spore-pollen, clay mineral and mineral composition test were used to indicate the kinds of sedimentary substances. The results obtained show that the formation of different paddy soils are deeply influenced by the sedimentary environments. There are four sediments in the Jia hu plain, they are Tai hu lake coastal deposits, continental deposits, marinecontimental deposits and laeustrine deposits respectively The different sediments affect significantly the distribution, characteristics and development of paddy soils.