Soil Carbon and Nitrogen Storages Changes in a China's Modern Agricultural Ecosystem

摘要

Agricultural modernization is changing nutrients biogeochemical cycles in soil as well as regional and global environmental changes. Taking a typical agricultural county of as an example, the article studied the changes of topsoil (0~20cm) bulk, contents and storages of organic carbon and total nitrogen in an agricultural county of North China due to agricultural reform process from 1983-2004, by taking soil samples and experimental determination. The results showed that soil pH decreased, bulk increased lightly, the contents of organic carbon and total nitrogen significantly increased by 70% and 133% respectively, and the storages of organic carbon and total nitrogen in the county increased by 72% and 113% respectively from traditional agriculture to modern. Agricultural modernization including heavy chemical fertilizers inputs, machine irrigation and agricultural mechanizations were the important factors driving these changes.