Soil organic matter and soil nutrient turnover has been a major research area in Western biogeochemistry (Paul and Clark 1991). Soil nutrients constrain NPP and interact strongly with climate change in controlling vegetation response. Soil organic matter is one of the largest reservoirs of carbon in the earth system and is quite dynamic in response to either land use or climate. The Chinese effort in these areas was not as evident in their global change program as were other efforts (as is the case in the United States as well) but some work is ongoing.
The CAS Nanjing Institute of Soil Science conducts considerable research on soil organic matter and has published a compendium of soil properties, including nutrients and organic matter for the major soil regions of China, as well as a national soil survey. This institute has also conducted studies of organic matter turnover in paddy soils that are integrated with CH4 studies.
The CAS Northwest Institute of Soil and Water Conservation has performed extensive studies of soil and nutrient loss due to soil erosion and is involved in integrated studies of soil erosion, crop productivity, and nutrient cycling.
The CAS Inner Mongolia Grassland Ecosystem Experiment Station has published extensive results on soil carbon and nutrient pools, inorganic nutrient levels and turnover, and stable isotope biogeochemistry of grassland plants (the latter in collaboration with Larry Tieszen of Augustana College, South Dakota). Some studies on microbial ecology have also been undertaken. The work reported from Inner Mongolia and similar work conducted at the CAS Xinjiang Institute of Biology, Pedology, and Desert Research is primarily descriptive in nature but provides valuable information. The value of Chinese data on soil element storage and turnover is twofold: it augments the global database on these properties and, because soil nutrients and nutrient turnover are controls over many aspects of atmosphere-biosphere exchange, it provides context for other process studies in China, such as on trace gases or biophysics.
Biogeochemistry is a relatively young discipline. Moreover, soil nutrient turnover and trace gas biogeochemistry, while central in the global change research agenda, have been slow to develop fully, lying as they do on the disciplinary boundaries of atmospheric chemistry, soil science, microbiology, and ecology. In the United States,