Zhiguo Li;Runhua Zhang;Xiujun Wang;Jieping Wang;Cuiping Zhang;Tian Che

Key Laboratory of Oasis Ecology and Desert Environment, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011 (China); Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China);Key Laboratory of Oasis Ecology and Desert Environment, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011 (China;Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 20740 (USA);Graduate University of Chinese Academy of Sciences, Beijing 100049 (China)

c system;mc;northwestern china;tc;cotton;mulchin

In northwestern China, there has been a change from traditional cultivation system (TC) with no mulching and flood irrigation to a more modern cultivation system (MC) using plastic film mulching with drip irrigation. A field study was conducted to compare soil CO2 concentrations and soil surface CO2 fluxes between TC and MC systems during a cotton growing season. CO2 concentrations in the soil profile were higher in the MC system (3 107-9 212 mu L L-1) than in the TC system (1 275-8 994 mu L L-1) but the rate of CO2 flux was lower in the MC system. Possible reasons for this included decreased gas diffusion and higher soil moisture due to the mulching cover in the MC system, and the consumption of soil CO2 by weathering reactions. Over the whole cotton growing season, accumulated rates of CO2 flux were 300 and 394 g C m(-2) for the MC and TC systems, respectively. When agricultural practices were converted from traditional cultivation to a plastic film mulching system, soil CO2 emissions could be reduced by approximately 100 g C m(-2) year(-1) in agricultural lands in arid and/or semi-arid areas of northern and northwestern China.