Biophysical controls of soil respiration in a wheat-maize rotation system in the North China Plain

Publication Type:
Journal Article
Citation:
Agricultural and Forest Meteorology, 2017, 246 pp. 231 - 240
Issue Date:
2017-11-15
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© 2017 Elsevier B.V. Croplands play a vital role in regional carbon budgets. We hypothesized that biophysical factors would be important for soil respiration in a wheat-maize rotation cropping system. Soil CO2efflux was measured using the closed chamber method, and net CO2exchange between the cropland and the atmosphere obtained by the eddy covariance technique in a winter wheat-summer maize double cropping system over four years (Oct 2002–Oct 2006). In addition to soil temperature, soil respiration was controlled by leaf area index and soil moisture in the wheat field and soil moisture in the maize field. Temperature sensitivity (Q10) of soil respiration was 2.2 in the wheat and maize growing seasons. In the wheat field, the Q10value during the sowing–returning green period (4.9) was more than that during the returning green–ripening period (2.0). On a monthly time scale, soil respiration was controlled by gross primary productivity in the wheat field, indicating that soil respiration was coupled with ecosystem photosynthesis. Annual soil respiration was 825 ± 73g C m−2in the wheat–maize rotation system in 2003–2006. Over a 4–year average, soil respiration was 355 ± 50 g C m−2in the wheat growing season and 470 ± 67 g C m−2in the maize growing season, which accounted for 43% and 57% of the annual value respectively. At an annual time scale, soil respiration contributed to 72% of ecosystem respiration in the winter wheat–summer maize double cropping system.
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