JOURNAL OF NATURAL RESOURCES ›› 2014, Vol. 29 ›› Issue (10): 1686-1695.doi: 10.11849/zrzyxb.2014.10.005

• Resource Ecology • Previous Articles     Next Articles

Responses of Soil Respiration to Land Use Changes in a Semiarid Region of Loess Plateau

GUO Hui-min1, ZHANG Yan-jun2, LIU Qing-fang4, JIANG Ji-shao1, LI Jun-chao4, WANG Rui4, LI Na-na2, LI Ru-jian2, GUO Sheng-li1,2, LI Chun-yue3   

  1. 1. Institute of Soil and Water Conservation, CAS and Ministry ofWater Resource, Yangling 712100, China;
    2. Institute of Soil and Water Conservation, Northwest A & F University, Yangling 712100, China;
    3. College of Tourism and Environmental Sciences, Shaanxi Normal University, Xi'an 710119, China;
    4. College of Resources and Environment, Northwest A & F University, Yangling 712100, China
  • Received:2013-10-10 Revised:2014-02-27 Online:2014-10-20 Published:2014-10-20

Abstract:

Understanding the responses of soil respiration to land use changes becomes critical in predicting soil carbon cycling under conversion of arable land into grassland on the Loess Plateau. From March 2011 to December 2012, CO2 efflux from the soil surface was measured from 8:00 to 12:00 am in clear days by a Licor-8100 closed chamber system (Li-COR, Lincoln, NE, US). Also, soil temperature and soil moisture at the 5 cm depth was measured using a Li- Cor thermocouple and a hand- held frequency-domain reflectometer (ML2x, Delta-T Devices Ltd, UK) at each PVC collar, respectively. Since returning cultivated land for 27 years, the mean grassland soil respiration (3.55 μmol·m-2·s-1) was averaged 2.61 times higher than paired cropland soil respiration (1.36 μmol·m-2·s-1) and the cumulative CO2-C emission in grassland (981 g C·m-2) was 2.75 times higher than that in cropland (357 g C·m-2). In 2011, the temperature sensitivity of grassland (Q10) improved by 24.5% compared with cropland, and in 2012 it reduced to 2.4%. We found marked differences in soil characteristics related to different landuse types: the mean grassland SOC (10.5 g·kg-1) was averaged 61.5% higher than paired cropland SOC (6.5 g·kg-1) and the SMBC (204 mg·kg-1) was averaged 34% higher than cropland (152 mg·kg-1). Soil moisture from 0-5 cm depth was much drier in cropland and significantly different between cropland and grassland except for winter. However, there were no clear differences between soil temperatures. SOC and soil moisture differences between cropland and grassland can explain the soil respiration difference caused by land-use change, which was confirmed by the validation results.

Key words: grassland, soil moisture, soil respiration, cropland, soil organic carbon, Loess Plateau

CLC Number: 

  • S152