Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6537798 | Agricultural and Forest Meteorology | 2013 | 10 Pages |
Abstract
Determining soil respiration from croplands is necessary for evaluating the global terrestrial carbon budget and how it is altered in future climates. This study explored seasonal characteristics and controlling factors of soil respiration in a typical cropland area in the North China Plain. Total soil respiration (RS) was partitioned into heterotrophic (RH) and autotrophic (RA) components using the root exclusion method. The experiments showed that the seasonal average RS values were 5.25 μmol mâ2 sâ1 for the wheat growing season and 6.00 μmol mâ2 sâ1 for the maize growing season. Seasonal average RH and RA values were 3.34 μmol mâ2 sâ1 and 1.91 μmol mâ2 sâ1, respectively, for wheat, and were 4.25 μmol mâ2 sâ1 and 1.75 μmol mâ2 sâ1, respectively, for maize. The seasonal average ratio of RA to RS (RA/RS) was 36% for wheat and 29% for maize. Over a whole year, RH was the dominant component of RS in both the wheat and maize growing seasons. RH increased exponentially with the average soil temperature collected in the upper 10 cm (TS0-10), with a Q10 value of 1.65. Soil water content (θ) had no discernible influence on RH when θ was between wilting point (θwp) and field capacity (θfc). A value of θ larger than θfc suppressed RH, which can be characterized by a quadratic curve. RA increased exponentially with TS0-10 in both of the wheat and maize growing seasons, and the corresponding Q10 values were 2.69 and 2.85, respectively. However, the temperature dependence of RA in the two crop seasons cannot be explained by a single temperature response curve. Moreover, the RA values for the wheat and maize growing seasons were more sensitive to temperature changes than RH at the study site. Soil water content had no discernible influence on RA in the wheat growing season but suppressed RA when water logging occurred in the maize growing season. However, RA recovered afterwards even when the soil water content was high. Comparisons between wheat respiration values collected at different sites showed that the seasonal average RS, RH and RA all correlate positively with mean air temperature, indicating that air temperature remains a good indicator for variations in soil respiration in different climates.
Keywords
Total soil respirationNCPRECOGPPRHCθfcθsQ10Gross primary productivityNet ecosystem exchangeHeterotrophic respirationAutotrophic respirationEcosystem respirationSoil respirationNorth China PlainThe North China PlainSoil temperatureMaizeSOCLeaf area indexLAIField capacitySoil volumetric water contentNEEWilting pointWheat
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Atmospheric Science
Authors
Quan Zhang, Hui-Min Lei, Da-Wen Yang,