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Soil respiration dynamics and major controlling factors in a coastal protective forest. |
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Abstract The soil respiration in 3 Casuarina equisetifolia plantations with different ages in a coastal sub-tropical ecosystem was monitored with an LI-8100 Automated Soil CO2 Flux System from May 2006 to April 2007. Diurnal dynamic of soil respiration featured two peaks, with the maximums at 8:00~10:00 and 14:00~16:00, and with the minimum at 20:00~22:00. Seasonal dynamic of soil respiration featured a single peak, with the maximum at June or July and the minimum at December or January. Soil respiration had a highly exponent relation to soil temperature at 5 cm depth, and a highly linear relation to soil water content of the upper 20 cm. In addition, regression equation—R=a×ebT×W c could better predict soil respiration than using respective independent variable, and the R2 values were 0.69、0.92 and 0.90 for the 3 plantations, respectively. Soil respiration rates were the highest in middle-age plantation, followed by the mature plantation, and the lowest was young-age plantation. With the increase of plantation age, the variation of soil respiration was more sensitive to the change in soil temperature and soil moisture.
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Received: 17 October 2008
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