Study on respiration of soils in the Jiulongjiang river basin and its effect factors

Soil respiration has become the largest source that terrestrial ecosystems release CO₂ to atmosphere, and it plays an important role in global carbon cycle. In this paper, dynamic variation of soil respiration and effect of temperature, water content and organic matter in three different habitats (vegetable plot, bamboo grove, banana forest) were evaluated using a laboratory soil incubation experiment.The findings indicated: (1) Under the different water content condition, the soil respiration speed has certain difference along with the temperature. Among 15~35°C, soil respiratory rate in the vegetable plot, the bamboo grove, the banana forest, respectively, is 11.15~32.45, 9.42~30.34, 20.99~30.34 mgCO₂kg^-1·h^-1. Soil respiration´s change scope in the vegetable plot and the bamboo grove is higher than that in the banana forest soil. Soil respiration speed and water content in the vegetable plot soil and the banana forest assume the obvious inverse correlation, but soil respiration speed and water content in the bamboo grove has not obvious correlation. The temperature coefficient Q10 varied from 0.94~1.7 in vegetable farmland, 0.95~1.62 in bamboo grove earth, 0.95~1.03 in banana forest earth, according to water content variation. In three types of soil, the vegetable plot soil is most sensitive to the temperature, next is the bamboo grove soil. But the banana forest soil is lowest to the temperature sensitivity. (2) The content order of high activity organic matter in the soil is: the vegetable plot soil >; the bamboo grove soil >; the banana forest soil; therefore the soil carbon storehouse, particularly the activated carbon storehouse´s storage quantity is affecting the effect of temperature on soil respiration to a great extent. But the content order of total active organic matter is: the bamboo grove soil >; the banana forest soil >; the vegetable plot soil. Hence, changes of these fact- - ors have indicated complexity on the soil respiration research.