不同降雨处理对北京西部山区油松林土壤呼吸的影响

Effects of Rainfall on the Pinus Tabulaeformis Forest Soil Respiration in Western Mountain Areas of Beijing

采用碱液吸收法(AA法)测定了北京西部山区不同降雨处理的典型油松林的土壤呼吸速率,同时测定了土壤呼吸测定点的土壤温度、土壤水分及气温和湿度等气象因子。结果表明,5、10mm降雨处理对油松林土壤呼吸都有促进作用,而20、50mm降雨处理以及50mm频率降雨则一定程度抑制土壤呼吸。降雨导致土壤含水率升高并造成土壤呼吸的温度敏感性降低,Q10为1.1左右;7cm剖面处土壤温度、空气温度、大气相对湿度对各降雨处理的土壤呼吸速率的直接效应最为显著,其中温度是影响土壤呼吸的主要因素。

Soil temperature, soil moisture, air temperature, humidity and other meteorological factors were monitored where soil respiration rates were measured in the Pinus tabulaeformis forest in western mountain areas of Beijing by using the alkali absorption technique. The results showed that rainfall treatments of 5 mm and 10 mm promoted the soil respiration, while rainfall treatments of 20 mm , 50 mm and frequency rainfall treatments of 50 mm inhibited soil respiration. The increase of soil moisture, caused by rainfall, reduced the temperature sensitivity of soil respiration and QIO was about 1. 1. The soil temperature at 7 cm , air temperature, relative atmospheric humidity were the most significant factors that affected soil respiration rate under all rainfall treatments, and the temperature played the most important role in soil respiration.