不同环境因子对樟子松人工林土壤有机碳矿化的影响

Effects of environmental factors on soil organic carbon mineralization in a Pinus sylvestris var.mongolica plantation.

土壤有机碳矿化是土壤向大气释放CO2的最大净输出途径,其与植被的净初级生产力的差值是判断生态系统碳源或碳汇的关键。本研究以科尔沁沙地10年生樟子松人工林生态系统为研究对象,采用室内培养实验方法,测定了不同温度、土壤含水量以及碳、氮添加条件下土壤有机碳矿化的速率。结果表明:土壤有机碳矿化速率随温度和土壤含水量的升高分别呈指数和线性增长,不同的土壤水分条件下土壤有机碳矿化的温度敏感性不同;在土壤含水量最小时(田间持水量的10%),土壤有机碳矿化的温度敏感性最低;土壤有机碳矿化对水分的敏感性在低温条件下(10℃)显著低于在适温和高温条件下(20℃～30℃)。土壤中有机碳含量的增加显著提高土壤碳矿化速率,氮的添加对土壤有机碳矿化没有显著影响,但随着土壤有机碳含量的增加,土壤氮素含量对土壤碳矿化速率产生影响。

Soil organic carbon mineralization is the major pathway of soil carbon release into atmosphere. To investigate the relationships between soil organic carbon mineralization and environmental factors is of significance in studying global carbon cycle and its potential feedback to climate change. With incubation test, this paper studied the effects of temperature, soil moisture, and carbon and nitrogen addition on the mineralization rate of soil carbon （ Cmin ） in a 10- year old Pinus sylvestris var. mongolica plantation at Keerqin Sandy Lands. The results indicated that the Cmin increased exponentially with the temperature from 10 ℃ to 30 ℃, and positively lin- early increased with soil moisture content from 10% water hold capacity （WHC） to 100% WHC. The dependence of soil carbon mineralization to temperature （Q10） was different under different soil moisture conditions. When the soil moisture content was 10% WHC, the Q10 value was the smallest. The sensitivity of soil carbon mineralization to soil moisture content was significandy lower at low temperature （ 10 ℃ ） than at suitable or high temperature （20 ℃-30 ℃ ）. Carbon addition increased the Cmin, while nitrogen addition had less effect. However, with the increase of soil organic carbon content, the Cmin was affected by soil nitrogen content.