内蒙古大青山华北落叶松成熟林生长季土壤呼吸研究

Study on Soil Respiration Characteristics of Mature Forest of Larix principis-rupprechtii in Daqing Mountains of Inner Mongolia

以内蒙古大青山华北落叶松成熟林为研究对象,对生长季林地土壤呼吸速率及土壤温度、湿度进行定位监测,分析了土壤呼吸速率变化特征与土壤水热因子之间的相互作用规律。结果表明:(1)林地土壤呼吸速率有明显的季节动态变化和日变化规律。生长季5～9月土壤呼吸速率大小表现为:7月﹥8月﹥9月﹥5月﹥6月;月平均呼吸速率值区间在1.272～3.702μmol·m^(-2) s^(-1),平均值为2.323μmol·m^(-2) s^(-1)。生长初期5月、中期7月和末期9月的单日呼吸速率变化均呈单峰曲线,峰值在12:00～16:00出现,最小值在03:00～06:00出现。(2)生长季林地土壤呼吸速率对土壤湿度的敏感性高于土壤温度,与土壤0～15 cm层湿度之间具有极显著的指数相关关系(P﹤0.01),与温度之间存在显著的线性关系(P﹤0.05)。土壤呼吸速率与土壤温度、湿度之间具有极显著的复合线性关系(P﹤0.01),线性模型对生长季土壤呼吸碳通量的预测具有参考意义。

Taking mature forest of Larix principis-rupprechtii in Daqing Mountains as research object, the soil respiration rate, soil temperature and moisture in the growing season have been located and monitored, and the interaction has been analyzed among the changing characteristics of soil respiration rate and soil hydro-thermal factors. The results show there are obvious seasonal and diurnal changes in soil respiration rate. The soil respiration rate in the growing season from May to September is July > August﹥September > May > June, the monthly average respiration rate is 1.272-3.702 μmol·m-2 s-1, the average value from May to September is 2.323 μmol·m-2 s-1. Changes of daily respiration rate in May, July and September show a trend of single-peak curve, with the highest respiration rate value occurring during 12:00 to 16:00 each day, and the minimum respiration rate value occurring during 03:00 to 06:00 each day. The sensitivity of soil respiration rate to soil moisture is higher than that to soil temperature in the growing season. Generally, there is an extremely significant exponential correlation between soil respiration and soil moisture at 0-15 cm soil layer(P﹤0.01), there is a significant linear relationship between soil respiration and soil temperature(P﹤0.05). It has a significant compound linear relationship between soil respiration rate and soil temperature & humidity(P﹤0.01). The linear model can be used to predict soil respiration flux.