滇中云南松林土壤呼吸季节动态及其影响因子研究

Soil Respiration and Its Affecting Factors of Pinus yunnanensis in the Middle Regions of Yunnan

采用Li-6400-09便携式土壤呼吸室对澄江尖山河流域云南松土壤呼吸速率进行定位测定,并对土壤呼吸的影响因子进行分析。结果表明：土壤呼吸具有明显的季节变化特点,云南松次生林土壤呼吸波动范围为0.77-4.22μmol·m^-2·s^-1,湿季土壤呼吸速率显著高于干季（p〈0.05）;土壤呼吸速率与土壤温度和土壤水分的相关性均达到显著水平,且与土壤水分相关性最紧密,它能够解释云南松林土壤呼吸的57.9%-69.4%;双因素模型较好地拟合了土壤温度和土壤含水量对土壤呼吸的交互作用,两者共同解释了土壤呼吸速率变化的74.5%-81.6%;相关分析表明,不同土壤化学指标对土壤呼吸速率的影响存在差异。土壤呼吸速率与土壤易氧化有机碳、全氮、水解氮及pH均呈显著的正相关关系,且与土壤全P含量呈极显著的正相关关系（p〈0.01）,而与土壤C/N则呈极显著的负相关关系。因此,西南地区严重干旱的情况下,土壤含水量的减少成为云南松林土壤呼吸季节变化的主控因子,其次为土壤化学性质的影响。

With a portable soil respiration chamber （model Li-6400-09）, the soil respiration （Rs） of Pinus yunnanensis forest in the watersheds of Jianshan River of Chengjiang was measured from April 2012 to March 2013. The results were as follows： the soil respiration presented significant seasonal variations, ranged from 0.77 to 4.22 μmol · m ^-2 · s^-1 and the rate of Rs in dry season was significantly higher than that in wet season. Rs was found to be significant related with soil temperature and soil moisture. Rs had a strong correlation with soil moisture, which was responsible for about 57.9%-69.4% of the seasonal variation in Rs. The equation of interactions had much more predicative power than that using temperature and water as single independent variables, soil temperature and soil moisture together could explain 74.5% - 81.6 % Rs. The coefficients of soil properties to Rs had no unified conclusion. The significant impacts of ROC, TN, AN, TP and pH on Rs were positive, while that of C/N was negative. The results indicated that the soil water under the severe drought had become the main control factor of Rs in the study, whereas soil properties also had some significant influences on Rs.