作 者 ：高宇 樊军 米美霞 王力 彭小平
期 刊 ：植物营养与肥料学报 2013年 19卷 5期 页码：1207-1217
关键词：土壤呼吸；水蚀风蚀交错区；土地利用方式；土壤温度；土壤水分含量；
Keywords:soil respiration, water-wind erosion crisscross, land-use pattern, soil temperature, soil moisture,
摘 要 ：为准确评估黄土高原水蚀风蚀交错区土壤呼吸速率季节变化影响因素及其对不同土地利用方式的响应，于2009~2012年植物生长季节，选取6 种当地典型的土地利用类型，应用红外气体分析法对土壤呼吸速率进行测定，并结合土壤水、热与养分因子进行分析。结果表明， 水蚀风蚀交错区退耕会显著改变土壤呼吸强度，该区典型农地的土壤呼吸速率为1.06～1.39 μmol/（m2·s），农地转变为裸地的过程中，土壤呼吸速率下降为原来的42%～63%，尤其在植物生长旺季的7、 8、 9 三个月下降明显。 农地弃耕后建设人工草（灌木）地使土壤呼吸速率提高了109%～200%，农田撂荒样地土壤呼吸速率约为农地的79%～179%，农地略高于长芒草地和荒草地。该区土壤呼吸速率变化的主导因子为土壤温度，尤其与10 cm土层的土壤温度相关性最好，土壤呼吸速率与土壤含水量之间拟合优度较差， 但土壤温度与含水量双因子指数模型Rs=a·ebT·θc 对该地区土壤呼吸速率的拟合均优于相应的单因子模型。10 cm土层的土壤呼吸温度敏感性系数（Q10值）排序为：无植被生长样地（裸地，2.09）>农地（农地、坡地农地，2.07～1.69）> 撂荒地（坡地撂荒地、撂荒地、梯田撂荒地，1.71～1.53）>草（灌木）地（柠条地、苜蓿地、长芒草地、荒草地，1.51～1.42），可见随着未来气温的升高，在生态系统土壤呼吸整体有可能增加的背景下，退耕还林（草）会降低土壤呼吸对温度的敏感性，且Q10值随土壤含水量降低而降低。土壤呼吸速率与土壤有机质、全氮之间有极显著的正相关关系。因此，水蚀风蚀交错区土壤呼吸受到土壤温度、水分、养分及土地利用方式的显著影响。
Abstract:In order to assess the impact of different land-use types with different soil moisture and temperature on seasonal soil respiration, we chose 6 kinds of typical land-use plots in the water-wind erosion crisscross region of the Loess Plateau at Liudaogou Watershed during growth seasons of the year 2009-2012 Soil respiration was measured by the Closed-Dynamic-Chamber Infrared gas analyzer (IRGA), and the relationships between soil respiration and soil temperature, soil moisture, soil nutrient were analyzed. The results showed that the management of land conversion from farm-lands to grass-lands or shrub-lands would cause significant changes to soil respiration in the water-wind erosion crisscross region. The soil respiration of farmlands is 1.06-1.39 μmol/（m2·s）, and soil respiration is decreased to 42%-63% in the management of land conversion from farm-lands to bare lands, especially in July, August and September. The annual soil respiration rate is increased by 109%-200% following the conversion of abandoned plough-lands to artificial grass (shrubs) lands, and is about 79%-179% of farm land to abandoned lands. The annual soil respiration rate of farm-lands is a little higher than those of grass lands or S. bungeana lands. The soil respiration is dominantly controlled by the soil temperature, and 10 cm soil temperature has the best correaltion with soil respiration, while there is a poor correlation between soil respiration and soil moisture. The index model of the double-factors (soil respiration fitting with soil temperature and soil moisture, Rs=a·ebT·θc) is better than those of the single factor ones. The Q10 values in 10 cm soil layers are in the order of: plot with no plants (bare land, 2.09) > farm lands (crop lands and crop lands on slope, 2.07-1.69) > abandoned lands (abandoned lands on slope, abandoned lands and abandoned lands on terrace, 1.71-1.53) > grass (shrubs) lands (C. Korshinkii land, alfalfa land, S. bungeana land, alfalfa land on slope and wild grass land, 1.51-1.42). In case of the temperature increasing, the management of land conversion from farm-lands back to grass-lands or shrub-lands could reduce the sensitivity of soil respiration to temperature under the background of increasing soil respiration in the ecological system, and the Q10 would decrease with the decrease of soil moisture. Soil respiration could be significantly related with soil organic matter and total nitrogen. Therefore, soil respiration in water-wind erosion crisscross regions is significantly affected by soil temperature, soil moisture, soil nutrients and land use patterns.
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