Effects of soil phosphorus availability, temperature and moisture on soil respiration in Eucalyptus pauciflora forest
Effects of soil phosphorus availability, temperature and moisture on soil respiration in Eucalyptus pauciflora forest
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DOI：
10.1023/a:1004279300622
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发表时间：
1997-03-01
期刊：
影响因子：
4.9
通讯作者：
Raison, RJ
中科院分区：
文献类型：
--
作者：
Keith, H;Jacobsen, KL;Raison, RJ
土壤呼吸速率（CO2流出）测定了一年的成熟少花桉树林在未施肥和磷肥施肥的地块。土壤CO2排放呈现明显的季节性趋势，平均日排放速率为124 ~ 574 mg CO2 m（-2）hr（-1）。温度和水分是引起土壤CO2排放变化的主要变量，通过一年多的试验研究了温度和水分对土壤CO2排放的影响，结果表明，土壤温度对土壤CO2排放的影响最大，并呈极显著的对数关系（r（2）= 0.81）。在夏季，当温度高于10摄氏度时，土壤和凋落物水分会降低，这导致了土壤CO2排放量的下降。在冬季，当温度低于10摄氏度，土壤和凋落物水分始终很高，因此它们的变化对土壤CO2排放影响不大。多元回归模型，包括土壤温度，土壤和凋落物水分占97%的变异率的CO2排放，因此可以用来预测土壤CO2排放在这个网站具有较高的精度。土壤中碳的年排放总量估计为7.11 t C ha（-1）yr（-1）。该模型被用来预测如果温度和湿度条件发生变化，这一年通量的变化。在何种程度上，该模型的系数不同的网站和森林类型需要testing.Increased土壤磷的有效性导致树木的茎生长的大幅增加，但土壤CO2排放率约8%的减少。这种减少建议是由于较低的根系活性，减少分配同化地下根系活性改变时，P被添加到小区内的微型网站，并通过整个树根系在小区水平。地下碳通量与温度、湿度和养分可用性的这些关系为了解和预测森林生态系统响应土地利用管理或气候变化的潜在变化提供了重要信息。
Rates of soil respiration (CO2 efflux) were measured for a year in a mature Eucalyptus pauciflora forest in unfertilized and phosphorus-fertilized plots. Soil CO2 efflux showed a distinct seasonal trend, and average daily rates ranged from 124 to 574 mg CO2 m(-2) hr(-1). Temperature and moisture are the main variables that cause variation in soil CO2 efflux; hence their effects were investigated over a year so as to then differentiate the treatment effect of phosphorus (P) nutrition.Soil temperature had the greatest effect on CO2 efflux and exhibited a highly significant logarithmic relationship (r(2) = 0.81). Periods of low soil and litter moisture occurred during summer when temperatures were greater than 10 degrees C, and this resulted in depression of soil CO2 efflux. During winter, when temperatures were less than 10 degrees C, soil and litter moisture were consistently high and thus their variation had little effect on soil CO2 efflux. A multiple regression model including soil temperature, and soil and litter moisture accounted for 97% of the variance in rates of CO2 efflux, and thus can be used to predict soil CO2 efflux at this site with high accuracy. Total annual efflux of carbon from soil was estimated to be 7.11 t C ha(-1) yr(-1). The model was used to predict changes in this annual flux if temperature and moisture conditions were altered. The extent to which coefficients of the model differ among sites and forest types requires testing.Increased soil P availability resulted in a large increase in stem growth of trees but a reduction in the rate of soil CO2 efflux by approximately 8%. This reduction is suggested to be due to lower root activity resulting from reduced allocation of assimilate belowground Root activity changed when P was added to microsites within plots, and via the whole tree root system at the plot level. These relationships of belowground carbon fluxes with temperature, moisture and nutrient availability provide essential information for understanding and predicting potential changes in forest ecosystems in response to land use management or climate change.