摘要
利用LI-8100土壤碳通量测量仪测定了在自然升温下的强碱土土壤呼吸速率、温度(气温和土壤温度)、湿度(空气相对湿度和土壤湿度)数据,通过分析它们的相关关系,探讨土壤呼吸速率的变化特征及其主要影响因素,建立了相应的回归模型并进行了精度检验。结果表明:(1)各实验土壤呼吸速率的日变化过程均呈单峰型,日间为正呼吸,夜间为负呼吸。(2)平均气温由4.4℃升至15.84℃和17.61℃时,平均土壤呼吸则由-0.07μmol m-2 s-1增加至0.07和0.31μmol m-2 s-1。温度越高,土壤呼吸速率越大。(3)土壤呼吸速率与气温、土壤温度、土壤湿度呈正相关,与空气相对湿度呈负相关,并且随着温度的升高,相关系数均不断增大。实验1中气温与土壤呼吸的相关系数为0.75,实验2、3则增至0.96和0.98。(4)土壤呼吸速率的最主要直接影响因子为气温,土壤湿度通过气温对土壤呼吸速率的间接影响与气温的影响相当。(5)土壤呼吸速率无论与温、湿度中单个因子还是温湿度双因子构建的回归方程,其拟合优度和模型精度均随温度的升高而增大,在气温与土壤呼吸速率构建的方程中,其R2由实验1的0.5544增至实验2、3的0.9284和0.9685,RMSE则由0.7055减至0.3011、0.1560。
Soil respiration rate, temperature(both air and soil temperatures), and humidity(relative air humidity and soil moisture) had been measured under natural temperature condition by using LI-8100 automated soil CO2 flux system. This study made the correlation analysis, established regression models, and tested their accuracy in order to discuss the variation characteristics of soil respiration rate and its influencing factors in strong alkaline soil. The results showed that:(1) The diurnal variation characteristics of soil respiration rate in each experiment presented a simple peak, positive respiration occurred in daytime and negative respiration occurred in nighttime.(2) The average air temperature increased from 4.4 ℃ to 15.84 ℃ and 17.61 ℃, and the average soil respiration increased from-0.07 to0.07 and 0.31 μmol m-2s-1. Air temperature increased with soil respiration rate.(3) The soil respiration rate was positively correlated with air temperature, soil temperature and soil moisture, but negatively correlated with relative air humidity. The correlation coefficient rose with the increase of temperature. The correlation coefficient between air temperature and soil respiration was 0.75 in the experiment 1. It increased to 0.96 and 0.98 in experiment 2 and 3,respectively.(4) The air temperature was the most directly related factor to soil respiration rate. And the indirect effect of soil moisture on soil respiration rate through air temperature was equivalent to the effect of air temperature.(5) The goodness of fit and model accuracy increased with rising temperature in the regression equations, which were established between soil respiration rate and temperature and / or humidity. For example, in the regression equation between air temperature and soil respiration rate, the R2 of experiment 1 was 0.5544, which increased to 0.9284 and0.9685 in experiment 2 and 3, respectively. And the RMSE decreased from 0.7055 in experiment 1 to 0.3011 and0.1560 in experiment 2 and 3, respectively.
出处
《土壤通报》
CAS
CSCD
北大核心
2015年第2期355-361,共7页
Chinese Journal of Soil Science
基金
国家自然科学基金(41171165
41261049)
北京市属高等学校高层次人才引进与培养计划项目(IDHT20130322)
北京联合大学人才强校计划资助项目(BPHR2012E01)
中国博士后科学基金资助项目(2013M532100)资助
关键词
强碱土
土壤呼吸
温度
水分
Strong alkaline soil
Soil respiration
Temperature
Humidity
