晋西黄土区土壤呼吸日变化特征及其与环境因子的关系

土壤呼吸是陆地生态系统的碳循环中土壤碳的主要输出途径,利用便携式土壤呼吸测定仪LCpro+对晋西黄土区6种典型植被类型进行土壤呼吸速率的测定,另外同时测量相关的温度、湿度等环境因子,进而对土壤呼吸的日变化特征及与土壤温度和土壤湿度进行简单相关性分析和回归分析。结果表明:试验区内不同植被类型土壤呼吸速率日变化呈单峰型,中午12:00~13:00最大,凌晨5:00~6:00最小,均值由大到小依次为耕地(5.846)、次生林(4.305)、油松林(3.858)、刺槐林(3.456)、灌草地(2.220)、荒草地(1.355),退耕还林有利于减少土壤CO2输出;土壤呼吸与土壤温度的回归分析符合指数正相关关系,Q10值由大到小依次为灌草地(2.03)、耕地(1.88)、荒草地(1.86)、次生林(1.82)、油松林(1.75)、刺槐林(1.73),土壤呼吸与土壤湿度关系为对数模型的负相关模型,由多元回归分析得出土壤呼吸最主要的决定力是土壤温度。

Variation of soil respiration and its relationship with environmental factors in the Loess Plateau of Western Shanxi

Soil respiration is the main output pathway of soil carbon in the carbon cycle in terrestrial ecosystems.From the determination of soil respiration rate and temperature,humidity to the six kinds of typical vege-tation types in the Loess Plateau of Western Shanxi and the simple correlation and regression analysis of the diurnal variation of soil respiration and soil temperature and soil moisture,the results showed that: Different vegetation types of soil respiration rate change was a single peak,which grew to the largest at noon(12:00~13:00) while reduced to a minimum in the morning(5:00~6:00).The mean of soil respiration descending order cultivated land(5.846),secondary forest(4.305),Pinus tabulaeformis forest(3.858),Robinia pseudoacacia forest(3.456),shrub grassland(2.220),waste grassland(1.355).This indicates that returning farmland to forests is conducive to reduce the output of CO2 from soils.Soil respiration and soil temperature,a positive correlation of regression analysis in line with index,show that,Q10 descending turn for shrub grassland(2.03),cultivated land(1.88),waste grassland(1.86),secondary forest(1.82),Pinus tabulaeform is forest(1.75),Robinia pseudoacacia forest(1.73).The relationship of soil respiration and soil humidity is the negative correlation of thelogarithmic model.Draw force of soil respiration in the mostimportant decision is the soil temperature by multiple regression analysis.