温带湖泊周边湿地原生草地与人工林土壤碳释放差异性分析

Daily change in wetland soil respiration and its relation to environmental factors

采用红外气体分析法对东平湖湿地人工杨树林和自然草地土壤碳通量进行测定,分析了6:00到18:00两种生境下群落土壤碳通量日变化规律,及其对温度、水分等环境因子的响应。结果表明:(1)两种生境群落的土壤碳通量日动态都呈单峰曲线,但人为耕作过的土壤碳通量明显高于原生草地,土壤碳通量均在6:00达到最小值,杨树林土壤碳通量的最大值出现在12:00,而草地群落土壤碳通量最大值在14:00左右;(2)人工林土壤碳通量与近地面大气温度、土壤温度的相关性均低于草地,且两种生境群落土壤呼吸与近地面大气温度的相关性(P<0.01)均好于与土壤温度的相关性(P<0.05)。土壤碳通量对近地面大气温度的敏感性Q10值大于土壤温度的敏感性,人工林土壤呼吸温度敏感性Q10值小于草地。土壤碳通量与近地面大气相对湿度之间具有显著线性方程关系(P<0.01),人工杨树林和草地的相关系数分别为:0.399、0.29。杨树林土壤碳通量与土壤体积含水量相关性差(P<0.05),湿地草地土壤CO2释放量与土壤体积含水量的相关性不显著(P>0.05),这可能由于土壤体积含水量日变化较小,而不能很好的解释日变化尺度上的土壤呼吸变化;(3)对湿地地土壤碳通量的日变化与土壤养分和盐分相关分析得出,人工林土壤中的有机质和全盐与土壤碳通量具有显著关系(P<0.05),而草地土壤碳通量与土壤养分和盐分相关性均非常差,说明人工林生境土壤有机质和全盐是影响土壤碳通量的一个重要因素,而对草地的影响较小。该结果可以为华北平原东部地区以及温带湖泊湿地的土壤碳通量研究提供参考。

Soil CO2 emission rates in artificial poplar plantation and meadow on Beach Land were investigated by using Infra Red Gas Analysis（IRGA）technique, and the soil respiration changes in relation to environment factors were analyzed during6：00-18：00. The results showed： （1） the daily changes of the soil respiration rate of the Wetland present as single peak curve. The order of soil CO2 emission rates is artificial poplar 〉meadow, they direct that on beaches soil respiration have spatial variability. The daily change had amaximum value at 12：00, and aminimnm value at about 6：00 in poplar plantation; In meadow, the daily change had aminimum value at about 6：00 too, the amaximum value at about 14：00; （2） Soil respiration was observed to significantly correlate to air temperature（P〈0.01） and soil temperature（P〈0.05）. The sensitivity coefficient of the soil respiration to air temperature above ground are superior to the soil temperature. The different sensitivity coefficients to temperature, Q10, Poplar soil respiration temperature sensitivity indicators Ql0 value is less than the meadow; The quantitative relation between the artificial poplar plantation and meadow soil respiration rate and soil moisture can be described with linear function of two variables. In contrast, the relationship between the soil respiration of two communities and soil water content is not good. （3） The soil organic matter and salinity of plantation has a significant relationship （P 〈0.05） with soil carbon flux, and soil nutrient and salinity of meadow are very poor, plantation habitat of soil organic matter and total salt is an important factor affecting soil respiration, and less impact on meadow. The research can lay a scientific foundation for future soil respiration study in eastern north China plain and similar ecological system.