不同采伐强度下土壤温湿度对毛乌素沙柳林地土壤呼吸的影响

发布时间：2018-04-25 12:03

本文选题：沙柳 + 采伐强度　；参考：《内蒙古农业大学》2017年硕士论文

【摘要】：为分析采伐强度对沙柳林地土壤呼吸的影响,在毛乌素沙地设置采伐强度分别为30%(轻度采伐)、50%(中度采伐)、70%(重度采伐)的沙柳林地作为实验样地,并设置了对照样地,利用Soilbox 土壤呼吸测量系统,对所有样地的土壤呼吸速率及影响因子进行测定,用来探究各样地土壤呼吸速率的季节波动趋势、日变化规律,以及土壤温湿度两个主要非生物影响因子与土壤呼吸速率之间的关系。以此更加深入了解土壤呼吸作用的变化过程,估算年通量。测定的结果如下:1.由于采伐的原因,各采伐强度的样地土壤温度均高于对照样地,并且样地土壤呼吸速率的温度敏感性也因此产生了变化,Q10值均高于对照样地。重度采伐样地的土壤湿度明显低于其他各样地的土壤湿度,然而其他样地的土壤湿度之间的差异并不显著。各样地土壤温度与呼吸速率均可拟合成指数模型,并且二者的相关性很显著。在每一个观测月中,就土壤温度而言,至少能解释土壤呼吸速率季节变化差异的62.0%～73.9%。土壤湿度与土壤呼吸速率二者之间的关系很复杂,虽然有一定的相关关系,但是相关性不显著。不同采伐强度样地的土壤呼吸速率与土壤温度、土壤湿度两个因子共同作用之间有极显著的相关性,土壤呼吸速率变化的64.4%～90.4%可以由两者来共同解释。2.各采伐样地中不同年份沙柳林地的土壤呼吸速率均呈单峰曲线格局分布,随着月份波动比较明显。采伐均提高了土壤的呼吸效率,第一年和第二年中度采伐强度样地的土壤呼吸速率显著高于其他样地,轻度采伐样地的土壤呼吸速率和重度采伐样地的差异不明显,但均明显高于对照样地的土壤呼吸速率。3.对各处理样地的土壤呼吸速率进行日观测实验时发现,土壤呼吸速率日变化幅度从大到小的顺序为中度采伐,轻度采伐,重度采伐及对照样地,轻度采伐样地和重度采伐样地的土壤呼吸速率的曲线比较接近。在温度敏感系数Q10方面,对照样地的数值高于其他处理样地。在轻度采伐的干扰下下,土壤呼吸速率受土壤湿度的影响较小;重度采伐样地用两种模型模拟出来的相关系数值较高,重度采伐样地的土壤呼吸速率受土壤湿度影响较大。4.采伐干扰使土壤呼吸组分速率也产生了变化。各样地土壤异养呼吸的变化幅度与自养呼吸的变化幅度进行比较,结果都是前者大于后者。就平均自养呼吸速率的平均值而言,在中度采伐样地中达到最大,最小的是轻度采伐样地;而平均异养呼吸速率方面,轻度采伐样地的最大,中度采伐样地的最小。各处理样地土壤自养呼吸贡献率从24.27%到54.40%不等,大小顺序依次是:中度采伐样地重度采伐样地对照样地轻度采伐样地。就土壤自养呼吸速率和土壤温度之间的联系进行研究发现,只有对照样地未使两者达到显著相关的水平。土壤温度变化能表示各个组分呼吸速率的27.2%～70.5%。只有重度采伐样地的异养呼吸速率与土壤湿度之间存在相关性,其他各样地的组分呼吸速率均没达到显著的相关水平。对所有样地的组分呼吸速率进行观测分析,就土壤温度和土壤湿度的复合作用而言,双因子复合能够对土壤呼吸进行解释的范围是34.6%～76.8%,与土壤温度相比比较接近,且相关性显著。说明双因素的复合作用受土壤湿度的影响,但是影响不大。
[Abstract]:In order to analyze the effect of cutting intensity on soil respiration in Salix forestland, the cutting intensity in Maowusu sandy land was 30% (mild cutting), 50% (moderate cutting) and 70% (severe cutting) as experimental plots, and a control sample was set up, and the soil respiration rate and influence on all samples were used in the Soilbox soil soil respiration measurement system. Factors are used to determine the seasonal fluctuation trend of soil respiration rate, diurnal variation, and the relationship between two main abiotic factors and soil respiration rate in soil temperature and humidity. In order to further understand the change process of soil respiration and estimate annual flux. The results are as follows: 1. due to logging The soil temperature of each cutting intensity is higher than that of the control sample, and the temperature sensitivity of the soil respiration rate is also changed, and the Q10 value is higher than that of the control. Significant. All soil temperature and respiration rate can be synthetic index model, and the correlation of the two is very significant. In each observation month, in terms of soil temperature, the relationship between soil moisture and soil respiration rate two, which can explain the seasonal variation of soil respiration rate at least 62% ~ 73.9%., is complex, although there is a certain extent. The correlation is not significant. There is a significant correlation between soil respiration rate and soil temperature and soil moisture two factors. The 64.4% ~ 90.4% of soil respiration rate changes can be used to explain the soil respiration of Salix Forestland in different years of.2. felling. The rate showed a single peak curve pattern distribution, and the soil respiration rate increased with the month fluctuation. The soil respiration rate in the first and second years was significantly higher than that of other samples, and the difference of soil respiration rate and the severe cutting land in the light cutting plots was not obvious, but both were obviously higher than those of the other plots. The soil respiration rate of the same soil.3. showed that the soil respiration rate of the soil respiration rate was in the order of moderate cutting, mild cutting, severe cutting and control, and the curves of soil respiration rate of mild and severe cutting plots were close. The value of temperature sensitivity coefficient Q10 is higher than that of other processing plots. Under the interference of light cutting, soil respiration rate is less affected by soil moisture, and the number of related lines simulated by two models in severe cutting plots is higher, and soil respiration rate of severe cutting plots is greatly influenced by soil moisture and.4. logging. The disturbance made the rate of soil respiration component change. The change range of soil heterotrophic respiration was compared with that of autotrophic respiration, and the result was that the former was greater than the latter. At the rate of respiration, the largest and moderate felling plots were the smallest. The contribution rate of soil autotrophic respiration varies from 24.27% to 54.40%, and the order of the size is in the order of moderate harvesting land with severe cutting plots. The relationship between soil autotrophic respiration rate and soil temperature is studied. It is found that the change of soil temperature can indicate that there is a correlation between the respiration rate and the soil moisture rate of 27.2% ~ 70.5%. of the respiration rate of each component, and the rate of respiration rate of the other regions is not significant. As for soil temperature and soil moisture, the range of soil respiration is 34.6% to 76.8%, which is close to the soil temperature, and the correlation is significant. It shows that the double factors are affected by soil moisture, but the effect is not significant.

【学位授予单位】：内蒙古农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S714

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