黄土和风沙土藓结皮土壤呼吸对模拟降雨的响应

发布时间：2018-06-05 19:13

本文选题：生物结皮 + 土壤类型　；参考：《生态学报》2017年11期

【摘要】：生物结皮土壤呼吸是干旱和半干旱生态系统碳循环的重要组成部分,但目前其对降雨的响应规律尚不明确。针对黄土高原黄土和风沙土上发育的藓结皮,分别进行2、4、6、10、20、30、40 mm的模拟降雨,并使用便携式土壤碳通量分析仪测定雨前和雨后藓结皮的呼吸速率,对比分析降雨量对藓结皮呼吸速率的影响;同时,在40 mm降雨后的0—24 h连续测定藓结皮的呼吸速率变化,分析藓结皮呼吸速率随雨后历时的变化规律。结果显示,7种降雨量后两种土壤上藓结皮的呼吸速率均显著升高,黄土上藓结皮呼吸速度的增幅为2.89—6.38倍,风沙土上藓结皮呼吸速率的增幅为0.73—4.38倍。0—6 mm降雨中,两种土壤上藓结皮的呼吸速率均随降雨量增加而迅速升高,二者成显著线性正相关关系;6—40 mm降雨中,黄土上藓结皮的呼吸速率随降雨量增加而缓慢升高,但风沙土上藓结皮的呼吸速率随降雨量增加而快速降低。两种土壤上藓结皮的呼吸速率随雨后历时表现出相似的变化规律,即雨后迅速升高、之后逐渐降低,并在24 h左右回归到雨前水平;但黄土上藓结皮的呼吸速率在雨后即刻达到峰值,而风沙土上藓结皮的呼吸速率在雨后30 min左右方达到峰值。黄土上藓结皮的呼吸速率一致高于风沙土上的藓结皮,前者在不同降雨量和雨后历时中平均比后者高150.0%和59.6%。此外,藓结皮呼吸速率与表层土壤含水量存有显著相关关系,在含水量较低(小于约4%)时二者显著正相关,在含水量较高(大于约4%)时二者对于黄土上藓结皮为正相关、对于风沙土上藓结皮为负相关。研究表明,黄土高原藓结皮土壤呼吸对降雨响应快速而直接,但其响应规律对于黄土和风沙土上的藓结皮是不同的,总体而言黄土上藓结皮对降雨的响应更为持久有效。
[Abstract]:Biofilm soil respiration is an important component of carbon cycle in arid and semi-arid ecosystems, but its response to rainfall is unclear. In view of the moss crust developed on loess and eolian sandy soil on the Loess Plateau, the simulated rainfall was carried out on the basis of the moss crusts, which were 24 ~ 4 ~ 6 ~ 6 ~ 10 ~ 10 ~ 20 ~ 30 ~ 40 mm, respectively. The respiration rate of moss crust before and after rain was measured by a portable soil carbon flux analyzer. The effects of rainfall on the respiration rate of moss crust were compared, and the changes of respiration rate of moss crust were determined continuously from 0 to 24 hours after 40 mm rainfall, and the variation regularity of respiration rate with the duration of rain was analyzed. The results showed that the respiration rate of moss crust on loess was 2.89-6.38 times and that of moss crust on windy sand was 0.73-4.38 times .0-6 mm in rainfall, after 7 kinds of rainfall, the respiration rate of moss crust on two kinds of soil increased significantly. The respiration rate of moss crust on loess soil increased 2.89-6.38 times, and that of moss crust on windy sand soil increased by 0.73-4.38 times. The respiration rate of moss crust on both soils increased rapidly with the increase of rainfall, and the respiration rate of moss crust on loess increased slowly with the increase of rainfall during the rainfall of 6-40 mm in which there was a significant linear positive correlation between them. However, the respiration rate of moss crust decreased rapidly with the increase of rainfall. The respiration rate of moss crust on the two soils showed a similar change with the duration of rain, that is, it increased rapidly after rain, then decreased gradually, and returned to the level before rain at about 24 h. However, the respiration rate of moss crust on loess reached a peak immediately after rain, while that on windy sand soil reached a peak about 30 min after rain. The respiration rate of moss crust on loess is higher than that on wind-sand soil, the former is 150.0% and 59.6% higher than the latter in different rainfall and duration after rain. In addition, there was a significant correlation between the respiration rate of moss crust and the soil moisture content in the surface soil, and a positive correlation between them when the water content was lower (less than 4 parts), and when the water content was higher (> 4 parts), they were positively related to the crust of moss on loess. There was a negative correlation for moss crust on sandy soil. The results show that the soil respiration of mossy crust on the Loess Plateau is rapid and direct to rainfall, but its response law is different for the moss crust on loess and wind-sand soil. Generally speaking, the response of mossy crust on loess is more durable and effective to rainfall.
【作者单位】：中国农业大学资源与环境学院;中国科学院水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室;沈阳农业大学水利学院;
【基金】：国家自然科学基金项目(41671221) 中央高校基本科研业务费专项资金(2016QC007,2016QC063)
【分类号】：S154

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