黄土丘陵区油松、沙棘人工林土壤呼吸动态及其对土壤温度和水分的响应

发布时间：2019-07-02 12:20

【摘要】：作为陆地生态系统碳通量的重要组成部分,土壤呼吸在维持全球碳循环及碳平衡中具有重要作用。以黄土丘陵区油松、沙棘人工林为研究对象,于2015年6月至2016年5月,采用LI-8100土壤碳通量测量系统,分别观测二者的土壤呼吸(Rs)、5 cm土壤温度(T)和水分(W),分析2种人工林Rs的动态特征及其对T和W的响应。结果表明:1)季节尺度油松、沙棘人工林Rs夏季(6—8月)最高(2.31和2.89μmol CO_2/m~2·s),冬季(12—2月)最低(0.60和0.65μmol CO_2/m~2·s),年均值分别为1.51和1.92μmol CO_2/m~2·s,年呼吸总量分别为18.90和22.81t CO2/hm2·a,冬季呼吸量占年呼吸总量比例分别为14.67%和12.65%;日尺度最高值出现在10:00—16:00,最低值均出现在6:00。2)季节尺度2种林分Rs与T均呈显著指数关系(P0.01),与W则呈显著线性负相关(P0.01),且沙棘林全年尺度土壤呼吸Q10值(1.40)显著高于油松林(1.34,P0.01)。3)日尺度上,油松、沙棘人工林W分别大于13%和12%时,T对Rs的解释量(R2)均有所提高。因此,在充分考虑温度和水分对土壤呼吸影响的同时,加强冬季土壤呼吸的观测,对未来气候变化条件下,区域碳循环估算模型的完善具有重要意义。
[Abstract]:As an important part of terrestrial ecosystem carbon flux, soil respiration plays an important role in maintaining the global carbon cycle and carbon balance. From June 2015 to May 2016, soil carbon flux measurement system (LI-8100) was used to observe the dynamic characteristics of soil respiration (Rs), 5 cm soil temperature (T) and water (W), analysis of Rs and their responses to T and W in Pinus tabulaeformis and Hippophae rhamnoides plantations in loess hilly region. The results showed that: 1) the highest (2.31 and 2.89 渭 mol CO_2/m~ 2 路s),) of seasonal scale Pinus tabulaeformis and Hippophae rhamnoides plantation in summer (June-August) were the lowest (0.60 and 0.65 渭 mol CO_2/m~ 2 路s), respectively), and the total annual respiration was 18.90 and 22.81 t CO2/ hm2 路a, respectively. the results showed that the annual respiration of Pinus tabulaeformis and Hippophae rhamnoides plantation was 1.51 and 1.92 渭 mol CO_2/m~ 2 路s, respectively. The proportion of winter respiration to the total annual respiration was 14.67% and 12.65%, respectively. The highest value of daily scale appeared at 10: 00 鈮，

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