【摘要】：作為陸地生態(tài)系統(tǒng)碳通量的重要組成部分,土壤呼吸在維持全球碳循環(huán)及碳平衡中具有重要作用。以黃土丘陵區(qū)油松、沙棘人工林為研究對象,于2015年6月至2016年5月,采用LI-8100土壤碳通量測量系統(tǒng),分別觀測二者的土壤呼吸(Rs)、5 cm土壤溫度(T)和水分(W),分析2種人工林Rs的動態(tài)特征及其對T和W的響應(yīng)。結(jié)果表明:1)季節(jié)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),年均值分別為1.51和1.92μmol CO_2/m~2·s,年呼吸總量分別為18.90和22.81t CO2/hm2·a,冬季呼吸量占年呼吸總量比例分別為14.67%和12.65%;日尺度最高值出現(xiàn)在10:00—16:00,最低值均出現(xiàn)在6:00。2)季節(jié)尺度2種林分Rs與T均呈顯著指數(shù)關(guān)系(P0.01),與W則呈顯著線性負相關(guān)(P0.01),且沙棘林全年尺度土壤呼吸Q10值(1.40)顯著高于油松林(1.34,P0.01)。3)日尺度上,油松、沙棘人工林W分別大于13%和12%時,T對Rs的解釋量(R2)均有所提高。因此,在充分考慮溫度和水分對土壤呼吸影響的同時,加強冬季土壤呼吸的觀測,對未來氣候變化條件下,區(qū)域碳循環(huán)估算模型的完善具有重要意義。
[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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