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新疆南部农田裸地土壤呼吸变化特征 被引量:3

Characteristics of Soil Respiration in Bare Soil of Farmland in the South of Xinjiang
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摘要 于2012-06-28-2013-01-08在新疆焉耆盆地设置农田裸土桶装培养试验,采用动态密闭气室法(Li-8100,USA),监测地表温度和土壤呼吸地表通量的日变化和季节变化。试验包括3个处理:原土、含1.25%和2.5%玉米秸秆的混合土。结果表明:①土壤呼吸速率日变化特征均呈单峰型曲线,最高值出现在12:00-16:00,最低值在5:00-7:00。②土壤呼吸速率季节变化特征为:夏季最大,冬季最小。其中,在夏季有2个峰值:出现在7月中下旬和8月中下旬。通过相关性分析发现:3个处理土壤呼吸速率与地表温度的相关性在夏季均不显著(P〉0.05),在秋季均呈极显著相关(R^2〉0.90,P〈0.01),在冬季均呈显著相关(R^2〉0.40,P〈0.05)。夏季和冬季的土壤呼吸温度敏感性(用Q10值表示)分别为1.21~1.52和1.65~2.25。 Soil surface CO2 efflux, or soil respiration, is a major component of the global terrestrial carbon cycle because it may constitute about three-quarters of total ecosystem respiration. The changes in soil surface CO2 efflux, the primary CO2 source to the atmosphere from terrestrial ecosystems, directly influences the local and regional car- bon budgets. In this study, a incubation experiments were conducted in the Yanqi Basin using farmland bare soil from June 28,2012 to January 8,2013. Diurnal and seasonal variations of soil respiration and soil surface tempera- ture were determined under three treatments( original bare soil and bare soil mixed with 1.25% and 2.5% of maize straw) by using an Automated Soil CO2 Efflux System( LI -COR 8100). The results indicated that there was obvious diurnal variation of soil respiration under all three treatments. The maximum rate of soil respiration occurred between 12:00 - 16:00( Local time), the minimum between 5:00 - 7:00. On average, the total amount of carbon released during daytime accounted for about 58% - 70% of that for the whole day. There were seasonal variations of soil res- piration under all three treatments, showing similar two-peaked curves in middle to late July and middle to late Au- gust. During the whole observation period, the total amount of carbon released was 370 g · m^-2,361 g · m^-2 and 329 g · m^-2 for the 2.5% straw + soil, 1.25% straw + soil and bare soil,respectively. The exponential relationships between the rate of soil respiration and soil surface temperature for all three treatments were highly significant in au- tumn (R^2 〉0. 9,P 〈0.01 ) ,significant in winter (R^2 〉0.4 ,P 〈0.05) but no significant in summer (P 〉0.05). The Q10 values for the bare soil, 1.25% straw + soil and 2.5% straw + soil were all larger in winter( 1.65 - 2.25 ) than in summer( 1.21 - 1.52).
出处 《干旱区研究》 CSCD 北大核心 2015年第3期453-460,共8页 Arid Zone Research
基金 国家自然科学基金项目(41101100 41403072) 中德合作项目(GZ867) STS项目(KFJ-EW-STS-006-3)
关键词 裸地 土壤呼吸 地表温度 日变化 季节变化 焉耆盆地 bare soil soil respiration soil surface temperature Q10 values diurnal variation seasonal varia-tion Yanqi Basin
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