MICROMETEOROLOGICAL AND CHAMBER MEASUREMENTS OF CO2 FLUX FROM BARE SOIL
MICROMETEOROLOGICAL AND CHAMBER MEASUREMENTS OF CO2 FLUX FROM BARE SOIL
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DOI：
10.1016/0168-1923(93)90053-k
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发表时间：
1993-12-01
影响因子：
6.2
通讯作者：
DUGAS, WA
中科院分区：
文献类型：
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作者：
DUGAS, WA
土壤二氧化碳(CO2)通量的准确测量很重要，因为该通量是地表碳收支的重要组成部分，也是土壤微生物和根系活动水平的良好指标。1992年12月，在德克萨斯州坦普尔的Blackland研究中心，用土壤箱和Bowen比率/能量平衡(BREB)方法连续4天测量了裸土的半小时CO2通量。在田间的9个位置连续进行了土室二氧化碳测量。使用了三个CO2 BREB系统。CO2通量在清晨和日落后接近于0，接近中午时最大(略小于0.1mgm(-2)S(-1)(2.3mmolm(-2)S(-1)。这九个位置的小室二氧化碳通量的变异系数(CV)全天平均为40%，这表明需要进行大量小室测量才能获得具有代表性的二氧化碳通量测量结果。三个系统的每日BREB CO2通量的变异系数均小于2%，说明三个系统的BREB CO2通量是相等的。两种方法得到的通量之间有很好的一致性。在整个测量期间，小室和BREB二氧化碳平均通量分别为0.039和0.042 mg m(-2)S(-1)，而两种方法半小时通量的均方根差为0.017 mg m(-2)S(-1)。这两种方法是互补的，都可以用于土壤CO2通量的测量。室法成本低，使用方便，并提供了在太空中重复测量的可能性。BREB方法在较大的空间范围内集成，因此受土壤CO2通量的高空间变异性的影响较小。
Accurate measurements of carbon dioxide (CO2) flux from soil are important because this flux is an important component of the surface carbon budget, and a good indicator of the level of soil microbial and root activity. Half-hour CO2 fluxes from bare soil were measured using soil chamber and Bowen ratio/ energy balance (BREB) methods for 4 days in December 1992, at the Blackland Research Center, Temple, TX. Soil chamber CO2 measurements were made sequentially at nine positions in the field. Three CO2 BREB systems were used. The CO2 flux was approximate to 0 in the early morning and after sunset and was maximum (slightly less than 0.1 mg m(-2) s(-1) (2.3 mu mol m(-2) s(-1))) near midday. The coefficient of variation (CV) of chamber CO2 fluxes across the nine positions averaged 40% throughout the day, indicating the need for a large number of chamber measurements to obtain a representative CO2 flux measurement. The CV of the three daily BREB CO2 fluxes was less than 2%, indicating the BREB CO2 fluxes from the three systems were equal. There was good agreement between fluxes from the two methods. The average chamber and BREB CO2 fluxes for the entire period of measurements were 0.039 and 0.042 mg m(-2) s(-1), respectively, while the root mean square difference between half-hour fluxes from the two methods was 0.017 mg m(-2) s(-1). The methods are complementary and can both be used for soil CO2 flux measurements. The chamber method is low cost and easy to use, and offers the possibility of replicated measurements over space. The BREB method integrates over a large spatial area and is thus less affected by the high spatial variability of soil CO2 flux.