The accurate estimate of grassland carbon (C) is affected by many factors at the large scale. Here, we used six methods (three spatial interpolation methods and three grassland classification methods) to estimate C storage of Chinese grasslands based on published data from 2004 to 2014, and assessed the uncertainty resulting from different integrative methods. The uncertainty (coefficient of variation, CV, %) of grassland C storage was approximately 4.8% for the six methods tested, which was mainly determined by soil C storage. C density and C storage to the soil layer depth of 100 cm were estimated to be 8.46 ± 0.41 kg C m−2 and 30.98 ± 1.25 Pg C, respectively. Ecosystem C storage was composed of 0.23 ± 0.01 (0.7%) above-ground biomass, 1.38 ± 0.14 (4.5%) below-ground biomass, and 29.37 ± 1.2 (94.8%) Pg C in the 0–100 cm soil layer. Carbon storage calculated by the grassland classification methods (18 grassland types) was closer to the mean value than those calculated by the spatial interpolation methods. Differences in integrative methods may partially explain the high uncertainty in C storage estimates in different studies. This first evaluation demonstrates the importance of multi-methodological approaches to accurately estimate C storage in large-scale terrestrial ecosystems.
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机译：草地碳（C）的准确估算在很大程度上受到许多因素的影响。在此，我们使用6种方法（三种空间插值方法和三种草地分类方法）基于2004年至2014年发布的数据估算中国草地的碳储量，并评估了不同整合方法所带来的不确定性。所测试的六种方法的草地碳储存的不确定性（变异系数，CV，％）约为4.8％，这主要由土壤碳储存确定。估计土壤密度为100 cm时的C密度和C储量分别为8.46±0.41 kg C m -2 和30.98±1.25 PgC。生态系统C的储量由0–100cm土层中的地上生物量0.23％±0.01（0.7％），地下生物量1.38％±0.14（4.5％）和29.37±1.2％（94.8％）Pg C组成。通过草地分类方法（18种草地类型）计算出的碳储量比通过空间插值方法计算出的碳储量更接近平均值。整合方法的差异可能部分解释了不同研究中碳储量估算的高度不确定性。这项首次评估证明了使用多种方法准确估算大型陆地生态系统中碳储存的重要性。
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