Soil organic matter (SOM) anchors global terrestrial productivity and food and fiber supply. SOM retains water and soil nutrients and stores more global carbon than do plants and the atmosphere combined. SOM is also decomposed by microbes, returning CO2, a greenhouse gas, to the atmosphere. Unfortunately, soil carbon stocks have been widely lost or degraded through land use changes and unsustainable forest and agricultural practices. To understand its structure and function and to maintain and restore SOM, we need a better appreciation of soil organic carbon (SOC) saturation capacity and the retention of above- and belowground inputs in SOM. Our analysis suggests root inputs are approximately five times more likely than an equivalent mass of aboveground litter to be stabilized as SOM. Microbes, particularly fungi and bacteria, and soil faunal food webs strongly influence SOM decomposition at shallower depths, whereas mineral associations drive stabilization at depths greater than ∼30 cm. Global uncertaint...

中文翻译：

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土壤碳生态：池、脆弱性以及生物和非生物控制

土壤有机质 (SOM) 支撑着全球陆地生产力以及食物和纤维供应。SOM 保留水和土壤养分并储存比植物和大气总和还要多的全球碳。SOM 也会被微生物分解，将温室气体 CO2 返回到大气中。不幸的是，由于土地用途的变化以及不可持续的森林和农业做法，土壤碳储量已广泛丧失或退化。为了了解其结构和功能并维持和恢复 SOM，我们需要更好地了解土壤有机碳 (SOC) 饱和能力以及 SOM 中地上和地下输入的保留。我们的分析表明，根部输入被稳定为 SOM 的可能性大约是同等质量的地上凋落物的五倍。微生物，尤其是真菌和细菌，和土壤动物食物网强烈影响较浅深度的 SOM 分解，而矿物组合驱动深度大于 30 厘米的稳定。全球不确定...