了解土壤特性对生态系统生产力的控制机制对于在气候变化下维持生产力和提高恢复力至关重要。在这里,我们研究了表土深度的控制(例如,关于长期生态系统生产力的视野)。我们使用了全国范围内的表土深度观测值(n=2401)和五个生态系统(农田,森林,草原,牧场,灌木丛)超过36年(1986-2021年),遍及美国。表土深度和阵之间的关系主要与水的可用性有关,这在草地下的干旱地区尤其重要,灌木丛,和农田(r分别为.37、.32、.15,p<.0001)。表土深度每增加10cm,在干旱地区,PPI增加了114到128gCm-2year-1(r=.33和.45,p<.0001)。在保持其他变量(气候,植被,母体材料,土壤类型)常数表明,表层土壤深度的阳性控制主要发生在农田(0.73,置信区间为0.57-0.84)和灌木丛(0.75,置信区间为0.40-0.94)。深表土和浅表土之间的3GPP差异很小,没有统计学意义。尽管干旱地区的表土深度对生产力的积极控制,其贡献(系数:.09-.33)与热量(系数:.06-.39)相似,但小于水(系数:.07-.87)。生态系统生产力对极端气候的复原能力在不同的生态系统和气候区域有所不同。在大多数生态系统中,在极端气候下,较深的表层土壤增加了稳定性并降低了生物多样性。尤其是在灌木丛和草原。在气候变化下,干旱地区表土的保护以及土壤深度表示和水分保持机制的改善对于固碳生态系统服务至关重要。这些发现和关系也应包括在地球系统模型中。
Understanding the controlling mechanisms of soil properties on ecosystem productivity is essential for sustaining productivity and increasing resilience under a changing climate. Here we investigate the control of topsoil depth (e.g., A horizons) on long-term ecosystem productivity. We used nationwide observations (n = 2401) of topsoil depth and multiple scaled datasets of gross primary productivity (GPP) for five ecosystems (cropland, forest, grassland, pasture, shrubland) over 36 years (1986-2021) across the conterminous USA. The relationship between topsoil depth and GPP is primarily associated with water availability, which is particularly significant in arid regions under grassland, shrubland, and cropland (r = .37, .32, .15, respectively, p < .0001). For every 10 cm increase in topsoil depth, the GPP increased by 114 to 128 g C m-2 year-1 in arid regions (r = .33 and .45, p < .0001). Paired comparison of relatively shallow and deep topsoils while holding other variables (climate, vegetation, parent material, soil type) constant showed that the positive control of topsoil depth on GPP occurred primarily in cropland (0.73, confidence interval of 0.57-0.84) and shrubland (0.75, confidence interval of 0.40-0.94). The GPP difference between deep and shallow topsoils was small and not statistically significant. Despite the positive control of topsoil depth on productivity in arid regions, its contribution (coefficients: .09-.33) was similar to that of heat (coefficients: .06-.39) but less than that of water (coefficients: .07-.87). The resilience of ecosystem productivity to climate extremes varied in different ecosystems and climatic regions. Deeper topsoils increased stability and decreased the variability of GPP under climate extremes in most ecosystems, especially in shrubland and grassland. The conservation of topsoil in arid regions and improvements of soil depth representation and moisture-retention mechanisms are critical for carbon-sequestration ecosystem services under a changing climate. These findings and relationships should also be included in Earth system models.