TropSOC - Tropical soil organic carbon dynamics along erosional disturbance gradients in relation to variability in soil geochemistry and land use

土壤对侵蚀干扰的响应是预测温室气体从土壤到大气的通量以及未来地球系统动力学的一个很大的不确定性。这在很大程度上是由于热带非洲等偏远地区缺乏数据，但也是因为从较小规模到较大规模的知识转移不足。热带非洲是气候和土地利用变化的热点。该地区面临着不断增长的人口、原始森林的砍伐和土壤侵蚀造成的退化。因此，预计热带非洲在本世纪将经历土壤生物地球化学循环和生态系统一级土壤、植物和大气之间的碳(C)通量的重要变化。特别是，与温带气候区相比，热带地区的碳动态有何不同尚不清楚，我们对碳循环的大部分机械过程的理解都是从温带气候区衍生出来的。重要的是填补这一知识空白，因为热带生态系统提供具有全球重要性的服务，如植物和土壤中的碳储存、土壤肥力、植物生产力以及最终的粮食供应。拟议的TROPSOC项目的主要目标是发展对刚果盆地东部研究的热带非洲土壤中碳的固存和释放的机械理解。该区域提供了独特的组合：(I)土壤形成的不同地质母质和(Ii)不同程度的人类活动干扰，这些干扰发生在潮湿的热带气候条件下，原始森林被高比率地转化为农业用地。TROPSOC将在回答以下问题方面做出重大贡献：1.土壤、植物和大气之间的养分通量和C分配将如何演变并与控制因素：矿物、地形和植被有关？2.地球化学如何控制、相互作用或调节侵蚀干扰对热带土壤临界带C循环的严重程度？3.我们如何以空间显式的方式模拟控制热带土壤C动态的机制？TROPSOC将对提高我们对热带土壤系统碳的空间分布和归宿的影响因素的理解做出重要贡献。到项目结束时，我们将更好地了解导致热带土壤中碳的空间分布和归宿的因素。我们将制作基准数据产品和建模工具，帮助弥合对热带C循环的情节尺度过程理解和大规模建模之间的差距。这最终将有助于减少与陆地碳通量和土壤对干扰的反应相关的不确定性，这是当前地球系统模型和生态系统服务评估中最大的不确定性之一。

The response of soils to disturbance by erosion is one of the great uncertainties in predicting greenhouse gas fluxes from soils to the atmosphere and, hence, future earth system dynamics. This is largely due to a lack of data in remote areas, such as tropical Africa, but also due to an inadequate transfer of knowledge from smaller to larger scales. Tropical Africa is a hotspot of both climate and land use change. The region faces growing population, deforestation of primary forests and degradation of soils due to erosion. Hence, tropical Africa is expected to experience important changes to both soil biogeochemical cycling and ecosystem level carbon (C) fluxes between soil, plants and the atmosphere in this century. In particular, it is unclear how C dynamics differ in the Tropics compared to temperate climate zones, from which most of our mechanistic process understanding on C cycling is derived. It is important to fill this knowledge gap since tropical ecosystems provide services with global importance, such as C storage in plants and soils, soil fertility, plant productivity and ultimately food supply. The main objective of the proposed TROPSOC project is to develop a mechanistic understanding of C sequestration and release in the soils of Tropical Africa, studied in the Eastern part of the Congo Basin. This region provides a unique combination of (i) geologically diverse parent material for soil formation and (ii) different levels of disturbance by human activity, taking place under a humid, tropical climate regime, where pristine forests are converted into agricultural land at high rates. TROPSOC will make a significant contribution to answering the following questions: 1. How will nutrient fluxes and C allocation between soils, plants and the atmosphere evolve and differ in tropical systems in relation to the controlling factors: mineralogy, topography and vegetation? 2. How does geochemistry control, interact with or mediate the severity of erosional disturbance on C cycling in the critical zone of tropical soils? 3. How can we model the mechanisms controlling tropical soil C dynamics in a spatially explicit way? TROPSOC will make a significant contribution to improving our understanding of the factors that give rise to the spatial distribution and fate of C of tropical soil systems. By the end of the project, we will have a better understanding of the factors that give rise to the spatial distribution and fate of carbon in tropical soils. We will have produced benchmark data products and modeling tools that will help to bridge the gap between plot scale process understanding and large scale modeling of tropical C cycling. This will ultimately help to reduce the uncertainty associated with terrestrial C fluxes and the response of soils to disturbance, which is one of the greatest uncertainties in current Earth System Models and ecosystem service assessments.