LTREB Renewal: Long-term detrital controls on soil organic matter stabilization

随着时间的推移，全球气候变化、森林管理做法的变化以及大气中污染物的变化都将相互作用，改变森林生产力和植物凋落物(例如落叶)返回森林地面。然而，目前尚不清楚土壤中的有机质数量是否会随着凋落物投入的变化而成比例地变化，或者是否存在可能导致土壤不成比例变化的非线性相互作用。了解增加或减少土壤有机质的过程对于了解全球碳平衡至关重要，因为土壤有机质中的碳超过了储存在植物体内和大气中的碳的总和。土壤和大气之间的碳流量也很大，土壤每年释放的碳量大约是化石燃料燃烧的10倍。泥土(碎屑输入和去除处理)实验于1997年在俄勒冈州的H.J.安德鲁斯实验森林开始，是一项长期研究，通过增加地上木材输入、消除地上输入、消除地下(根)输入或同时消除地上和地下输入来控制凋落物。这项实验旨在解决这样的问题：是什么控制了森林土壤中碳的长期储存？SOM的哪些化学和物理部分最稳定？增加投入能增加土壤碳储量，还是最大土壤碳储量更多地取决于气候和土壤矿物组成？监测土壤中碳储量的变化将产生不同处理下碳稳定和损失的时间过程。了解控制土壤碳的机制不仅对森林管理至关重要，而且对准确预测森林对气候变化的反馈也是至关重要的。土壤实验是环境科学中独一无二的，特别适合于探索凋落物质量和数量在确定土壤碳稳定方面的作用，这在当前的生态系统模型中是一个重要的未知因素。在这个项目中，还将把重点放在本科生荣誉学生的培训上，结果将被纳入俄勒冈州立大学的必修荣誉生态学课程。该项目将利用安德鲁斯森林的长期生态研究计划，与森林管理者和公众进行接触。项目数据和采样土壤都将免费提供给世界各地的研究人员。长期核心数据已经在安德鲁斯森林网站和污垢网站上提供。

Global climate change, changes in forest management practices, and changes in pollutants in the atmosphere will all interact to alter forest productivity and return of plant litter (for example, leaf fall) to the forest floor over time. However, it is not known whether the amount of organic matter in soils will change in proportion to changes in litter inputs, or whether there might be non-linear interactions that may lead to disproportional soil changes. Understanding processes that increase or decrease soil organic matter is critical for understanding the global carbon balance, as carbon in soil organic matter amounts to more than the carbon stored in plant mass and in the atmosphere combined. The flux of carbon between soils and the atmosphere is also large, with the annual amount of carbon released from soils about 10 times that due to fossil fuel combustion. The DIRT (Detrital Inputs and Removal Treatments) experiment, started at the H.J. Andrews Experimental Forest in Oregon in 1997, is a long-term study where litter is manipulated either by increasing above-ground wood inputs, eliminating aboveground inputs, eliminating belowground (root) inputs, or eliminating both above- and belowground inputs. The experiment is designed to address such questions as: What controls the long-term storage of carbon in forest soils? What chemical and physical parts of SOM are most stable? Can added inputs increase soil carbon storage, or is maximum soil carbon storage more determined by climate and soil mineral makeup? Monitoring changes in carbon storage in the DIRT plots will generate a time course of carbon stabilization and loss under the different treatments. Understanding the mechanisms that control soil carbon is vital not only to forest management, but also to the accurate prediction of feedbacks from forests to climate change. The DIRT experiment is unique to environmental science and uniquely suited to explore the role of litter quality and quantity in determining stabilization of soil carbon, a significant unknown in current ecosystem models. In this project, focus will also be placed on training of undergraduate Honors students, with results incorporated into a required Honors Ecology course at Oregon State University. The project will leverage the Long-Term Ecological Research program at the Andrews Forest for outreach to forest managers and the public. Both the project data and the sampled soils will be made freely available to researchers across the world. The long-term core data are already available on the Andrews Forest web site and the DIRT web site.