OPUS: Biogeochemistry of Amazonian Terrestrial Ecosystems

砍伐森林、农业扩张和气候变化是对南美洲亚马逊盆地生态系统完整性的重大威胁。这些变化对作为动植物生命基本营养的碳、氮、磷和其他化学元素的循环的影响决定了森林受到干扰后植被再生的速度、各种农业做法的可持续程度、土壤排放的温室气体的数量和类型以及地下水和河流的污染量。在过去的22年里，该项目的首席研究员与来自许多国家的科学家和学生在亚马逊盆地不同地区的具体研究项目上进行了合作。早期的研究表明，土壤养分的循环对于维持几乎没有幸存树木的牧场、年轻的重新生长的森林和较老的(较少受到干扰的)森林是多么重要。然后进行了一项大型实验，从一片较老的森林中分流了一些雨水，结果表明可用水是多么重要，即使在其他看起来如此丰富的地方也是如此。最后，最新研究的重点是大豆和玉米种植制度中更集约农业的影响，这些种植制度越来越多地取代亚马逊某些地区的森林，以及火灾在盆地南部森林退化中所起的作用。亚马逊的变化是大规模和快速的，这给研究带来了挑战和机遇。目前的项目是专门为解决两个主要问题而设计的，目的是试图将调查员在该区域的所有先前研究联系起来。首先，碳、氮和磷的相对数量如何影响亚马逊盆地的植物生长和森林、牧场和作物系统的可持续管理？其次，这些土地利用的哪些组合是最可持续的，以及随着气候变化和火灾变得更普遍，这种变化可能会如何，正如预测的那样？除了面向科学受众的同行评议专著外，调查还将撰写一本关于营养循环对亚马逊森林和农场可持续性管理的重要性的书，面向非专业读者，将以英语、葡萄牙语和西班牙语出版。这本书将使用跨亚马逊盆地气候梯度的养牛场、小农户农业、大规模农业和各种类型的森林管理的真实例子，将每个例子的叙述和数据编织在一起。这本书的一个主要重点是确定砍伐森林、农业和火灾影响土壤有效氮和磷平衡的情况，以及它们在高度反差但具有代表性的生态系统中对植物生长和碳储存的相对重要性。碳、氮和磷比例的变化被认为是将追求的关键。随着农业和牛肉生产的加强，营养物质的管理在整个地区将变得越来越重要和具有挑战性。该项目将综合过去25年的数据和研究结果，这些数据和研究结果对解决这一问题至关重要。调查员处于一个独特的位置，可以为广大受众提供关于亚马逊自然资源管理、环境科学和可持续发展主题的可访问、可靠、重要和愉快的阅读。

Deforestation, agricultural expansion and climate change are significant threats to the integrity of ecosystems in the Amazon Basin of South America. The effects of these changes on the cycling of carbon, nitrogen, phosphorus and other chemical elements that are essential nutrients for plant and animal life determine how fast vegetation regrows after forests are disturbed, the degree to which various agricultural practices are sustainable, the amounts and types of greenhouse gases that are emitted from soils, and the amount of pollution in groundwater and rivers. Over the last 22 years, the principal investigator of this project has worked with scientists and students from many countries on specific research projects in different parts of the Amazon Basin. Early work showed how important the cycling of soil nutrients is for sustaining cattle pastures with few surviving trees in them, for young re-growing forests, and for older (less disturbed) forests. A big experiment was then conducted where some rain was diverted from an older forest, with the results showing how important water availability is, even in places where it otherwise seems so abundant. Finally, the focus of the most recent research has been on the impacts of more intensive agriculture in the soy and corn cropping systems that have increasingly replaced forests in some parts of the Amazon, along with the role that fire plays in the degradation of forests in the southern part of the Basin. Changes in the Amazon are large scale and rapid, which presents both challenges and opportunities for research. The current project is designed specifically to try and link all of the prior research of the investigator in this region for addressing two main questions. First, how do the relative amounts of carbon, nitrogen and phosphorus affect plant growth and the sustainable management of forests, cattle pastures and crop systems across the Amazon Basin? Second, what combinations of these land uses are the most sustainable and how might this change as the climate changes and fire becomes more widespread, as is predicted? In addition to a peer-reviewed monograph for scientific audiences, the investigate will write a book about the importance of nutrient cycling for the sustainability management of Amazonian forests and farms that is intended for a non-specialist audience and will be published in English, Portuguese and Spanish. The book will use real examples of cattle ranching, small-holder farming, large-scale farming, and various types of forest management across the climate gradients of the Amazon Basin, weaving together narratives and data for each.A major focus of this effort is the identification of circumstances where deforestation, farming and fire affect the balance of soil available nitrogen and phosphorus and their relative importance for plant growth and carbon storage in highly contrasting, but representative, ecosystems. Variation in the ratios of carbon, nitrogen and phosphorus is the presumed key that will be pursued. As agriculture and beef production intensify, management of nutrients will become increasingly important and challenging across the entire region. This project will synthesize data and study results from the past quarter century that are central to addressing this issue. The investigator is in a unique position to provide accessible, reliable, important and enjoyable reading for a wide audience on the topics of natural resource management, environmental science and sustainability in the Amazon.