Distinguishing Root from Soil Contributions to Soil Respiration: Exploration of a New Approach

区分根系和土壤对土壤呼吸的贡献：探索新方法

• 批准号: 0343766
• 负责人: German Mora
• 金额: $ 40万
• 依托单位: Iowa State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-01 至 2008-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0343766&HistoricalAwards=false
• 关键词: Distinguishing; Root; Soil; Contributions; Respiration

Over recent decades concentrations of CO2 in the atmosphere have increased steadily, primarily due to the combustion of fossil fuels. This finding has generated substantial debate concerning the possible consequences for our global environment, since CO2 is a greenhouse gas. Of the CO2 emissions from fossil fuel combustion and cement manufacture, about 30% is absorbed by the oceans and about half remains in the atmosphere. The remaining 20% is assumed to be absorbed by plants and soils. Since that process is not well understood, a major gap in understanding how Earth will respond to increasing atmospheric CO2 concentrations exists. To fill this gap, we need a better understanding of the processes of plant growth and decomposition in soils. That need remains because of our perpetual lack of tools for investigating robustly that dark, dirty, and obscure world belowground. We have developed a new approach that takes advantage of precise measurements of isotopes of carbon, physiological differences among plant species, computer modeling, and a combination of experimental field and laboratory studies, to divide the belowground ecosystem into its major components. We propose that we can distinguish, and thus investigate independently, the separate but simultaneous processes of plant (root) growth and organic matter decomposition, and thus provide a new tool for understanding what we cannot see. Living soils are where organisms, land, water, and atmosphere interact the most. By shedding light on this murkiest of ecosystems, we expect to advance significantly our capacity to investigate a host of biogeochemical processes that influence our waters, our air, the productive capacity of our land and, potentially, our climate.

近几十年来，大气中的二氧化碳浓度稳步上升，这主要是由于化石燃料的燃烧。由于二氧化碳是一种温室气体，这一发现引发了关于全球环境可能产生的后果的大量争论。化石燃料燃烧和水泥生产排放的二氧化碳中，约30%被海洋吸收，约一半留在大气中。剩下的20%被植物和土壤吸收。由于这一过程还没有被很好地理解，因此在理解地球将如何应对大气中二氧化碳浓度的增加方面存在一个重大空白。为了填补这一空白，我们需要更好地了解植物在土壤中的生长和分解过程。这种需求仍然存在，因为我们永远缺乏工具来深入调查那个黑暗、肮脏和晦涩的地下世界。我们开发了一种新的方法，利用碳同位素的精确测量，植物物种之间的生理差异，计算机建模，以及实验现场和实验室研究的结合，将地下生态系统划分为其主要组成部分。我们提出，我们可以区分并独立研究植物（根）生长和有机物分解的分离但同时发生的过程，从而为理解我们看不见的东西提供一种新的工具。活土壤是生物、土地、水和大气相互作用最大的地方。通过揭示这个最黑暗的生态系统，我们期望大大提高我们调查一系列生物地球化学过程的能力，这些过程影响我们的水、空气、土地的生产能力，甚至可能影响我们的气候。