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Plant nutrition as Earth System Science: understanding the links between plant nutrient gain and soil carbon storage.

植物营养作为地球系统科学：了解植物养分增益和土壤碳储存之间的联系。

基本信息

批准号：
NE/N015460/1
负责人：
Lorna Street
金额：
$ 68.2万
依托单位：
University of Edinburgh
依托单位国家：
英国
项目类别：
Fellowship
财政年份：
2016
资助国家：
英国
起止时间：
2016 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FN015460%2F1
关键词：
Plant nutrition Earth System Science

项目摘要

We do not fully understand how plants access nutrients from the soil. This makes it difficult to model carbon (C) cycling in terrestrial ecosystems - and to know how terrestrial C storage might respond to global change. This fellowship project aims to improve our understanding of plant nutrition and by doing so increase our ability to accurately predict feedbacks between climate and the terrestrial C cycle.The ways in which plants obtain nutrients from the soil, and especially nitrogen (N), are known to be important in determining how quickly soil organic matter (SOM) decomposes and therefore how much C is stored in soils. For example, plants and their associated symbiotic root fungi (mycorrhizas) are known to "prime" SOM decomposition by producing enzymes capable of degrading more resistant organic compounds. Recent evidence also suggests that the form in which plant take up nutrients, whether as inorganic (mineral) ions or as C-containing organic molecules, has an impact on rates of SOM decomposition. The problem is that whilst we know that complex plant-mediated effects on soil C storage exist, we do not understand them well enough to include them in models of the C cycle. Current knowledge suggests that plant nutrition may have a large impact on soil C storage in nutrient-limited environments such as the Arctic. Arctic ecosystems store large amounts of C - approx. 35-45% of total global terrestrial C is found in Arctic and permafrost soils. The future of Arctic soil C under warming conditions is highly uncertain and is a focus of NERC research (e.g. through the recent £5m Arctic Research Programme). There is a particularly pressing need to understand the interactions between plant nutrition and soil C storage in Arctic environments and this is where the fellowship activities will be concentrated. It has long been assumed that inorganic N ions provide most of the N that plants need but there is now growing evidence that organic forms of N also play an important role in sustaining plant growth. In addition to implications for the global C cycle, understanding organic N nutrition therefore has potential ramifications for crop production and food security.The relative importance of organic N to plants has been impossible to measure until now because existing techniques are limited by experimental artefacts. This fellowship proposes new isotopic methods that can quantify the importance of organic N to plants for the first time. These novel techniques include growing plants which are isotopically distinct from the soil, in order to trace the uptake of C-containing organic nutrients from the soil into plant tissues (Continuous Depleted Radiocarbon (CDER) labelling). Experiments will also be carried out at Arctic field sites, in which the isotopic signatures of plants and soils will be used to test the linkages between plant nutrient demand and SOM decomposition under different conditions. The proposed techniques will make it possible to quantitatively test the ways in which plant nutrition impacts decomposition in soils. This new information will then be used to update C cycle models to improve representation of plant nutrient uptake, and test the future impact of environmental change on soil C storage in the Arctic. The outcome of this project will be a significant improvement in our understanding of plant nutrition and of the vulnerability of Arctic C stocks to global change.

我们并不完全了解植物是如何从土壤中获取养分的。这使得很难对陆地生态系统中的碳(C)循环进行建模，也很难知道陆地碳储存可能如何应对全球变化。该奖学金项目旨在提高我们对植物营养的了解，并通过这样做提高我们准确预测气候和陆地碳循环之间反馈的能力。植物从土壤中获得养分的方式，特别是氮(N)，被认为是决定土壤有机质(SOM)分解速度以及土壤中储存了多少碳的重要因素。例如，植物及其相关的共生根真菌(菌根)通过产生能够降解更具抗性的有机化合物的酶来“启动”SOM分解。最近的证据还表明，植物吸收养分的形式，无论是作为无机(矿物)离子还是作为含碳的有机分子，都会影响土壤有机质的分解速度。问题是，尽管我们知道存在复杂的植物对土壤碳储存的影响，但我们对它们的理解还不够充分，无法将它们包括在碳循环的模型中。目前的知识表明，在营养有限的环境中，如北极，植物营养可能会对土壤碳储存产生很大影响。北极生态系统储存了大量的C-约。全球陆地碳总量的35%-45%存在于北极和永久冻土中。北极土壤碳在变暖条件下的未来是高度不确定的，是国家环境研究中心的一个研究重点(例如，通过最近的GB 5M北极研究计划)。尤其迫切需要了解北极环境中植物营养和土壤碳储存之间的相互作用，这是研究金活动将集中的地方。长期以来，人们一直认为无机氮离子提供了植物所需的大部分氮，但现在越来越多的证据表明，有机形态的氮在维持植物生长方面也发挥着重要作用。除了对全球碳循环的影响外，了解有机氮营养对作物生产和粮食安全也有潜在的影响。有机氮对植物的相对重要性直到现在还不可能衡量，因为现有的技术受到实验人工制品的限制。这项研究首次提出了新的同位素方法，可以量化有机氮对植物的重要性。这些新技术包括种植与土壤同位素不同的植物，以追踪从土壤中吸收含碳有机营养到植物组织中的情况(连续耗尽放射性碳标记法)。还将在北极实地进行实验，利用植物和土壤的同位素特征来测试不同条件下植物养分需求与土壤有机质分解之间的联系。拟议的技术将使定量测试植物营养影响土壤分解的方式成为可能。这些新信息将被用于更新碳循环模型，以改进植物养分吸收的代表性，并测试未来环境变化对北极土壤碳储存的影响。该项目的成果将大大改善我们对植物营养和北极碳储量易受全球变化影响的认识。