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.

我们不完全了解植物如何从土壤中获取养分，这使得模拟陆地生态系统中的碳（C）循环变得困难，也难以了解陆地碳储存如何应对全球变化。植物营养，从而提高我们准确预测气候和陆地碳循环之间反馈的能力。众所周知，植物从土壤中获取养分，尤其是氮 (N) 的方式对于确定土壤有机质的速度非常重要例如，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“引发”SOM 分解。植物吸收养分的形式，无论是无机（矿物）离子还是含碳有机分子，都会影响 SOM 的分解速率。尽管我们知道植物对土壤碳储存存在复杂的影响，但我们对它们的了解还不够深入，无法将其纳入碳循环模型中。目前的知识表明，植物营养可能对营养有限环境中的土壤碳储存产生重大影响。北极生态系统储存了大量的碳——全球陆地碳总量的约 35-45% 存在于北极和永久冻土土壤中。研究（例如通过最近的 500 万英镑北极研究计划）特别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，长期以来人们一直认为无机碳储存是研究金活动的重点。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，有机形式的氮在维持植物生长方面也发挥着重要作用，因此，除了对全球碳循环的影响之外，了解有机氮营养也具有潜在的影响。农作物生产和粮食迄今为止，由于现有技术受到实验制品的限制，有机氮对植物的相对重要性还无法测量。该研究项目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。包括种植与土壤同位素不同的植物，以追踪植物组织从土壤中吸收含碳有机养分的情况（连续贫化放射性碳（CDER）标签实验也将在北极进行）。植物和土壤的同位素特征将用于测试不同条件下植物养分需求和 SOM 分解之间的联系，所提出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。然后，这些新信息将用于更新碳循环模型，以改善植物养分吸收的代表性，并测试环境变化对北极土壤碳储存的未来影响。该项目的成果将显着提高我们的理解。植物的营养和北极碳储量对全球变化的脆弱性。