Towards a Better Understanding of the Soil-Plant-Atmosphere-Water Continuum

更好地理解土壤-植物-大气-水连续体

• 批准号: RTI-2017-00315
• 负责人: Madramootoo, Chandra
• 金额: $ 10.93万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Research Tools and Instruments
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=616631
• 关键词: Towards; Better; Understanding; Soil; Plant

Our NSERC supported research is aimed at designing agricultural water management systems which conserve water and energy, while at the same time enhancing crop productivity. Studies are being undertaken to define crop water stress by developing models based on measurements of various plant canopy atmosphere parameters including vapour pressure deficit, canopy temperature, relative humidity, photosynthetic rate, and CO2 fluxes. However, preliminary work from our water management field studies has shown that NO2 fluxes are more environmentally significant than CO2. Nitrous oxide (N2O) is a significant greenhouse gas, influenced by the rate and timing of fertilizer application, irrigation and drainage practices, as well as by precipitation. High water tables contribute to soil anaerobic conditions, thereby promoting denitrification. We installed static Plexiglas chambers in the field, and manually collected gas samples in syringes, which we brought back to the lab for N2O analysis, using gas chromatography. This was a very time consuming and tedious method, and resulted in a backlog of samples in the lab, which took an inordinate amount of time to analyze. Furthermore, since we sampled manually, we often missed peak emissions, and were not able to accurately capture rainfall and fertilization effects. In addition, we often did not capture emissions due to increased microbiological activity under warmer soil temperatures during the spring thaw. There are two other complications with the collection of data manually. Firstly fluxes are not linear with time, so simple linear extrapolation between data points leads to erroneous estimates of N2O. Secondly, our data showed tremendous variability in N2O fluxes within sites. This leads us to believe that there are geospatially variable soil microbiological hotspots, influencing fluxes and we need to distinguish biological sources of N2O. We propose to use a PICARRO G5131-i N2O Concentration and Isotopes Analyzer, in order to overcome the above challenges, and to generate a better understanding of crop productivity under various soil-water conditions. It continuously and rapidly measures N2O gas concentration and isotopes (eg. δ15N). Through a Distribution Manifold we can simultaneously measure N2O concentrations and isotopomer ratios in up to 16 field-based chambers. The Small Sample Isotope Module 2 (SSIM2) of the Analyzer measures gas evolution from soils, vegetation, as well as the incorporation of stable labels into living organisms, which will completely modernize our method of evaluating N reactions in microbial-soil-plant environments. We will also be able to measure dissolved N2O evolution, an under-reported source of N2O. Approximately 25 graduate students will be trained in the use of the Analyzer. Through their training, they will become Canadian leaders in advanced environmental management for sustainable agriculture.

我们的 NSERC 支持的研究旨在设计节约用水和能源的农业用水管理系统，同时提高作物生产力，通过开发基于各种植物冠层大气参数（包括水蒸气）测量的模型来定义作物水分胁迫。然而，我们的水管理现场研究的初步工作表明，NO2 通量比 CO2 更具有环境意义。一种重要的温室气体，受施肥率和时间、灌溉和排水措施以及降水的影响，高地下水位会导致土壤厌氧条件，从而促进反硝化。 我们在现场安装了静态有机玻璃室，并在注射器中手动收集气体样品，然后将其带回实验室使用气相色谱法进行 N2O 分析。这是一种非常耗时且繁琐的方法，并导致样品积压。实验室需要花费大量时间进行分析。此外，由于我们手动采样，我们经常错过峰值排放，并且无法准确捕获降雨和施肥效应。春季解冻期间土壤温度升高导致微生物活动增加导致的排放量 手动收集数据还存在两个问题：首先，通量与时间呈非线性关系，因此数据点之间的简单线性外推会导致 N2O 的估计错误。 ，我们的数据显示地点内 N2O 通量的巨大变化，这使我们相信存在地理空间变化的土壤微生物热点，影响通量，我们需要区分 N2O 的生物来源。 我们建议使用 PICARRO G5131-i N2O 浓度和同位素分析仪，以克服上述挑战，并更好地了解各种土壤-水条件下的作物生产力，它可以连续快速地测量 N2O 气体浓度和同位素（例如 δ15N）。通过分配歧管，我们可以同时测量多达 16 个现场室中的 N2O 浓度和同位素比率。分析仪的同位素模块 2 (SSIM2) 可测量土壤、植被中的气体演化，以及将稳定标记纳入生物体中，这将使我们评估微生物-土壤-植物环境中氮反应的方法完全现代化。能够测量溶解的 N2O 演变，这是一种未被充分报道的 N2O 来源。 大约 25 名研究生将接受分析仪使用方面的培训，通过培训，他们将成为加拿大可持续农业先进环境管理领域的领导者。