The present and future greenhouse gas budget of bioenergy crops in the UK

生物能源是英国政府应对气候变化计划的关键组成部分。大气二氧化碳水平上升的主要原因之一是燃烧化石燃料，释放出储存了几个世纪的碳回到大气中。为了减少化石燃料的使用，我们可以种植农作物作为能源。生物能源(或“生物质”)作物是“碳中性”的；当燃烧发电时，它们只会向大气中释放与固定数量相同的二氧化碳。因此，不会向大气中释放“额外的”二氧化碳。芒属和短轮换矮枝柳是英国种植的主要生物能源作物。它们在生理、营养需求和管理方面与目前更传统的可耕作作物不同。这种差异对生物地球化学循环和土壤微生物学的影响，特别是与温室气体一氧化二氮(N2O)和甲烷(CH4)的产生和氧化有关的影响尚不清楚。为了巩固未来生物能源种植系统的管理并准确预测未来的温室气体清单，确定这一点是至关重要的。在这个项目中，我们将测量芒属和SRC柳树的二氧化碳、甲烷和N2O的排放量，并将这些排放量与邻近种植的常规作物的排放量进行比较。我们将进一步研究产生N2O的过程，并在一系列受控环境和管理条件下使用稳定同位素技术量化CH4氧化速率，并使用分子技术将这些排放与相关微生物种群的任何差异或变化联系起来。这些信息将被用来开发CEH的Jules社区模型，对这些生物能源作物的水、能源、碳和温室气体平衡进行参数化，并模拟英国土地在目前和未来气候下如果被转换为种植芒属和SRC柳树的温室气体排放。

Bioenergy is a key component of the UK Government's plans for tackling climate change. One of the major causes of increased atmospheric CO2 levels is the burning of fossil fuels releasing carbon that has been stored for centuries back into the atmosphere. In order to cut our use of fossil fuels we can grow crops for energy. Bioenergy (or 'biomass') crops are 'carbon neutral'; when burned to generate electricity they only release the same amount of CO2 back into the atmosphere as they fixed. Thus no 'extra' CO2 is released into the atmosphere. Miscanthus and short rotation coppice (SRC) willow are the dominant bioenergy crops grown in the UK. They differ from more traditional current arable crops in terms of their physiology, nutrient requirements and management. The impact of such differences on biogeochemical cycling and soil microbiology, particularly in relation to the production and oxidation of the greenhouse gases nitrous oxide (N2O) and methane (CH4), is unknown. It is essential to determine this in order to underpin future management of bioenergy cropping systems and to accurately project future greenhouse gas inventories. In this project we will measure emissions of CO2, CH4 and N2O from Miscanthus and SRC willow, and compare these to emissions from adjacently growing conventional crops. We will further investigate the processes producing N2O and quantify CH4 oxidation rates using stable isotope techniques under a range of controlled environment and managment conditions, and using molecular techniques will link these emissions to any differences or changes in the microbial population responsible. This information will be used to develop the JULES community model of CEH, parameterising water, energy, carbon and greenhouse gas balances for these bioenergy crops, and to simulate greenhouse gas emissions for UK land if converted to growing Miscanthus and SRC willow under present and future climates.