Dissertation Research: Phosphorus mobilization by legume cover crops in agricultural systems

论文研究：农业系统中豆类覆盖作物的磷动员

• 批准号: 1308818
• 负责人: Peter Vitousek
• 金额: $ 1.98万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-06-01 至 2015-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1308818&HistoricalAwards=false
• 关键词: Dissertation; Research; Phosphorus; mobilization; legume

Agricultural productivity is often limited by the availability of soil nutrients, including phosphorus (P). Phosphorus availability in soils is limited because most soil P is not directly available to plants and natural inputs are insufficient to replace P removed by harvest. Applications of fertilizers or manures are thus required to maintain soil fertility and yields, but economically viable P reserves are declining and P losses from agricultural systems degrade aquatic ecosystems. This project evaluates whether cover crops, especially legumes, could provide P fertility for cash crops while reducing P input requirements by mobilizing soil P (converting P bound to soil minerals and organic matter into plant-available forms). The central objective is to identify how different species of cover crops could mobilize P. To do so, complementary approaches ? field measurements in long-term experiments, greenhouse studies, and computation of P budgets ? will be used. Measures will be taken of different forms of soil P, processes that mobilize P, transfer rates of P from cover crop to cash crop, and the overall importance of P mobilization by cover crops relative to other P fluxes at the farm scale.This project will contribute to the development of alternative fertilization strategies that could maintain soil fertility while reducing costly P inputs. It will test whether using cover crops could contribute to this goal and provide a better understanding of P transformations in soils where different plant species grow. Because results from this project should be directly relevant to farm practitioners, this research will be coupled with outreach activities to disseminate results widely, including making the data publicly available, contributing to cover crop databases, and transferring knowledge through activities held outside of academic circles (field days, non-technical publications). This project will also involve undergraduate students and provide them with basic training in ecosystem science.

农业生产力通常受到包括磷（P）在内的土壤养分的可用性的限制。土壤中的磷的可用性受到限制，因为大多数土壤P无法直接用于植物，并且自然输入不足以替代收获的P。因此，需要肥料或肥料的施用以维持土壤生育能力和产量，但是经济上可行的P储量正在下降，农业系统的P损失降低了水生生态系统。该项目评估覆盖作物，尤其是豆类是否可以为现金作物提供p生育能力，同时通过动员土壤P来减少P输入要求（转换为土壤矿物质和有机物成植物可用形式）。核心目的是确定不同种类的覆盖作物如何动员P。这样做，互补的方法？长期实验，温室研究和P预算计算中的现场测量？将使用。将采取不同形式的土壤P，动员P的过程，P从覆盖作物到现金作物的转移速率以及P动员作物的总体重要性相对于农场规模的其他P通量，该项目将有助于替代施肥策略的发展，从而降低土壤生育能力，同时降低成本成本的P输入。它将测试使用覆盖作物是否可以促进这一目标，并更好地了解不同植物物种生长的土壤中的P转化。由于该项目的结果应与农场从业人员直接相关，因此这项研究将与外展活动相结合，以广泛传播结果，包括公开可用数据，为涵盖农作物数据库做出贡献，并通过在学术界（现场日，非技术出版物）外举办的活动来转移知识。该项目还将涉及本科生，并为他们提供生态系统科学的基础培训。