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.

农业生产力常常受到土壤养分供应的限制，包括磷 (P)。土壤中磷的利用率是有限的，因为大多数土壤磷不能直接被植物利用，并且自然投入不足以替代收获时去除的磷。因此，需要施用化肥或粪肥来维持土壤肥力和产量，但经济上可行的磷储量正在下降，农业系统的磷损失使水生生态系统退化。该项目评估覆盖作物，特别是豆类是否可以为经济作物提供磷肥力，同时通过动员土壤磷（将与土壤矿物质和有机质结合的磷转化为植物可利用的形式）来减少磷输入需求。中心目标是确定不同种类的覆盖作物如何调动磷。为此，需要采取补充方法吗？长期实验、温室研究和磷预算计算中的现场测量 ?将被使用。将针对不同形式的土壤磷、磷动员过程、磷从覆盖作物到经济作物的转移率以及覆盖作物磷动员相对于农场规模其他磷通量的总体重要性采取措施。该项目将有助于开发替代施肥策略，以保持土壤肥力，同时减少昂贵的磷投入。它将测试使用覆盖作物是否有助于实现这一目标，并更好地了解不同植物物种生长的土壤中的磷转化。由于该项目的结果应与农场从业者直接相关，因此该研究将与外展活动相结合，以广泛传播结果，包括公开数据、为覆盖作物数据库做出贡献以及通过在学术界之外举行的活动转移知识。现场日、非技术出版物）。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。