Heidi Peterson

Sustainable Phosphorus Management and the Need for a Long-Term Perspective: The Legacy Hypothesis

Perspective: The Legacy Hypothesis Philip M. Haygarth,*,† Helen P. Jarvie,‡ Steve M. Powers, Andrew N. Sharpley, James J. Elser, Jianbo Shen, Heidi M. Peterson, Neng-Iong Chan, Nicholas J. K. Howden, Tim Burt, Fred Worrall, Fusuo Zhang, and Xuejun Liu †Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, U.K. ‡Centre for Ecology and Hydrology, OX10 8BB, Wallingford, Oxfordshire, U.K. University of Notre Dame, Environmental Change Initiative, South Bend, Indiana 46617, United States Division of Agriculture, University of Arkansas, Fayetteville, Arkansas 72701, United States School of Life Sciences, Arizona State University, Tempe, Arizona 85287, United States Center for Resources, Environment and Food Security, China Agricultural University, Key Laboratory of Plant-Soil Interactions, Ministry of Education, Beijing 100193, P. R. China Minnesota Department of Agriculture, Pesticides and Fertilizer Management Division, Saint Paul, Minnesota 55155, United States University of Bristol, Queen’s School of Engineering, BS8 1TH, Bristol, U.K. Durham University, Department of Geography, DH1 3LE, Durham, U.K. Durham University, Department of Earth Sciences, DH1 3LE, Durham, U.K.

Water Resources Sustainability Indicator: Application of the Watershed Characteristics Approach

The quantification of the renewable flux (i.e. sustainable limit) of the hydrologic system is the prerequisite for transitioning from unsustainable to sustainable water resources management. The application of the Watershed Characteristics Approach to estimate the renewable flux of the hydrologic system was demonstrated using Minnesota’s (USA) Twin Cities Metropolitan Area (TCMA). The methodology quantified the relationships between landscape properties and water balance characteristics, resulting in the development of functioning hierarchical hydrogeological units with corresponding recharge rates. This renewable flux is a key quantitative characteristic for the assessment of a sustainability indicator. The key indicator of sustainable water use is the ratio of the renewable capacity of the hydrologic system to the water use by humans and the environment. By incorporating water use estimates for the TCMA relative to the calculated recharge rates, sustainability indicators for groundwater and total flux were calculated for the metropolitan area. As far back as the 1890s, declines in TCMA groundwater levels have been observed, which correspond to the unsustainable groundwater extraction estimates identified in the results of this study. The non-stationary characteristics of urban watersheds influenced by ongoing land use/land cover changes as illustrated in this paper, emphasizes the need for conservative hydrologic planning to achieve sustainable water management. This approach can also be applied to other metropolitan areas as a hydrologic tool for decision-makers to design sustainable water policy and prevent the over-extraction of the water flowing through the hydrologic system.

Agricultural Phosphorus Balance Calculator: A tool for watershed planning

Best management practices implemented to minimize agricultural phosphorus (P) water quality impacts typically focus on retaining nutrients rather than improving P use efficiencies. Although it is now well understood that long-term reduction of P loadings requires achieving a watershed level P balance, this concept is generally not incorporated in watershed planning. This paper develops a detailed P balance for the Albert Lea Lake watershed, a high production agricultural watershed in south-central Minnesota, United States. Watershed specific crop and livestock management data were acquired through personal interviews, surveys, feedlot permits, and site visits. These data, together with published resources, were used to develop an open-source Agricultural P Balance Calculator to compute P use efficiencies of livestock operations, crop production, and collectively, the watersheds agricultural system. In 2010, the P use efficiency was 1.7, indicating that more P was being exported from the watershed as agricultural products than imported, implying that crops were “mining” P from watershed soils. The Agricultural P Balance Calculator enables users to identify production areas where P use efficiency strategies could be incorporated into conservation implementation planning, thereby enhancing prospects for meeting P reduction goals.