PIRE: Hydrologic Redistribution and Rhizosphere Biology of Resource Islands in Degraded Agroecosystems of the Sahel

该项目将使美国、塞内加尔和法国的研究人员和学生能够合作研究萨赫勒地区的原生灌木如何影响土壤湿度和土壤微生物组成，以及当这些灌木与粮食作物一起种植时，如何可能代表一种新的基于生物学的方法来提高半干旱农业生态系统的产量。萨赫勒脆弱的环境受到荒漠化和土壤退化的威胁，严重降低了农业生产力，并对当地社区产生了负面影响。在萨赫勒地区，木本灌木与行作物共存，每年春天都会被砍伐和焚烧。该研究小组之前对萨赫勒地区两种主要的灌木物种——senegalensis和Piliostigma reticulatum进行了研究，记录了它们从潮湿的地下土壤向干燥的表层土壤吸水的能力，并在根部周围生长出独特的微生物群落。该研究小组将研究灌木的水力举水是否能减少干旱时期附近作物的缺水压力，以及灌木的根区微生物群落是否能刺激邻近作物的生长，例如通过增强固氮作用。他们还将测试这些灌木在根区固碳的潜力，以及比粪肥、堆肥或种植其他树木更能改善土壤的潜力。该团队的基础水文和土壤微生物学研究应该为开发一套灌木作物系统提供所需的信息，这些系统可以减少干旱影响，并通过微生物增强来优化植物生长。这种农业系统可以恢复目前退化的景观，并在萨赫勒地区建立可持续的农业生态系统。这些成果可以使萨赫勒地区的所有国家受益，这些国家总共有近1500万公顷（6万平方英里）的半干旱土地，目前大部分以破坏性的农业方式耕种。PIRE的跨学科和国际研究团队汇集了分子微生物学、水文学、土壤物理学、植物生态学和农学方面的必要专业知识，以承担并完成这一重要的现实世界项目。该项目的教育影响包括加强致力于指导和培训国际学生骨干的科学家之间现有的长期伙伴关系。该项目将通过以下方式提供跨文化、语言建设和国际研究经验：1)为美国本科生提供非洲暑期研究实习机会；2)允许美国博士生在非洲进行论文研究；3)让美国学生公开宣传他们的国际经历——在当地学校，参加美国和塞内加尔学童之间的“笔友”项目，并通过国际教育合作项目网站上的学生博客；4)通过MicroTrop培训项目培训美国热带微生物生态学和水文学领域的早期职业科学家和博士；5)在农村贫困的背景下，让所有参与者面对萨赫勒地区的生态挑战。中央州立大学是一所历史悠久的黑人大学，该校师生的积极参与将有助于该项目实现其目标，即在科学领域加强招募女性和代表性不足的少数民族。方案活动的一个重要成果将是参与者分享经验，这将不可避免地产生终身的相互作用和国际联系。该项目将加强美国机构的能力，使其研究、科学网络、学生培训和课程国际化。该项目将把俄亥俄州立大学和中央州立大学内部和之间的许多单位（如国际事务、非洲研究办公室、国际农业项目和语言系）的互补优势联系起来，并加强它们之间的互补优势，以便为该项目参与者制定一个具有凝聚力的出发前文化指导、语言培训和后勤支助方案。该项目的综合教育和研究工作将成为美国大学在自然资源和农村贫困背景下在发展中国家进行最先进环境研究的典范。该方案的项目资金还将与其他资金一起用于在非洲进一步推广和应用成果。例如，PI和他的机构将在塞内加尔加斯顿·伯杰大学（UGB）开展一个由美国国际开发署（USAID）资助的项目，开发一个农业生态学学位课程，包括电子教育和远程学习合作。该小组及其研究和教育工作将丰富美国国际开发署教育项目的内容，并补充美国国际开发署关于非洲粮食安全的倡议。院校包括：俄亥俄州立大学哥伦布分校和伍斯特分校；加州大学默塞德分校；美国农业部农业研究局（ARS）在俄勒冈州立大学；和中央州立大学（OH）。外国合作伙伴包括：捷斯大学（塞内加尔）；农业研究所（以色列农业研究所）（塞内加尔）；人力资源发展研究所（法国）；IRD热带微生物生态学实验室（塞内加尔）；和法国微生物研究所（法国）。该项目由美国国家科学基金会国际科学与工程办公室和环境生物学部共同资助。

This PIRE project will enable a partnership of U.S., Senegalese, and French researchers and students to examine how native shrubs of the Sahel region influence soil moisture and soil microbial composition and how such shrubs, when planted with food crops, might represent a new biologically-based way to improve production in semi-arid agroecosystems. The vulnerable environment of the Sahel is threatened by desertification and soil degradation, seriously reducing agricultural productivity and negatively impacting local communities. In the Sahel, woody shrubs co-exist with row crops and are cut back and burned every spring. The team's previous research on the two dominant shrub species of the Sahel, Guiera senegalensis and Piliostigma reticulatum, documented their ability to draw water from wet sub-surface soil to dry surface soil and to grow unique microbial communities around their roots. The PIRE team will examine whether the hydraulic lifting of water by shrubs can reduce water stress to nearby crops during dry periods and whether the shrubs' root-zone microbial communities stimulate adjacent crop growth, for example by enhancing nitrogen fixation. They will also test the potential of these shrubs to sequester carbon in their roots zones and to improve soils more than manure, composts, or planting other trees. This team's fundamental hydrologic and soil microbiology research should provide the information needed to develop of a set of shrub-crop systems that reduces drought effects and optimizes plant growth via microbial enhancement. Such agricultural systems could restore currently degraded landscapes and lead to sustainable agroecosystems in the Sahel. These outcomes could benefit all countries in the Sahel which together have almost 15 million hectares (60,000 square miles) of semi-arid land that are largely now farmed with destructive agricultural practices. The PIRE interdisciplinary and international research team brings together the requisite expertise in molecular microbiology, hydrology, soil physics, plant ecology and agronomy to undertake and complete this important real-world project. The educational impacts of this PIRE project include strengthening the existing long-term partnerships among scientists committed to mentoring and training an international cadre of students. This project will deliver a program of transformative cross-cultural, language building, and international research experiences by: 1) providing U.S. undergraduates summer research internships in Africa; 2) enabling U.S. Ph.D. students to conduct their dissertation research in Africa; 3) engaging U.S. students in public outreach about their international experiences -- at local schools, in a "pen pal" program between U.S. and Senegalese schoolchildren, and via a student blog on the PIRE website; 4) training U.S. early career scientists and Ph.D.s in tropical microbial ecology and hydrology through the MicroTrop training program and; 5) exposing all participants to the ecological challenges of the Sahel within a rural poverty context. The active participation of faculty and students from Central State University, a Historically Black University, will help this PIRE project meet its goal to enhance the recruitment of females and underrepresented minorities in science. An important outcome of the PIRE activities will be the participants' shared experiences that will inevitably produce lifelong interactions and international linkages. The project will strengthen the capacity of the U.S. institutions to internationalize their research, scientific networks, student training, and curricula. The PIRE project will link and reinforce the complementary strengths of many units (e.g., international affairs, African studies offices, international agriculture programs, and language departments) both within and between Ohio State and Central State Universities to develop a cohesive program for pre-departure cultural orientation, language training, and logistical support for PIRE participants. The comprehensive educational and research effort of this PIRE project will be a model for U.S. universities to conduct state-of-the art environmental research in a developing country within a natural resource and rural poverty context. The PIRE project funds will also be leveraged with other funding for additional outreach and application of results in Africa. For example, the PI and his institution will conduct a US Agency for International Development (USAID)-funded project developing an Agroecology Degree Program at the University of Gaston Berger (UGB) in Senegal, including E-education and distance learning collaborations. The PIRE team and its research and education efforts will enrich the content of the USAID education project and complement USAID's initiative on Food Security for Africa.U.S. institutions include: Ohio State University at Columbus and at Wooster; University of California at Merced; USDA-Agricultural Research Service (ARS) at Oregon State University; and Central State University (OH). Foreign partners include: University of Thies (Senegal); Institut Sénégalais de Recherches Agricoles (ISRA) (Senegal); Institut de Recherche pour le Développement (IRD) (France); IRD Laboratory of Tropical Microbial Ecology (LTME) (Senegal); and IRD Laboratoire Commun de Microbiologie (France).This project is cofunded by NSF's Office of International Science and Engineering and the Division of Environmental Biology.