Dissertation Research: Impact of monsoon rains on soil microbial communities in an arid grassland

论文研究：季风降雨对干旱草原土壤微生物群落的影响

• 批准号: 1210525
• 负责人: Egbert Schwartz
• 金额: $ 1.48万
• 依托单位: Northern Arizona University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2014-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1210525&HistoricalAwards=false
• 关键词: Dissertation; Research; Impact; monsoon; rains

Microbial communities are important regulators of organic matter decomposition and nutrient cycling in soils. In arid regions such as Arizona and New Mexico about half of the annual total precipitation occurs during the summer monsoon season when plant growth is rapid and nutrient requirements are high. This study will investigate how monsoon rains and plant growth impact the soil microbial community in these arid regions. Three separate experiments will be conducted to assess how soil microbial biota is influenced by 1) timing of the water addition, 2) degree of moisture, and 3) plant growth. Instantaneous changes in bacterial community composition are expected with watering, while a delayed response is predicted for the fungal community. In plots where moisture is withheld, changes in the structure of both bacterial and fungal communities are predicted to be less pronounced. Finally, plant removal is expected to prevent establishment of many fungal populations and some bacterial strains. Arid land ecosystems are undergoing change with grasslands being replaced by desert shrubs. Understanding how the soil microbial community responds to seasonal rains is critical to understanding organic matter decomposition and nutrient cycling in desert ecosystems, which in turn, is important for understanding vegetation dynamics. A partnership with a local Native American-serving K-8 school will allow the researchers to bring their research into the classroom, with lessons centering on the three sisters planting scheme -- a traditional Native American companion planting of corn, beans, and squash.

微生物群落是土壤有机质分解和养分循环的重要调节者。在亚利桑那州和新墨西哥州等干旱地区，大约一半的年总降雨量发生在夏季季风季，此时植物生长迅速，对养分的需求很高。这项研究将调查季风雨和植物生长如何影响这些干旱地区的土壤微生物群落。将进行三个不同的实验，以评估土壤微生物区系如何受到1)加水时间、2)水分程度和3)植物生长的影响。随着浇水，细菌群落组成的瞬时变化是预期的，而真菌群落的反应则是延迟的。在保持水分的地块中，细菌和真菌群落结构的变化预计不会那么明显。最后，移除植物有望防止建立许多真菌种群和一些细菌菌株。干旱土地生态系统正在发生变化，草原被沙漠灌木取代。了解土壤微生物群落对季节性降雨的响应对于了解沙漠生态系统中有机质的分解和养分循环至关重要，而这反过来又对了解植被动态非常重要。与当地一所提供美洲原住民服务的K-8学校的合作将使研究人员能够将他们的研究带入课堂，课程重点是三姐妹种植计划--一种传统的美国原住民种植玉米、豆类和南瓜的同伴种植计划。