Restoration of soil biodiversity and ecosystem function following agricultural legacies

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

Intensive agricultural production is necessary to feed a growing world population. Unfortunately, modern agriculture can degrade soil ecosystems in ways that compromise the other services we depend on soils to provide for us. Millions of acres of farmland have been retired from production in the Midwestern US in the last few decades, and this land provides an opportunity to restore soil services on a large scale. However, the legacy of agriculture may prevent the successful reestablishment of healthy soil ecosystems, especially when native tree species rely on specialized microbial associations to thrive. This project aims to fill gaps in our knowledge of how soil ecosystems recover, or not, when lands are retired form agriculture, or when trees are planted directly into agricultural systems (agroforestry). It will also develop new methods for enhancing the success of tree planting into formerly agricultural land. This project is a collaboration between researchers at the University of Wisconsin-Madison and the Savanna Institute, a non-profit dedicated to improving and promoting agroforestry practices in the Midwestern US. Societies depend on landscapes that serve multiple purposes, including food production and ecosystem services like carbon sequestration. However, long term studies find that despite regenerative practices, soil carbon is not effectively sequestered in annual row crop settings. Moreover, high input agriculture leaves soil legacies that can inhibit the establishment of plant communities and soil functions like carbon sequestration. This may be especially likely when incorporating trees reliant on unique plant-microbial interactions. This project will investigate the development of soil ecosystems after agricultural abandonment or the establishment of agroforestry practices, and test how coupled soil carbon and nitrogen cycles respond to variation in soil community states induced by different times since agricultural abandonment and restoration practices. Finally, it will develop restoration strategies that promote soil community structure and function recovery through alteration of tree nursery conditions. This project seeks to transform our understanding of how soil microbial communities and food webs drive carbon and nitrogen cycling by taking advantage of the disruptions caused by agricultural legacies and recovery following land restoration or agroforestry. This project will directly inform conservation practice by setting quantifiable targets for soil biodiversity and ecosystem function in restoration or agroforestry settings and by piloting new tree propagation methods to enhance beneficial microbial associations. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.