Interactions Among Plants, Soil, and Microorganisms and Their Roles in Stabilizing the Nebraska Sand HillsEPA Grant Number: F5F11522
Title: Interactions Among Plants, Soil, and Microorganisms and Their Roles in Stabilizing the Nebraska Sand Hills
Investigators: Payne, Kimberly R.
Institution: University of Nebraska at Lincoln
EPA Project Officer: Carleton, James N
Project Period: August 1, 2005 through August 1, 2007
Project Amount: $74,344
RFA: STAR Graduate Fellowships (2005) RFA Text | Recipients Lists
Research Category: Academic Fellowships
The Nebraska Sand Hills are currently stabilized by native prairie grasses. Approximately 800 to 1000 years ago this region was subjected to a period of intense drought. The vegetation was lost and sand dunes were actively moving. There is concern that future climate change could lead to prolonged drought in this region. If the vegetation is lost again, the cattle industry of Nebraska could suffer great losses and the recharge zone of the High Plains Aquifer could be adversely affected. In order to understand the factors that stabilize the sand dunes, one must understand how plants, soil, and microorganisms interact to aggregate and stabilize the soil. Exploring these complex relationships will provide key insights into how this ecosystem functions, and thus, how to it manage to support future productivity and sustainability
Assess the impact of vegetation disturbance on the belowground ecosystem and how its deterioration affects geomorphic and ecological stability.
Four treatments have been prescribed to eight 120 m diameter plots at the University of Nebraska’s Barta Brothers’ Ranch as part of the Sand Hills Biocomplexity Project. The treatments include control, grazed control, and short and long-term disturbance. In the disturbance plots, an herbicide will be used to kill the vegetation. The vegetation in the short-term disturbance plots will be kept dead for one year and allowed to returned during the second growing season; the long-term disturbance plots’ vegetation will be killed for the duration of the experiment. The short-term disturbance plots will test the resilience of the system. The long-term disturbance will test the ability of the system to resist destabilization. Six sub-plots have been established in each plot. Three sub-plots are located on upland positions and three are located in lowland positions; varying the topographic location of sub-plots will allow for the effect of topography to be monitored. Belowground dynamics will be monitored using a variety of analyses. Fatty acid methyl ester analyses will determine which microbes dominate the soil community and how the community changes after vegetation loss. Wet aggregate stability, soil respiration, and nitrogen and carbon pool dynamics will be monitored. Root biomass and length, aboveground vegetative cover, and soil erosion will also be measured.
It is known that soil microorganisms, especially fungal hyphae, aid aggregation in sandy soils and increase soil stability. However, once the vegetation is dead, the soil microorganisms will lose an important carbon source; a resultant decrease in soil stability will become apparent. The short-term disturbance plots should remain stable and recover any lost functions during the second growing season. However, in the long-term disturbance plots the soil’s surface should destabilize due to the decline of root biomass and microorganisms, specifically mycorrhizal fungi, during the second growing season.