The effects of biochar amendments on native and invasive prairie plants

Melinda M Adams, Purdue University

Abstract

Prior to European settlement, North American prairie covered more than 240 million acres across central North America. By the start of the twentieth century, most of the prairie was lost as farmers rapidly converted prairie to cropland. Consequently, as much as 99% of original tallgrass prairie has been depleted. Prairie soils were historically deep and rich in black carbon, which had accumulated from thousands of years of biomass production, decomposition and storage as labile and stable soil organic matter. The addition of carbon to soil systems has been suggested as a means to reduce or eliminate the establishment of exotic species and encourage the growth of native prairie. Biochar, a carbon rich product formed by the incomplete combustion of biomass, has been shown to improve soil quality and increase plant growth. Although considerable research has been conducted on its use for crop production in tropical soils, biochar has yet to be studied in tallgrass prairie ecosystems, even though fire has historically been an important ecological aspect of the prairie system. The goal of our research was to assess the response of a native perennial grass, Andropogon gerardii (big bluestem), and a non-native herbaceous perennial, Lespedeza cuneata (sericea) to biochar and nitrogen amendments both individually and in competition. In our first experiment, we found that biochar generally increased the growth of big bluestem and decreased the growth of sericea at higher rates of biochar. Biochar had a greater effect on plant growth in a sand soil than in a silt soil. This suggests that the effects of biochar on prairie plant growth may be highly dependent on soil characteristics and plant species. Our second experiment supported the hypothesis that big bluestem but not sericea growth was increased when biochar was added to soil. However, biochar did not shift competitive outcomes between sericea and big bluestem; sericea out-competed with big bluestem. Our research suggests that biochar has the potential to increase the growth of big bluestem and may be a useful tool for prairie restoration.

Degree

M.S.

Advisors

Gibson, Purdue University.

Subject Area

Agronomy|Plant sciences|Range management

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