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Title:Perennial energy crops on riparian buffers affect nitrogen cycling microbial communities
Author(s):Kim, Hyemi
Advisor(s):Lee, DoKyoung
Contributor(s):Yannarell, Anthony; Voigt, Thomas
Department / Program:Crop Sciences
Discipline:Crop Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Perennial grass
Nitrogen cycle
Nitrogen fixation
Real-time PCR
Soil microbial community
Abstract:Production of perennial bioenergy crops on farmland that is suboptimal for food crops has been suggested for ecosystem services such as mitigating greenhouse gas emissions and reducing nutrient loss while producing sustainable bioenergy feedstocks. Even though we understand the relationship between N fertilization and energy crop biomass production, our understanding of the interaction between the soil N cycle and bioenergy crop production is limited. The objective of this study was to determine the effects of perennial energy crop management practices, including grass species (switchgrass, prairie cordgrass, Miscanthus x giganteus, and a grass mixture), harvest timing (at anthesis and after a killing frost), and N application rate (0, 56, and 112 kg N ha-1) on soil functional microbial communities involved in the N cycle on a wet marginal riparian buffer. We investigated the abundances of genes encoding the enzymes of N cycling functional groups involved in ammonia oxidation (amoA), nitrite ammonification (nrfA), denitrification (nirK, nirS, norB, and nosZ), and N fixation (nifH). The results indicated that N application significantly affected the abundance of four different functional enzyme groups. The abundance of bacterial amoA (AOB) increased as N fertilization increased, thereby increasing the proportion of AOB compared to archaeal amoA (AOA). The nitrite reductase genes, nrfA and nirS, were more abundant in the plots with 56 kg N ha-1 applied; however, the nirK nitrite reductase, the same functional gene as nirS, did not differ across N applications. Overall, AOA, nrfA, and norB were correlated with each other as were AOB, nirK, and nosZ. Our data implies that management practices of perennial grasses, especially N application, could have significant impacts on changes in soil microbial communities within the rhizosphere.
Issue Date:2018-04-20
Rights Information:Copyright 2018 Hyemi Kim
Date Available in IDEALS:2018-09-04
Date Deposited:2018-05

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