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Document Type

Thesis - University Access Only

Award Date

2015

Degree Name

Master of Science (MS)

Department

Plant Science

First Advisor

Sandeep Kumar

Abstract

With the advent of second generation biofuels, there has been an increased interest in using corn (Zea mays L.) stover as a cellulosic feedstock. Excessive removal of corn stover contributes to the degradation of important soil quality indicators. Addition of cover crops may help to mitigate these negative effects. This study assesses the impacts of corn residue removal and cover crops on soil organic carbon, soil organic matter, particulate organic matter, soil aggregation and greenhouse gas (GHG) fluxes. Three residue removal treatments (low residue removal, LRR; medium residue removal, MRR; and high residue removal, HRR), each with and without a cover crop treatment, were evaluated. Residue removal significantly impacted selected soil quality indicators and an effect from cover crop treatments was noticed seven years after implementation. The LRR treatment resulted in 17% more soil organic carbon (SOC) averaged over four years, increased aggregate stability, and on average 28% more microbial activity immediately after residue treatments were applied. The LRR treatment also increased soil organic matter (SOM) and particulate organic matter (POM) concentrations as compared to HRR treatments. Cover crops significantly impacted fine fraction of POM (fPOM) concentrations directly after the residue removal treatments were applied in 2012. Soil surface CO2 fluxes peaked with temperature increases, while N2O fluxes increased with soil moisture increases. Methane fluxes responded to both increases in temperature and moisture. No identifiable trend was found for the impact that residue and cover crop management have on GHG fluxes. Additional research needs to be done monitoring GHG fluxes from this management system to better understand the impacts of residue and cover crop management.

Library of Congress Subject Headings

Soils -- Quality -- South Dakota Crop residues Cover crops Corn Soybean

Description

Includes bibliographical references

Format

application/pdf

Number of Pages

173

Publisher

South Dakota State University

Rights

In Copyright - Educational Use Permitted
http://rightsstatements.org/vocab/InC-EDU/1.0/

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