Document Type

Thesis - Open Access

Award Date

2016

Degree Name

Master of Science (MS)

Department

Agronomy, Horticulture, and Plant Science

First Advisor

Sandeep Kumar

Keywords

cover crops, soil, soil health

Abstract

Grasslands have been rapidly converted to croplands over the last decade in the northern Great Plains. This conversion can reduce soil health and increase the region’s ability to pollute the Missouri and Mississippi rivers. Therefore, the need for integrated crop livestock (ICL) practices that can protect the region’s native prairies are strongly encouraged. Introducing livestock into arable cropping systems can improve nutrient cycling, soil health, and provide economic benefits. However, the detailed information about the impacts of ICL system on soil health is still lacking in the Northern Great Plains region. Therefore, the present study was conducted under a corn (Zea mays L.)- soybean (Glycine max L.)-rye (Secale cereale L.) rotation with no-till system at the Southeast Research Farm near Beresford, South Dakota to assess the effects of ICL systems on selected soil health parameters. Cover crops blends (Brassica/Legume-based blend, Grass-based blend, Equal blend) were planted after the rye (Secale cereale L.) crop, and grazing treatments (with and without) were applied after the cover crops establishment. Cover crops were grazed from November 2 through November 12, 2015. Concerns regarding the role of hoof traffic from livestock adversely affecting the nearsurface soil conditions, soil health, and hydrological properties under no-till systems will be discussed. Data showed that the use of diverse cover crop mixtures provided increased biomass on the surface that can alleviate the compaction impact under these integrated crop-livestock systems. Surface (0-5 cm depth) bulk density was not significantly impacted by grazing. Some soil physical and hydrological properties were significantly affected due to the high moisture content of the soil during the grazing period. Soil organic carbon at 0-5 and 5-15 cm depths was also unaffected by grazing, except that at corn-phase, it was significantly lower under grazing treatment compared to that of ungrazed treatment. Carbon fraction data was studied to find the impact of shortterm grazing on the microbial biomass, labile and stable carbon fractions from 0-5 cm and 5-10 cm depths. Grazing had no effect on beta-glucosidase enzyme activity or microbial biomass carbon. However, legume and grass blend cover crops increased the beta-glucosidase enzyme activity compared to that of control treatment. Results from this study conclude that short-term (one-year) grazing did not negatively impact the soil surface physical, hydrological, and biological properties in southeastern South Dakota

Library of Congress Subject Headings

Grazing -- Environmental aspects -- South Dakota.

Soil ecology -- South Dakota.

Cover crops -- South Dakota.

Integrated agricultural systems.

Sustainable agriculture.

Soil conservation.

Description

Includes bibliographical references (pages 47-48)

Format

application/pdf

Number of Pages

57

Publisher

South Dakota State University

Rights

Copyright © 2016 Colin Tobin

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