Document Type

Thesis - Open Access

Award Date

2018

Degree Name

Master of Science (MS)

Department / School

Agronomy, Horticulture, and Plant Science

First Advisor

David E. Clay

Abstract

Sustainable land management involves the management of land, water, biodiversity and other resources that meet human requirements while maintaining ecosystem services. In the northern Great Plains (NGP), the combined impacts of landuse and climate variability have placed many soils at the tipping point of sustainability. The objectives of this study were to: 1) calculate land-use changes from 2006 to 2012 and from 2012 to 2014 in South Dakota and Nebraska; 2) assess if land use changes had impacted on soil sustainability; 3) calculate variation in total carbon budget and turnover due to seasonal climate variability, biomass quality and soil properties; and 4) determine effect of fire and on the CO2 emissions, soil temperature and soil moisture. For South Dakota and Nebraska, 43,200 and 38,400 points, respectively were visually classified from high resolution imagery in 2006, 2012, and 2014 into five different categories (cropland, grassland, Habitat, NonAg, and Water). From 2006 to 2014, 910,000 million hectares were converted from grassland to cropland in South Dakota and 360,000 hectares were converted from grassland to cropland in Nebraska. In South Dakota, approximately 92% of the land-use changes occurred on land suitable for crop production (Land Capability Class, LCC ≤4), whereas in Nebraska 80% of the land-use changes occurred on land considered suitable for cropland (LCC ≤4). In the second study, the impact of season on above ground decomposition kinetics were investigated. This work showed that the winter season exhibit the lowest rate of litter decomposition, followed by spring and summer. The results indicated that the plant biomass C: N ratio and temperature explained 52 and 45%, respectively of the measured changes in biomass decomposition. Sites producing biomass with a low C: N ratio had higher first order rate constants than sites with high C: N ratios. These findings indicate that the winter period cannot be ignored when assessing carbon turnover. In the third study, the impact of annual fire on CO2-C emissions was investigated. Total carbon lost, soil temperature and moisture contents were higher in fire than control treatment.

Library of Congress Subject Headings

Land use, Rural -- South Dakota.
Land use, Rural -- Nebraska.
Sustainability.
Soils -- Environmental aspects -- South Dakota.
Soils -- Environmental aspects -- Nebraska.
Climatic changes.

Description

Includes bibliographical references

Format

application/pdf

Number of Pages

103

Publisher

South Dakota State University

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Rights Statement

In Copyright