Degree Type

Thesis

Date of Award

2014

Degree Name

Master of Science

Department

Agronomy

Major

Environmental Science

First Advisor

C. Lee Burras

Abstract

In 1862, Iowa State University was the first college to become a land-grant university. Today, their mission has expanded beyond the Iowa farmer to the global farmer and more broadly the agricultural world. As part of this global perspective, Iowa State University has chosen to be the first US university to evaluate itself in an environmental context through a carbon assessment of its soils. The carbon content of Iowa State's 6,392 hectares was evaluated to an 18 and 100 cm depth using two databases. The carbon flux of Iowa State University's land, given a change in management, was estimated using a soil carbon sequestration equation as well as `expert' assumptions. Lastly, through a case study at the McNay Memorial Research Farm in Chariton, Iowa, the accuracy of one of the major tenets of Soil Science, the soil map unit polygon, was evaluated. We found that Iowa State University currently holds approximately 1.5 billion kg of TC to a 100 cm depth according to WSS, and 1 billion kg of SOC according to ISPAID. Total carbon is indeterminable using ISPAID because SIC was not tabulated in that database. Soil organic carbon was quantified using both databases and is strongly correlated in the surface 18 cm, but divergent when the whole profile to a 100 cm depth is included. Maximum future carbon stocks were estimated after 30 years of perennial grass management, and ISU's land could conceivably increase their stocks by 35%. At the SMU level, we find that profiles within one SMU polygon differ, and not in a predictable manner. Total carbon and total nitrogen, however, did vary according to land management particularly in the surface soil layers. Here, again, we find the theme of predictability in the surface horizon of soils, but uncertainty when the entire soil profile is considered.

Copyright Owner

Catherine Rosson DeLong

Language

en

File Format

application/pdf

File Size

99 pages

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