Date of Graduation

5-2013

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Environmental Dynamics (PhD)

Degree Level

Graduate

Department

Environmental Dynamics

Advisor/Mentor

Popp, Michael P.

Committee Member

Brye, Kristofor R.

Second Committee Member

Coffey, Kenneth P.

Third Committee Member

Nalley, Lawton L.

Fourth Committee Member

West, Charles P.

Keywords

Social sciences; Biological sciences; Health and environmental sciences; Cow-calf production; Greenhouse gas emissions; Net return repercussions

Abstract

Cow-calf producers in the Ozark Highlands region are under continuous pressure to improve economic efficiency. Additionally, estimating greenhouse gas (GHG) emissions from cow-calf and forage production processes may become increasingly important as policy makers seek to mitigate or reduce agriculture's role in climate change. As such, this analysis had three objectives. Objective 1: Provide a model that could be used by cow-calf producers, extension agents, and researchers to evaluate GHG and net return (NR) repercussions when modifying site characteristics, production methods, and inputs. Objective 2: Develop a user guide such that the methodology for estimating cow-calf GHG emissions and NR can be adapted to other regions and livestock / cropping enterprises based on different site characteristics, production methods, and inputs. Objective 3: Using the tool, estimate the profit-maximizing hay and pasture forage species composition, cow stocking rate, and seasonal calving distribution for three sizes of operations under four fertilization strategies.

A spreadsheet-based model was developed at the University of Arkansas as part of this dissertation and an M.Sc thesis. It lends itself for extension to the Ozark Highlands eco-region by helping producers analyze changes in GHG emissions and NR that result when production methods, inputs, and site characteristics are changed. Benchmark farm operations and default parameters were provided to represent three sizes of farm operations (Small, Medium, and Large). The reference manual, developed as part of this analysis, outlines the scientific principles and methodology utilized to estimate GHG emissions and NR.

In addition to the producer and extension use, the tool allows researchers to estimate profit-maximizing inputs or production methods for specific farm parameters and scenarios. Using the profit-maximizing function of the model the optimal forage species composition, calving distribution, and stocking rate were estimated for three operation sizes (Small, Medium, and Large) and four fertilization strategies (Lime, Low, Medium, and High). For the scenarios modeled, results revealed that a January-February calving season provided the greatest NR and that matching forage species composition with calving distribution was an important factor in determining operation profitability. Additionally, result from the optimization of calving season, forage species composition, and stocking rate suggested that GHG emissions from cow-calf production can be reduced.

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