Dissertation
Sustainability of No-Till, Organic, and Mixed Crop-Livestock Systems on the Palouse
Washington State University
Doctor of Philosophy (PhD), Washington State University
2022
DOI:
https://doi.org/10.7273/000005157
Abstract
Modern agriculture in the United States is highly specialized, with a large degree of separation between crop and livestock systems and a heavy reliance on external inputs, such as synthetic fertilizers and pesticides. As discussed in Chapter 1 (Introduction), while these practices have increased crop yields, they have also contributed to greenhouse gas emissions, soil degradation, and natural resource depletion. Alternative systems, which include organic, no-till, and mixed crop-livestock systems, have been shown to have the potential to increase soil health and profitability. However, to assess the long-term sustainability of these alternative systems, it is necessary to integrate soil health measurements with ecological resilience theory, and to assign a monetary value to the ecosystem services provided by these agroecosystems. Major soil health concerns that threaten sustainability of cropping systems worldwide and in the Palouse region of the inland Pacific Northwest include erosion, soil organic matter loss, acidification, nutrient depletion, and declining soil biological health. In Chapter 2, we use historical trends from the Palouse region to demonstrate how ecological resilience theory can be used to compare the efficacy of different agricultural practices with regards to soil erosion, soil organic matter loss, and acidification. In Chapter 3, we then apply ecological resilience theory to evaluate the ecological and economic sustainability of four different cropping systems on the Palouse: a no-till system having a 3-year spring pea-winter wheat-spring wheat rotation with conventional herbicide and fertilizer use (NT); a mixed crop/livestock system having a 3-year pea-winter wheat-spring wheat rotation with livestock integration and reduced herbicide and fertilizer use (MIX); an organic system that integrates sheep and intercropping into an adaptive rotation with three years of alfalfa/grass hay and six years of grain cereals and legumes (ORGcrop); and an organic system that integrates sheep into an eight-year rotation with six years of alfalfa/grass hay and two years of grain cereals and legumes (ORGhay). Lastly, in Chapter 4, we estimate the monetary value of four ecosystem services associated with the major soil degradation processes of topsoil retention, pH stabilization, climate change mitigation, and N cycling, and a fifth ecosystem service of food/feed production.
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Details
- Title
- Sustainability of No-Till, Organic, and Mixed Crop-Livestock Systems on the Palouse
- Creators
- Alexandra G Davis
- Contributors
- John P Reganold (Advisor)David R Huggins (Advisor)Lynne A Carpenter-Boggs (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Crop and Soil Sciences, Department of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 187
- Identifiers
- 99901019236301842
- Language
- English
- Resource Type
- Dissertation