Agroecology in the United States: Pathways Toward Agroecosystem Redesign and Agri-Food System Transformation
In Chapter 1, I report the results from a field experiment conducted in Maryland and New York that compared the yield and quality trade-offs among four cultivars per winter cereal species (barley, cereal rye, and triticale) grown as forage and harvested at eight crop growth stages. Although barley cultivars maintained higher quality than cereal rye and triticale, yield was substantially lower. Cereal rye exhibited a desirable balance between yield and quality early in the season, whereas triticale provided the benefit of a slightly longer “harvest window” to obtain high-quality forage later in the season. In Chapter 2, I assessed the effect of winter cereal cover crop cultivar selection among three species and cover crop termination-soybean planting date on cover crop growth stage and biomass, weed biomass, soybean density and yield, and cover crop reseeding in organically managed no-till planted soybean production. Differences among species indicated that triticale performed better than barley and as well as cereal rye in terms of biomass production, weed suppression, and soybean yield, but the effect of cultivar was inconsistent across response variables and sites. In Chapter 3, I analyzed a national survey of organic fruit and vegetable farmers, which showed that fewer agroecological practices were used and a greater degree of “conventionalization” was observed on large farms. Intercropping, insectary plantings, and border plantings were at least 1.4-times more likely to be used on small (0.4–39 cropland ha) than large (≥405 cropland ha) farms, whereas reduced tillage was less likely and riparian buffers were more likely on small than medium (40–404 cropland ha) farms. In Chapter 4, I used a mixed-methods analysis of national survey results and findings from interviews with farmers in California and New York to assess the labor-intensity of agroecological practices. I showed that farmers who did not use agroecological practices perceived a greater labor requirement than farmers who had experience using a given practice; labor shortages were more problematic on medium and large farms; and the main strategy on large farms for managing labor-related challenges was to increase mechanization, despite already being the most mechanized farm type across sizes.
agroecology; cover cropping; farm size; forage quality; labor; organic agriculture
Ryan, Matthew R.
Kerr, Rachel Bezner; Power, Alison G.
Soil and Crop Sciences
Ph. D., Soil and Crop Sciences
Doctor of Philosophy
Attribution-NonCommercial-NoDerivatives 4.0 International
dissertation or thesis
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