Date of Award
Master of Science (MS)
Geography & Geographic Information Science
Background: Crop diversity is a part of the overall biodiversity of the world and includes the diversity of crops produced to feed humankind and those associated with domesticated animal grazing or feeding. A decline in diversity can reduce productivity of the farmlands by degrading soil health and introduction of plant diseases. So, it is crucial to study crop diversity and find the causes behind it to impede catastrophic consequences.Objectives: The purpose of this study was to explore changes in crop diversity and the factors affecting the changes in diversity by county and survey townships in the Red River of the North Valley (RRV), from 2007 to 2017. Methods: I used the U.S. Census of Agriculture and Cropland Data Layer (CDL) from the USDA National Agricultural Statistics Service (NASS) to calculate and analyze crop diversity of the RRV. I calculated the Shannon Diversity and Shannon Equitability indexes for 2007, 2012, and 2017. I obtained the economic and political data from USDA Farm Service Agency’s (FSA) Conservation Reserve Program (CRP) and NASS website. I downloaded the average annual temperature and precipitation data from the North Dakota Agricultural Weather Network (NDAWN) website. I collected the STATSGO soil data from the DATA.GOV website. I mapped the data using ArcGIS Pro. I generated maps for Shannon Diversity, Equitability, and the changes in index values between 2007 and 2017 and hotspots of diversity by townships for these years. I also produced maps showing commodity prices, average value of rented land, average rental rate, acres of land under CRP contract, average rent payment of CRP, average annual temperature, and precipitation, soil texture, hydrologic groups and organic matter in the RRV. Then, I developed a statistical model to explain the effects of different variables on crop diversity. Results: I found that the overall crop diversity in the RRV decreased over the years. At the county level, diversity and equitability are reduced along the Red River in the southern and eastern parts of the RRV. I observed a similar pattern at the township level. Additionally, I found hotspots of diversity change along the Red River in the northern part of North Dakota and coldspots in the eastern part of Minnesota in the RRV. Commodity prices and land value increased in the RRV but acres of land under CRP decreased over the years. The statistical analyses show significant positive association between diversity and acres of land under CRP, precipitation, commodity prices and latitude and significant negative association between diversity and soil organic matter and longitude with a R^2 value of 0.678. I also found “Year” to be a significant variable when used as an interaction term with location (latitude and longitude) of counties. Conclusion: A decrease in diversity and equitability is a matter of concern because it might lead to future economic implications of increased monocropping and create imbalances in environmental sustainability. This study highlights the importance of crop diversity by showing the rapid changes occurred in the RRV and investigating the factors associated with it.
Ara, Zinat, "Changes In Crop Diversity And Associated Drivers In The Red River Of The North Valley" (2023). Theses and Dissertations. 5226.
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