Browsing by Author "Ott, Matthew"

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    Four Cover Crops Dual-Cropped With Soybean: Agronomics, Income, And Nutrient Uptake Across Minnesota
    (2018-02) Ott, Matthew
    Many agricultural watersheds in Minnesota have toxic levels of phosphorus and nitrogen, much of which originates in agricultural fields that are fallowed from October through May. Autumn-sown winter cover crops can be used to retain these nutrients. Soil NO3-N levels and and quantities of N sequestered by winter rye (Secale cereale), Tillage Radish® (Raphanus sativus), and the oilseed crops, winter camelina (Camelina sativa), and pennycress (Thlaspi arvense) were evaluated in a relayed cover crop/soybean production system at three sites spanning the north-south climatic gradient of Minnesota. Tillage Radish® sequestered the most N in autumn, but winter-killed and had high soil NO3-N levels in spring. Winter rye was terminated chemically by early May at each site, whereas the oilseed crops were allowed to grow into June to full maturity and their seeds were harvested. In autumn through early May, winter camelina and pennycress sequestered about 25% less N than winter rye. However, they often sequestered ≥ 2.5 times more N than winter rye when compared at maximum seasonal biomass (up to 130 kg N ha-1), with some of this N coming from spring fertilizer application. The relative amount of applied N captured by oilseeds, defined here as applied N sequestration efficiency, was 95% and 68% for winter camelina and pennycress, respectively. Winter camelina yields ranged from 600 to 1100 kg ha-1, while pennycress yields ranged from 900 kg ha-1 to 1550 kg ha-1. When combined with yields of relay-cropped soybean, net income for relay-crop systems was generally equivalent to mono-cropped soybean.
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    Improvement of Oilseed Cover Crops Camelina (Camelina sativa L. Crantz) and Pennycress (Thlaspi arvense L.) Genetics and Associated Agronomics for the Upper Midwestern Landscape
    (2022-12) Ott, Matthew
    Camelina (Camelina sativa L. Crantz) and pennycress (Thlaspi arvense L.) are being developed as a winter annual oilseed cover crops for the Upper Midwest to aid in overcoming global food security and ecological challenges. Chapter one of this dissertation introduces readers to these winter annual species and reviews relevant published literature. Early maturity is a crucial trait for these cover crops to improve their fit into crop rotations with summer annual crops. A camelina line with early maturity was characterized on an agronomic and genetic level in chapter two. This research led to an increased genetic understanding of flowering time in general for camelina as well as an optimized KASP marker for genotyping growth habit, also included in chapter two. Unlike camelina which has a long history of human cultivation, pennycress has only recently been undergoing domestication. One of the key domestication traits needed in pennycress is reduced seed dormancy, and a line of pennycress with this trait was characterized in field and controlled experiments in chapter three. To improve the economic and ecological potential of pennycress, an agronomic optimum nitrogen rate (AONR) and economic optimum nitrogen rate (EONR) are needed. An AONR and EONR for pennycress were also identified in field experiments in Minnesota described in chapter four.