Spring camelina N rate: balancing agronomics and environmental risk in United States Corn Belt |
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Authors: | Jane M F Johnson Russ W Gesch Nancy W Barbour |
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Institution: | USDA-Agricultural Research Service-North Central Soil Conservation Research Laboratory, Morris, MN, USA |
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Abstract: | Camelina (Camelina sativa (L.) Crantz) seed oil has desirable properties for producing advanced biofuels and as a healthy cooking oil. It has been grown for centuries, but basic recommendations for nitrogen (N) fertilizer requirements are still needed to support widespread industrial cultivation across North America. A replicated N-response plot-scale study was conducted on a northern Mollisol soil for two growing seasons to 1) determine seed and oil yield, seed oil content, and vegetative response; 2) determine indices of N use efficiency; and 3) measure post-harvest residual inorganic soil N as an index of environmental risk. Seed and oil yield response to N fertilization was described with a quadratic function, which predicted maximum seed yield (1450 kg ha?1) and oil yield (580 kg ha?1) at about 130 kg N ha?1. However, seed and oil yield did not differ significantly among N-rates above 34 kg N ha?1. Seed oil content averaged 400 g kg?1 among all N rates. Agronomic efficiency declined above 34 kg N ha?1, which coincided with an increase of post-harvest soil nitrate-N plus ammonium-N (residual N). Considering N use efficiency, simple cost analysis, and risk associated with residual N, a rate of 34 kg N ha?1 is recommended. |
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Keywords: | Agronomic efficiency soil nitrogen camelina nitrogen use efficiency alternative crops |
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