Nitrogen and sulfur application effects on camelina seed yield, fatty acid composition, and nutrient removal

Effective management of nitrogen (N) and sulfur (S) in camelina [Camelina sativa (L.) Crantz] production is important to ensure optimum seed yield and oil composition. The objectives of this study were to determine camelina seed yield and oil concentration and to estimate nutrient removal and N use efficiency (NUE) as influenced by N and S application. Field experiments were conducted to evaluate the effects of S rates (0 and 20 kg·ha−1) and N fertilizer rates (0, 22, 45, and 90 kg·ha−1) on camelina productivity and fatty acid composition over two growing seasons (2014 and 2015). Results showed S application had no effect on seed yield and oil concentration. Averaged across N rates, protein concentration increased with S application compared with the control. Seed yield showed quadratic response to N fertilizer application with maximum yield occurring at 54 kg N·ha−1; however, economic optimum N rate ranged from 18 to 43 kg N·ha−1. Nutrient removal, protein concentration, protein and oil yield, and estimated biodiesel were maximum at 45 kg N·ha−1. The maximum amounts of N, phosphorus, potassium, and S removed were 49, 8, 10, and 7 kg·ha−1, respectively. NUE and N agronomic efficiency decreased when N fertilizer rates were above 22 kg N·ha−1. Application of N or S had no effect on proportions of saturated fatty acid, monounsaturated fatty acid, and polyunsaturated fatty acids. Our findings suggest camelina required 18–43 kg N·ha−1 when grown in rain-fed systems in water-limited environments.