Advanced cropping systems for food, feed and energy production in the northern Great Plains

The sustainability of the northern Great Plains (NGP) is at risk because food, feed, and energy are produced mainly in very short crop rotations or monocultures. To achieve high productivity monocultures require high inputs, such as fertilizers and pesticides. One way to improve the sustainability of cropping systems is increasing plant diversity and improving land use efficiency. Diverse and advance cropping systems reduce the need of external inputs such as nitrogen fertilizer, decrease water pollution, and provide food for pollinators and wildlife. The first part of this research focuses on evaluating how winter camelina (Camelina sativa L.), an industrial oilseed can be grown on the same land in a 12 month period in North Dakota, by double cropping with corn (Zea mays L.), soybean (Glycine max L. Merr., or forage sorghum [Sorghum bicolor (L.) Moench]. The results indicated that camelina can be grown with forage sorghum producing both oil for biofuel (camelina) and feed for livestock (forage sorghum). Also, camelina can be grown with soybean to produce edible oil for food (soybean) and oil for biofuel (camelina). Relay and double-cropping systems have a positive energy balance and higher energy efficiency than monocultures. Of the double- and relay-cropping systems studied, the camelina-forage sorghum relay treatment produced the highest energy efficiency at all three locations in both years. Both forage sorghum in monocrop and the camelina-sorghum in relay have good potential for biofuel and energy feedstock production in the NGP. The second part of this research focuses on increasing forage production sustainability. Alfalfa (Medicago sativa L.) and 13 perennial grass species were evaluated in monoculture or binary mixtures. Results indicated that alfalfa in mixtures with grasses has higher forage yield and quality in comparison with alfalfa or grass in monoculture. Alfalfa-grass mixtures have several other benefits such as increased stand persistence, N use efficiency, and homogeneous seasonal forage yield distribution.