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The transdisciplinary field of agroecology provides a platform for experiential learning based on an expanded vision of research on sustainable farming and food systems and the application of results in creating effective learning landscapes for students. With increased recognition of limitations of fossil fuels, fresh water, and available farmland, educators are changing focus from strategies to reach maximum yields to those that feature resource use efficiency and resilience of production systems in a less benign climate. To help students deal with complexity and uncertainty and a wide range of biological and social dimensions of the food challenge, a whole-systems approach that involves life-cycle analysis and consideration of long-term impacts of systems is essential. Seven educational case studies in the Nordic Region and the U.S. Midwest demonstrate how educators can incorporate theory of the ecology of food systems with the action learning component needed to develop student potentials to create responsible change in society. New roles of agroecology instructors and students are described as they pursue a co-learning strategy to develop and apply technology to assure the productivity and security of future food systems ABSTRACT The transdisciplinary field of agroecology provides a platform for experiential learning based on an expanded vision of research on sustainable farming and food systems and the application of results in creating effective learning landscapes for students. With increased recognition of limitations of fossil fuels, fresh water, and available farmland, educators are changing focus from strategies to reach maximum yields to those that feature resource use efficiency and resilience of production systems in a less benign climate. To help students deal with complexity and uncertainty and a wide range of biological and social dimensions of the food challenge, a whole-systems approach that involves life-cycle analysis and consideration of long-term impacts of systems is essential. Seven educational case studies in the Nordic Region and the U.S. Midwest demonstrate how educators can incorporate theory of the ecology of food systems with the action learning component needed to develop student potentials to create responsible change in society. New roles of agroecology instructors and students are described as they pursue a co-learning strategy to develop and apply technology to assure the productivity and security of future food systems.

The use of cover crops can decrease soil erosion, weed density, and nitrate leaching while improving soil quality. We investigated nine cover crops, winter rye (Secale cereale L.), winter triticale (× Triticosecale Wittm. ex A. Camus), two winter canola (Brassica napus L.), winter camelina [Camelina sativa (L.) Crantz], spring barley (Hordeum vulgare L.), spring oat (Avena sativa L.), turnip (B. rapa L.), and hairy vetch (Vicia villosa Roth), as sole crops and selected binary and trinary mixtures and their influences on subsequent corn (Zea mays L.) productivity. A control treatment of no cover crop was included. Cover crops were no-till drilled immediately after soybean [Glycine max (L.) Merr] harvest. The study was a randomized complete block conducted in five environments over 2013-2014 and 2014-2015. Across environments, rye and rye mixtures produced the greatest spring aboveground biomass (758 kg ha -1 ), C, and N accumulation, had some of the lowest spring soil nitrate concentrations, and generally produced the lowest corn leaf chlorophyll. Rye accounted for more than 79% of spring aboveground biomass accumulation in rye mixtures. Triticale and camelina monoculture produced approximately 50% less biomass than rye or mixtures with rye. Cover crops in monoculture and mixtures did not influence surface soil temperature, soil P or K concentrations, weed density, weed community, or corn yield. Cover crops had limited influence on volumetric soil water content. Cover crop mixtures had no advantages over monocultures except for increasing fall stand density. Turnip and vetch had limited winter survival while barley, oat, and canola winterkilled. ABSTRACT Th e use of cover crops can decrease soil erosion, weed density, and nitrate leaching while improving soil quality. We investigated nine cover crops, winter rye (Secale cereale L.), winter triticale (× Triticosecale Wittm. ex A. Camus), two winter canola (Brassica napus L.), winter camelina [Camelina sativa (L.) Crantz], spring barley (Hordeum vulgare L.), spring oat (Avena sativa L.), turnip (B. rapa L.), and hairy vetch (Vicia villosa Roth), as sole crops and selected binary and trinary mixtures and their infl uences on subsequent corn (Zea mays L.) productivity. A control treatment of no cover crop was included. Cover crops were notill drilled immediately aft er soybean [Glycine max (L.) Merr]harvest. Th e study was a randomized complete block conducted in fi ve environments over 2013-2014 and 2014-2015. Across environments, rye and rye mixtures produced the greatest spring aboveground biomass (758 kg ha -1 ), C, and N accumulation, had some of the lowest spring soil nitrate concentrations, and generally produced the lowest corn leaf chlorophyll. Rye accounted for more than 79% of spring aboveground biomass accumulation in rye mixtures. Triticale and camelina monoculture produced approximately 50% less biomass than rye or mixtures with rye. Cover crops in monoculture and mixtures did not infl uence surface soil temperature, soil P or K concentrations, weed dens...

Forage Brassica spp. have been shown to produce adequate amounts of herbage during the cooler months of the fall, thus allowing extension of the grazing season in higher latitudes. The objective of this study was to determine if the nutritive quality of initial and regrowth herbage was influenced by planting and harvest date. In 1987, 1988, and 1989, three Brassica spp. (rape [B. oleracea L.], turnip [B. rapa L.] and turnip hybrid [B. rapa L. × B. pekinensis L.]) were planted in late May to early June, late June to early July, and late July to early August and were harvested each year at 64, 76, or 85 DAP. The plants regrew 60, 70, or 80 d and were harvested. Nutritive components measured were CP, NDF, ADF, Ca, Mg, and P. Nutritive levels declined with warmer temperatures and low soil moisture levels particularly during July and August. Neutral‐detergent fiber and ADF levels were higher, while the CP levels were lower in herbage from the earliest planting date compared with the later planting dates, regardless of species and year. The levels of Ca, Mg, and P were influenced by species and planting date. In general, the regrowth herbage had a lower fiber and a higher protein content than the initial herbage. The variation in nutritive quality among the three species was relatively small. Of more importance to the producer is that the quality of brassica herbage is more comparable to a concentrate than a traditional forage because of the relatively low fiber and high protein content.