Core Ideas Winter annual oilseed crops are being used in annual cropping systems to add value. We explored trade‐offs in oilseed yield and provision of ecosystem services. Oilseed cover crop yield was greatest when harvested late rather than early. Pennycress and camelina reduced N in the soil profile compared to soybean alone. To gain additional value from land during winter fallow periods in corn (Zea mays L.)–soybean [(Glycine max (L.) Merr.] rotations, growers in the Upper Midwest are considering winter annual oilseed crops such as field pennycress (Thlaspi arvense L.) and winter camelina [Camelina sativa (L.) Crantz]. The objective of this study was to (i) explore trade‐offs between soybean and winter oilseed crop yield as influenced by timing of winter oilseed crop harvest and of soybean planting, and (ii) evaluate how inorganic soil N was affected by the presence or absence of pennycress or camelina. Field experiments were conducted at three sites in Minnesota to evaluate yield of field pennycress and camelina winter oilseed crops planted in a double‐crop system or planted early or late in a relay‐cropping system. Soybean grain yield was reduced in one of the three sites in 2014 and at all sites in 2015. However, the addition of a winter oilseed crop in a relay‐ or double‐crop system increased the total oilseed production. The optimal cropping strategy for achieving maximum total oilseed crop yield was dependent on environment. Winter oilseed crop yield tended to be greatest when harvested late rather than early in either a relay‐ or double‐crop system. Pennycress and camelina significantly reduced inorganic soil N along the entire soil profile compared to soybean alone, especially in the spring (53–72%) and autumn (18–19%) when the potential for N loss is greatest. Pennycress and camelina, when integrated with soybean in a late‐planted relay‐ or double‐crop system, increased total crop yield while providing critical ecosystem services.

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In this study, we have synthesized six analogs of a trehalose-pentaethylenehexamine glycopolymer (Tr4) that contain (1A) adamantane, (1B) carboxy, (1C) alkynyl-oligoethyleneamine, (1D) azido trehalose, (1E) octyl, or (1F) oligoethyleneamine end groups and evaluated the effects of polymer end group chemistry on the ability of these systems to bind, compact, and deliver pDNA in cultured HeLa cells. The polymers were synthesized in one-pot azide-alkyne cycloaddition reactions with an adaptation of the Carothers equation for step-growth polymerization to produce a series of polymers with similar degrees of polymerization. An excess of end-capping monomer was added at the end of the polymerizations to maximize functionalization efficiency, which was evaluated with GPC, NMR and MALDI-TOF. The polymers were all found to bind and compact pDNA at similarly low N/P ratios and form polyplexes with plasmid DNA. The effects of the different end group structures were most evident in the polyplex internalization and transfection assays completed in the presence of serum, as determined by flow cytometry and luciferase gene expression respectively. The Tr4 polymers end-capped with carboxyl groups (1B) (N/P = 7), octyne (1E) (N/P = 7), and oligoethyleneamine (1F) (N/P = 7), were taken into cells as polyplex and exhibited the highest levels of fluorescence, resulting from labeled reporter plasmid. Similarly, the polymers end-functionalized with the carboxyl groups (1E at N/P = 7), octyl groups (1E at N/P = 15) and, in particular, the oligoethyleneamine groups (F at N/P = 15) yielded dramatically higher reporter gene expression in the presence of serum. This study yields insight into how very subtle structural changes in the polymer chemistry such as end groups can yield very significant differences in the biological delivery efficiency and transgene expression of polymers used for pDNA delivery.

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Diversification of agroecological systems to enhance agrobiodiversity is likely to be critical to advancing environmental, economic, and social sustainability of agriculture. Temperate-zone agroecological systems that are currently organized for production of summer-annual crops can be diversified by integration of fallow-season and perennial crops. Integration of such crops can improve sustainability of these agroecological systems, with minimal interference with current agricultural production. Importantly, these crops can provide feedstocks for a wide range of new bio-products that are forming a new agricultural bioeconomy, potentially providing greatly increased economic incentives for diversification. However, while there are many fallow-season and perennial crops that might be used in such a "bioeconomic" strategy for diversification, most are not yet well adapted and highly-marketable. Efforts are underway to enhance adaptation and marketability of many such crops. Critically, these efforts require a strategic approach that addresses the inherent complexity of these projects. We outline a suitable approach, which we term "sustainable commercialization": a coordinated innovation process that integrates a new crop into the agriculture of a region, while intentionally addressing economic, environmental and social sustainability challenges via multi-stakeholder governance. This approach centers on a concerted effort to coordinate and govern innovation in three critical areas: germplasm development, multifunctional agroecosystem design and management, and development of end uses, supply chains, and markets. To exemplify the approach, we describe an ongoing effort to commercialize a new fallow-season crop, field pennycress (Thlaspi arvense L.).