Project : USDA ARS

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Research Project: Enhancing Cropping System Sustainability Through New Crops and Management Strategies

2019 Annual Report

Objectives
Our long-term goal of this project is to develop new oilseed crops (e.g., cuphea, calendula, and camelina) and innovative crop management and weed control strategies that reduce and/or efficiently use costly agricultural inputs. Ultimately, the integration of these new crops, new knowledge and management strategies will provide producers with economically and environmentally-sustainable cropping systems. Over the next five years our research will focus on the following objectives: Objective 1: Identify and develop new crops and innovative management strategies to efficiently utilize agricultural inputs, improve cropping efficiency and productivity, as well as enhance various ecosystem components in short-season high stress environments. Sub-objective 1A. Identify species and varieties of new and alternative oilseed crops that show the best agronomic potential for biofuel/bioproduct feedstock production. Sub-objective 1B. Develop new methods and improve existing strategies to integrate and manage new, alternative, and traditional crops to produce food, feed, fuel, and bioproducts. Sub-objective 1C. Develop diversified crop sequences that are economically sustainable using new and traditional crops with the aim of improving health and abundance of pollinators and other beneficial insects. Objective 2: Develop novel and innovative weed control strategies, evaluate their effectiveness (primarily in short-season, high-stress environments), and integrate into cropping strategies. Sub-objective 2A. Optimize entirely new techniques for controlling weeds that are appropriate for row crops in the NCB and elsewhere. Sub-objective 2B. Integrate new and existing tactics with weed biology into sustainable management systems.

Approach
Our goal is to develop new oilseed crops and innovative crop and weed management strategies that diversify and improve the efficiency of cropping systems and reduce costly agricultural inputs while adding new economic and environmental benefits. Two mutually supporting approaches will be taken to accomplish this goal. The first employs a series of experiments to identify new oilseed crop genotypes for biofuels/bioproducts feedstock best suited for the northern Corn Belt, develop best management practices for their production, and develop strategies to integrate them with traditional crops into modified systems. The second involves developing new weed control strategies and increased knowledge of microclimate interactions with weed biology to design and optimize weed management protocols to deploy in new cropping systems that include new, alternative and traditional crops. Together, the outcomes of this research will enhance land-use efficiency and provide new economic opportunities and new ecosystem benefits, such as nutritional resources that promote healthy pollinator populations.

Progress Report
Field studies will be completed in FY19 to evaluate the use of chemical desiccation and swathing to hasten the harvest of winter camelina and pennycress to facilitate double-cropping early maturing cultivars of soybean. Analysis of last year’s results indicate that these methods when applied at the proper growth stage can speed up the harvest of camelina and pennycress by as much as one to two weeks. This allows earlier planting of double crop soybean which results in greater yields. In collaboration with scientists from the University of Florida and ARS in Maricopa, Arizona, a multi-location field study was initiated to evaluate 15 different spring camelina accessions for resistance to water-limiting conditions. Twelve of the camelina genotypes being evaluated were previously selected in Arizona for tolerance to drought and improved productivity and seed quality attributes. Last year a study was initiated and in this FY period it is being duplicated in collaboration with ARS researchers from Fargo, North Dakota, to evaluate the use of early maturing semi-dwarf sunflower hybrids to double-crop after the harvest of winter camelina. An early maturing hybrid selected and provided by our Fargo collaborator was able to reach full maturity when double-cropped after winter camelina and produced around 1700 kg ha-1 of seed which is on par with what producers in Minnesota on average produce with monocrop full-season sunflower varieties. As expected, double-crop treatments (i.e., camelina followed by sunflower) used more soil moisture during the growing season than the monocrop full-season sunflower controls. One of the primary goals of recent research is to develop better practices for establishing cover crops, particularly winter oilseeds into corn-soybean systems. Previous data were analyzed, and a study duplicated in FY19 in collaboration with University of Minnesota partners to assess the use of chemical desiccation of corn to hasten its harvest in the fall to allow direct drilling of winter camelina using an aggressive no-till drill to displace corn residue and facilitate improved seed-soil contact. Corn was desiccated when grain was at the ½ milk line, ¾ milk line, and black layer (physiological maturity). The earliest desiccation which was done August 30 resulted in enabling winter camelina to be planted by late September/early October, at least 2.5 weeks earlier than non-desiccated corn. Earlier planting of camelina also led to much improved stand establishment. However, the earliest desiccation led to a 14% reduction in corn grain yield. Economic tradeoffs between corn and camelina grain yields and drying time/costs will be evaluated after collecting another year of data. A new field experiment was initiated to determine the effectiveness of using shorter relative maturity corn hybrids (RM) as an additional means to harvest corn as early as possible to allow direct planting and establishment of winter oilseeds (i.e., camelina and pennycress). Because corn residue following harvest has been an issue for establishing winter oilseeds and other cover crops, the effects of removing corn stover before planting winter oilseeds is also being evaluated. A new field experiment was initiated to determine optimum N fertilizer rate and application timing for winter camelina production. Nitrogen rates between 0 and 120 kg ha-1 applied in fall or spring or split between fall and spring are being evaluated. Camelina harvesting and final soil sampling will be completed for the first year during the summer of FY19.

Accomplishments
1. Improved management for winter camelina production. Farmer interest in growing winter camelina as a cash cover crop is increasing. ARS researchers at Morris, Minnesota, identified currently available winter camelina genotypes that are highest yielding and have the greatest winter survival for production in the upper Midwest. Moreover, Morris researchers identified the best seeding methods including rate, depth, and row spacing, as well as optimum rates of N fertility, for increasing camelina productivity. Results benefit farmers, agronomists, extension educators, and the specialty oilseed industry interested in expanding commercial camelina production.

2. Profitability of abrasive weeding in organic crops. In organic grain and vegetable crops, weeds that emerge within rows greatly impact yield and are difficult to control. An alternative to hand-weeding is using air-propelled grit to control small weed seedlings. ARS researchers in Morris, Minnesota, collaborated with South Dakota State University researchers to evaluate the profitability of using abrasive weeding to control weeds in organic corn, tomato, and peppers. Abrasive weeding was not profitable in organic corn production as compared with just mechanically tilling between rows and reduced net income by $90 to $1430/acre, which was largely dependent on abrasive grit cost and the cost to own a four-row grit applicator. However, abrasive weeding was profitable in organic tomato and pepper production, increasing net income by $4960 to $13460/acre. Results benefit organic farmers, weed scientists, extension educators, and others interested in new forms of weed control for organic crops.

3. Oilseed cover crops reduce unwanted soil nitrogen loss. Contamination of water from the leaching and runoff of labile soil nitrogen and phosphorus from corn-soybean cropping systems in the upper Midwest is a major concern. Mostly this loss occurs during fall and spring when the soil is left bare between summer crops. Winter annual cover crops can use left-over nitrogen and phosphorus from the previous crop and keep these nutrients from contaminating water. ARS researchers from Morris, Minnesota, in collaboration with University of Minnesota scientists demonstrated that winter camelina and pennycress grown as “cash” cover crops are just as effective as winter rye at using excess nitrogen and preventing its escape from agricultural system into water ways. Camelina and pennycress, however, have the added benefit that they can be harvested for their oilseeds for additional profit. This information will benefit farmers interested in cover cropping and agricultural scientists, extension educators and consultants developing new cover crop systems.

4. Economics of relay-cropping soybean with winter oilseeds. Farmers have been slow to adopt cover crops because they are an added expense. The winter oilseeds camelina and pennycress provide environmental benefits as cover crops but also can be harvested for their seeds while growing soybean as a second crop. Researchers at ARS in Morris, Minnesota, and University of Minnesota collaborated to demonstrate that soybean relayed-cropped with winter camelina and pennycress at different sites from northern to southern Minnesota generated as much net income as growing a single crop of soybean. Thus, if farmers precede their soybean crops with either of these winter oilseeds, they are likely to gain many environmental benefits without losing any income. Results will benefit farmers interested in cover cropping and agricultural scientists, extension educators and consultants developing new cover crop systems.

U.S. DEPARTMENT OF AGRICULTURE

Soil Management Research: Morris, MN