Revised February 2022.
Field pennycress (Thlaspi arvense) has traditionally been identified as a winter annual weed of pastures, cropland, nurseries and horticultural crops. Though introduced from Eurasia, it is currently found throughout the United States. A member of the Brassicacea or mustard family, it is being developed as an oilseed crop and as a cover crop in summer annual row cropping systems.
Part of the growing interest in the crop potential of field pennycress is that it can be grown in parts of the Corn Belt in the fall, winter, and spring, ‘sandwiched’ between corn and soybean crops. Its production requires few inputs, little labor, and no land charge, if annual land production costs are charged to the two summer annual crops in the rotation. Grown in this manner, field pennycress can serve as protective green cover to the soil in the late fall and early spring, be a good source of food for pollinators in early spring before many other plants flower, and the harvested seed can be a potential source of income.
Field pennycress oil is suitable for biodiesel, which can be used alone or mixed with petroleum-based diesel to lower the emission of hydrocarbons, carbon monoxide and other pollutants in engine exhaust. Recent research has shown that field pennycress derived biofuels may qualify as an advanced biofuel and as biomass-based diesel as defined by the Renewable Fuels Standard.
Seed meal remaining after oil extraction for biodiesel production has several potential uses. Seed meal can be further processed to yield aviation fuel. Moreover, with proper processing it can be used as an animal feed and as a source of protein for human consumption.
Field pennycress is a prolific seed producer, producing up to 15,000 seeds per plant. These seeds can form a long-lived seedbank (up to 20-30 years), making it difficult to eradicate from an area once a population becomes established. The likelihood of field pennycress becoming a viable commercial crop will depend on the development of varieties with less seed dormancy and that are less prone to shattering. With current germplasm, seed yields of 1,500 to 2,000 lbs per acre have been achieved in research trials, but in farm production scenarios, yields of 700 to 900 lbs per acre are more typical. Accessing seeds of pennycress may be challenging until commercial varieties are developed and released. Contacting someone in one of the networks linked below may be a good place to start when looking for seed or information on available production contracts.
Agronomic research on commercially producing field pennycress is somewhat limited. Nevertheless, the basic techniques and equipment needed are similar to those used for winter cereal production. Avoid planting pennycress into corn fields that were treated with a full-rate HPPD-inhibiting herbicide as residues of this class of herbicides can injure emerging pennycress seedlings. Field pennycress is fall-seeded, with the optimum planting date similar to that recommended for winter wheat for a given region. When growing pennycress between corn and soybean crops, it can be aerially seeded into standing corn; drilling pennycress after corn harvest may be too late to establish a viable crop stand in more northern regions of the USA and heavy corn stover may reduce pennycress establishment. When seeding after corn harvest vertical tillage prior to seeding may improve establishment. Seeding rates used in recent research reports varied from 1 to more than 20 lbs per acre, with 5 lbs per acre being adequate in most situations and higher seeding rates recommended when broadcasting compared to drilling and when seeding into dry conditions. When drilling, seeding equipment used for small grains and oil seed crops can be used and the seeding depth should be very shallow (~1/4 inch deep).
No herbicides, insecticides, or fungicides are recommended for pennycress production. Projected nutrient removal for a crop is 50 lbs per acre nitrogen, 20 lbs per acre phosphorus, and 20 lbs per acre potassium. In some situations, no additional fertilizer is required beyond that applied to the preceding corn crop for successful production. However, when nitrogen is deemed to be needed, 50 lbs per acre in early spring as the plant begins to bolt is recommended. Current pennycress lines are prone to shatter when dried to a low moisture content. Direct combing is possible, but pennycress should be harvested as soon as is practical after it has reached maturity in order to avoid shattering losses.
Field operations costs to produce field pennycress will be similar to those for winter small grains. Where production costs differ from small grains are for: seed, fertility removal, and land costs. When grown as an additional crop in a corn-soybean rotation, the cost for land can be shared with the other crops. There may be additional soil health benefits of having a living cover during the fall, winter and spring that that are not be easily quantified in the cost benefit analysis of growing field pennycress.
Farmers have observed the success of this volunteer winter annual weed as a cover crop in some years. The concept of planting field pennycress solely as a cover crop has been studied in Minnesota for both soil quality and nutrient sequestration and for benefits to honeybees. Seed production of field pennycress can be a good source of income if there is interest by neighboring farmers in using field pennycress as a cover. Seed laws apply to the production and sale of field pennycress seed as with other crop seeds.
In 2021 there were no commercial processors of field pennycress in the U.S. Farmers wanting to grow pennycress may have the opportunity in the future to contract with a processor. At that time, processors may have access to improved seed varieties that have improved agronomic characteristics and more desirable end use qualities than are found in currently available lines. As an example of emerging opportunities, in 2022, CoverCress Inc. will contract with growers, mainly in Illinois, for the production of a proprietary variety of pennycress with an improved agronomic and quality profile.
Pennycress seeds contain up to 36% oil. This oil can be extracted using the cold press method; hexane is not required in its extraction. The oil contains up to 38 percent erucic and 22 percent linoleic fatty acids. The erucic acid in the oil of native field pennycress types makes it undesirable for human consumption, but it is well suited for biodiesel production. Biodiesel from field pennycress oil performs better at lower temperatures than biodiesel made from soybean oil.
Following oil extraction, the remaining seed meal contains 32 to 35% protein, some fat and carbohydrates. Pyrolysis of the defatted seed meal can be used in the production of aviation fuel. The seed meal of unimproved genotypes of field pennycress, due to high amounts of glucosinolates, cannot be used for human food or fed directly to livestock in high quantities without further processing. Recent breeding efforts have shown potential for developing lines with reduced glucosinolates which may help resolve this concern in the future. Though there is a significant growing demand for plant derived proteins in general, there is currently no commercial use for proteins isolated from field pennycress. Research to date has shown potential for protein isolates from the seed meal to be suitable for human food and non-food industrial uses, however.
The seed meal offers potential as a biofumigant and/or for weed seed germination suppression because of its high level of glucosinolates. Furthermore, it can be a source of fertilizer for high-value horticultural crops for both conventional and organic growers.
Sources and Background Information and Networks
Production and Evaluation of Biodiesel from Field Pennycress (Thlaspi arvense L.) Oil, 2009, Energy Fuels.
Producing Stable Pyrolysis Liquids from the Oil-Seed Presscakes of Mustard Family Plants: Pennycress (Thlaspi arvense L.) and Camelina (Camelina sativa), 2010, Energy Fuels.
Extraction of Proteins from Pennycress Seeds and press cake, 2013, Industrial Crops and Products.
Preparation, composition and functional properties of pennycress (Thlaspi arvense L.) seed protein isolates, 2014, USDA-ARS.
Report on Minnesota Plant Based Proteins for Food, Agricultural Utilization Research Institute.
Biofumigant Compounds Released by Field Pennycress Seedmeal, 2005, USDA-ARS.
Soybean Seed Yield and Quality as a Response to Field Pennycress Residue, 2012, Crop Science.
Cover Crops Can Benefit Bees, Farmers’ Bottom Line, 2015, The Land.
The Pennycress Resource Network, University of Western Illinois, USDA.
Forever Green Initiative, University of Minnesota and USDA Agriculture Research Service (ARS)
Integrated Pennycress Research Enabling Farm & Energy Resilience Project
Management of pennycress as a winter annual cash cover crop. A review, 2019, Agronomy for Sustainable Development.
CoverCress 2022 Grower Handbook.