Planting Date, Herbicide, and Soybean Rotation Studies 

with Field Pennycress (Thlaspi arvense L.)

Winthrop B. Phippen1, Billee John2, Mary E. Phippen1, and Terry Isbell3

1School of Agriculture, Western Illinois University, Macomb, IL 61455, USA

2Southern Illinois University, Edwardsville, IL 62025, USA

3National Center for Agricultural Crops Utilization Research, USDA, ARS, Peoria, IL, 61604, USA

ABSTRACT

Thlapsi arvense L. (field pennycress) is a new crop being 

investigated for its potential as a possible off season source for biodiesel 

and as an additive to petroleum based products in the Midwest. For 

pennycress to be successfully adopted by producers, off season production 

must have minimal impact on the current crop rotations. 

One objective of this study was to determine the optimal fall 

planting date for field pennycress in Illinois to maximize seed yield in early 

spring. Other objectives were to identify potential herbicides for 

pennycress production and to assess the impact of pennycress residue on 

subsequent soybean crops.

During the fall of 2009, the winter line ‘Patton’ was planted in 

replicated plots from September 1st to November 3rd. In spring 2010, each 

plot was evaluated for seed yield, total seed oil, fatty acid methyl ester 

content, along with several other agronomic traits. Replicated herbicide 

trials with active ingredients alachlor (Intrro), pendimethalin (ProwlH2O), 

and clopyralid (Stinger) at three different labeled rates were conducted 

across 2 growing seasons. Replicated soybean plots were planted 

following pennycress across 5 planting dates in 2009 and 2010. Soybeans 

were evaluated for seed yield, stand establishment, seed protein and oil 

quality and compared to soybeans following fallow ground.

Planting dates when soil temperatures were above 15.5oC resulted 

in an average of 1,568 kg ha-1. Seed yields declined steadily as soil 

temperatures drop to 10oC. Below 10oC, fall planted pennycress seed did 

not germinate until spring. Total oil steadily declined while fatty methyl 

esters remained uniform across planting dates. Alachlor and 

pendimethalin demonstrated the least amount of pennycress injury. 

Pennycress rotation with soybeans resulted in no impact on soybean stand 

establishment or protein and oil quality across all five planting dates.

Early fall planting, the potential for herbicide use, and no impact 

on following soybeans helps pennycress move forward as a viable crop in 

the Midwest.

Development of diverse and renewable feed stocks for the 

production of fuel will become a most certain priority for the U.S. 

agriculture sector. However, displacement of crops that produce the 

world's food from tillable land is a concern. One approach to solve both 

needs for food and fuel is to rotate both types of crops through the same 

land in one extended growing season. The potential new crop, field 

pennycress (Thlaspi arvense L.) offers a short winter growing season 

allowing a full season soybean to be grown on the same acreage 

immediately following harvest.

Pennycress is a common plant throughout the Midwest and is a 

member of the mustard family (Brassicaceae). Pennycress grown as a 

winter annual forms a rosette of leaves up to 6" across throughout the 

winter months with a central stem and several side stems terminating in 

erect racemes of small white flowers in early spring (Warwick et al., 

2002). Flowers are pre-dominantly self-pollinated and produce up to 14 

seeds that are half the size of a canola seed with a 1000 seed weight of 

0.83 grams. The seed was found to have 36% oil with the major fatty acid 

as erucic at 38.1%, iodine value of 115 (Moser et al., 2009). Wild stands 

can approach 2,000 pounds of seed per acre. 

Pennycress has been investigated for oil potential (Clopton and 

Triebold, 1944) and as a potential new source for erucic acid in several 

industrial applications (Van Dyne et al., 1990). More recent studies have 

looked at pennycress production as a potential bio-fumigant providing an 

eco-friendly alternative to methyl bromide (Vaughn et al., 2005; 2006). 

Pennycress oil meets all the parameters required for biodiesel and 

demonstrates better cloud point and oxidative stability than soy.

The objectives of this study were to determine the optimal fall 

planting date for field pennycress in Illinois to maximize seed yield in 

early spring. Other objectives were to identify potential post emergent 

herbicides for spring weed control and to assess the impact of pennycress 

residue on subsequent soybean crops.

Plant Date Study: Pennycress line ‘Patton’ was planted in Macomb, IL over 9 separate weeks in the 

fall of 2009 from September 1st to November 3rd (Figure 1). Each planting date plot consisted of 9 

drilled rows 7.5 cm apart and 3.5 m long. Each planting date was replicated 4 times and maintained 

by hand weeding. One square meter was harvested by hand from each plot in late May and early June 

and analyzed for seed yield, total oil content, and oil constituents. Weather data was collected at the 

planting site. 

Herbicide Trials: In fall 2008 and 2009, the pennycress line ‘Patton’ was drilled into 30 plots 

measuring 3.1 m by 4.5 m. Just prior to flowering in early April of the following spring, rates of half, 

1x, and 2x labeled rate were applied for each of the herbicides containing the active ingredients 

alachlor (Intrro), pendimethalin (ProwlH2O), and clopyralid (Stinger). Each rate was replicated three 

times with plots receiving no herbicides serving as a control. Plots were evaluated 14 days after 

herbicide application for plant injury. Sub-samples were harvested from each plot measuring 1.5 m x 

3.0 m and analyzed for seed yield, total oil content, and oil constituents.

Soybean Rotation Studies: In spring 2009 and 2010, Pioneer ‘93M11’ soybeans were drilled into 

pennycress stubble for five consecutive weeks from mid May to late June. Prior to each planting date, 

pennycress was cut by a string trimmer with all material remaining in the field. Control plots were 

planted on fallow ground following wheat the previous season. Both pennycress and control plots 

were replicated three times on the same Ipava soil type. All plots were hand harvested in late fall and 

analyzed for oil and protein profiles.

Oil, Protein, and Data Analysis: Total oil content was determined by nondestructive pulsed NMR 

(Bruker Minispec PC 120, 180-mm absolute probehead) on whole pennycress seed. Medium-chain 

triglycerides were extracted and derivatized into fatty acid methyl esters for gas chromatography 

analysis. The fatty acid methyl esters were analyzed using an Agilent 6890 gas chromatograph with a 

flame ionization detector. Soybean protein was evaluated using NIR (Near Infrared Reflective) 

Spectroscopy. Data was analyzed using analysis of variance (ANOVA) with statistical differences 

declared at P<0.05. 

Figure 3. Minimum air temperature, maximum air temperature, and 

4” bare soil temperature data collected during planting date study.

Figure 2. Total seed oil yield for pennycress line 

‘Patton’ across different fall planting dates.

INTRODUCTION

RESULTS AND DISCUSSION 

MATERIALS AND METHODS

Figure 4. Variation of seed oil fatty acids across planting dates. Figure 5. Photo of planting date study indicating variation in 

plant maturity at time of first harvest May 24.

Figure 1. Planting date study at Macomb, Illinois. Photo taken April 7,2010.

Figure 6. Total seed yield following herbicide treatments in 2009 and 2010.

0

200

400

600

800

1000

1200

1400

1600

1800

0.5x Intrro 1x Intrro 2x Intrro 0.5x Prowl H2O 1x Prowl H2O 2x Prowl H2O 0.5x Stinger 1x Stinger 2x Stinger Untreated check

Seed Yield (kg/ha)

2009

2010

Planting Date and 

Treatment

Percent 

Protein

Percent 

Oil

Palmitic

Acid

C16:0

Stearic

Acid

C18:0

Oleic

Acid

C18:1

Linoleic

Acid (ω6)

C18:2

Alpha

Linolenic

Acid (ω3)

C18:3

May 20 - Control 40.6 20.2 12.6* 3.7 20.4 54.8 8.5

May 20 - Pennycress 39.6 20.0 12.6 3.7 20.9 54.3 8.4

May 27 – Control 39.9 20.5 12.7 4.1 20.7 53.6 9.0

May 27 – Pennycress 40.4 20.3 12.5 3.9 20.8 54.4 8.5

June 3 - Control 40.0 20.3 12.4 4.3 22.3 52.5 8.5

June 3 - Pennycress 40.5 20.4 12.7 3.8 21.2 53.8 8.5

June 10 - Control 39.4 19.6 12.6 3.9 22.5 52.1 8.9

June 10 - Pennycress 39.7 19.9 12.9 3.7 22.0 52.8 8.5

June 17- Control 39.2 19.5 12.2 3.7 19.6 55.1 9.4

June 17 - Pennycress 39.3 19.4 13.3 3.4 19.2 54.3 9.8

Plant Date Study: The first five planting dates occurring in September were not 

found to be significantly different from each other in terms of total seed oil 

content (Figure 2). However, as soil temperatures declined throughout the fall 

(Figure 3), stand establishment declined resulting in a significant decrease in seed 

and total oil yield. The percentage of seed oil constituents remained constant for 

the September planting dates, with erucic acid levels declining and oleic acid 

levels increasing towards the later planting dates (Figure 4). The early 

establishment of the September planting dates also allowed for harvest on May 

24th, while later planting dates were harvested on June 11th (Figure 5). 

Herbicide Trials: The 2010 growing season was extremely wet and cold 

resulting in a poor stand establishment leading to very low yields overall (Figure 

6). However, 2009 resulted in significant differences between herbicide 

applications (Figure 7). Herbicide injury was noticed on all treated plants (Figure 

8), however only 1x and 2x rates of clopyralid (Stinger) resulted in significant 

yield loss when compared to the control. No significant differences were found 

in total seed oil or oil constituents across all herbicide treatments. 

 

Soybean Rotation Studies: All five planting dates of soybeans following 

pennycress resulted in slightly higher yields when compared to the control plots 

(Figure 9). The slight bushel increase following pennycress may have been the 

result of increased soil moisture due to higher ground cover. Soybeans were 

planted directly after cutting pennycress (Figure 10). No significant differences 

could be found in either seed oil constituents or protein profiles between 

soybeans following fallow ground and soybeans following pennycress (Table 1). 

Figure 10. Soybeans drilled into pennycress stubble replicated across five planting dates.

Clopton, J.R. and H.O. Triebold. 1944. Fanweed seed oil: potential substitute for rapeseed oil. 

Ind. Eng. Chem. 36:218-219.

Moser, B.R., G. Knothe, S.F. Vaughn, and T.A. Isbell. 2009. Production and evaluation of 

biodiesel from field pennycress (Thlaspi arvense L.) Oil. Energy and Fuels, 23:4149-

4155. 

Van Dyne, D.L., M.G. Blase, and K.D. Carlson. 1990. Industrial feedstocks and products from 

high erucic acid oil: crambe and industrial rapeseed. Univ. Missouri-Columbia, 

Columbia, MO.

Vaughn, S.F., T.A. Isbell, D. Weisleder, and M.A. Berhow. 2005. Biofumigant compounds 

released by field pennycress (Thlaspi arvense) seedmeal. Journal of Chemical Ecology 

31(1): 167-177.

Vaughn, S.F., D.E. Palmquist, S.M. Duval, and M.A. Berhow. 2006. Herbicidal activity of 

glucosinolate-containing seedmeals. Weed Science 54 (4):743-748.

Warwick, S.I., A. Francis, and D.J. Susko. 2002. The biology of Canadian weeds. 9. Thlaspi 

arvense L. (updated). Canadian Journal of Plant Science 82: 803-823.

LITERATURE CITED

This project was supported by the Agriculture and Food 

Research Initiative competitive grant # (2010-85117-20535) of the 

USDA National Institute of Food and Agriculture.

RESEARCH FUNDING

Figure 8. Herbicide injury seen 14 days after

treatment with 1x clopyralid.

a

a a a

a a

a

ab

b

a

26.00

27.00

28.00

29.00

30.00

31.00

32.00

33.00

34.00

35.00

36.00

Percent Oil

Figure 7. Total seed oil yield in 2009 after herbicide treatments. 

Different letters atop bar graphs indicate significant differences at the 

P<0.05 level.

Table 1. Protein and seed oil analysis of soybeans planted after pennycress and 

fallow ground in 2009.

*Percentage of total seed oil by weight.

-10

0

10

20

30

40

50

60

70

80

90

9/1/2009 9/21/2009 10/11/2009 10/31/2009 11/20/2009 12/10/2009

Degrees Fahrenheit

max temp F

min temp F

4"soil bare F

29

30

31

32

33

34

35

36

Percent Oil

0

5

10

15

20

25

30

35

40

Percent Oil

Oleic C18:1 d9

Linolenic C18:3d9

Erucic C22:1

Identifying an ideal September planting season will significantly 

improve a producer’s chance of harvesting high yielding pennycress prior to 

planting soybeans. Applications of alachlor and pendimethalin based herbicides 

show promise in helping control weeds and minimizing impact on pennycress 

seed yield. No adverse effects have been seen in soybeans following 

pennycress production. With excellent biodiesel properties, a very short 

growing season, and no impact on subsequent soybeans, pennycress offers 

tremendous opportunities for producers to diversify and capitalize on 

diminishing the US demand for foreign based oils.

CONCLUSIONS

Figure 9. Dry bushel yield for soybeans across 5 planting date in 2009

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

20-May 20-May 27-May 27-May 3-Jun 3-Jun 10-Jun 10-Jun 17-Jun 17-Jun

Dry Weight Seed Yield (bushels/hectare)

Fallow Following Pennycress