BIOFUELS

Planting, Harvesting, & Double Cropping Info

Planting and Harvesting Answers

to Frequently Asked Questions of Pennycress & Camelina

grown in Minnesota and Northern Iowa

Harvesting Camelina on Wayne Johnson's demonstration plot in North Central Iowa 7-17-12 (above photo).

WHAT ARE THE BASIC REQUIREMENTS FOR PLANTING THESE ENERGY CROPS?

Camelina and Pennycress are known to grow on poor quality soils without irrigation.  Water needs are estimated to be 12”–14” per year minimum, but 20” per year is better.  Excessive soil moisture or standing water stresses the plants which can inhibit growth in the early stages or inhibit seed production after the pods have formed (some pods may be empty or have very few seeds).  These plants are self-pollinating.

DOES THE SOIL HAVE TO BE PREPARED IN ANY SPECIAL WAY?

Soil testing is is needed to determine the current nutrient availability and whether fertilizer should be added.  Test results from the previous 2 years should be suitable.  For best results, soil should be tilled to produce a good seed bed; deep furrows will impair germination.  No till techniques have also been successful.  With soft soils such as sand, rolling prior to planting is preferable.

WHAT ARE THE SPECIFICS ABOUT PLANTING CAMELINA AND PENNYCRESS?

Camelina and Pennycress seeding rate should be 6-10 lbs/acre (higher rate seems to be better). Getting a dense stand of these crops is important in order to prevent other plants from taking over.   Seeding depth:  ¼” or just lay it on the surface followed by rolling.  Rolling ensures good contact with the soil which is essential for successful germination.  With very loose, sandy soils, rolling may be necessary before and after seeding.  Be careful that the seeds do not get pressed too deep into the soil.      

Planting technique–Camelina and Pennycress: drill, air drill or broadcast (drill creates rows, might be better for double-cropping).  Grass seeders, alfalfa seeders, Brillion planter are reported to work for planting.  Due to the small size of the seeds, mixing them with fertilizer at a ratio of 2-3:1 by weight (fertilizer:seeds) will prevent them from passing through the seeder too quickly.  The prill size of the fertilizer is important; if it is too large, the seeds will settle to the bottom of the hopper.  Another option with the Brillion seeder is to plug half the holes for more consistent seeding.  

Sandy soil can be very soft and make it difficult or not possible to plant seed with a Brillion seeder.  The front roller of the implement, which drives the agitator just plows the soil instead of engaging it and spinning like it should.  A broadcast seeder or fertilizer spreader would be better under such conditions. 

Best time to plant Camelina–Spring:  when soil reaches 38°F (usually in March).

Best time to plant Camelina–Fall:  September–early October.  Soil temperature should be between 50° and 60°F. to ensure germination before first frost. 

Best time to plant Pennycress–Fall:  September–early October.  Soil temperature should be between 50° and 60°F. to ensure germination before first frost.  It is essential that Pennycress overwinters or the rosettes will not bolt (produce a tall stem) or mature.   

Germination time for  Camelina and Pennycress is 1-2 weeks.

WHAT ARE ABOUT DOUBLE CROPPING THESE ENERGY CROPS?

Plants to double crop with: Soybeans, Emmer and  seed beans have been grown concurrently with Camelina.  Green beans, red clover, timothy, and oats may be possibilities.  Pennycress has been seeded (dropped from the air) into standing corn during the summer.  It has been demonstrated that soybeans can be planted into Spring or Fall planted Camelina.  This can be done where the Camelina has been broadcast seeded or where it has been planted in rows.  Soybeans should be planted while the Camelina is still in the rosette stage. Crops such as green beans or others that get planted later can work in a sequential cropping situation; fall-planted Camelina can sometimes be harvested in June which opens up the opportunity to plant a late season crop afterwards.

IS THERE A SPECIFIC HARVESTING TECHNIQUE FOR CAMELINA AND PENNYCRESS?

Direct combining works well.  The combine should be fitted with a fine screen, set the sieves to an almost closed position, run it at slow ground speed, set the concaves fairly close and adjust the fan speed to prevent blowing seed out the back.  Further adjustment of the concaves might be necessary.  Some combines are equipped to recycle the seeds to help remove broken seed pods and other plant fragments.  Swathing is also a technique that can be used.  In the presence of soybeans, cut plants about 10 inches above ground or a height that is above the soybeans, but still allows capture of the seed pods.

WHAT IS THE PREFERRED HARVESTING METHODS OF THESE ENERGY CROPS?

Approximate harvest date is June for Pennycress and Fall planted Camelina and late June to early July for Spring planted Camelina.  Application of a dessicant or an herbicide such as Roundup® prior to harvest will enable other weeds to pass through the combine; small seeds like Camelina tend to stick to greenery.  Mature seed pods are somewhat prone to shattering.  Ideally, seeds should be harvested when their moisture content is roughly 8% as this moisture level works best when crushing the seed to extract the oil.

WHAT IS THE PREPARATION OF SEED FOR MARKET FOR CAMELINA OR PENNYCRESS?

Prior to crushing the seed for the oil, it must be cleaned to remove other plant material and stones.  If the moisture is high, it must be dried to about 8%.   Commercial seed dryers are available but due to the size of the seeds (1-2 mm), the dryer may need to have a fine screen installed to prevent the seeds from leaking out.  

Seed storage: Seed must be stored at <13% moisture to discourage mold.  Camelina seed does not require storage over the winter (hard seeded characteristics) in order to get a good germination percent.   Seeds can be stored in rigid tote bins or in flexible bags called FIBC’s (Flexible Intermediate Bulk Containers) that have capacities up to 2000 lbs.

WHAT ARE THE NECESSARY FERTILIZER AND NUTRIENT LEVELS NEEDED FOR THESE ENERGY CROPS?

Soil should be analyzed for:  N, P, K, Ca, Mg, Zn, S, pH, organic % and texture.  Nitrogen should be between 40 and 70 units; 90 units is too high.  Sulfur should be around 10-15 units.  They have been grown in soil with pH 5.8-7.9.  It has been reported that Camelina yielded a maximum of 900 lbs/acre when grown in soil containing 1% organic matter regardless of what was done to fertilize it (personal correspondence with B. Schafer).

WHAT SHOULD BE DONE ABOUT WEED CONTROL FOR CAMELINA AND PENNYCRESS?

Camelina is planted in the early Spring and it is actively growing prior to the time when most other plants get going.  In dense stands, it can out-compete other plants because of this and herbicide use can sometimes be avoided.  If necessary, herbicides that can be used include Roundup®, Prowl®, Poast®, and Treflan®.  Deep sod can make it difficult for pre-plant or pre-emergent herbicides.  Roundup® can be used for site preparation.  Treflan® for sites that previously had small grain crops.  Prowl H2O® can be used prior to planting Camelina.

ARE THERE ANY PLANT DISEASES ASSOCIATED WITH THESE ENERGY CROPS? 

Camelina is susceptible to white mold.  Pennycress has very little susceptibility to diseases, mold or insects.

WHAT IS THE CURRENT SEEDMEAL VALUE OF CAMELINA?

The selling price for Camelina seedmeal is currently estimated at $250/ton.