Biomass Producer Handbook - Project Liberty

08 March 2012
Published in Blog

All you ever wanted to know about stover/cobs bailing ...(NB: For on-the-go Corncob collection, only, click here)

Biomass Producer Handbook - Project LibertyBiomass Producer Handbook - Project Liberty

Program Overview

Project LIBERTY is a commercial-scale cellulosic biorefinery that is scheduled to begin operations in late 2013. The plant will use feedstock, cob and high cut material to produce ethanol and various by-products.

  • Uses over 280,000 bone-dry tons of biomass each year
  • Coexists with POET Biorefining – Emmetsburg using existing infrastructure
  • Supports Renewable Fuel Standard 2
  • Serves as a model for cellulosic ethanol technology across corn regions

Figure 1Figure 1

Figure 1

Figure 2Figure 2

Figure 2

Figure 3Figure 3

Figure 3

Figure 4Figure 4

Figure 4

Figure 5Figure 5

Figure 5



  • Cobs & high cut material
  • Modified stover collection (see collection SOP, available from the Emmetsburg Commodities Team)
  • 25% residue removal or less (1 – 1.5 BDT/acre)
    • Surface stays blanketed with residue
    • No to little nutrient replacement needed


  • Research demonstrates that grain yield on corn- on-corn acres can be as high as 5%
  • Residue Management
    • Get paid for your residue
    • Darker soil surfaces in spring, which leads to faster germination
    • Increasing corn yields lead to excess residue which will need to be removed to heat the soil
  • Farm operation expansion/diversification
  • Rural economic development
  • Lessen the dependence on foreign oil
  • Additional revenue source for corn farmers

Combine Setup

Setting up your combine properly is important for many reasons. It minimizes dirt & nutrient loss, as well as time you’ll save by making proper windrows.

  1. Corn Head
    • Stalk stompers required (Figures 1 & 2)
    • Four stompers required for the middle four rows (Figure 2)
    • Entire head can be outfitted with stompers without concern
      • Chopping head optional
  2. Discharge
    • Chopper & spreaders need to be disengaged to form biomass windrow (Figures 3 & 4)

Baler Setup

Setting up the baler is just as important, proper setup will reduce dirt in bales, as well as wear and tear on your baler.

  1. Baling
    • Biomass should be baled 24 - 48 hours after harvesting, if weather permits
    • Baling should not start until the dew has burned off
    • If biomass is impacted by moisture (i.e., rain), it should be left to dry out for 2 – 4 days before baling depending on the precipitation amount
    • All round bales should be formed to 5.5’-5.8’ tall bales
    • All round bales should be wrapped a miniumum of 4 wraps of net wrap
  2. Baling Direction
    • The baler should bale in the same direction that the combine traveled
    • The stalks should be leaning away from the baler pickup which will help to limit damage to the baler’s pickup
  3. Pickup Height
    • The baler pickup should be set so that the tines leave 1½ - 2” of ground clearance (Figure 5)
    • To set, place baler on level ground. Using a 2x4, set the tooth height to the point of it just touching the 2x4
    • This setup is to minimize the pick up of rocks and dirt
    • If the ground is soft, the pickup height may need to be adjusted
    • If tine marks can be seen in the dirt, the baler pickup is positioned too low
  4. Speed - Proper ground speed is usually 6-8 mph


  1. Do not rake stover to form windrows.
  2. Make sure the baler pickup is not running in the dirt and the bales are not filled with dirt.
  3. Do not use twine. All bales must be wrapped at minimum of four times with net wrap.

Bale Storage - Round Bales
Observations – Stack Configurations

Biomass Producer Handbook - Project LibertyBiomass Producer Handbook - Project Liberty

Single Row

Biomass Producer Handbook - Project LibertyBiomass Producer Handbook - Project Liberty

2-High Pyramid

Biomass Producer Handbook - Project LibertyBiomass Producer Handbook - Project Liberty

Mushroom Stack

After the bale is made, it is necessary to store it properly for use all year round. The following shows the best storage practices.

Single Row

  • Pros
    • Single row provides the best overall storage profile
    • Best at shedding water
    • Best at drying out
    • No bales touching for netwrap to freeze to
  • Cons
    • Needs the most storage space of any formation

2-High Pyramid

  • Pros
    • Provides a concentrated storage footprint
  • Cons
    • Channels water between bales
    • Bales tend to freeze together in the winter
    • Bottom bales lose more of their integrity
    • Bottom bales do not dry easily after rain

Mushroom Stack

  • Pros
    • Provides the lowest storage footprint of all round bale storage options
    • Top bale held together extremely well
  • Cons
    • The bottom bale’s integrity is not strong enough to support the upper bale making it hard to maintain longer than 2 - 3 months at a time
    • Moisture is funneled directly into the bottom bale accelerating decomposition

Round Bale Recommendations

  • POET recommends round bales be placed in Single Rows with a 1-foot minimum gap between each row.
  • Single rows provide the best opportunity for minimized dry matter losses, while preventing netwrap from sticking to other bales.
  • Storage locations should be well drained and diverted away from water. Standing water will absorb into bales and accelerate dry matter loss.
  • Mushroom stacks should not be built; they are a poor storage configuration.

As you lose dry matter, you are losing mass decreasing the value of your biomass. The chart below shows you stack formations that work best for preserving your bale and your value.

% Dry Matter Loss

% Dry Matter Loss% Dry Matter Loss

Bale Storage - Square Bales
Observations – Stack Configurations

Biomass Producer Handbook - Project LibertyBiomass Producer Handbook - Project Liberty

Tarped Stacks

Biomass Producer Handbook - Project LibertyBiomass Producer Handbook - Project Liberty

Untarped Stacks

Tarped Stacks

  • Pros
    • Provides the best storage of all options outside of indoor storage
    • Bales maintain quality throughout year
    • Very low dry matter loss seen
    • Cost of tarp is recovered by the dry matter savings once summer begins
  • Cons
    • Takes additional time to tarp and untarp stacks
    • Additional cost of a tarp

Untarped Stacks

  • Pros
    • Works well in short term storage and in cold storage months
    • No additional costs
  • Cons
    • The top bale degrades very quickly once summer begins
    • In many cases, the top bale was a total loss and could not be handled

General Observations

Stack Heights

  • Stacks should be created in bale heights of 3 or 6 bales high on 3’x4’x8’ bales, or 2 or 4 bales high on 4’x4’x8’ bales
  • Any other height will cause additional loading time as individual bales will need to be loaded for transport
  • When stacking square bales, ensure ground surface is level and flat and stack is built tightly so as to limit bale movement

Square Bale Recommendations

  • If square bales are going to be stored from harvest until March, no tarp would be recommended.
  • If square bales are going to be stored past March, the cost of a tarp should be covered by the savings seen in bale dry matter.
  • Proper tightening and maintenance of the tarp will allow it to last longer and be used across more tons, therefore lowering the investment cost per ton.
  • Find storage locations that are well drained and that water is diverted away from; standing water will absorb into bales and accelerate dry matter loss.

% Dry Matter Loss

% Dry Matter Loss% Dry Matter Loss

Bale Quality Metrics: Standards maintaining quality of inbound feedstock

  • Moisture - Just as corn is corrected to 15.5% moisture to create a level comparison, we will purchase biomass on a Bone Dry Ton (BDT) basis to compare all bales equally
    • Shrunk to 0% = BDT
    • 0 - 35% = No dock
    • 35 - 50% = $5/BDT dock
    • 50%+ = Rejected
  • Ash – Dirt and rock material found in bales that cannot be used or converted in the conversion process
    • 0 - 15% = No dock
    • 15 - 25% = $10/BDT dock
    • 25%+ = Rejected

Financial Penalties

Trailer Cleaning Fee
All trailers need to be cleaned off prior to scaling out. A $35 reduction fee will be added to the scale ticket if trailer is not cleaned.

Broken Bales
Broken bales will not be tolerated on inbound deliveries. If a bale is determined to be inadequate for handling off the trailer or breaks when being unloaded from a self-unloading trailer, a $40 fee will be added per bale to the scale ticket. Excessive broken bales may result in loads being rejected or future deliveries stopped.

Late Deliveries
Deliveries will be scheduled on a weekly basis. If the tonnage scheduled for delivery is not delivered in the proper week, a $2/BDT reduction to the contract price will be administered. If issues arise where deliveries cannot be made by the producer, the producer is responsible for contacting POET to work through the situation.


  • Use correct strapping protocol to minimize lost bales and ensure public safety.
  • Self-dumping trailers will be phased out in 2012
  • Deliveries will be based on a delivery date chosen by the producer.
  • If deliveries cannot be made when scheduled, make sure to contact the Emmetsburg commodities team to address the situation.


POET strives to make its feedstock supply system sustainable. We want our producers to strive for sustainability as well. A three-year study published in June 2011 by Dr. Douglas Karlan, United States Department of Agriculture in conjuntion with Iowa State University will show you ways to achieve that sustainability. The study concluded with good management, corn stover can safely and sustainably be harvested from fields.*

Biomass Producer Handbook - Project LibertyBiomass Producer Handbook - Project Liberty
  • Best practices:
    • Do not harvest stover from areas subject to erosion
    • Use appropriate soil conservation practices to protect and improve soil
  • 1 - 1.5 BDT/acre of corn stover can safely be harvested from fields*
  • Routine soil testing and plant analysis should be used to monitor effects of stover harvest and all farming operations
  • Depending on location, an increase in phosphorous (P) and potassium (K) fertilizer application rates was found to be profitable
    • Clarion-Nicollet-Webster soil association suggests that plant availability of both P and K is likely being affected by the high pH and Ca concentrations in the soil more so than by the slight increase in removal due to stover harvest
  • Results are consistent with regional results associated with the USDA Renewable Energy Assessment Project (REAP) team and the Sun Grant Regional Partnership Corn Stover Teams

*Fields similar to the one tested

Iowa State University Soil Overview Summary of the Emmetsburg, IA Test Plot

  • Soil Nutrient Removal
    • No trend in soil fertility between treatments from soil samples
    • No significant removal of P, but reasonable amount of K (10-40 lbs) depending on treatment
    • Local soil tests tend to dominate recommendations, with spatial trend
  • 2010 Fertilizer Recommendations
    • Spatial trend between reps. (Correct nominal rates by REP)
    • Nominal nitrogen (N)
    • Nominal P
    • Nominal K
      • Low cut ( 90%), High cut (50%), and 2-Pass Baler treatments (Rake & Bale) – 40 lbs/ac K
    • Nominal K plus
      • Cob Only and Conventional, Material Other Than Grain (MOG) Treatments (POET Treatments) – 10 - 15 lbs/ac K
  • 2011 Fertilizer Recommendations
    • Nominal N
    • Nominal P
    • Nominal K
      • Conventional – no additional K needed
      • Cob Only and Conventional , MOG Treatments (POET Treatments) – 10 lbs/ac K needed
      • Low cut ( 90%), High cut (50%) and 2-Pass Baler treatments – 25 lbs/ac K needed

Conclusions drawn from combined ISU and USDA data

  • Little to no impact is seen in soil fertility by removing 1-1.5 BDT of residue
  • Both N and P application levels remain the same as the conventional treatment
  • Only K rates may need increased; however, only an additional 10 - 15 unit of extra P2O5 are needed ($5 - $8/acre)


Biomass collection offers a unique path to saving and earning money, increasing yields, managing your residue and tillage, and increasing the efficiency of your operation.


  • Most producers raising corn-on-corn have seen an increase in yield where they removed cobs and high cut material the year before
  • Yield increases are most likely being caused by:
    • Darker soil surfaces that are allowing soils to warm faster, resulting in quicker germination and better stands.
    • Less nitrogen is being used in the breakdown of the residual cobs and high cut material, leaving more for the crop.
    • Enhanced microbial activity due to reduced residue and nitrogen needs, microbial pathways are freed up.

Table 1. Average and relative corn grain yields as affected by various stover harvest treatments

Biomass Producer Handbook - Project LibertyBiomass Producer Handbook - Project Liberty

For more information:

Emmetsburg Commodities Team

POET Biomass Team

Fill out our online contact form.


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