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Harvesting Crop Residue: What is it worth?

Bales of corn residue

Dollar Value of Crop Residue

The plant residue left in the field after harvest is a valuable resource. Increasing demand for harvested crop residue has left many producers wondering whether they should bale and sell their crop residue or leave it in the field. To help make that decision producers should consider the following:

Cost of harvesting the residue

Based on the custom baling price of $11.80 per large round bale, the cost of harvesting residues can range from $60-70/acre depending on how many bales there are per acre. If the average bale weighs 1,200 lbs., that works outs to about $20/ton.

Value of removed nutrients

Based on data from the Agricultural Research Service's (ARS) National Soil Tilth Lab, a ton of corn residue contains bout 37 lbs. of nitrogen (N), 3.5 lbs. of phosphorous (P2O5), 33 lbs. of potassium (K2O). Based on fertilizer prices from the fall of 2008, the estimated cost of nutrients removed would be about $46/ton (see table). If you remove 3-4 tons of residue per acre (5-6 round bales) the value of the nutrients removed would be $138 to $185 per acre.

Fertilizer Value of Nutrients in One Ton of Corn Residue*

 

 

Element

Concentration in residue (%)

Pound per ton

Fertilizer nutrient price (.lb)**

Value of nutrients in residue ($/ton)

a

b

c = (b/100) x 2,000

d

e = c x d

N

1.85

37

55

$20.35

P2O5

.175

3.5

1.06

$3.71

K2O

1.65

33

.67

$22.11

Total Value

 

 

 

$46.17

*Based on Table 1 from Al-Kasi, et al, 2008. The Effect of Residue Management on Soil and Water Quality.
**Based on October 2008 fertilizer prices. Substitute current prices in column d and multiply by column c to get value of each nutrient per ton of corn residue.

Erosion Control

The value of maintaining crop residue on the soil surface to control soil erosion is well documented. all the NRCS conservation plans for highly erodible land (HEL) require that a minimum amount of crop residue be present to control soil erosion. The amount of residue required varies depending on soil type, crop rotation, tillage system and existing conservation practices. Producers with HEL fields should contact their local NRCS office to review their conservation plan and discuss the potential impact of harvesting crop residue before they remove any from the field.

Soil Organic Matter/Soil Health

Perhaps the most important factor to consider before harvesting crop residue is the impact on soil organic matter. Soil organic matter contributes directly to the nutrient availability, nutrient holding capacity, and water holding capacity of a soil. It also plays a significant role in the formation of water stable aggregates in the soil which affects infiltration, aeration and drainage.

Soil organic matter also plays a significant role in soil health as it provides carbon an energy for soil microorganisms are essential for nutrient cycling in the soil and some form mutually beneficial relationship with plant roots providing nutrients to the plants in exchange for energy in the form of simple sugars.

Removing crop residue in excess of what the soil can tolerate will ultimately result in the deterioration of the soil resource and declining yield. Research by the USDA-Agricultural Research Service at the University of Nebraska Agricultural Research and Development Center found an average yield decrease of 6% over five years for continuous no-till corn when an average of 50% of the crop residue was removed each year (Varvel et al, 2008). While the nutrients removed can be replaced, the functions of soil organic matter are not so easily mitigated

Ways to Reduce the Impact of Residue Removal


Producers who do decide to harvest crop residue have several options to reduce or minimize the impact of crop residue removal.

1. Reduce or eliminate tillage operations
Tillage operations could bury much of the remaining crop residue and increase the rate of residue decomposition adding to the negative effects of crop residue removal. Switching to a no-till system would reduce the negative impacts of crop residue removal.

2. Reduce the number of years low residue crops are grown in the crop rotation
The negative impact of harvesting crop residue is greater if the rotation includes low residue crops such as soybeans. Switching from a corn-soybean rotation to a continuous corn, corn-corn-soybean or corn-soybean wheat rotation would somewhat offset the negative impact of removing crop residue.

3. Consider growing a cover crop
Establishing a cover crop prior to harvest or immediately after harvesting crop residue would minimize the negative impacts of crop residue removal. Cover crops protect the soil surface, enhance soil biology, capture remaining nutrients and, if legumes are included, add nitrogen back into the system.

4. Consider adding manure
Manure will not only replace some of the nutrients that were removed with the crop residue but will also add some organic matter back into the system. Manure alone would not be adequate for soil erosion control on HEL fields because it would not provide enough cover to protect the soil. Manure would work best in combination with a cover crop.

References

Mahdi Al-Kaisi, Associate Professor, Iowa State University, The Effect of Reside Management of Soil and Water Quality.
Douglas Karlen. 2008. Agricultural Research Center National Soil Tilth Lab, Ames, Iowa. GSA-SSSA 2008 Presentation Alabama Energy Summit, Sept. 17, 2008.