Interest and adoption of baling crop residues has seemed to increase over the last few years. The need for livestock bedding is highly understandable. However, if the baling goes beyond the needs of livestock and manure replacement to the soil is limited, soil health is probably diminished. The National Agriculture Statistics Service (NASS) estimates for livestock inventory in South Dakota have not shown drastic increases in livestock numbers. For example: NASS reported that from Jan1, 2010 to Jan 1, 2014 the number of all cows remained the same at 1,730,000 as well as other cattle estimates. Due to a somewhat non-changing cattle numbers in South Dakota, where are all the crop residue bales going?
Effects on Soil Health
The concerns for residue baling are paramount to soil health concerns.
Removing crop residues can lead to:
- Decreased soil organic matter.
- An unprotected soil surface that can lead to increased erosion.
- Surface soil structure degradation that reduces soil water infiltration and air exchange.
- Crop nutrient removal.
Effects on Soil Potassium Levels
Plant potassium is primarily contained in the crop residue (See iGrow publication: The Value of Crop Residue). Fortunately, potassium is very water soluble and can be leached into the soil with adequate precipitation. However, this past fall has been relatively dry and therefore resulting in possibly large potassium removal rates with crop residue baling. A 155 bu/a corn crop may contain up to 93 lbs of K2O/acre. Today the value of this K2O is approximately $33.32/acre ($430/ton potash). With past experience in soil testing it has been noted that approximately 10 lbs of K2O will change soil test extractable K by 1 ppm. Therefore, if the crop residues are removed from fields with higher soil test extractable K levels the influence of this removal might not be detectable. This is not the case with many fields in Eastern South Dakota. Soil test extractable K levels are on a decline because of higher crop grain removal in the past 20 years. Please consider the impacts of crop residue removal on soil health as well as the value of potassium removal before deciding to bale crop residues.