Cover crops’ impact on water quality
Research has shown that cover crops have a positive effect on water quality, does that apply to Michigan?
The MSUE Cover Crops Team of Dr. Dale Mutch, Dr. Dean Baas, Christina Curell and Paul Gross worked together to assess the amount of sediment and phosphorus that cover crops can reduce to improve Michigan water quality.
These data are based on seed dealers’ written and phone surveys, National Agricultural Service Statistics (NASS), county soil surveys, NRCS: 1) Wind Erosion Prediction System (WEPS), 2) Revised Universal Soil Loss Equation Version 2 (RUSLE2), 3) CORE4 Conservation Practices Training Guide—phosphorus entrapment estimate. Also contributing to the process was the MSU Median Soil Test Values for Minerals Soils in Michigan Counties.
We estimate on average cover crops will reduce sediment 1,840 pounds/acre from wind erosion and will decrease sediment 340 pounds/acre from water erosion. Cover crops are estimated to reduce phosphorus by 0.30 pounds/acre from wind erosion and 0.04 pounds/acre from water erosion.
Based on our surveys and other resource materials, we estimate that 1.1 million acres were planted in cover crops in 2011 when including wheat, and 400,000 acres of cover crops were planted excluding wheat. Seed dealer comments have indicated at least a doubling of cover crop seed sales over the last year.
Therefore, cover crop adoption is estimated to have had the following impacts in Michigan (not including wheat):
- Sediment lost to wind erosion was reduced by 370,000 tons
- Sediment lost to water erosion was reduced by 136,000 tons
- Phosphorus loss from wind erosion was reduced by 120,000 pounds
- Phosphorus loss from water erosion was reduced by 15,400 pounds
Total combined wind and water erosion reductions from MSUE cover crop programming:
Sediment = 506,000 tons; Phosphorus = 135,400 pounds