By Peter Tomlinson, Environmental Quality Specialist
Note: The following article is a slightly edited excerpt from Water Quality Best Management Practices, Effectiveness, and Cost for Reducing Contaminant Losses from Cropland, K-State Research and Extension publication MF-2572, August 2015.
Kansas State University Research and Extension faculty have conducted field, laboratory and computer modeling studies on the effect of crop management practices on the runoff of pesticides, nutrients and sediments/suspended solids from no-till crop fields. This article and chart list recommended best management practices (BMPs) for no-till cropping systems, along with the effectiveness of a BMP in reducing edge of field surface runoff of a contaminant, and an estimated cost of implementing BMPs.
The percent reduction in surface runoff by adopting a listed BMP is the effectiveness obtained from adoption of a single new BMP. It is not appropriate to consider the effectiveness of the adoption of several BMPs to be additive.
A reported BMP cost is the expected loss in grower profitability associated with adoption. Alternatively, it can be treated as the payment-to-producer required to encourage adoption. BMP costs and effectiveness figures are based on research, farm data and professional estimates.
The table below contains the cost and effectiveness of reducing the edge-of-field surface runoff of contaminants from the adoption of various BMPs in a no-till system. The data on reduction of surface runoff by adopting a BMP are relative to a no-till corn and grain sorghum field where atrazine herbicide is applied pre-emergence (herbicide broadcast, surface applied following crop planting but before crop emergence), phosphorus (P) and nitrogen (N) fertilizer broadcast applied before planting the crop, with greater than 1% slope on upland clay or clay loam soils. For wheat and other crops, the comparison benchmark is P and N fertilizer broadcast applied, unincorporated, no-till before planting the crop, with greater than 1% slope on upland clay or clay loam soils.
| Best Management Practice | Cost/Acre | Atrazine* | Soluble Phosphorus* | Total Phosphorus* | Nitrogen* | Suspended Solids* |
| Post-emergence herbicide applications | $5.48 | 50% | 0% | 0% | 0% | 0% |
| Use of alternative herbicides to atrazine | $11.69 | 100% | 0% | 0% | 0% | 0% |
|
Band herbicides, N and P on the soil surface before or at planting, typically 30% of surface area, weeds between rows controlled with cultivation |
$7.95 | 50% | 20% | 20% | 25% | 0% |
| Subsurface apply P or N fertilizer | $13.25 | 0% | 70% | 50% | 70% | 0% |
| Apply atrazine in fall for next year's row crop | $5.48 | 50% | 0% | 0% | 0% | 0% |
| Apply herbicide in early spring, May 1 | $5.48 | 50% | 0% | 0% | 0% | 0% |
|
Use split applications of herbicide, e.g. half to two- thirds before May 1 and half to one third at planting |
$5.48 | 25% | 0% | 0% | 0% | 0% |
|
Use reduced soil-applied herbicide application rates followed by post-emergence application |
$5.48 | 33% | 0% | 0% | 0% | 0% |
| Crop rotations | 0% | 30% | 25% | 25% | 25% | 25% |
| Establish vegetative buffer strips | a/ | 25% | 25% | 50% | 35% | 50% |
|
Do not spray/apply herbicides or nutrients within 100 feet of streams or near where runoff enters a stream |
b/ | 20% | 25% | 25% | 25% | 0% |
| Use weed scouting/integrated pest management | $5 | 0-50% | 0% | 0% | 0% | 0% |
| Contour farming (without terraces) | $9.43 | 20% | 20% | 30% | 20% | 20% |
| Terraces with tile outlets | c/ | 10% | 10% | 30% | 10% | 30% |
| Terraces with grass waterways (with contour farming) | d/ | 30% | 30% | 30% | 30% | 30% |
| Soil sampling and testing | $1 | 0% | 0-25% | 0-25% | 0-25% | 0% |
| Sound fertilizer recommendations | $0 | 0% | 0-25% | 0-25% | 0-25% | 0% |
| Cover crops (fall, winter, spring) | e/ | 0% | f/Insufficient data | f/ | f/ | f/ |
*Percent reduction in surface runoff by adopting BMP
a/ Establishment cost of $150 per acre plus an annual cost equal to the average per acre land rental rate for the acreage within the buffer strip.
b/ Annual cost equal to the average per acre land rental rate for the acreage where herbicides and nutrients are not applied (i.e., acres within 100 feet of streams or before runoff enters a stream).
c/ One time installation cost of $522 per treated acre plus an annual cost of $13.20 acre.
d/ One-time installation cost of $320 per treated acre plus an annual cost of $13.20 per acre plus an annual cost equal to the average per acre land rental rate for the acreage within the grassed waterway.
e/ Cover crop seed mixes range from $10 to 50 per acre, average no-till planting costs of $15.48 per acre, chemical costs of $11.69 per acre, and chemical application costs of $5.48 per acre.
f/ At the present time there is insufficient data to determine reductions from the use of cover crops in a no-till production system. Research has been initiated in Kansas and Iowa.
Source for Custom Farm Rates: www.agmanager.info/farmmgt/machinery/Tools/KCD_CustomRates(Feb2014).pdf.
