In areas where the groundwater is vulnerable to nitrate contamination, following nitrogen fertilizer best management practices (BMPs) alone may not be enough to reduce the amount of nitrate leaching into groundwater to meet water quality goals. In these cases, the MDA encourages farmers to consider practices and activities that go beyond traditional nitrogen fertilizer BMPs. These are referred to as Alternative Management Tools (AMTs). In many cases these practices are developed and used by farmers and implemented in ways that are relevant for local conditions and opportunities. The MDA will work with the local agricultural community to encourage and incentivize these practices. The MDA will also continue to work toward providing technical and financial resources regarding the effectiveness of these alternatives.
Under the Groundwater Protection Rule approved AMTs may be used as a substitute for the adoption of specific nitrogen fertilizer BMPs within individual Level I and Level 2 Drinking Water Supply Management Areas (DWSMAs).
Farmers have many choices of alternative practices that may fit into their operation. All of these have one thing in common: they can reduce nitrate-nitrogen leaching and reduce the inherent risk of nitrogen loss.
The MDA, in consultation with scientists at the University of Minnesota and others, is currently reviewing scientific research and is writing documents that describe each approved AMT.
AMTs which are approved are posted on the Approved AMTs page.
The MDA is encouraging farmers, crop consultants, or others to suggest new AMTs. The MDA will review the suggested AMTs using a scientifically based AMT evaluation process, including a review of documentation of expected nitrate leaching loss reductions, a review of the scientific literature, consultation with Land Grant university experts, input from the agricultural industry and commodity group leaders, computer modeling, and other relevant information, such as research trial data. Please see the AMT review process to learn how to suggest a new AMT.
Further, the MDA has identified the potential future AMTs listed below. The list is not intended to be an all-inclusive list, but rather examples of practices the MDA may consider as AMTs.
Many of these practices have well documented reductions for nitrate-nitrogen leaching. Specifically, they can reduce nitrogen input needs and /or increase overall uptake of nitrogen making less available for leaching. For some alternative cropping systems, the AMTs may be conditional as they require already-established BMPs to be followed, such as, using nitrogen fertilizer recommendations from the University of Minnesota.
Increasing continuous cover can be accomplished by diversifying crop rotations, adopting perennial cropping systems, and incorporating cover crops.
- Crops with low nitrogen application needs and land cover
- Perennial forage (alfalfa, clover, grass pasture and others)
- Pasture and hayland
- Crops with relatively low nitrogen requirements, such as small grains (e.g., wheat, oats, rye, barley, triticale) and canola
- Perennial grains
- Selection of lower nitrogen requiring varieties and adjusting seeding density
- Forever Green crops and other innovative crops and cropping systems that have the potential to be the next generation of low nitrogen input or nitrogen management crops.
- Set-aside programs – continuous cover
- Land swapping to relocate high-intensity crops from vulnerable areas to a less sensitive location
- Land retirement
- Variable rate irrigation water management
- Crediting nitrogen from irrigation water
- Conservation tillage or residue management
- Equipment – robots, highboys, drones, others
- Data gathering and interpretation software and equipment
- Use of crop sensors to determine nitrogen crop needs
- Seed hybrids – through selection of crop varieties that have been shown to use nitrogen more efficiently, or allow greater nitrogen uptake
- reduced nitrogen input varieties,
- drought tolerant varieties,
- new varieties with traits that can increase nitrogen uptake (e.g. expanded root systems, nodulation)
- Use of soil, plant and/or fertilizer amendments that have been demonstrated effective under similar cropping and climatic conditions
Enrollment in the Minnesota Agricultural Water Quality Certification Program
A combination of practices protecting water quality is normally required to be certified through the MAWQCP. Obtaining certification is therefore considered adequate and appropriate as an AMT as a substitute for all BMPs.