Reading and interpreting a nutrient management plan (NMP) can be intimidating. The plan has a lot of charts, numbers and symbols. Restriction maps include a lot of squiggly lines, different-colored hash marks and a multitude of setback symbols that aren’t immediately obvious.

“While all of these pieces are vitally important, we can approach the NMP with a very simple concept: Everything in the plan is there to minimize the risk of nutrients that you apply leaving the field,” explains Zach Sutter, nutrient management planning specialist with Rock River Laboratory. With this in mind, there are a few things Sutter recommends growers think about before they even open their NMP to ensure they remain in compliance:

1. There are two ways nutrients leave the field: down and off.

“Due to the way nitrogen interacts with the soil, it can easily move down through the soil profile and into groundwater when conditions are right,” says Sutter. “Certain soil types are higher-risk than others.”

On wet soils and soils that have shallow depth to bedrock, Sutter explains that the groundwater (or the path to groundwater) is simply closer to the area of nutrient application and plant growth. On permeable soils (sandy soils), nitrogen does not cling to soil particles, and water moves quickly through the soil profile. “Growers know their soils better than anyone. Think about which fields might contain these risky soil types and refer to your plan or plan writer for how to safely apply nitrogen on them,” recommends Sutter.


Phosphorus is primarily a risk if it leaves the field and enters a water body (lake, stream, pond, river, etc.). Sutter shares, “I like to think of it this way: If there was a flat field with no water body nearby, there would be minimal risk of phosphorus leaving that field and entering a water body. Even in a worst-case scenario, much of the phosphorus that does leave the field would be absorbed by forest and grassland before it reaches a water body.” He advises farmers to think about what fields might be high-risk and refer to their plan and plan writer for information on management options for high-risk fields.

2. The risk of nutrients leaving the field increases as the time between application of nutrients and establishment of a growing crop increases.

Soil loss inevitably means nutrient loss. It is an unfortunate fact of our weather and cropping systems that our fields are likely to be bare, or have minimal cover, during the times of highest risk for soil loss (i.e., high precipitation in spring, before planting and fall after harvest). Sutter explains management decisions that reduce soil loss, such as reducing tillage, cropping on the contour, planting cover crops and installing buffer areas, will make compliance easier.

“Contrary to some rumors you might have heard out in the countryside, manure can be applied on most farms in the winter,” says Sutter. “Winter manure applications are the most restrictive elements of an NMP and require careful attention to rate and placement to remain in compliance.”

Fall nitrogen applications can be a risk when applied on sensitive soils described above. “Fall applications of commercial nitrogen are mostly not allowed. Manure is allowed on fall nitrogen-restricted soils, but there are restrictions based on the soil type,” says Sutter. He advises, “If it isn’t possible to wait until spring to haul on these soils, refer to your plan and plan writer for options. Management practices for compliance include: rate limitations, waiting until soil temperatures have cooled, surface-applying manure and use of nitrification inhibitors.”

If the principles of nutrient management planning are simple, the rules, regulations and procedures for putting a plan together are far from it. One big challenge is keeping up-to-date with regulations. Sutter shares, “In the past few years, erosion factors known as ‘T’ and ‘K’ numbers for many Wisconsin soils have been updated by the Natural Resources Conservation Service (NRCS). The NRCS has also put out a new 590 Standard which has been incorporated into Ag, Trade, and Consumer Protection (ATCP) Code 50 by the Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP). Finally, the Department of Natural Resources (DNR) has revised Natural Resource (NR) Code 151 to include new performance standards for shallow soils over Silurian dolomite bedrock.”

If it sounds like it must be a full-time job to keep up with all these acronyms and administrative codes, that’s because it is. Professional NMP writers must be certified (certified crop adviser [CCA] is the most common) and participate in continuing education to maintain certification.

“CCAs develop relationships with the various government agencies receiving NMPs so the grower can focus on implementing the plan in the field rather than having to worry about details like the submission process or plan formatting,” explains Sutter.

An NMP is a tool. It is a tool for staying in compliance with rules and regulations, and it is a tool for managing a farm sustainably and profitably. Understanding NMPs will make compliance easier and unlock the potential economic and sustainability benefits that come along with creating and following such plans. But growers don’t have to understand each and every nuance of the multitude of rules and regulations governing NMPs.

As Sutter shares, “Understanding the basic principles of nutrient management planning and hiring a CCA to write the plan allows the grower to focus on in-field implementation and have the ease of mind that on the ‘on paper’ compliance is being handled effectively and responsibly by a professional.” end mark

PHOTO: Spreading manure. Courtesy photo.

Founded in 1976, Rock River Laboratory is a family-owned laboratory network that provides production assistance to the agricultural industry through the use of advanced diagnostic systems, progressive techniques, and research-supported analyses. Employing a team of top specialists in their respective fields, Rock River Laboratory provides accurate, cost-effective and timely analytical results to customers worldwide.

—Excerpts from Rock River Laboratory press release