MDA Fertilizer rules to affect local farming methods

The Minnesota Department of Agriculture is updating its rules for nitrogen application, and nearly half of Rock County’s farmers could be affected.
A draft rule has been released, and the public comment period closes Aug. 25. The rule, designed to reduce nitrates in groundwater, has two parts.
Part 1 is directed at farm ground in “vulnerable groundwater areas,” defined as areas where nitrates move easily through the soil into the groundwater.
These soils, which tend to be on near-surface bedrock, comprise a good share of northern Rock County farm ground (see the map).
According to the proposed rules, nitrogen application in these areas will be restricted in the fall and on frozen soil.
An MDA map identifies specific vulnerable soils, and if more than half of a county section is classified as vulnerable, farmers in the entire section would be banned from fall and frozen soil application.
(As the rule-making process continues, these classifications may change to affect smaller areas.)
If less than 50 percent of a section has vulnerable groundwater, fall and frozen soil application is restricted on fields with near-surface bedrock or poor soil.
Part 2 of the MDA nitrogen fertilizer rule is directed at farmers in areas with high nitrates in groundwater.
Nitrate data from public and private wells is used to prioritize problem areas and to determine if mitigation — such as cover crops — is necessary.
A local advisory team of producers and ag professionals will advise the MDA on appropriate methods and support implementation of these activities.
Doug Bos of the Rock County Soil and Water Conservation District was on the original advisory team that wrote the draft plan. He said he felt that all interests are adequately represented with the 25-member team.
“This isn’t something the MDA dreamed up in a closet,” said Bos, assistant Land Management Director.
“They worked with all Minnesota producer groups, universities and soil and water folks like me. It’s a very good group of people who put this together over a two-year process.”
The rule-making process was recently extended to include more public input meetings. Change may be adopted in early 2019.
 
It’s all about the water
Bos said many Rock County farmers are already implementing better practices in vulnerable areas.
Data released earlier this year showed elevated nitrate contamination in more than half the wells tested.
Battle Plain, Clinton, Luverne, Magnolia, Mound, Rose Dell and Vienna townships were targeted for testing private wells based on their “vulnerable” soil types and a high percentage of row crops.
“It paints the picture we are getting nitrates in our water,” Bos said in March when the well tests were released.
He has been working with farmers in vulnerable areas to improve fertilizer application methods, especially for corn.
Research shows that only half of fertilizer applied to cornfields is absorbed and utilized; the rest is susceptible to water runoff and leaching into aquifers, depending on soil type, past crops and other factors.
Further compounding nitrogen loss is the fact that climate change is delivering rain in “extreme weather events,” according to Bos, who notes that in the past 20 years, 30 percent of local rain has come in hard downpours.
“We have to find a way to spoon-feed it (to crops) to prevent nitrogen from getting into our water,” Bos said in March.
He said farmers are receptive to the changes because fertilizer is expensive and it’s in their interest to keep it from leaching into groundwater.
For many affected producers, it could be just a matter of applying the majority of their nitrogen after planting when the corn is still small.
Bos said spring fertilizing could go a long way toward reducing nitrogen contamination, especially if it’s combined with cover crops.
“Cover crops can reduce nitrate leaching by 50 percent,” Bos said. “Not only does it hold soil and increase water-holding capacity – it holds those nutrients until the next cropping year.”
For this reason, cover crops are becoming increasingly popular across the country.
But Rock County’s nitrate problems won’t have easy solutions.
Restricting fertilizer application to spring will create hardships for some farmers, especially those who rely on commercial applicators who have a hard time keeping up in the spring.
In some of the most vulnerable areas, the answers might be even more difficult, Bos said.
“In these areas, because of their soil porosity, it’s difficult to raise a nitrogen-needing crop and keep the nitrogen out of the water,” Bos said.
“It might mean raising something else … And if they can’t financially do it …  We can’t just say, ‘Sorry, you can no longer grow crops here.’”