Iowa farmer uses regenerative practices to build soil natural matter, decreasing need for fall fertilizer.
Kelly Nieuwenhuis rarely uses fertilizer in the fall on the 2,700 acres of corn and beans he farms with his brothers in OBrien County, Iowa. The third-generation farmer applies fertilizer in the spring, and his farming practices allow him to apply far less than the suggested quantity.
” We leave 90 percent of our acres untouched in the fall,” he said, “and over the winter season the corn stalks and everything weaken so much that we can hit it when with a vertical tillage tool [in the spring] and then plant soybeans right into that.”
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Nieuwenhuis started one-pass vertical tillage 7 years earlier, however his family started reducing tillage back in the 1990s. As a result, his soils are abundant in raw material. In some fields, raw material rises as high as 6.5%.
Confidence in his Soils Fertility Led Nieuwenhuis to Stop Applying Fall Fertilizer
” We were seeing our organic matter being built, and we understood there was additional nutrient holding capabilities and better water holding capabilities, and we saw the credits available there for our next growing season,” he said.
Cutting out the fall fertilizer application not only saves Nieuwenhuis significant money and time, its also great for the environment and water quality. Nutrient loss from farms can be especially troublesome in the fall if fertilizer is used on frozen or saturated ground. Snow and rain get rid of nutrients that are not able to percolate through the soil.
Building soil raw material is one method to decrease nutrition loss in the fall and winter season. Experts say there are other more instant steps that farmers can take. These include:
Assessing soil nitrate levels with a soil test prior to choosing to make fall applications A soil test can help minimize total application amount or possibly show that an application is unneeded.
Utilizing a nitrification or a stabilizer inhibitor to keep nitrogen longer in a usable type and make sure soil temps are below 50 F degrees before making any fall applications.
Taking advantage of residual soil nitrate and considering split applications, including in season applications at the v3 or v6 phase for circumstances.
Planting a cover crop
Eliminating fall fertilizer application can conserve farmers money and benefit the environment. If fertilizer is applied on frozen or saturated ground, Nutrient loss from farms can be specifically bothersome. © Chris Helzer/TNC
” Ideally, we are not applying nitrogen in the fall, but if a grower is thinking about a fall application, it is essential to validate existing soil nitrate levels with a soil test to represent any residual nitrogen that is left in the soil,” said Paige Frautschy, director of agriculture at TNC Iowa.
Recommendations for Keeping Nitrogen in the Soil
Since soil retains more nitrogen during a dry spell year, frautschy notes that its especially crucial to test soil in locations where there has actually been substantial drought. Crops utilize less nitrogen, but there is also a major reduction in the amount of nitrogen lost to leaching and denitrification, according to Michael Castellano, professor of agronomy at Iowa State University.
The second recommendation is to make sure that all fall nitrogen applications have a nitrification inhibitor, or a stabilizer, and are used when the soil temperature is 50 F degrees or less, to keep the nitrogen in a functional type longer and prevent losses from denitrification, volatilization or leaching.
Nieuwenhuis has actually been utilizing a stabilizer with his urea applications for the last five years and states hes very delighted with it.
Such losses can occur within hours of using urea-containing fertilizer. As soon as urea is included into the soil, through tillage, injection, or light rainfall, ammonia volatilization is significantly decreased.
Nitrification inhibitors are chemical substances that momentarily decrease populations of the germs in soil (Nitrosomonas and Nitrobacter) that convert ammonium to nitrate, which can quickly leach out of soil. These compounds likewise prevent denitrification, or the microbial procedure that turns nitrate to nitrogen gas, causing further nutrient loss.
More About TNCs Work in Agriculture
The 3rd suggestion is to benefit from recurring soil nitrate and use split fertilizer application during the growing season.
Castellano says that a bit majority a pound of nitrogen is eliminated in each bushel of corn collected. That means, for instance, “for a farmer that applies 200 pounds of nitrogen an acre and has 200 bushels per acre corn yield, there could be almost 100 pounds of nitrogen still residing in the soil.”
Factoring in that recurring nitrogen into fall fertilizer planning is “essential for water quality given that it minimizes prospective nutrient losses– especially if we have heavy fall or spring rains following a drought year. Were likewise seeing record high fertilizer costs, so its advantageous for the farmers bottom line too,” said Frautschy.
Reservoir of Nutrients
Research also reveals that each percent of raw material in the soil launches 20 to 30 pounds of nitrogen, 4.5 to 6.6 pounds of P2O5, and 2 to 3 pounds of sulfur per year. Growers who have actually built the raw material in their soils can take benefit of that reservoir of nutrients without diminishing the reserves.
Splitting the spring fertilizer application by applying a starter fertilizer and the rest when the plant is actively growing can assist avoid nutrition loss from heavy rainfall events.
“Theres a much better opportunity that the crop will actually be able to use that fertilizer in the spring, throughout the growing season, versus if youre using it in the fall,” noted Frautschy, including that fertilizer might be cheaper or simpler to use in the fall, however it is also susceptible to loss as it is exposed to freeze thaw cycles, rain, and so on. These losses might cancel out any potential expense savings.
Last, professionals advise planting a fall cover crop, like winter season rye. “Cover crops can quickly keep 25 pounds of nitrogen per acre or more by scavenging and holding excess nitrogen in the soil and releasing it back as they decompose in the spring, making it available for future crops to use up. Cover crops are likewise fantastic tools for developing soil health and for protecting our important soils from wind and water disintegration.
Nieuwenhuis is running a trial of cover crops, comparing no till and cover crops to very little till with cover crops, and examining the impact on weed pressure, herbicide usage, and nutrient holding capability, in addition to on yield.
“I genuinely think our soils are our best filter system we can have and if you got a good organic matter and your water is going through that, that raw material holds the nutrients,” he said.
As an outcome, his soils are rich in natural matter. Snow and rain wash away nutrients that are unable to percolate through the soil.
Structure soil natural matter is one method to minimize nutrition loss in the fall and winter months. “Cover crops can quickly retain 25 pounds of nitrogen per acre or more by scavenging and holding excess nitrogen in the soil and launching it back as they disintegrate in the spring, making it readily available for future crops to take up. Cover crops are also great tools for building soil health and for protecting our valuable soils from wind and water erosion.
