Pop-up fertilizer applications allow for closer and quicker nutrient uptake, but farmers need to watch out to avoid direct fertilizer-to-seed contact.
A closer look at a fertilizer trend gaining pop-ularity
No two snowflakes are alike. The same could be said of fertilizer programs, which can vary widely from farm to farm and across geographies, according to J.C. Remsberg, marketer with A.J. Sackett & Sons.
"So many factors can affect how fertilizer is used, such as size of operation; soil property and conditions; and current fertility levels," Remsberg says. "Different areas in the country do different things."
Although each fertilizer strategy is a little different, every good fertilizer strategy has one thing in common: They all deliver the nutrients the crop needs, when the crop needs it. That’s why the allure of pop-up fertilizers has become so strong in recent years; more farmers see it as a means to help their crop get a faster, stronger start.
"We see it as a good investment, especially in this part of the country," says Kerry Baldwin, a farmer in North Dakota. "We want to do everything we can to get the plant growing a little faster. With a limited growing season, we want to get the crop out fast."
Safety considerations. Baldwin’s planter set-up delivers a liquid blend of nitrogen, phosphorus and potassium (NPK) in each row before a disk turns over ½" to 1" of soil ahead of the seed drop to avoid the fertilizer making direct contact to the seed.
One concern with the use of pop-up fertilizer is the potential for salt injury on germinating corn. If the fertilizer concentration in the soil surrounding the seedling is high enough, water can move out of the seedling and into the soil, a potentially lethal process.
Some researchers, such as Michigan State University Extension soil scientist Kurt Steinke, say there are other, safer alternatives to pop-up fertilizer applications.
"Many times, the risks of reduced germination and yield loss outweigh potential benefits," he says. "Fertilizer placement 2" below and 2" beside the seed—2x2—can improve efficiency and poses minimal risk injury.
Pop-up fertilizer applications can be successful at lower application rates, Steinke says. The key is to pay close attention to know your soil’s cation exchange capacity (CEC). The CEC is a soil’s relative ability to hold and release various elements and compounds, including ammonium, potassium, magnesium and others. It’s almost like a sponge absorbing water or a cast iron pot absorbing heat.
"For corn production, we do not recommend placing more than 5 lb. of nitrogen plus potash in contact when the CEC is less than 7 and no more than 8 lb. when the CEC is 8 or greater," Steinke says. "This is because lower CEC soils have less reaction between the fertilizer and soil. That causes the soil solution’s salt concentration to remain high."
Soil moisture also can have a profound effect on how pop-up fertilizers perform, he adds. Higher moisture is preferred. Under dry conditions, fertilizer salts remain near the seed for longer periods of time.
Equip yourself. Farmers need to understand equipment challenges when considering pop-up or 2x2 fertilizer applications, says Robert Mullen, PotashCorp director of agronomy.