More farmers are switching to pop-up fertilizer where it's placed directly with the seed. That's an observation made recently by Bob Nielsen, Purdue University Extension corn specialist.
From the field it's also obvious some are going to two-part starter fertilizer applications, applying row starter either two inches to the side and two inches below the seed, or some variation of that, plus pop-up fertilizer in the row.
Several people setting up new planters over the past couple of years, especially those in reduced tillage, have gone this route.
The only problem is that you must watch how much fertilizer of certain types you place directly with the seed, Nielsen says. Too much can cause burn and injury, and cause the plant to get off to a slow start, if at all – certainly not the faster start you're hoping for.
The nutrients to watch are nitrogen and potassium, he says. If you farm heavy soils, the upper limit is about five pounds per acre of N and K combined. This is actual units of N and K. Going above that combination can set germinating seeds up for problems.
If you farm sandy soils, the problem is even more critical. On sandy soils Nielsen says the upper limit of N and K combined should be about three pounds per acre as pop-up applied in the row.
Another critical issue with starter fertilizer is making sure that if you think you're applying starter fertilizer to the side and below the seed, that the starter fertilizer discs are indeed delivering the fertilizer where you want it. If the discs are out of alignment and deliver even higher rates of N and/or K often used in row starter too close to the seed, you will be set up for plant in jury problems again.
It's worth checking to make sure your fertilizer openers and delivery system is putting fertilizer where you want it, even on new planters.