If you read Indiana Prairie Farmer whether hard copy or online magazine on this site (Go to 'more prairie farmer in upper right corner), then you probably recognize Crops Corner and Hoosier Bug Beat column titles. Information for these columns comes from a rotating panel of members of the Indiana Certified Crop Advisors group.
Here's a sneak preview from March. The discussion starts here, continues tomorrow at this site and concludes in the March issue of the magazine. What do you do if someone is pushing you to avoid high-priced potash this year by going to a low volume solution? Or what do you need to know if you already use low-volume pop-up fertilizer to supply nutrients?
Jesse Grogan with LG Seeds, based in Lafayette, starts with 'it depends.' You need to know how your soil responds to potash and if you have a short or long-term management plan when it comes to soil fertility management, he advises.
"Placement and rate are important factors," Grogan says. "Pop-up fertilizers can be very effective in early season for increased plant growth in cool and wet soils, and in corn-following-corn rotations."
He notes that potash in pop-up fertilizers is usually at lower rates so seed is not injured by salt concentrations, especially in sandy or coarse soils. However, it's an issue at some point in all soils. If you're applying nitrogen in the pop-up as well, those units add to the potash units to determine total salt content applied in the row.
"If soil test levels of potash is adequate than the pop-up rate could prevail," he suggests. "If soil test levels are less than critical values, then band applications can be best to improve soil fertility value and crop response.
"Highest potassium uptake for corn is at the tassel stage, so adequate levels of potassium where roots have moisture contribute to highest yield. Usually long-term management programs for potash pay off in more yield and profitability than annual plans."
If you're using pop-up fertilizer and want to make sure the amount you're using won't injure corn seedlings, consult the Purdue University Corn & Soybean Field Guide. The 2011 edition contains a table that shows maximum amounts that can be applied within the row without risking injury or death of seedlings. The amount you can safely apply in the row as pop-up is far less than the total amount you would need to apply if your soil is testing low on potassium in soil tests.