Over the last several years, input expenses for no-tillers in general have increased by approximately 21%, and one of the highest-costing inputs is fertilizer.

The No-Till Farmer 5th Annual No-Till Operational Benchmark Study found fertility products were the biggest expense in 2012, averaging $94,713 per farm — almost $27,000 more than the average cost in 2009.

With big dollar amounts like this at stake, it’s important for no-tillers to ensure fertilizer is being taken up by corn and utilized.

This especially applies to phosphorus because its uptake is more dependent on how and where it’s applied, Agro-Culture Liquid Fertilizers senior research manager Jerry Wilhm told attendees at the National No-Tillage Conference earlier this year.

Plant Uptake

Wilhm says phosphorus uptake in corn starts early on, continues with more rapid uptake through the R5 growth stage and levels out around the dent stage. While no-tillers may consider using starter or pop-up fertilizers to provide nitrogen, they can also be beneficial for phosphorus.

“There is a phosphorus response early, particularly with corn — even in high-phosphorus soils — because the soil phosphorus has to be released through a biological procedure,” he explains. “A lot of the soil microbes and processes aren’t working yet in cold soils when we first start planting corn.”

There are three ways nutrients can migrate from where they’re originally placed to the plant roots for uptake. One method is root interception, where roots grow to reach the fertilized zone in the soil. Wilhm cautions against believing roots can…