Mark Warren, UF/IFAS Extension Levy County Agriculture Agent

Farmers across North Florida are expressing concern about high and rising fertilizer costs as they look to the upcoming season. While there isn’t much that we can offer in terms of supply chain issues and prices, there are other considerations that may help manage costs as we move toward a more “prescriptive level” of fertilizer management.

Whether you are producing hay, grazing livestock, growing corn, watermelons, or peanuts, I think that we all know that optimizing soil fertility is essential to producing a respectable crop. Proper fertilizer management may not guarantee “bragging rights”, but not applying it adequately will surely take you out of contention.

As much as we all understand this basic concept of fertility, we need to also recognize that there are other factors at play. A closer look at some these factors may provide opportunities for improved nutrient-use efficiencies.

Soil Testing

I’m sure that almost everyone conducts soil tests before applying any and all fertilizer, but if you don’t… why not? When fertilizer was cheap (I can’t remember when that was), it was easy just to make general recommendations. Applying the same amount every year, back then, we may have over applied some elements, but who noticed.

Regardless of the element, higher than required rates do not increase profits, but can certainly add to costs. If it isn’t needed, ask your supplier what the difference in price would be if you backed off the unnecessary constituents.

It doesn’t matter what accredited lab that you use to test your soils, but the basis for the interpretations and recommendations do matter. Be sure that the recommendations you are receiving are calibrated to Florida soils, crops, and growing conditions. Any accredited lab can provide a nutrient analysis, but the specific crop recommendations need to be based on data from Florida research.

You may be able to cut application rates of some of the components by applying fertilizers based on soil tests. This may produce some savings.

Soil pH

Most, if not all, of the more intensive farmers in our area monitor and adjust soil pH seasonally. They have learned that this practice has a proven return on investment (ROI). I do, however, hear from time-to-time of producers who either don’t monitor soil pH or who make blind and random lime applications.

Soil pH, the measure of soil acidity, critically affects the availability of several nutrients in the soil solution. Some of these nutrients may already be present in the soil and organic matter; others are those that you must buy and apply. Either way, if the soil pH isn’t properly adjusted, the nutrients may not be as readily available as needed. This would mean that you aren’t getting the full value of your investment.

Remember that a high soil pH can be as much or more of a problem than a soil with a low pH. Unlike some soil tests, soil pH tests are simple and undisputed.

Testing and required applications for soil pH should be done well in advance of your projected planting dates. Dolomitic limestone is affordable in comparison to other amendment materials, but unlike fertilizer it takes time to produce the desired effect.

Equipment Optimization

There are a variety of systems across our area used to make applications of soil amendments (fertilizer, lime, micro-nutrient applications). Whether you are slinging, broadcasting, banding, injecting, spraying… the goal is uniform, precise and and targeted applications.

As expensive and important as this input is, we can’t afford to be applying it anything short of precisely.

  • Reducing overlaps and skips can be a significant opportunity for improved efficiencies.
  • Stopping application while making turns and then wrapping the field when done may be beneficial.
  • This may be the year to invest in GPS guidance, if you have not already.
  • In drip systems we have discovered that much of the liquid fertilizer wasn’t being fully flushed from the lines. This might result in uneven applications.
  • Alternative delivery systems and materials might be a reasonable consideration. (banding vs. broadcasting, coated vs. water soluble)

Take a critical look at your delivery systems and see if there might be a place where some improved efficiency might pay off. You wouldn’t use a paint roller to add flames to your hot rod.

Fertilizer Timing/ Placement

I understand that planting season is a busy time and that the scheduling of labor, equipment, seed, chemicals, and irrigation is tricky, but strategic timing of fertilizer applications deserves close evaluation.

Starter fertilizers may be essential for many crops, but for some, such as cool-season forages, it may be better to wait until adequate emergence and moisture are confirmed.

When required, starter fertilizers applied pre-plant run the risk off inefficient use. Applying these materials too early or too deep could result in losses that never produce a response. Consider the risks of leaching rain events and placement too far from the root zone. Adjusting these practices has been proven that significant gains in efficiency can be realized.

Split applications are another consideration that many producers already employ. While balancing crop needs and application inputs, the closer we can move to a spoon-fed system, the more efficient fertilizer utilization will become. This is why most irrigated corn crops have most of the nitrogen applied through the irrigation systems. Nitrogen is easily lost in our sandy soils due to leaching, so why put more out there more than the plant can use at that given moment. Consider the size of the root system and the current plant requirements when making timing and placement decisions.

Fertilizer Drop Spreader

A fertilizer drop spreader provides more precise fertilizer placement for the crop. Credit; Mark Warren, UF/IFAS

I have no grand illusion that I have mentioned anything that most of you didn’t already know, but I do know that there are always things that we can all do better. As concerning as the current situation is relevant to fertilizer prices, I know that the American farmer is the most resilient thread of our economic fabric. Now is the time to “Up Your Game!”

For additional support or questions, contact your UF/ IFAS County Agriculture Agent.
There are many great resources on nutrient stewardship available through the 4R Nutrient Stewardship website.
Another great place to start is the UF/IFAS publication The 4 Rs of Fertilizer Management.