Agriculture Reference
In-Depth Information
How to Apply Fertilizers
Traditionally, the best time to apply the soil-building mineral fertilizers is in spring or
fall. Many soil consultants have a preference for fall, but if it's spring right now and you
have a soil test showing you what you need to do, start now. It can take three or more years
to correct nutrient imbalances in the soil, so I like to get going right away.
Other fertilizers are applied regularly throughout the year, especially liquid fertilizers
and biostimulants that keep a crop growing. On a farm, the soil-building mineral fertilizers
might be applied all at once because it can become uneconomical to make too many passes
over the field. In a small garden, I prefer to split my fertilizer up into two to four applica-
tions per year. For example, instead of applying 40 pounds of calcitic lime all at once in the
fall, I might apply 20 pounds in the fall and 20 pounds the following spring.
When it comes to determining how much to apply, the soil lab will tell you that. For
those who like math, here's a brief explanation of one way they might figure it out if
they're using the base saturation numbers. It's not as confusing as it initially looks, but it's
also not necessary for us to worry about this because they will do it. If the calculations
don't interest you, skip ahead to the next chapter. The main reason I'm including them here
is so you can see the logic behind fertilizer recommendations. This works for each major
nutrient and the equation is as follows:
CEC x saturation lbs./acre x saturation deficit / raw material nutrient
Let's use the same test as we did in the soil nutrient testing chapter to go through the
equation.
