How to manage fertilizer in times of high input prices

2021 has given us many challenges.  We have seen uncertainty while getting parts for our equipment, possible chemical shortages, and a drastic increase in all input pricing including fertilizer.  Fertility is the staple food source for our plants; therefore it is very difficult to maintain high yield levels without an established and consistent fertility program.

Soil fertility’s process is a cycle of nutrients with both organic and inorganic forms, like fertilizer and crop residue breakdown, called mineralization.  The soil goes through a balancing act of immobilization and mineralization to create the availability of the major nutrients to the soil microorganisms.  So by breaking the cycle of your normal annual fertility program could lead to not having the correct amount of fertility available to the growing crop.

There are several ways to manage fertilizer and soil fertility in a year like 2022 where fertilizer prices have over doubled in cost over the 2021 season:

• Crop Removal – Crop removal can be used as a band-aide to help maintain soil fertility levels from the year before.  This means applying the amount of fertility that was removed from the previous crop. 
  • 200 bushels of corn remove 70 lbs/ac of P2O5, 50 lbs/ac of K2O and 16 lbs of Sulfur.  
  • 24 tons of corn silage removes 74 lbs/ac of P2O5, 175 lbs/ac of K2O, and 26 lbs/ac of Sulfur. 
  • 60 bushels of soybeans remove 44 lbs/ac of P2O5, 72 lbs/ac of K2O and 11 lbs/ac of Sulfur. 
  • 5 Ton of alfalfa removes 60 lbs/ac of P2O5, 245 lbs/ac of K2O and 27 lbs/ac of Sulfur.
• Variable-rate application – This is applying fertilizer at different rates across the field where soil tests help determine the need for the major nutrients by the acre.  This doesn’t necessarily put less fertilizer on your field, BUT it does a better job of placing fertilizer where it needs it the worse.
• Changing crop rotations – A few guys have been talking about planting more soybeans and less corn OR soybeans-on-soybeans.  The thought process behind this is to eliminate the need for a nitrogen application like in the crop of corn to save that expense.  With this practice, it comes with some risk, just like with corn-on-corn extra precautions on disease need to be taken.  Also like I say, “treat soybeans as a crop and not a rotational interim for corn”.  This means you still need to fertilize for that crop!

No matter what you decide to do, fertility is an extremely important part of your operation to maintain high yields, keep your soil healthy and keep the fertility cycle going.