Posted 5/3/2021 19:07 (#8985585) Subject: Fertilizer/Soil test interpretation
I have always had trouble figuring out soil tests and fertilizer recommendations when it comes to P2O5/P and K2O/K. My soil tests give results in P & K. Quite a bit of the literature I have read gives values in P2O5 and K2O. And critical levels of each seem to range all over the board. Would P2O5 and P be interchangeable, as well as K2O and K? When it comes to figuring out my fertilizer recommendations, I have always used N, P, & K, and figured from there.
The co-op I use can supply 18-46-0, 0-0-60, & 46-0-0
As an example, if I fertilize a hay field for 3 T/acre yield, and recommendations per ton of yield are 40# N, 15# P2O5, and 50# K2O. (120-45-150)
If I used 100# 18-46-0, 250# 0-0-60, and 220# 46-0-0
This would give me 119.2 N - 46 P - 150 K
This should cover my removal rates.
Just an example to make the numbers easy. But, am I on the right track?