I sometimes wonder when the categories were developed for when the soil is in low, medium or high. I’ve been farming for 35 years during which time yield per acre went from 130 being average to over 200 bushels per acres being average. Population went from 24,000 back in 1985 to now I plant 40,000 in a twin row configuration. So a soil test for phosphorus of 30 ppm is considered high then and now. I wonder what kind of soil test levels these high yield guys are shooting for, I’d say they would consider 30 ppm to be on the low side.

What is the multiplication by 2.3 for