Q. How can we help boron stay in the soil?
A. I’ve described before how boron is required to be added annually, or multiple times per year, as a reflection of rainfall. You should add half a pound of actual boron per 10 inches of rainfall per year, until your soil has demonstrated the ability to hold onto boron.
We know that boron is an anion — it’s negatively charged. It doesn’t adhere or adsorb onto soil colloids — onto the negatively charged exchange capacity. What really holds boron stable in soil is biologically active carbon, which has positive exchange sites that can hold onto boron.
But I think there’s another part to the story. I’m using boron as an example here, but the same holds true for a number of other elements, particularly iodine and molybdenum. The majority of the boron in biologically healthy soils is not attached to inert carbon; it’s held within microbial bodies — particularly fungal populations. So, one way of describing a soil’s ability to hold onto boron, or onto molybdenum or iodine, is to describe the soil fungal population. It holds onto those anions — those negatively charged particles.
Therefore, when you apply fungicide that disrupt, or destroys, or greatly decrease a soil’s fungal population, you reduce that soil’s ability to hold onto boron and other important anions.
From John Kempf’s Eco-Ag U presentation at the 2025 Acres U.S.A. conference. Recordings of the conference are available at conference.acresusa.com/recordings-2025.
