Posted 9/15/2021 09:24 (#9221360 - in reply to #9221052) Subject: RE: Managing Potash in the root zone.
I dint have any experience with cec that low. I'm more in the upper teens to mid 20s plus. P might move 1/4" and k very slightly more. K is very cec driven as well as moisture like you alluded to. A percent O.M. is something like 400 cec. So increasing o.m. could go a long way. I think I would do a series of samples split at certain depths over a year to have a better handle on where your k is. It's just difficult to do it accurately after fertilizing as you likely will get inflated results at least in the split where k was placed. Also results will change week to week depending on soil moisture changes. You would need to look at the complete test and all the indicators and k influences to try to adjust samples to a common or more apples to apples kind of comparison. It is not just a straight forward compare the results of k ppm by any means. Different crops have different types of roots. But for the most part crops are not going to be able to take up significant quantities of PK from very deep depths. A vast majority of the fine hairs are going to be found in the top 6-10". The roots going deeper are predominantly getting water, n, and s. There just insnt the oxygen and kind of biology deep in soil like shallow.