Posted 10/17/2020 11:27 (#8550183 - in reply to #8549807) Subject: RE: Soil grids
garyl - 10/17/2020 06:42
Goose You are very passionate about your work and Im sure your clients apperiate your thoroughness. I think you are assuming my post as somehow being challenging or negative to your comments and are being way too defensive. One of the precepts of the whole precision farm industry is that soil "fertility" as measured by soil test are homogenous and repeatable inside of a relatively small area. Everyones milage may very in that regard. I have spoken to several long term precision technology users who after many years of using soil test numbers for VR fertilizer rec are moving to yield based crops removal type recommendations. I'm not sure where things go from here. Everyone has good results using soil test based VR for Ph, but personally after over 20 years on some fields in my mind P&K are still a work in progress. Yes I know I didn't do this right or I didn't do that right and there is little need to convince you otherwise but that is the trend I am seeing
No I'm not taking offense. I'm very clearly asking you questions about your statements that were not clear to me or that you just alluded to. I'm curious and asking for clarification. Its hard to learn if you don't have all the details of what someone else is doing.
Much of the precision ag industry and farmers wishes is based on convenience and a lack of understanding or a misunderstanding and trying to over simplify things. I dont doubt many are going to crop removal based recs as it is easier and quicker to do than boots on the ground.
P and K is very complex if you truly understand the chemistry (and i dont, but) and crop response and you take the time to calculate it all. There are about 6 factors from a complete soil analysis that need to be analyzed to build an accurate P or K rec. Most computerized scripts use only PPM. Sometimes this gets close, but often it's off one way or the other and may be off for different reasons year to year.
Here at least, many believe fertility is homogenous, and those willing to learn are finding even on table top flat rrv single soil type fields, it is far from homogenous.
I'm not saying I know everything or doing it all right. Its a balance of many aspects and there are a number of ways above average agronomists get to similar end results. Unfortunately I see many kicking out very poor quality quick and easy precision ag and turning growers sour on the concept.
I'm just fortunate enough to know or have tracked down several industry pioneers and leaders that have helped me learn many behind the scenes details or understand the fine print of satellite imagery, statistics and scripts in software, fertility, population, etc, that many in precision ag dont know, but use the end product of someone else's work.