Last week we had a call with Jason Schley from Next Level Ag in South Dakota. We were looking at some soil samples we pulled a few weeks ago; they ran them through their lab and learned a lot of information, including a few things we hadn’t seen before. One of the questions that came up in that call was “what is our soil pH at varying depths?”. So, we headed out to the field with a handheld soil pH tester every inch to find out the answer. 
Our soils here in northeast Kansas that we had pulled these soil samples off of are naturally low pH and we typically apply lime to bring that soil pH up. Our suspicion was that we were going to have really high pH (or higher pH) in the top inch or two, but we were wondering how far down that lime had worked into the soil over time, and how much lower is the pH as we go deeper? What is that doing to nutrient availability and nutrient tie up?
It was very interesting to see the different layers in the soils. There really weren’t any surprises, but still interesting data that will help us learn and adjust. We tested three different scenarios:
A Non Irrigated Area.
An area that has been irrigated by center pivot for 21 years with really high pH and high bicarbonate water (surface water out of a pond).
An area that has been subsurface drip irrigated for the past 8 years.
What we found in the soil was that the pH was higher (around 5.8-6.2) in the top inch or two, but then it dropped really quickly to 5.4-5.8. We even saw some numbers under 5 as we got down to the eight, ten and twelve inch depth in the soil. This would suggest that our lime application is only going into the top 2 inches or so. We strip till here on our farm, so this isn’t necessarily a surprise.
We don’t deep till, or do any tillage at all except strip till to apply nitrogen, phosphorus and potassium. Our lime is put out over the top, and we have limed these fields for the last 30 to 40 years. We also saw a lot of good earthworm activity; overall very impressed with the soil health and tilth. We had a rye cover crop on one of the fields, so it was exciting to see how that is coming along.
Watch the video for more information.
Here is all the data that from our sampling program. Any questions or comments, email Kurt Grimm at kurt@nutradrip.com. www.nutradrip.com