Today we will be discussing soil pH. Last week we had a call with Jason Shley 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?”. Today we are going to the field and testing the soil with a handheld soil pH tester every inch to find out the answer.
What and Why
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 is that we are going to have really high pH (or higher pH) in the top inch or two, but we are wondering how far down that lime has worked down 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:
1. a non-irrigated area
2. an area that has been irrigated by center pivot for 21 years with really high pH, high bicarbonate water (surface water out of a pond)
3. an area that has been subsurface drip irrigation for the past eight 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.
Our plan is to take this data back to office and put together a summary, so more on this later. Any questions or comments, email Kurt Grimm at firstname.lastname@example.org.