Soil Testing. It’s that time of year when most Turfheads are gonna pull some soil tests. My experience is that for many (if not most) this is done as kind of a box check. You know you have to do it, because that’s what you do this time of year. A lot of Turfheads tell me that soil tests are one of those things that they understand as well as a fourth or fifth language. So let’s Rock our Spock and geek a bit with some ideas about soil testing.
The confusion hasn’t really helped anyone and if you don’t work with this kind of thing nearly every day, then the language (words like Saturated Paste Extraction and Mehlich-III and P-Sorbtion Curve) may as well be written in Klingon and we Vulcans don’t do Klingon.
Because of this lack of grokking, soil testing has gotten a bit of a bad rap. And inside of that, there are now all kinds of ideas and theory about how one should really read a soil test. The confusion hasn’t really helped anyone and if you don’t work with this kind of thing nearly every day, then the language (words like Saturated Paste Extraction and Mehlich-III and P-Sorbtion Curve) may as well be written in Klingon and we Vulcans don’t do Klingon. I don’t want to really get into the whole this vs. that thing here, but I’d love to address a few things that may help you when you go to collect some important data.
- Soil Tests are never a bad thing. People who don’t know how to read them are bad, but the tests themselves are good. Data is good.
- You get what you pay for. Want the cheap test? Get cheap or incomplete data. Paying a bit and perhaps even using a couple different methods on the same sample is worth it.
- Sticking with the same lab is paramount. I can’t tell you the number of times a super will open up a big file of tests spanning several or more years from as least as many labs. Impossible to make the comparison.
- Bar Graphs aren’t really that important. A lot of people are looking for a picture of high or low or whatever in the form of an easy to use bar graph. Imagine if we approached all of your planning this way. Just let someone else tell you the highs and the lows and… oh wait, that’s Wall Street. Learn the numbers. It’s better for you.
- Pull enough samples. Unless you are on a regular data collection routine, make sure you cover your different soil types, indicator and good citizen greens and some clubhouse flower beds too. Data is good.
- Don’t always repeat the same samples. Repeat some, but always add a few areas in and set up a good rotation to get through all of your key areas in a 2-3 year cycle.
- Pre-season and Post-season samples are a good idea. Especially if you have poor water or a drought situation or that sort of thing.
- Sampling during the season is not a bad idea either. When your place is apt to change, a good sampling routine might tell you what’s happening. This is where I really love Paste Extracts, by the way. They show so much of what’s happening right now.
- Not every number of that test sheet is an actual test. Some values are calculations. Make sure you know which is which. Your lab or your consultant can and should be able to help you understand which numbers are which. Use the actual tested for numbers for your test to test comparisons.
- Sampling depth is key. Make sure to let your lab know what your sample depth is and make sure you sample to that depth. Those calculated numbers I talked about above depend on you getting this right.
There are 10 things you need to know and may not have thought about in regards to getting soil test info that matters. If you wanna geek out with some of the numbers, comment below and throw up some questions. I’ll use them for fodder for future posts.
I believe that soil tests are an agronomic planning tool and not a fertilizer sales tool. That doesn’t mean your agronomic supply supplier can’t be involved, but if the material coming to you looks like it is driven to create a list of things to buy read number 1 and number 2 above. Rinse. Repeat.