If you’re new to growing, growing in a new field or simply wanting to improve what you’re growing, you need to get to know your soil better.
Vicki Morrone, an organic field crop and vegetable outreach specialist at Michigan State, talked about soil matchmaking at the most recent Great Lakes Expo with her presentation, “Your First Date with the Soil.”
Much like getting to know that new dating app match, there are certain questions to “ask” your soil on your “first date.”
- What is your texture? There are typically three main types: Sand is coarse and gritty. It offers drainage but doesn’t hold water. Clay is fine and smooth. It holds water but sometimes a little too well. Silt is like a mixture of sand and clay, offering the values of the other two textures.
For a quick check on soil texture, Morrone suggested using the ribbon testing. Take a small handful of soil and then add a bit of water to wet it to form a not-too-wet paste. Take the soil ball and squeeze it between your index finger and your thumb. Pinch and squeeze the soil between these two digits and try to form a ribbon as long as possible. A very long ribbon (about two inches) is heavily clay. If it’s about an inch long, it’s likely silt. If there’s no ribbon, it’s more sandy.
- What has been grown in the field the last few years? Was it an annual mixed vegetable patch? Cover crops? Perennials? Knowing what has been in the soil can help you find out what will work best there going forward.
- Are there any areas of concern? Are there a lot of difficult weeds? (Morrone suggested planting sorghum/sudangrass as a cover to smother them.
Are any areas prone to flooding? A whole field may have more than one texture – and handle water different.
What about erosion issues? You may need plastic, mulch or living mulch to keep that soil covered.
Does the soil crust at all? When rain breaks down soil aggregates into smaller particles, they can cement together when the soil dries. If it does crust, seeds may have issues germinating.
- Should I soil test? Yes, at least every two years, Morrone emphasized. “It’s like a report card,” she said. “Tests will show strengths and weaknesses and needs – and it is more important under hoop houses,” since they don’t tend to move.
When collecting soil for a test, take all observations into consideration. Find a lab where you will get the soil tested. You want to find a certified lab as close to your farm as possible. Check out alta.ag/certified-labs. Morrone also recommended using the same lab over time for consistency.
Be sure to collect soil from all across a field. Collect enough samples to give good results.
To collect a good soil sample, use a soil probe or trowel to reach about six inches deep. Scrape away any plant materials from your surface and then push the trowel into the soil and put each sample into a bucket. Collect soil from the center, edges, left and right sections of a field. If part of a field has a very different (texture, drainage, etc.), collect and test that separately.
Morrone also highly recommended utilizing USDA-NRCS’s Web Soil Survey. NRCS has soil maps and data available online for more than 95% of the nation’s counties. Find it at websoilsurvey.nrcs.usda.gov/app.
“Each time we take a soil test we want to check that nutrients are in the right range for good crop growth; that organic matter has increased; and that the pH is good for crop growth (around 6.8 to 7),” Morrone said. The ultimate goal with organic matter is to track it and build it.
If that first date with the soil goes well, what do growers need to keep an eye on? The best pH should be around neutral (7.0). There should be good levels of the big three fertilizing elements – nitrogen, potassium and phosphorus. There should also be a good percentage of organic matter.
Getting to know your soil takes time, so do what you can to set your relationship up for success as soon as you can.
by Courtney Llewellyn
