Soil and Forage Testing

Dirt I finally got my soil and forage samples sent off to a lab. I’ve wanted to do this for some time, but have been procrastinating! I consulted with my Farm Planner at the NRCS Snohomish Conservation District to ask what labs they currently recommend. She sent me two local lab names, and I chose Soiltest Farm Consultants in Moses Lake, WA; which is the place WSU is currently recommending.

She also referred me to this helpful Soil Test Interpretation Guide, produced by Oregon State University. This was definitely worth reading before choosing the tests I wanted done. Reading through the menu of possible soil and forage tests is dizzying. I called the lab to ask for some advice, and got a little more help; but still needed to do some reading to understand what the different tests are and why you’d choose one over another.

Why and What I’m Testing

Right now, I’m mostly interested in knowing what the copper and sulfur availability is to my sheep, because those two elements are key players in hoof, skin and hair/wool health; and hoof health is currently my big priority. But copper can be bound by molybdenum, and I’ve heard we’re high in Mo here, so it’s important to test for that too.

According to the soil interpretation guide, sulfur easily leaches from our wet Western soils, so it’s more accurate to assess its presence in the forage. And, molybdenum concentrations in soil are nearly too low to measure, so this is also best assessed in forage analysis (does that mean it concentrates more in the plant than in soil? I’m not sure.). Copper is typically analyzed in both soil and forage.

I Chose Four Tests

For the soil analysis, I ended up choosing a more expensive, but broader test, designed for west-of-the-Cascades. I think in future years, I can probably get by with a less expensive sub-test that focuses on the minerals I’m most interested in. But I thought for the first time, it would be good to get a broad baseline, to which I can compare in future years if I start tweaking the soil fertility with additives.

For the forage analysis, I selected the base analysis (which will tell me some things about protein content and total digestible nutrients), the wet chemistry total elements (which will indicate copper, sulfur, and other minerals) and an additional test for molybdenum. The total cost for the four tests was $118, plus about $10 to ship the box. grass

Collecting and Packing the Samples

The Soiltest website doesn’t have a lot of advice on collecting or packaging the samples, and the guy on the phone was fairly casual about his instructions too. I’ve read of other soil test labs that want you to dry out the dirt in your oven, and get the moisture off of the grass before you send it. The idea is that the material is constantly changing, and even a day sitting in a plastic bag will alter the nutrient profile from what it was when you dug the sample, because of microbial action. But, since I knew the lab will get the samples the next day and they promise a one-day turnaround, I figured it was safe to send things damp.

For the forage sample, I just walked around and snipped off a lot of random plant samples from all over the field, and included blackberry, dandelion and buttercup leaves with the grass, because those are all present in fair quantities, and the sheep eat them all. I tossed the trimmings in a paper grocery bag to mix them up well, then grabbed a sandwich-bag-sized sample to send. I blotted it well with paper towel, and packed it in a manila envelope so it could breathe.

For the soil, I used an ordinary shovel, and took about twelve samples from random parts of three fields, trying to get a consistent core of 0-12” deep from each hole. I mixed those thoroughly in a clean plastic wheelbarrow, then scooped out two heaping cups, and emptied them into a carefully washed and dried milk carton. I stapled the top, put that inside an open-top plastic bag; and packed the whole thing in a box with bubble wrap packing. And labeled both samples with the farm name and date. I drove the box straight to the UPS office and sent it off.

Now I can’t wait to receive the results!

2 thoughts on “Soil and Forage Testing

  1. bruce king says:

    I’ve got saltwater under my grass, so I have reasonably high levels of sulfur present, according to the test I did. But I had to apply lime at a reccomended rate of 6 tons per acre to bring the PH in line for row crops.

    That’s a lot of lime.

    • workingcollies says:

      Bruce, yeah, I have reservations about going down the path of soil amendment. I’ve heard from a fertilizer salesman that one might expect to spend several hundred dollars per acre for them to till, fertlize and add seed, to improve a graze. I’m not ready to spend that kind of money, yet. 😛 But it will be nice to at least know where I’m at with what I’ve got, and hopefully I can compensate reasonably well with supplements for the animals.

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