Tuesday, March 2, 2010

Soil Testing

I received some good email on tissue testing so I might as well go into soil testing again. So many farmers and gardners don't do it. Some get along well and some get frustrated and quit.

All of the people I work with test their soil and apply nutrients based on these tests.

The beginning of these tests go back to 1845 with Von Liebig and others who are remembered for their work in this book at this link:


I remember studying these concepts as a young person, fascinated with science, chemistry and biology.

LuAnn was talking about the Turning Point garden this morning and I was thinking we didn't apply everything recommended on the soil test last y ear. Some of the vegetables tasted like yuck, I thought the flavor in sweet corn and green beans was lacking so I need to revisit that soil test result from a year ago. I really need a new one but we missed the ideal fall window. At least they got the radishes planted and the radishes will release a lot of nutrient at planting time.
Getting people on a soil sampling schedule is like pulling teeth. No one wants to do it. Most farmers leave it up to their suppliers but some do their own. My supplier won't use the test I want unless I pay extra for it because it does cost more.

Sampling is really quite easy. You borrow a soil probe or buy one for around $100 like the one I use from and pull soil cores out of an area of similar soils. That would be your garden or one fifth of your field. The 50 acre field behind the house has three major soil zones that can be easily broken into five for more detailed analysis.

You probe the topsoil in most cases whether it is 3 inches deep or 30 inches deep. Most top soils are at least 7-8 inches deep so that becames you probing target. My soils are good enough I probe 12 inches and I may probe separate samples at 2-4 inches to see if my notill practices are tying up any elements like potassium.

For many farmers I would be happy with one good random sample from the whole field though it would not show the zones. This field was farmed in 3 pieces for years so there are three major management zones.

You crumble and dry the samples if needed to fit into a school milk carton size sample bag so you always have soil left over. Thorough mixing determines the result of the random samples.

Let's look at Turning Point.

Phosphorous is VL, very low.
Potassium is medium.
Sulfur is low.
Zinc is medium.
Manganese is low.
Copper is medium.
Boron is low.

I would recommend at least 200 lbs of MAP, mono ammonium phosphate fertilizer which is 11-52-0 analysis and will give you 100 lbs or so of phosphorous on a per acre basis.

I recommend 100 lbs of Muriate of Potash or Potash which will give you 60 lbs of potassium per acre basis.

To get your needed sulfur, the cheapest form I have found is ammonium sulfate fertilizer which is about equal in nitrogen and sulfur, 100 lbs per acre.

You need a pound actual of manganese in manganeses sulfate and a pound actual per acre boron. Twenty Mule Team boron is granubor and I think Crop Production Services near you carries it.

Organic gardners wouldn't get near this recommendation but they would spend 10 times more trying to do it. We are farmers and this is how we farm. I don't think we have shortened anyone's life yet and I think we have kept billions of people alive.

If you can get manure for your phosphorous and little bit of everything else, great. You also add organic matter and humus. Takes awhile to turn organic matter into humus, thus all the compost bin advertizements.

Even though this will cost around a thousand dollars for your 3 acre garden, this is a low cost, bare bones recommendation for another good crop and better tasting vegetables this year.

I need a good Turning Point picture from last year to top this blog off.


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