Saturday, September 24, 2011

Soil Testing

The other day, I went out and bought a soil testing kit from my local garden supply mega-store. I was curious, because there had been that crop circle in last year’s wheat crop, and I wondered if the soil wasn’t in poor condition, especially since those damned European Buttercups are supposed to really eat up the nitrogen in the soil.

So I bought a testing kit and on Wednesday I used it. It came with four plastic test tubes, each for testing a different aspect of the soil -- ph, nitrogen, phosphorus and potassium. For each of them, with small amounts of variation, you put some soil in a tube, add in some water, drop a chemical pill into the water and shake for a long time. Then compare the color of the water to the laminated color chart and read the results.

I took four samples from around my field and it took about 90 minutes to run through it four times, and by the third time through I had streamlined the process pretty well. My results were:

PH: between 6-7 across the field.
Nitrogen: no reading. Either my chemical were bad or there was no nitrogen anywhere in that field.
Phosphorus: Medium.
Potassium: Medium.

So what does that mean? According to _Small-Scale Grain Raising_ wheat likes a ph of 6.4, so that’s not too bad. It needs nitrogen, certainly, but how much I don’t know. SSGR says a “typical” nitrogen supplement would be 30 lbs. of nitrogen per acre or 3+ tons of manure per acre. After some quick math that would be 0.017 x 30 = 0.51 pounds of nitrogen or 0.017 x 6000 = 102 pounds of manure. But that’s only “typical” and I think I am “desperate”. So I think a trip to my local garden store or coop is in order.

SSGR gives advice on adding phosphorus to a regular rotation of wheat, but doesn’t say what it wants, so I’m going to assume I’m okay. And it says that wheat doesn’t see to respond to artificial additions of potassium, but I’m probably good on that anyway.

So the big problem is nitrogen, which could be fixed by crop rotation (SSGR suggests rotating it with soybeans) but I’d really like to at least get a good harvest of grain before growing the peas or lentils.

So, off to get advice!

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