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Humeston, IA | While nitrogen soil sampling isn’t an exact science, it may be useful here.
Take 0-12” cores every 3 inches for 30 inches (11 cores) perpendicular to your application path. You’ll likely hit one if not two of the bands. Mix all the cores together and send to a lab for analysis of Nitrate (NO3) and Ammonium
(NH4). Need both nitrogen forms in the analysis. When you get the results, add the two in ppm together and multiply by 4 to get pounds per acre. Then find what % of the total N is Ammonium to get a sense of how much still exists.
The sample analysis should cost <$30; you might pay someone that much or slightly more, say total of $100 or less. Do this at a few locations in the field (total cost of say $500 or less). This is much less expensive than the $9000 or so you’d spend applying another 150 lbs N/ac; you may determine it needs none, some or all but you’ll be better informed to make that decision. | |
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Would you add more nitrogen?
