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--- library:articles:cornstalk_n_test 2010/03/12 13:35
+++ library:articles:cornstalk_n_test 2015/09/22 14:49 current
@@ Line 83: / Line 83: @@
   - Once Spectrum Analytic receives the samples, we will dry the samples. The samples will be ground and analyzed for nitrate N concentrations. Concentrations are expressed as ppm (parts of nitrate-N per million parts of dry stover).
+ =====Cornell University Cooperative Extension =====
+{{:library:articles:corn_stalk_nitrate_test_after_silage_cutting.pdf|Taking a Corn Stalk Nitrate Test Sample After Corn Silage Harvest}}
+If the silage cutting height in the field exceeds 14 inches, they suggest collecting the standard 8 – inch section of stalk from the 6 – 14 inch height. When stubble height is less than 14 inches but greater than 8 inches, stalk samples can be taken between 2 and 8 inches off the ground. In order to use the standard interpretation of Nitrate-N (NO3-N) level that was published by Iowa State University and others, the Nitrate-N, ppm levels will need to be converted because stalk nitrate levels are higher in the lower portions of the stalk. With 2-8 inch samples, laboratory values need to be divided by 1.5 (6-14 inch stalk nitrate-N results ppm/1.5) for the test results to be comparable.
+According to Cornell bulletin stalk samples may be taken at silage harvest (60-70% moisture) and grain harvest (20-30% moisture) without any major effect on the corn stalk nitrate test results. Collecting samples in the field up to five days after harvest will not affect corn stalk nitrate results (assuming no significant rainfall, soil disturbance or manure application in that time period).