Corn Stalk Nitrate Test (CSNT)
The Corn Stalk Nitrate Test (CSNT) reflects nitrogen (N) availability during the growing season. The test is based on the fact that corn plants deficient in N will usually mobilize stored N from the lower portions of the stalk and leaves up to the developing grain. For N deficient plants, this can result in lower stalk N concentrations at the end of the season. Conversely, plants that take up excessive amounts of nitrogen (beyond that needed for maximum yields) will store N in the lower stalk resulting in higher stalk N concentrations at the end of the season.
CSNT results are most useful when evaluated over a period of several years on the same field. Crop history, manure applications, N fertilization, soil type and growing conditions all impact the N status of the plant. This test should not be used for first year corn following sod.