Why test for nitrates?
Corn that has been stressed all summer due to drought may have few if any ears, and usually will have an energy value 85 to 100 percent of normal corn silage. The worst problems occur when the drought is severe enough to produce dead leaves. Although nitrate levels in drought-stricken corn may be high, 30 to 60 days after ensiling more than half the nitrates are converted to ammonia, which can be utilized by the rumen bacteria. For this reason, nitrate toxicity rarely occurs when feeding ensiled drought corn. However, if the drought damage was extreme and high levels of nitrogen were applied to the soil, a nitrate test on the silage should be conducted. This test can be done during ensiling to get an idea of how high the nitrate level is. Dividing the results by half puts you in the ballpark of what nitrate levels are. Retesting after the 30-60 day period gives you a better estimate of nitrate levels. The following precautions will reduce nitrate levels in plants and reduce feeding pro