Nitrate content of corn and sorghum silage may also be caused by weeds in the silage. Certain weeds accumulate nitrate when shaded or partially killed by herbicides. Raising the cutter bar to exclude such weeds as well as the basal corn and sorghum stalks, which may have a high nitrate content, may be beneficial. Herbicides destroy nitrate accumulating weeds, making pastures and forage crops safer. All forage plant parts contain some non-protein nitrogen that can be used or excreted by animals.
Concern arises with forages containing more nitrate than animals can effectively tolerate.
Disruption of normal plant growth increases the probability for nitrate accumulation in leaves, stems and stalks. Plant damage from insects and certain weed control chemicals. Immaturity at harvest. In hay, enzymes continue to reduce nitrate for a short time during curing. Little further change occurs after the moisture becomes low enough to allow storage.