What causes the nitrate problem encountered in forages?
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. Factors favoring accumulation of nitrate in plants include: • Drought (plant injury and concentration of nitrate in soil solution). • High temperatures (rapid transpiration of water, concentrating nitrate not used). • Shading and cloudiness (reduced protein synthesis). • Deficiency of plant food nutrients (phosphorus, potassium, calcium). • Excessive soil nitrogen (manures, legume, residues, effluents and solid wastes, and nitrogen fertilizer). • Plant damage from insects and certain weed control chemicals. • Immaturity at harvest.
