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Potassium in Grasses

Most perennial grasses harvested twice per season should maintain high yields with approximately 1.5% K in spring growth forage (harvested at flowering or later) and 1.2% K in regrowth forage (harvested in the fall). Visible K deficiency symptoms in grass will not appear until forage K content drops to around 0.8% K or lower. Deficiency symptoms are difficult to identify and attribute to K, because symptoms are similar to those due to drought or normal senescence. Deficiency of K is seen as a yellowing and browning of dying leaf tips and margins. Potassium fertilization does not have a large effect on DM yield of cool-season perennial grasses under a low intensity harvest management regime.