DISTRIBUTION OF POTASSIUM, CALCIUM, MAGNESIUM, AND SODIUM IN GRASSES AT PROGRESSIVE STAGES OF MATURITY

Distribution of potassium (K), calcium (Ca), and magnesium (Mg) in timothy and bromegrass cut at eight progressive dates was similar in both grasses. Highest concentrations were usually found in leaves, lowest at the base of stems, with levels in stems increasing toward the center or tips. With progressive maturity, K, Ca, and Mg content of stems decreased whereas in leaves and heads, K decreased, Ca increased, and Mg remained relatively constant. Sodium (Na) showed little change with progressive cutting dates but low concentrations of this element suggest an inadequate supply in the soil to permit deposition in the plant.In both grasses, ratios of K/Ca, K/Mg, K/(Mg+Ca), were large. These ratios stayed relatively constant in leaves throughout the season but decreased in heads and stems with progressive cuttings. The Ca/Mg ratio tended to be higher in stems than in heads.