| Abstract: | Abstract Two rates of Mg, 0 and 56 kg/ha, were randomized within each of 43 cultivars that had previously been established in a randomized complete block design. The 43 cultivars consisted of 6 species. Forage samples were obtained in early spring and chemically analyzed for content of Ca, Mg and K. Grass species and cultivars with species significantly differed in content of Ca, Mg and K and in the ratio meq K/(meq Ca + meq Mg). Significant interactions of Mg with species and Mg with cultivars within species were observed. At the relatively low level of soil Mg and Mg rate, no cultivar contained 0.20% Mg, a value often used to identify proneness to grass tetany. However, no cultivar had an average meq ratio, K/(Ca + Mg), greater than 2.2, a value often used in diagnosing potential tetany problems that might be associated with intake of low Mg forage. The interaction of cultivar with Mg rate indicates that fertilizer Mg level influenced cultivar content of Mg, and that the effect was not consistent for all cultivars. |
