Chemical Composition and Fertilizer Response of Two Range Plants in Relation to Grass Tetany

Abstract

The chemical response of two species of annual range plants, soft chess and broad-leaf filaree, to nitrogen and potassium fertilization was studied in a field plot trial in Amador County, California. Heavy losses of cows due to grass tetany have been reported from that vicinity in recent years. The K/(Ca + Mg) ratio in soft chess was significantly higher than that in broad-leaf filaree, and fertilization with N and K increased the ratio in both species. Fertilization increased the concentration of K in broad-leaf filaree, but had little effect on the concentrations of Ca and Mg. In contrast, fertilization decreased the Ca and Mg percentages in soft chess but did not change the K concentration. The presence of alkaloids in soft chess was detected by a "spot-test" technique.