Abstract
A field experiment was conducted to clarify the effect of basal application of dolomite, and top dressing of nitrogen fertilizer on the yield, botanical composition and inorganic nutrient absorption of orchardgrass-alfalfa mixture. Dolomite were applied at three levels (60kg, 45kg and 30kg/a). Nitrogen fertilizer were top dressed at three levels of N_2, N_1 and N_0 (annually, 1.0kg, 0.5kg and none/a, respectively) from the second harvest year. These plots were replicated three times. The results are as follows: 1) Total dry matter yield in the first year was highest in dolomite 30kg/a plots, resulting from the differences in the yields at the first cutting, although there were no significant differences among dolomite treatments from the second to the fourth cutting. 2) After the second harvest year, interactions of dolomite and nitrogen fertilizer were recognized ; dry matter yields were higher in higher application plots. In the dolomite 30 or 45kg/a plots, yields of N_0 plot were lower than N_2 and N_1 plots due to the inferior growth of orchardgrass. However, in the dolomite 60kg/a plots, there were no significant differences in yields among N levels. 3) The proportion of alfalfa to total yield was higher in the higher dolomite and lower nitrogen plots. Especially, it was highest in the dolomite 60kg/a plots and nitrogen N_0 plots. 4) In the second and the third year, inorganic nutrient absorption in orchardgrass and alfalfa was significantly correlated with the dry matter yields and nitrogen absorption. Therefore, it was suggested that nitrogen absorption promoted the growth of orchardgrass and alfalfa, and increased the other inorganic nutrient absorption.
