The optimal combination and amount of major nutrients computed by the Home's systematic variation technique for the hilly pasture development. 1; Determination of the optimal combinations of anions N:S:P and cations K:Ca:Mg in fertilation on a grass-clover mixed sward

This pot experiments were conducted to find out the optimal fertilization ratios of the N:S:P anions and K:Ca:Mg cations of major nutrients in an orchardgrass/ladino clover mixed sward. The optimum ratios in equivalent basis were computed by the Homes systematic variations technique. The soil samples were collected from the newly reclaimed soils, which are located on colluvial hilly area with a good consideration for the hilly pasture development. The optimum fertilization ratios of major nutrients for the high yields by the forage species in a mixed sward were obtained (Table 4 in detail); N:S:P = 3:1:1 and K:Ca:Mg = 1:1:1 for grass and grass plus legume, and N:S:P = 1:6:43 and K:Ca:Mg = 1:3:1 for legume in general. The yield increases from the systematic variations in this mixed sward were laid in following order; N P S-group and K Mg Ca-group for grass and grass plus legume, and P S N-group and Ca Mg K-group for legume. Especially, the yields were greatly increased at the N-group for grass, and at the P and Ca-groups for legume. Soil pH-value was decreased at the S-group, and somewhat increased at the Ca-and Mg-groups. The content of available P2O5, CEC and base saturation were greatest with the CA-group. At the N-group, the N-contents were highest and the P-contents were lowest in grass and grass plus legume, which resulted in the highest Ca/P ratio of 2.15 among the anion groups. Whereas the highest Ca/P ratio of 9.20 in legume was obtained at the Ca-group. Legume showed in general higher Ca/P ratio and lower K/(Ca+Mg) ratio than these in grass. There were differences in the effects of systematic variations of major nutrients on the dry matter yields and the mineral yields. The optimum fertilization ratios of anions and cations for the high mineral yields were obtained (Table 8), which showed differences comparing with the ratios for the high dry matter yields. The antagonis between the cations K and Mg was known from the point of mineral yields of mixed forages