Abstract
Copper and zinc concentrations in soils and grasses were examined in the meadows of horse breeding farms. Soils and grasses were collected on the same points. Timothy in the meadows was examined as a representative grass species. The results are as follows : 1. The average value of the total Cu concentration in Residual Regosols, Andosols and Brown Forest Soils is lower than that of Brown Lowland Soils, Gray Lowland Soils and Gley Soils. 2. Soluble Cu was extracted with 0.1 N-HCl from the air-dried soil samples. Soluble Cu concentration was decreased with the increasing phosphate absorption coefficient. The Cu concentration was less than 1 ppm, when the phosphate absorption coefficient was more than 1400. 3. In case of the low soluble Cu soil, when 0.1 N HCl that contains 100 mell of protons (pH 1.07), was added to the soil, proton concentration in the 0.1 N HCl soil extracts was found to be lower than 12-13 me/l (pH 2.3<). At the same time, large amount of Al ion ranging from 40 me/l to 70 me/l was dissolved in the 0.1 N HCl extracts. 4. There was a few soil samples that contained soluble Zn lower than 1.5 ppm. In this case, the proton concentration in the 0.1 N HCl extracts was lower than 1 me/l (pH 3.0<). Thus the sum of Al3+, Ca2+ and Mg2+ ions in the 0.1 N HCl extracts was at high level above 70 me/l. 5. Cu and Zn concentrations in the timothy were a half compared with adequate concentrations in rations for horse. 6. It was found that Cu and Zn concentrations in the timothy have no correlation with the concentration of soluble Cu and Zn in the soils.
