The plant and soil material of this study were collected at a distance of 5—15 km one after the other from 90 farms in Southwest Finland, Satakunta and Ostrobothnia in the years 1966—67. The coefficients of simple and partial correlations between the contents of total magnesium or potassium or the ratios of K/Mg, Ca/Mg, Ca + Mg/K + Na in clover or timothy, the clover content of mixed ley, and the exchangeable cations or their ratios in soil were calculated separately for 1st year, 2nd year, and 3rd year or older leys. The results indicated that according to this rather limited material the potassium content and the ratio K/Mg in clover increased and the magnesium content and the ratio Ca + Mg/K + Na decreased significantly with the increasing clover content of the first year leys, even if the effects of the corresponding exchangeable cations and ratios in soil were taken into consideration. Clover and timothy in mixed ley possibly compete with each other for cations. Cation ratios and the cation content of timothy seemed to be independent of the clover content of the mixed ley, the properties of clover in 2nd year and older leys were likewise not dependent on it. Variations up to 43 % in the magnesium and potassium contents and the cation ratios of clover in first year leys were explained by vatiations in their clover content, and when the exchangeable cations of soil were also taken into account, from 1 to 76 % of this variation could be explained.
Influence of clover content of mixed ley on magnesium and potassium in red clover and timothy
