Calcium, magnesium and potassium in mineral soils from the southern half of Finland

Abstract

Abstract. 210 samples of mineral soils from the southern half of Finland with mainly an acid precambrian bedrock, were analysed for the total contents of Ca, Mg and K, and for the portion of these nutrients which could be exchanged by N NH 4 OAc (pH 7), dissolved by 0.1 N HCI at room temperature, or released by N HCI at 50°C.The total content of Ca was lowest in samples of heavy clay, 0.78±0.14 % in the surface soils and 0.92±0.10 % in the deeper layers. The mean content in the groups of other soils was at least about 1.1 %. The total content of Mg increased with an increase in the clay content (r = o.Bl***). It ranged from 0.6±0.1 % in the sand and fine sand samples to 1.53±0.19 % in the heavy clay soils of the surface layers and to 1.89±0.12 % in those of the deeper layers. Also in the groups of loam and silt soils and of the coarser clay soils, respectively, the Mg content was in the deeper layers higher than in the surface soils.The total content of K also increased with the clay content (r=o.73***) from 1.7 ± 0.1 % in the sand and fine sand soils to 2.74±0.21 % in the heavy clay soils of the surface layers and to 3.10±0.07 % in those of the deeper layers.The portion of exchangeable Ca was relatively high: in the groups of surface soils from more than one tenth to one third of the total amount. The corresponding average amounts released by even the more drastic treatment with acid were not markedly higher.Only a few per cents of total Mg were exchangeable and slightly higher amounts were dissolved by 0.1 N HCI, whereas the treatment with N HCI at 50°C released about half of the total Mg. Exchangeable K and K dissolved by 0,1 N HCI did not exceed 1 % of the total K, except slightly in the heavy clay soils; the average amounts released by N HCI ranged from 5 to 18 % of the total K.The plant availability of these nutrients was discussed.In a previous work (Kaila and Ryti 1968), characteristic differences in the total contents of Ca, Mg and K in various particle size fractions of some Finnish mineral soils were found. In all the 30 samples analysed, the Ca content was in the clay fraction (< 2/<m) distinctly lower than in the silt (2-20 /on) and fine sand (20 -200 /urn) fractions. The clay fraction again, was richest and the fine sand fraction poorest in total Mg. The K content varied in a way similar to that of Mg but differences between these three fractions were less marked. If this observation, which in respect to Ca seems

Comparison of and correlation between the characteristics of agricultural topsoil and subsoil at the southern coast of Finland

“…The exchangeable Ca and K contents, ECEC and plant available (Bray 1) P decreased, whereas exchangeable Mg and exchange acidity (AI + H) increased towards the subsoil. The same trend has been observed by Marttila (1965) and Kaila (1972) for the exchangeable cations and by Kaila (1971) for the ECEC in Finnish mineral soils.…”

“…Therefore the differences between the two soil layers are the same as they are in the nature. Marttila (1965), Kaila (1972Kaila ( , 1973 and Urvas et al (1978) for example, collected topsoil and subsoil samples mostly from different sites, furthermore the soil samples of both materials differed in number. The results of above studies may show a trend to bias from natural conditions.…”

“…Kaila (1971) studied the ECEC of Finnish mineral soils and observed the dependence on clay to be in both soil layers very close and the dependence on organic C to be low. Her material consisted of both virgin and cultivated soils with a narrower range of organic C % and a wider range of clay than in this material.…”

Leaching of Phosphorus, Calcium, Magnesium and Potassium in Barley, Grass and Fallow Lysimeters

“…However, the loss of the exchangeable cations by leaching may lead to deficiency and the need for liming of soil with material containing calcium and magnesium. Leaching of magnesium and potassium from the soil surface causes significant losses, but the deeper layers may also contribute to leaching (Kaila, 1973).…”