Tag Archives: magnesium

73–80 V. Loide, M. Nõges and J. Rebane
Assessment of the agrochemical properties of the soil using the extraction solution Mehlich 3 in Estonia
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Assessment of the agrochemical properties of the soil using the extraction solution Mehlich 3 in Estonia

V. Loide¹, M. Nõges² and J. Rebane²

¹Estonian Agricultural University, Kreutzwaldi 64, 51014 Tartu, Estonia; e-mail: valli.loide@mail.ee
²Agricutural Research Centre, Teaduse 4/6, 75 501 Saku, Estonia; e-mail: noges@pmk.agri.ee

Abstract:

To determine the requirement of macro- and microelements, seven extraction solutions have been employed in Estonian practice. Double lactate (DL) extraction has been used for determination of the phosphorus and potassium requirement, ammonium lactate (AL) extraction for determination of the calcium and magnesium requirement, and five more different extractions have been used for determination of microelements. Hence the need for a more appropriate extraction solution was due to the large number of the extraction solutions used until now, which made determination of the fertiliser requirement less efficient; also, in some cases, use of some extraction solutions did not yield reliable results in the case of particular plants. It was found in this study that the extraction solution Mehlich 3 is suitable for determining the fertiliser requirement of the soils of Estonia, considering their diverse agrochemical properties, while it allows to reduce the number of the extraction solutions. Also, employment of the extraction solution Mehlich 3 yielded more reliable results with respect to plants in the case of phosphorus, potassium, copper and, particularly, magnesium and manganese.

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71–82 V. Loide
About the effect of the contents and ratios of soil’s available calcium, potassium and magnesium in liming of acid soils
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About the effect of the contents and ratios of soil’s available calcium, potassium and magnesium in liming of acid soils

V. Loide

Agricultural Research Centre, Teaduse 4/6, 75501 Saku, Estonia; e-mail: valli.loide@mail.ee

Abstract:

Soils in Estonia are characterised by washing out, i.e. leaching, of calcium carbonates and magnesium carbonates. Calcium losses from the arable layer may amount 150–500 (600) kg ha-1 a year, resulting in excessive concentration of free hydrogen ions in the soil solution, and therefore these soils require liming. Relatively high doses of lime fertilisers have to be used in order to eliminate harmful acidity of the soils. Clinker dust, oil shale ash and milled limestone are the materials widely used as lime fertilisers at present. Soils in Estonia are often poor in both potassium and magnesium, and that is why clinker dust, which is relatively rich in potassium, has been a particularly valued lime fertiliser. Magnesium deficiency is being alleviated by adding dolomite meal to milled limestone. However, a non-uniform mixing of these lime fertilisers does not ensure their sufficiently homogeneous consistence. Large doses of lime fertilisers, which are not uniformly mixed, have a variable effect on the contents and ratios of calcium, potassium and magnesium in the soil. The trials showed that, as a result of an incorrect use of lime fertilisers, both calcium-to-magnesium and potassium-to-magnesium ratios in the soil may change to the detriment of plants, leading to lower yields.

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