Application of Dolostone Powder as Industrial Residual on Magnesium‐Deficient Arable Soils in Estonia

Abstract

About 60% (678,000 ha) of Estonian arable soils have a deficiency of plant‐available magnesium (Mg). The soils formed from dolostone (or dolomite rock) till are considerably richer in Mg than those formed from limestone‐rich and noncalcareous tills. Formerly, ground dolostone rock with a high content of mineral dolomite was used only as a soil liming material. Later, dolostone powder (DSP), received in the course of industrial manufacturing of dolostone rubble, was also applied for the mitigation of Mg deficiency in soil. The easily accessible resources of DSP as an industrial waste may also qualify as an Mg fertilizer. It soon became apparent, however, that with the application of DSP to the soil, an excessive quantity of Mg could be accumulated. This Mg surplus in soil destroys the equilibrium in plants' assimilation of nutrition elements and inhibits the normal development of agricultural crops. In our research, the influence of different DSP doses on the yield of red clover (Trifolium pratense L.), lucerne (Medicago sativa L.), barley (Hordeum vulgare L.), wheat (Triticum aestivum L.), and oil rape (Brassica napus L. var. Oleifera subvar. Annua) was studied on arable soils formed from different parent materials. We elucidated from the 2‐year experiment the high efficiency of DSP application in increasing the yields of Mg‐philic crops such as clover, lucerne, and oil rape. The negative influence of excessive Mg application on crop yields, especially in the first year of DSP application, is more clearly visible on soils that are calcium deficient for plant production. For the amendment of deficiency in Mg acid arable soils, 1–1.5 t ha⁻¹ of DSP should be used every 2 to 3 years. The broad application of industrial‐origin DSP is useful from at least three points of view: (1) industrially produced Mg fertilizers may be replaced by a readily available local industrial (mining) by‐product, (2) managing costs and territories for the disposal of industrial wastes will be reduced, and (3) it will be possible to attain complex and environmentally friendly utilization of local mineral resources.

Keywords:

• Arable soil
• calcium and magnesium interaction
• dolostone powder
• liming
• magnesium deficiency and surplus
• magnesium fertilizer

Acknowledgments

For help and support, we thank Enterprise Estonia, the Estonian University of Life Sciences, and Nordkalk AS.