The content of calcium and magnesium and the Ca:Mg ratio in cultivated plants in the context of human and animal demand for nutrients

Relationships between elements in biomass of plants which make up a food chain are related to the physiological role of each element. These relationships can be disturbed by different factors, particularly those related to the availability of individual elements to plants. Adverse effects of distorted relationships between the calcium and magnesium concentrations in biomass, which are caused by the low content of the two elements in soil and intensive fertilisation, mainly the application of nitrogen fertilisers, can manifest themselves as the occurrence of different human and animal diseases. The purpose of the study was to determine the Ca and Mg abundance in cereal grain (rye, wheat, oats, barley, maize), potatoes and staple vegetables, and in plants which are mainly used as animal feed (grasses, lucerne, clover, beet), in the aspect of human and animal nutrient demand, particularly in terms of the Ca:Mg ratio. The grain of cereal plants, which is the main ingredient of many food products, was found to be poor in Ca and Mg; moreover, the Mg content was higher than that of Ca, i.e. the Ca:Mg ratio was lower than 1, with the exception of maize, in which the Ca:Mg ratio was higher than 1. The plants used as feed were richer in the analysed elements; nevertheless, according to the literature data, their Ca and Mg content in a unit of weight does not meet the animals’ demand for these components. The average content of both elements in average yields of different plant species cultivated on fertile soils established the Ca:Mg ratio at 1.1, whereas in plant yields from poor soils this ratio is 1.7