Introduction:
Introduction. Cereal products play an irreplaceable role as a source of mineral salts. Defatted grain is by approximately 50% poorer in ash, compared to whole grain. The largest amount of mineral compounds are present in the germ of the grain and the peripheral layer of the seed. For centuries oats cultivars was an important fodder cereal in agriculture, and a component of the diet of poor people. A great genetic advancement was the cultivation of the hulled form of oat cultivars. Very beneficial features of the use of hulled oats provide an opportunity for the production of food of high biological quality, and balanced fodder for animals on ecology farms.

Objective:
The objective of the presented study was the investigation of the effect of varied amounts sown on accumulation of selected components – phosphorus, potassium, and calcium in the seed of naked and hulled species of oats.

Material and Methods:
During the period 2005-2007, field studies were conducted. Each year before the experiment the mean soil samples were collected in order to determine the granulometric composition, absorbed forms of phosphorus, potassium, and magnesium, soil reaction (pH) and content of humus. The results of studies were subjected to statistical analysis by means of the analysis of variance in individual years of the study and a 3-year synthesis. For detailed comparison of mean values the least significant differences (LSD) were calculated based on Tukey’s test, with the level of significance α = 0.05.

Results:
The content of potassium in the grain varied due to weather conditions in the years of study, sowing density rate and species. A relationship was also observed between individual years and sowing density rate, which evidences the fact that the content of potassium in the subsequent years changed according to the sowing density rate. The content of phosphorus in oat grain differed according to weather conditions and experiment conditions, i.e. sowing density rate and species applied. An increase in sowing density rate resulted in a lower content of phosphorus in oat grain. The contents of calcium in oat grain depended on weather patterns in the years of the study, sowing density rate and species. The content of calcium in the grain of naked species significantly differed, compared to that in hulled o

Conclusions:
The results of the study showed that the percentage of potassium in ash was the highest, followed by phosphorus and calcium. Naked species collected more potassium, compared to the hulled species.