Die Bodenkultur - Journal for Land Management, Food and Environment
E. Strobel, E. Ahrens, G. Hartmann, H. Kluge and H. Jeroch:
Contents of substances in wheat, rye and oats at cultivation under conventional and the conditions of organic farming
The contents of crude nutrients, starch, sugar, cell wall substances, non-starch-polysaccharides, arabinoxylans, minerals as well as apparent metabolisable energy corrected to zero N-retention were estimated in several varieties of winter wheat, winter rye and oats grown under conventional conditions or under the conditions of organic farming.
Whereas in the investigated cultivation year the content of crude protein was higher in the conventional produced winter wheat and oats than values from feedstuff tables, the content in the organic cultivated kinds of cereals were about 23 % until 38 % lower. On the other hand the content of nitrogen free extractives, crude ash, calcium and phosphorus was general higher under organic farming conditions than under conventional conditions. Non-phytate phosphorus was at conventional cultivation in winter wheat and oats lower, in rye however higher than under the conditions of organic farming. The cultivation method had hardly any influence on the calculated content of apparent metabolisable energy. A high variability occured in oats between the varieties, so that the higher content in case of the organic cultivation method was not significant. A higher content of soluble arabinoxylans and a higher extract viscosity was determined in conventional cultivated winter wheat. A generaly high extract viscosity with a considerable difference between the both cultivation methods was established in winter rye. This did not correlate with the content of arabinoxylans. This is an indication, that other fractions contribute to the gel formation. Also no correlation was observed in oats between the ß-glucan content, which was higher under conventional conditions, and the extract viscosity. This parameter was in this kind of cereals very low.
The low content of crude protein and consequently, the lower content of amino acids in cereals grown under organic cultivation conditions should be taken into consideration for the formulation of compound diets.
Key words: chemical composition, winter wheat, winter rye, oats, organic farming.