IONIC BALANCE VERSUS NUTRITIVE VALUE OF MEADOW VEGETATION
IN THE EARING AND FLOWERING PHASE OF Festuca pratensis Huds.

Henryk Janukowicz

Summary

Meadows are a valuable and important element of green lands and rural areas. Their special value is determined by both productive and natural aspects. Green lands are a source of forage which sometimes, particularly during summer seasons, entirely covers the requirements of bred animals. Meadows in rural areas are a landscape element and a habitat for rich flora and fauna.

The basis for 15-year (1987-2001) fertilization and meadow studies were three static experiments located in the Western Pomeranian province. The first experiment (Trzygłów) was carried out in typical dry-ground forest in the Rega River basin, on degraded black soil with a granulometric composition of light loamy sand. The second experiment (Rzęsin) was carried out in dried riverine forest in the Stuchowska Struga River basin , on leached brown soil with the granulometric composition of heavy loamy sand. The third experiment (Kołbacz) was carried out in typical riverine forest in the Płonia River valley, on brown alluvial soil with the granulometric composition of typical dusty soil. pH of three experimental soils was acidic or slightly acidic. The soils differed in the proportion of silt fraction, in organic carbon content, sorption capacity and the degree of base saturation . It was found during the studies that small losses of exchangeable basic ions, in particular of Ca²⁺ ions, occurred only from the sorption complex of brown soil in the Rzęsin experiment, which resulted in a  non-significant increase in the content of exchangeable H⁺ and in soil acidification within the most fertilized objects (N₂PK₃).

The studies were focussed on evaluation of the amount and nutritive quality of dry matter yields of meadow vegetation harvested in the earring and flowering phase of Festuca pratensis Huds. The following parameters of meadow vegetation were determined and proposed for evaluation: cation content [C], inorganic anion content [A] and organic anion content [C-A], as well as the following ionic balance indices: [C:A], [C:(C-A)] and [C⁺:C²⁺] which can be useful, in the author's opinion, in examining the amount and nutritive value of harvested plants.

The studies showed that meadow vegetation contained more inorganic anions [A] in variants first harvested during the earing phase of Festuca pratensis Huds., but more organic anions [C-A] in variants first harvested in the flowering phase of Festuca pratensis Huds. It was found that ionic balance in meadow vegetation is maintained mainly through metabolically controlled reduction of organic acids R-COO^-. Inorganic anions Cl^-, SO₄^2-, H₂PO₄^-and NO₃^- neutralize at most some 1/3 of K⁺, Ca²⁺, Mg²⁺and Na⁺ cations absorbed by plants. K⁺ prevailed among cations whereas Cl^- - among inorganic anions, which in fertilizer studies should be considered , in the author's opinion, as an indicator of the crop size and quality.