CHEMICAL COMPOSITION OF SPRING BARLEY (HORDEUM VULGARE L.) GRAIN CULTIVATED IN VARIOUS TILLAGE SYSTEMS

The study evaluated the chemical composition of spring barley grain sown in 3 tillage systems (main plots): a) conventional tillage (CT) - shallow ploughing and harrowing after harvest of the previous crop, ploughing in the autumn; b) reduced tillage (RT) only cultivator after harvest of the previous crop, and c) herbicide tillage (HT) only glyphosate (360 g L-1) after harvest of the previous crop. In the springtime, a cultivation set composed of a cultivator, a string roller and a harrow was used on all the plots. The second experimental factor was barley cultivar (subplots): 1) husked Tocada, and 2) naked-grain Rastik. The depth of tillage varied according to the intended purpose: shallow ploughing to 10-12 cm, autumn ploughing to 25-30 cm, and cultivator tillage to 10-15 cm. The soil under the experiment was Chalk Rendzina with the texture of sandy loam, rich in available phosphorus and potassium and slightly alkaline. The study demonstrated that the content of total protein and crude fiber in the grain depended only on a barley cultivar. In turn, the content of macro- and microelements was affected by both factors: the cultivar and tillage system. Herbicide tillage (HT) was shown to reduce the content of phosphorus (P), potassium (K), calcium (Ca), iron (Fe) and copper (Cu) in barley grain, compared to conventional tillage (CT). Simultaneously, it raised the phytate-P content of grain compared to reduced tillage (RT). The content of phytate-P was significantly higher in cv. Tocada than in cv. Rustik.