EFFECTS OF WATER SUPPLY AS AN ABIOTIC STRESS ON THE YIELDS AND AGRONOMIC TRAITS OF WINTER WHEAT (Triticum aestivum L.) ON CHERNOZEM SOIL

The effects of different water supply cropyears (2007 year=dry, with water stress; 2008 year=optimum water supply) on the yields and agronomic traits of wheat in different crop models (crop rotation, fertilization, irrigation) were studied. In non-irrigated treatment the maximum yields of winter wheat were 5590 kg ha(-1) in biculture (maize-wheat) and 7279 kg ha(-1) in triculture (peas-wheat-maize) in 2007 year characterized by water-deficit stress. In 2008 (optimum rain amount and distribution) the maximum yields were 7065 kg ha(-1) (biculture) and 8112 kg ha(-1) (triculture) in non irrigated conditions. In water-deficit stress cropyear (2007 year) the yield-surpluses of wheat were 2245 kg ha(-1) (biculture) and 1213 kg ha(-1) (triculture), respectively. The nutrient utilization of wheat was modified by abiotic (water) and biotic (leaf-and stem diseases) stress. The fertilization surpluses of wheat were 2853-3698 kg ha(-1) (non-irrigated) and 3164-5505 kg ha(-1) (irrigated) in a dry cropyear (2007) and 884-4050 kg ha(-1) (non-irrigated) and 524-3990 kg ha(-1) (irrigated) in an optimum cropyear (2008). The optimum fertilizer doses varied N150-200+PK in biculture and N50-150+PK in triculture depending on cropyear and irrigation. The abiotic stress (water deficit) influenced the agronomic traits (diseases, lodging) of winter wheat. The optimalization of agrotechnical elements provides 7,8-8,5 t ha(-1) yields in dry cropyear and 7,1-8,1 t ha(-1) yields of wheat in good cropyear, respectively.