The effect of mineral nutrition to crop weediness and grain yield of wheat.

Two wheat cultivars (Takovcanka and Ana Morava) were grown under field conditions at the long term experiment including different fertilization in Center for Small Grains Kragujevac as follows: a) control (without fertilizers), b) without N = two subvariants with diferent rate of P: 2P1 (80 kg P ha -1 ) and 2P2 (120 kg P ha -1 ), c) NP with two different rate of N application: 3N1 (80-100 kg NP ha -1 ) and 3N2 (120-100 kg NP ha -1 ) and d) 4N1 (8060 kg NP ha -1 ) and 4N2 (120-60 kg NP ha -1 ). Weediness depends of rate and variant of fertilization. The weed species Consolida regalis, Convolvulus arvensis, Polygonum aviculare, Cirsium arvens, Agropyrum repens, Polygonum convolvulus was dominant on fertilized plots. Those weeds represent strong competitors for nutrients, water and space. Differences in weeds communities were established in crops of two wheat cultivars grown under different regime of nutrition. The analyzed wheat cultivars expressed variability of grain yield depends of applied fertilizer variants. The lowest wheat grain yield was found on control variant. The highest grain yield and low weedinnes expressed both wheat cultivars Ana Morava (4480 kg ha -1 ) Takovcanka (4180 kg ha -1 ) on variant of NP fertilizer 4N2 (120-60 kg N ha -1 ).