VII. AlpsAdria Scientific Workshop Stara Lesna, Slovakia, 2008 695          Ivica DJALOVIC 1 –Milica CVIJOVIĆ 1 –Drago MILOŠEVIĆ 1 – Ilija KOMLJENOVIĆ 3 1 University in Kragujevac, Faculty of Agronomy–Cacak, Serbia, e–mail: maizescience@yahoo.com 3 Faculty of Agriculture, University of Banja Luka, Republic of Srpska, Bosnia and Herzegovina  The winter wheat (Triticum aestivum L. cultivar KG–56) was grown on degraded Vertisol of Central Serbia over the 2000–2005 periods . Acid reaction (pH in 1n KCl: <4.5), moderate supplies with total N (<0.15% N), low in AL–soluble P and adequate in AL–soluble K (<5.0 mg P2O5 and >15.0 mg K2O 100 g 1 , respectively) are main characteristics of the soil. Four steps of N fertilization (0, 60, 120 and 250 kg N ha 1 ) from two surces (CAN = calcium ammonium nitrate 27% N and Urea 46% N) on the constant P (80 kg P2O5 from two sources: MAP = monoammonium phosphate 11% N and 52% P2O5 and SP = superphosphate 17% P2O5) and K (60 kg K2O in form of KCl containing 60% K2O) fertilization were used in the experiment. Annual yields in 2005 were for 28% (grain) and 19% (straw) lower than in 2001. Depended on year, mean concentrations were in the ranges from 1.72% N to 2.40% N and from 0.25% to 0.33% P (grain), from 0.41% N to 0.55% N and from 0.032% to 0.056% P (straw). Grain N and P were considerably higher in 2005 (2.40% N and 0.33% P) compared to remaining four tested years (means: 1.96% N and 0.26% P). The analogous values for straw were 0.55% N and 0.056% P (2005), 0.42% N and 0.042% P (means 2001–2004). The highest grain and straw yields for 2001 were accompanied with the lowest grain and straw N and P concentrations. N rates considerably influenced wheat nutritional status and yields. For example, yield increases of N fertilization (means three N rates) were for 65% (grain) and 35% (straw) compared to unfertilized plot (t ha 1 : 2.22 and 3.65 for grain; 3.20 and 4.33 for straw). With that regard, the optimal N rate was 120 kg N ha 1 . N fertilization considerably increased grain and straw N, while P status was similar on three rates of applied N. In general, sources of N and P were less influencing factors of wheat nutritional status and yields and mainly resulted by non–significant differences of tested properties. ! winter wheat, vertisol, nitrogen fertilization, grain yield, straw yield, N uptake, P uptake. "!#$" Soil nutritional status is important factor of the field crop yields. With that regard, nitrogen (N), phosphorus (P) and potassium (K) supplies play are especially important role (Bergmann, 1992; Mengel and Kirkby, 2001; Németh, 2006; Pepo, 2007; Baric et al., 2007; Bertic et al., 2007; Drezner et al., 2007). Vertisol is soil of heavy texture and high capacity for absorption and imobilization of some nutrients for field crops. It is estimated that vertisol area in Serbia is about 700,000 ha or 25 % of agricultural land of the country (Živković and Djordjević, 2003). Aim of this study was testing N and P status in wheat grown on vertisol under application of different rates and forms of N and P fertilizers. $% "! &’! The winter wheat (Triticum aestivum L. cultivar KG–56 developed in Institute for Small Cereals in Kragujevac, Serbia) was grown on degraded Vertisol of Central Serbia over the 2000–2005 period. Acid reaction (pH in 1n KCl: <4.5), moderate supplies with total N (<0.15% N), low in AL–soluble P and adequate in AL–soluble K (<5.0 mg P 2 O 5 and >15.0 mg K 2 O 100 g 1 , respectively) are main characteristics of the soil. Four steps of N (fertilization kg N ha 1 : 0, 60, 120 and 250) from two surces (CAN = calcium ammonium nitrate 27% N and Urea 46% N) on the constant P (80 kg P 2 O 5 from two sources: MAP = monoammonium phosphate 11% N and 52% P 2 O 5 and SP = superphosphate 17% P 2 O 5 ) and K (60 kg K 2 O in form of KCl containing 60% K 2 O) fertilization were used in the experiment. In the treatment 0 kg N ha 1 only