Influence of fertilization on winter wheat yield, under the ecological conditions from the agricultural Research Station of Valu Lui Traian, Constanţa County

Winter wheat is a crop, which capitalizes very efficiently high fertilizer levels. Therefore, applying 80 kg/ ha active ingredient of N, together with 70 kg/ha active ingredient of P, has resulted in a statistically assured very significant yield increases of 1550 kg/ha (143 %), the average of the nine tested wheat varieties. Maintaining a constant phosphorus soil background (70 kg/ha active ingredient), corroborated to the application of other two nitrogen levels, higher with 40 kg/ha active ingredient of N, led to significant yield increases. From the N0P0 unfertilized background to the N80P70 background, a yield increase of 1550 kg/ha can be achieved. It diminished until 1090 kg/ha between N80P70 and N120P70 soil background and until 430 kg/ha between N120P70 and N160P70 soil background. The interaction between wheat varieties and fertilization rates pointed out the Alex Variety and the N160P70 fertilization rate, with a yield of 7800 kg/ha