Field studies were conducted in Romania, from 2006 to 2008, to determine the effect of rotations and fertilizer applications on the yield and quality of maize in irrigated sandy soils. The treatments comprised 3 years rotation (wheat, maize and soyabeans), 4 years rotation (wheat, lucerne, maize and soyabeans), wheat monoculture, maize monoculture, 2 years rotation (maize and wheat), 5 years rotation (wheat, lucerne, potato, maize and wheat), 3 years rotation (wheat, maize and groundnut), 6 years rotation (maize, groundnuts, wheat, sunflower, potato and wheat) and 4 years rotation (bean, wheat, maize and wheat) and fertilizer applications, i.e. 160 kg N and 80 kg P/ha, 80 kg N and 80 kg P/ha and control. Results showed that maize gave good seed yields, which varied between 4.5 q/ha on unfertilized variant and 38.5 q/ha in the 6 years rotation on 160 kg N and 80 kg P/ha. The most valuable rotations for maize were beans, soyabean, groundnuts or lucerne. Applying fertilizers in monoculture resulted only in small increases in production. The best variant with fertilizers was the 80 kg N and 80 kg P/ha, which increased the yields of all rotations used compared to the control. On all the rotations studied, the nitrogen fertilizer application improved the N content of maize seeds and directly increased the protein content, while other macro- and microelements in maize seeds registered small fluctuations, some of which were considered as constant no matter what kind of rotation was used.
