The paper presents the results of researches carried out within 2008 – 2011 period at ARDS Caracal, District Olt regarding the effect of several fertilizers on winter wheat crop on the cambic baticalcaric chernozem of the zone. The 2008 and 2009 years of the experiment have been less favorable for winter wheat crop yet 2011 has been very favorable which determined much higher yields. On average for three years of research the yields have been directly influenced by fertilizer rates, the nitrogen ones having the highest contribution to the wheat yield increase; however, little differences have been noticed between N 150 and N 200 rates and that proves the low efficacy of higher rates of nitrogen. T he interaction between nitrogen and phosphorus is favorable for winter wheat when the nitrogen rates are applied on P 40-80 background, which determine yields of 4,243 – 5,455 and 4,493 – 5,854 kg/ha; the applying of nitrogen different rates on higher P background of P 120 has determined pretty the same yield results, so, they are not recommended. Nitrogen fertilizers determine the highest increase in winter wheat yield yet the highest nitrogen rate, N 200 has limited the yield. Nitrogen – phosphorus interaction is favorable to winter wheat crop when the yield ranges between 4,243 – 5,455 kg/ha and 4,493 – 5,854 kg/ha; the highest phosphorus background, P 120 has limited the yields and it is not feasible economically. Productivity elements: plants height at harvest, the length of the ear, the number of ear branches and the number of grains in an ear has been favorable influenced by nitrogen and phosphorus rates yet the best results were given by the interaction between two fertilizers. The mass of 1,000 grains has been correlated with the yield, being higher were the yields were bigger: P 80 K 80 N 150 yet, especially, N 150 – N 200 P 80. The mass of 100 liters of grains has decreased or stayed at the same level as a result of different phosphorus rates, has increased after potassium application and has decreased after nitrogen rates application; this parameter has increased as a result of interaction between nitrogen and phosphorus and, especially with nitrogen – potassium. On the basis of researches carried out at ARDS Caracal within 2008-2011 period there can be recommended on the chernozem soil of the zone, in climatically favorable years, the following rate: N100-150 P 80; in less favorable years regarding rainfall: N 50-100 P80.

fertilizers, winter wheat, chernozem

Presentation: oral