The paper presents the partial results of researches regarding the agrochemical melioration of soils under control polluted by crude oil brought from the exploitation site at Suplacu de Barcău that took place at the Agricultural Research and Development Station in Oradea, Bihor County. The experimental device was made out of 1 m 2 micro parcels, spread out in subdivided parcels, in four repetitions, having three factors: A - the pollution by crude oil from Suplacu de Barcău,in two graduations a1-nonpolluted and a2-under control polluted with 3 % crude oil concentration;   B – the organic fertilization with manure (0, 50, 100 and 150 to/ha) and C – the mineral fertilization with complex fertilizer in doses: N 0 P 0 K 0 , N 100 P 80 K 70 , N 200 P 160 K 140 and N 300 P 240 K 210 . The experience was set out on a haplic luvosoil în the year 1993 and the soil was cultivated with millet in the first three years and with spring wheat in the last seven years of research. The millet hay average yield of studied variants is bigger in not polluted variant (44,91 q/ha) than in polluted by 3 % concentration of crude oil variant (40,16 q/ha) with 4,75 q/ha. Between annual and average yields of millet hay (q/ha) and the manure quantity and respectively mineral fertilizer doses was established linear and spatial linear correlations. The reply’s crop at the rate of complex fertilizer administrated is in proximity but the slope of the line for polluted variant show an increase of yield at one rate’s mineral fertilizer about 3,5 kg/ha while for the not polluted soil the increase is about 3,36 kg/ha. The shapes of the lines established for the first three researches years sows that the level of annual yields under the organic fertilizer system have a decrease tendency from the first year to the last year, on the not polluted variant while on the polluted variant the level of yield is smaller in the first year and afterward it stabilize to approximately 5 kg/ha for one unit of manure administrated. Analyzing the shapes of correlation lines established between the rates of mineral fertilizer and millet-hay annual yields we can see that this is approximately parallel and the differences between the yields on not polluted and polluted soil it reduced in the time of the first tree years of the observations. In the process of chemical melioration of soils polluted with crude oil the mineral fertilizer system is more important than the organic fertilizer system because of the nitrogen added in soil determine the equilibrium between organic carbon and nitrogen and these stimulate the activity of soil microorganisms, implicated in crude oil biodegradation.

oil pollution, crude oil, haplic luvosoil, agrochemical melioration

Presentation: oral