The aim of the studies and research on which the present paper is based was to assess the level of interdependency between the fertilization system and the yield for the sunflower crop in view of establishing some fertilization variants for different crop systems. The sunflower crop, together with maize and winter wheat, are grown on large areas in Banat plain, where the agricultural systems practiced are mostly vegetal, with simple rotations, often monoculture. Under the current social and economic conditions, with a major influence brought about by the financial crisis, the vegetal cultures in the area under research are intensive crop systems to various degrees. From the point of view of fertilization, as an element of technology, we can find different situations, from a total lack of fertilizers, to various doses of fertilizers, which in some cases can vary from one year to the other according to the economic power and the opportunities that may appear. We observed the interdependence between the mineral fertilization system and the amount of the yield. The fertilization schemes were made on PK combinations (where we had four variants: 0, 50, 100 and 150 kg/ha active substance) to which we added nitrogen in five variants (0, 50, 100, 150 and 200 kg active substance./ha). There are three types of fertilization systems that can be emphasized :“low fertilizer system”, for P0K0 and nitrogen variations from 0 to 200 kg/ha; this system is frequently met with in subsistence farms or in family farms where the budget for the entire technology is generally low, and fertilization is occasional and made with nitrogen-based fertilizers. The second type is “medium fertilizer or budget fertilizer system” for P50K50 and nitrogen variations from 0 to 200 kg/ha. Phosphorus and potassium-based fertilization, even if used within low limits, amplifies the effect of nitrogen-based fertilizers by up to 1.26 times when compared to the unilateral nitrogen fertilization. The third type is “high fertilizer system” for P100K100 and P150K150 and nitrogen variations from 0 to 200 kg/ha. Here we find the fertilization variants which generate the highest yields, because they amplify the effect of nitrogen fertilizers by 1.47-1.61 times when compared to the control variant. A balanced NPK fertilization brings the highest yields, with significant increase when compared to the control variant.

soil fertility; mineral fertilizers; fertilizer systems; sunflower crop production; correlation

Presentation: oral