RESEARCH REGARDING THE INFLUENCE OF NITROGEN AND PHOSPHORUS FERTILIZATION ON THE YIELD OF GRAIN SORGHUM HYBRIDS

The fertilization is an essential technological factor in improving yield. The purpose of this research was to evaluate the effect of fertilization and the answer of grain sorghum hybrids in terms of yield and its components. Research conducted over two agricultural years (2013/2014-2014/2015) was located in the South-Eastern Romania area and was based on a split plot design. The paper presents the results regarding the following tested factors: Factor A-grain sorghum hybrids: Alize, Aquilon, Arack; Factor B - fertilization levels: N0P0, N90P0, N90P60, N120P0, N120P60. Regarding fertilization, both the use of nitrogen (N) and the fertilization with complex fertilizers (nitrogen and phosphorus) generated the increase of yield and its components with values statistically assured for the three researched hybrids. The average yield was 7.83 t/ha, varying from 5.61 t/ha (Arack hybrid unfertilized) to 9.22 t/ha (Aquilon hybrid fertilized N120P60). Hectolitre mass was highly significant influenced by the use of fertilizers, the highest value (80.74 kg/hl) being recorded by the hybrid Arack fertilized N120P60. The maximum value of a thousand seeds weight was recorded by the hybrid Aquilon fertilized N120P60 (24.15 g) and the lowest value was recorded by the hybrid Alize unfertilized (19.03 g) with variations between +0.95 g (Arack hybrid fertilized N90P0) and +3.56 g (Aquilon hybrid fertilized N120P60).