Influence of mineral fertilizers and bacterial preparations on sunflower yield in the conditions of the Lower Don

Methods.  The article presents the results of a three-year field experiment to study the effect of mineral fertilizers and bacterial preparations with strains of associative nitrogen fixators on the yield of sunflower seeds in the Lower Don. The research was carried out at the Rostov state variety section in the Aksai district of the Rostov region in 2012–2014. The objects of research were sunflower hybrids of different maturation period: don 1448 (mid-late) and patriot (mid-ripe). During the field experiment, mineral fertilizers (ammonium nitrate (N 34,4 ), ammophos (N 12 Р 50 ), potassium chloride ( К 60 )), as well as bacterial preparations with strains of associative nitrogen fixators (PG5, Flavobacterin, 17-1, Mizorin 7), made at the all-Russian Institute of agricultural Microbiology (VNIISKHM), Pushkin, were used.Results.  On average, in 2012–2014 the yield of sunflower seeds in the control variant (without the use of fertilizers) hybrid don 1448 was 1.54, hybrid Patriot — 1.61 t/ha. The increase in yield when cultivating the medium-ripe hybrid Patriot when applying the optimal dose of mineral fertilizers N 40 R 50  was 0.46 t/ha or 28.4%, the average late hybrid don 1448 from the dose N 40 R 100  0.47 t/ha or 30.7%. Effective is the treatment of seeds of the hybrid Patriot with biological product PG-5. The increase in yield compared to the control was 0.37 t/ha or 23.0%. This increase is 5.4% less than the optimal version with a dose of mineral fertilizers N 40 P 50 . Seeds of the Don 1448 hybrid should be treated with Flavobacterin. But the increase in yield to control was only 0.12 t/ha or 7.8%, which is 3.9 times less than in the version with the highest yield with this hybrid, where fertilizers were applied at a dose of N 40 P 100 .