G. Milev1*, R. Todorova2
1Dobrudzha Agricultural Institute, 9520 General Toshevo, Bulgaria 2Trial Station on soybean, 5200 Pavlikeni, Bulgaria
Abstract. During 2011 – 2013 a multifactor field trial with the soybean cultivar Richie was carried out in the experimental field of Dobrudzha Agricultural Institute, General Toshevo. The aim of the investigation was to determine the effect of complex suspension foliar fertilizers from the group of Lactofols and of the bio stimulant Amalgerol premium on soybean grain yield under the conditions of Dobrudzha region. The trial was designed according to the split plot method in four replications of the variants, the size of the harvest plot being 12 m2. The testing involved one Amalgerol premium bio stimulant and three complex suspension fertilizers: Lactofol B, Lactofol O and Lactofol К/Ca. They were applied at phenophases beginning of flowering (R1) with a subsequent treatment 14 days later, and at mass flowering – beginning of pod formation (R2-R3) with a subsequent treatment 14 days later. The applied doses were 3500, 5000 and 6500 ml/hа. As a result of the three-year investigation it was found that under the conditions of extremely high temperatures during the growth season and severe soil drought in the region of Dobrudzha, the tested products did not have a significant positive effect neither on seed yield nor on 1000 seed weight.