Effects of Streptomyces <i>Biofertilizer</i> to Soil Fertility and Rhizosphere’s Functional Biodiversity of Agricultural Plants

Abstract

In the present study, a biofertilizer on the basis of Streptomyces fumanus gn-2 was used for the treatment of wheat and soybean seeds (dose 10 4 spore/ml) before planting them in soil with low fertility in order to determine the effect of this biological agent on germination rate; the growth of seedlings, shoots, and the maturation phase of plants; the rhizosphere’s functional biodiversity; and the resistance of these plants to pathogens. Seeds were soaked in the suspension for a period of two or three hours. During the growing season of the crop, no additional fertilizing and spraying of a biopesticide against diseases or pests occurred. Despite the soil having low fertility, low quantities of organic matter, and not having been before used for the cultivation of agricultural plants, this biofertilizer showed a strong stimulatory effect on the growth of seeds and seedlings of wheat and soybeans. The average germination and seed vigor increased by 1.5 - 2.0 times, and the phenophases were accelerated to three to five days. In all phases of vegetation, the ammonifying bacteria in the presence of an antagonist (a biological agent) developed rapidly and were constantly present in significant numbers in the rhizosphere. Streptomyces fumanus introduced into non-sterile soil entered into competition with the local soil microflora and had the ability to colonize the rhizosphere system of plants. The use of a formulation of Streptomyces gn -2 has improved the composition of rhizosphere microflora, attracting saprophytic microorganisms: ammonificators and oligotrophs. The presence of the biocontrol microorganism Streptomyces fumanus in the rhizosphere plays an important role in enhancing the growth and development of useful groups, such as nitrogen-fixing bacteria.