Application of bacterial preparations together with potassium humate Agro.Bio

Microorganisms in soil and biotic substances in agriculture in Ukraine

Soil microflora, multiplying in enormous quantities in the rhizosphere and on plant roots, synthesizes various biologically active substances during their life activity, just like some plants. These substances released by soil microflora activate plant growth and development.

Recently, among the diverse biotic substances in soil, vitamins of group B, vitamins C and K, inositol, biotin, para-aminobenzoic, nicotinic and pantothenic acids, and various auxins have been identified.

The microbiological literature contains quite extensive data on the ability of soil-inhabiting bacteria to synthesize biotic substances that stimulate plant growth and development. Recent studies have established that active producers of vitamins and heteroauxins are bacteria of the Pseudomonas group, which are widely distributed in soil.

Biotic substances contained in soil are products of metabolism of microorganisms and higher plants. Their physiological activity is determined by the fact that some biotic substances are high-molecular oxyacids with great chemical potential, while others are part of enzymes and accelerate many biochemical processes in the plant organism. By accelerating metabolism, activating photosynthesis and other processes, biologically active substances often have a significant impact on the yield of agricultural plants.

Research results

The study of the effect on plant growth and development of biologically active substances produced by bacteria was conducted by us in vegetation and field experiments on gray forest soils. The experiments used live cultures and preparations of killed cells of bacteria Pseudomonas fluorescens and Bacillus megatherium var. phosphaticum.

The action of biologically active substances synthesized by bacteria was studied in comparison with the direct effect on the plant of physiologically active salts of humic acids. The results of these studies are presented in Table 1.

On dark gray forest soil, the influence of the studied preparations on yield was weaker than on light gray soil.

Judging by the growth and development of oat plants, the growth effect of the studied preparations was not inferior to the action of humic compounds (0.005% solution of potassium humate). However, even in this case, bacterized plants stood out in their development.

Apparently, on light gray forest soil, conditions for the action of the studied preparations are more favorable than on dark gray soil. Since the effect of biotic substances varies significantly on different soils, subsequent experiments included a variant with sowing bacterized seeds in fertilized soil. It was assumed that the use of fertilizers would increase the positive effect of the studied preparations. Humic fertilizers were used as the fertilizing agent.

As shown by the results of vegetation experiments using humic fertilizers, which were applied at the rate of 1 g per vessel, their combination with growth substances from killed bacterial cultures gave the maximum yield increase (Table 2).

The highest effect was obtained on light gray forest soil. Moreover, the effect of the live culture preparation was not more effective than the effect of the killed culture preparation of Bac. megatherium var. phosphaticum.

Considering the great importance of close contact between rhizosphere microflora and the plant, it was necessary to establish the effect of growth substances produced by the studied bacteria depending on plant characteristics. For this purpose, experiments with barley were conducted.

Dark gray forest soils, being more fertile, contain a sufficient amount of biotic substances for plants. This is confirmed by the size of oat and barley yields from control sowings on light gray soil, which was almost two times lower than on dark gray soil.

Comparison of the effect of killed culture and live cells of the studied bacteria does not show great advantages of live culture preparations. This conclusion deserves great attention. The use of killed bacterial culture preparations in conditions detrimental to microorganisms due to alternating freezing and thawing of soil in early spring may become a promising technique for increasing agricultural crop yields.

What is the influence of humic fertilizers on microbiological processes occurring in the soil?

Conclusions

1. Bacterial preparations of killed bacterial cultures that have the ability to form biologically active substances have a positive effect on plant growth, development and yield. The effect of biologically active substances of bacterial origin depends on the biological characteristics of plants and soil properties.
2. The most effective is the combined use of bacterial and humic fertilizers, as exemplified by potassium humate Agro.Bio.
3. In Ukraine, the accumulation of the largest number of viable and active microorganisms in soil in early spring is possible only with the application of bacterial preparations.
4. The combined use of a number of bacterial preparations is the most effective means of enhancing soil microbiological activity.