Influence of the combination of microbiological and mineral fertilizers on the biological indicators of ordinary chernozem

The effect of soil bioactivation with effective strains of microorganisms on the intensity of its basal respiration (BR) and cellulose decomposition activity (CA) was studied. It has been shown that changes in the biological activity of soil depend on a number of factors, in particular on the use of mineral fertilizers. The results obtained and the patterns identified can be used in practice to calculate the optimal doses of applied fertilizers and increase the coefficient of their use by plants.

Introduction. For the sustainable development of agroecosystems in the conditions of intensified agriculture, it is necessary to study the patterns of formation and changes in the biological activity of the soil, as well as to search for ways of targeted control of individual biochemical processes.

Object. The object of the research was samples of ordinary chernozem collected at the experimental site of the Institute of Agriculture of the Kabardino-Balkarian Scientific Center of the Russian Academy of Sciences in the steppe zone of the Kabardino-Balkarian Republic.

Materials and methods. Seeds of winter wheat of the Yuzhanka variety were sown in 1-liter vessels in the amount of 16 pieces per vessel. The experiment was repeated 3 times. Mineral fertilizers in the form of nitroammophoska (NPK 16:16:16) were applied at the rate of 2 grams per vessel.

Results and conclusions. The data obtained as a result of the study indicate the positive effect of introducing effective strains of microorganisms into the soil. The absolute maximum value of basal respiration was noted during soil bioactivation in the Control + Bio variant and amounted to 13.7 μg CO₂/h/1 g of soil. The influence of plants on soil respiration manifested itself to varying degrees. When sowing plants in control soil (option 3 “K+R”), the rate of basal respiration increased by 4.3% to a value of 9.6 μg CO₂/h/1 g of soil. When sowing plants in soil enriched with microorganisms (option 4 “K+R+Bio”), an increase in values to 10.5 μg CO₂/h/1 g of soil was observed, which is 10.7% higher than in the control. The effect of mineral fertilizers in the soil on option 5 “K+NPK” led to a significant decrease in the intensity of soil respiration to 5 μg CO₂/h/1 g of soil. Against the background of soil enriched with strains of microorganisms in option 6 “K+NPK+Bio”, no inhibitory effect of mineral fertilizers was observed. In the variant with unenriched soil (variant 7), the basal respiration rate was 6.7 μg CO₂/h/1 g of soil. Based on the available results, it follows that in variants using mineral fertilizers and with vegetative plants, as well as their combinations on microbiologically enriched soil, the indicators of basal soil respiration are stable and vary within the range of 10.3-10.5 μg CO₂/h/1 g of soil. At the same time, the respiration rate of soil not enriched with microorganisms ranges from 5.0-9.6 μg CO₂/h/1 g of soil. From the above, we can conclude that the introduction of agronomically valuable strains of microorganisms into the soil can significantly reduce the inhibitory effect of mineral fertilizers on soil microbiota and maintain a higher intensity of biochemical reactions in it.

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