Abstract:
Transformations of soil organic matter into easily assimilated nutrient forms by plants are mediated, to a greater extent,
by soil microbiota. Soil biological activity characterizes both its fertility and the degree of environmental factors’
influence. The aim of the current study was to explore the influence of suboptimal soil water content, mineral fertilizers,
and plant variety on biological potential of soybean rhizospheric soil. Experiment was set up in greenhouse complex.
Two soil water content levels were examined: optimal – 70% water holding capacity (WHC) and reduced – 35% WHC,
established in the blossom–flowering stage. The treatments were: (1) NP soil fertilization and (2) deficient nutrient
content. Soybean plants were represented by two varieties, also, the soil without plants were taken into account.
Following biotic parameters were analyzed in the rhizosphere soil: C-MB (microbial biomass carbon), BSR (basal soil
respiration) and the H-FDA (fluorescein diacetate hydrolysis). The results highlights that C-MB and the general
hydrolytic activity (H-FDA) were reduced under temporary (17 days) soil water content deficiency. Estimated BSR as
functional activity of microbiota, showed higher values at 35% WHC. This could indicate that additional energy
expenses of bacterial community to maintain vital processes. Soil biological activity depended on the plant nutritional
condition, showing a clear increase at NP fertilization, especially at soil water content deficiency. It was found that the
examined parameters had greater levels in rhizosphere soil of Aura variety, compared to Clavera one. In soil without
plants values were the lowest.
