Effects of different fertilizer systems and hydrothermal factors on microbial activity in the chernozem in Ukraine

Abstract

Groups of microorganisms in soils perform the role of global biogeochemical membrane which provides metabolism of substances and energy between the pedosphere, lithosphere, hydrosphere and living organisms. Сlimate change has resulted in a complex combination of unpredictable changeability of the environment, which is a serious test for the stability and productivity for the natural and anthropogenically transformed ecosystems. Changeability of the hydrothermal factors causes serious changes in the structure and metabolic activity of soil microorganisms, the quality and properties of soil. We studied the impact of hydrothermal factors on the content of carbon, microbial biomass and organic substance in deep chernozem of a natural ecosystem (fallow) and an agroecosystem under different systems of fertilization of winter wheat. A close relationship (r = 0.69–0.79) was determined between the content of microbial biomass in soil and hydrothermal factors (air temperature and moisture). Excessive drought and high parameters of air temperature led to decrease in the content of microbial biomass by 1.5–2.8 times compared to the years with optimum parameters of hydrothermal regime (HTC = 1.0). Leveling out the impact of high temperatures on the productivity of the soil microbiota occurs at a sufficient amount of moisture, and also available nutrients. Drought (HTC = 0.4) and excessive moisture (HTC = 2.0) following heightened air temperatures reduce the release of СО2 from soil. Fallow soil usually has a high content of microbial carbon in the organic compounds of soil (Сmic/Сorg was 2%). In the agroecosystem, there was recorded a decrease by 26–32% of the Сmic specific share in the content of the organic compound of the soil compared to the natural analogue. With organic and organic-mineral systems of fertilization, an increase in Сmic/Сorg parameter occurs and the soil parameters become close to the soil of a natural ecosystem. The calculated ecological coefficients of the orientation of microbial processes in soil indicate a possibility of a balanced functioning of the microbial group and introducing organic and organic-mineral fertilizers, creating optimum conditions for the productivity of winter wheat.

Chernozems of Ukraine: past, present and future perspectives

“…Lebedeva and Ovechkin 1975;Papish 2017), soil biological activity of these soils (e.g. Demyanyuk et al 2018), dynamics of the soil organic matter (e.g. Mamontov 1975;Kravchenko et al 2012;Demydenko and Velychko 2015) and transformation of the soils due to agricultural activity (Gninenko and Kizyakov 1983;Poznyak 1990;Filon 1996;Demyanyuk et al 2018).…”

“…In the recent years, high technologies oriented on yield maximization have been implemented on large areas for growing of the market-oriented varieties of winter wheat, corn, sunflower and winter rape. However, the nutrients, especially nitrogen, are not balanced and a large portion of nutrients is consumed from the inner stock of chernozems (Filon 1996;Demyanyuk et al 2018). Also irrigation of chernozems in Ukraine is one of the powerful factors of human intervention within Steppe zone.…”

The Effect of Preprevious and Presuspended Inoculation of Seeds by Azotobacter Vinelandii 12m on Maize Productivity and Activity of Nitrogen Fixation Process

“…Загальновідомо, що різні агротехнічні заходи впливають на мікробне угруповання ґрунту, змінюють чисельність мікроорганізмів та структуру мікробіоценозу, напрям та активність біологічних процесів [25]. Це засвідчили і наші результати -у ґрунті агроценозу кукурудзи чисельність азотобактеру залежала як від попередника, так і від інокуляції насіння.…”