Influence of the pyrogenic impact upon the state of soil microbiocenosis of eight- and twenty-years old fallows(lea lands)
¹National Scientific Centre, Institute of Agriculture of NAAS of Ukraine, 2 b, Mashinobudivnikiv Str., Chabany vil., Kyiv- Svyatoshin Dist., UA08162 Kyiv Region, Ukraine
²National University of Life and Environmental Sciences of Ukraine, 15 Heroiv Oborony Str., UA03041 Kyiv, Ukraine
³National Academy of Agrarian Sciences of Ukraine, 9, Mykhailo Omelyanovych-Pavlenko Str., Kyiv, UA01010, Ukraine
⁴Estonian University of Life Sciences, Institute of Forestry and Engineering,
56 Fr.R. Kreutzwaldi Str., EE51006Tartu, Estonia
⁵Latvia University of Life Sciences and Technologies, Institute of Engineering and Energetics, Faculty of Engineering and Information Technologies, Ulbroka Research Centre, 1 Instituta Str., Ulbroka, Ropazu Region, Stopinu Municipality, LV2130 Latvia
*Correspondence: adolfs.rucins@lbtu.lv
Abstract:
The restoration dynamics of the biological activity of soils after fires of various intensity is an urgent problem. Pyrogenic effects (fires) affect the state of microscopic soil inhabitants: bacteria, micromycetes, etc., causing their death and reducing their physiological and biochemical activity. From a theoretical and practical points of view it is important to study changes in the community of the soil microorganisms during the restoration of phytocenoses in the post-pyrogenic areas. Investigations of Albebeluvisoil were carried out as an example in geographically close areas: 1 and 2 – soil, withdrawn from agricultural use in 1987 (twenty-years-old fallow); 3 and 4 – soil, withdrawn from agricultural use in 2000 (eight-years old fallow. Studies of the state of the post-pyrogenic and background sections of the eight-year-old and twenty-year-old fallows showed that the mechanism of the effect of fire upon the soil microbiocenosis differs 3 and 14 months after it took place. After the fire during a three-month period there are general processes that lead to a decrease in the number of unicellular living organisms, which also lose their physiological and biochemical activity, there is an increase in mineralization, based on compounds of elements such as carbon and nitrogen. The exception is humus. There is also an increase in soil phytotoxicity of soil. The conducted researches have established that after 14 months the processes of active decomposition of humus begin to decrease and in general the phytotoxicity of soil decreases. There are also observed processes of increase in the number of single-celled living organisms on the basis of nitrogen and phosphorus. After 26 months the consequences of the fire are minimized: the difference in the number of microorganisms and their physiological and biochemical activity becomes statistically unreliable, with the exception of micromycetes, mobilizers of mineral and organophosphates, nitrifying and denitrifying microorganisms; the difference in total biological activity is reduced from 12.6 to 8.67%, in phytotoxicity – from 16.0 to 2.89%.
Key words:
fallow (lea land), humus, microbiocenosis, mineralization, phytotoxicity, pyrogenic impact