Dynamics of soil moisture conservation areas of forest-steppe on the background of interdecadal climate variability

Author(s):  N.S. Kukharuk, candidate of Sciences, associate Professor, Belgorod National Research University, Belgorod, Russia, kuharuk@bsu.edu.ru

L.G. Smirnova , Dr., Prof., Belgorod Federal Agrarian Research Center of the Russian Academy of Sciences, Belgorod, Russia, lidya.smirnova@yandex.ru

A.G. Narozhnyaya, candidate of Sciences, associate Professor, Belgorod National Research University, Belgorod, Russia, narozhnyaya_a@bsu.edu.ru

Y.G. Chendev , Belgorod National Research University, Belgorod, Russia, chendev@bsu.edu.ru

G.P. Glazunov, candidate of Sciences, All-Russian Research Institute of Agriculture and Soil Erosion Control, Kursk, Russia, gennadij-glazunov@yandex.ru

Issue:  Volume 41, №25

Rubric:  Biological sciences

Annotation:  The purpose of scientific research is to identify response of soil moisture of chernozems in the forest-steppe zone to the dynamics of climatic parameters against the backdrop of the age-old climatic variability. Initial values of soil moisture under natural vegetation in absolute conservation areas of forest-steppe (from 1946 to the present) were analyzed. Soil moisture was measured once a month at a depth of 0 to 3 meters during the growing season (from April to October). By dint of a smoothing of the soil moisture data series by a polynomial trend (5th degree) arid and wet periods are identified. In the arid period soil moisture averaged 25.0%, in wet – 27.4%. During the study period, a moderate correlation was observed between soil moisture and hydrothermal coefficient (HTC) (r=0.51). Soil moisture reacts to HTC with a delay of 2–3 years. The tendency of increase in HTC values is noted, this means that there is an increase in the humidity of the territory against the background of positive temperatures growth during the study period. There is a decrease in the continentality of the climate. Chronosplit humidity 3 meter thickness of the chernozem was constructed. On the chronosplit the graphical display of areas with different humidity values reflects the distribution of humidification and drying areas in the 0–3 meters layer of soil. There was an increase in humidity up to 2 meters from 1948 to 1954 years. From 1977 to 1984 noted an increase in the depth of soaking of the soil to 2.5 meters. From 1989 to 2005 there is an increase in the moisture content of the territory and an increase in the depth of soaking to 3 meters. The humidifying zones are closed in the range of 30–40%. The only exception is the seasonal decrease in humidity along the profile. From 2006 until the end of the study period, the zones with a soil moisture content of 10 to 20% increase markedly. Spatial regions are distinguished at a depth of more than 2 meters with a moisture content of 0 to 10%. During this period, positive temperatures increase, which intensify evaporation processes and dry the soil to a considerable depth. Similar facts are observed in the soils of the southern steppes and are not characteristic of micellar-carbonate chernozem.

Keywords:  soil moisture, chernozems, conservation areas of forest-steppe, climatic variability, air temperature, precipitation, hydrothermal coefficient, climatic Bruckner cycle.

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