Haplic Chernozem Research Articles

Humus conditions of the Pre-Dnisterian Podolia Haplic Chernozems

The humus state of chernozems typical of Pre-Dnisterian Podolia is investigated. It has been established that for the content of humus the chernozems typical of the Pre-Dnisterian Podolia are low humus (2.78–3.98 %). With depth, the content of humus decreases gradually, indicating a uniformly accumulative type of distribution of organic matter in the soil profile. It is determined that in typical chernozems the phenomenon of moderate migration of humic acids is observed, thus forming a deep humus profile. Humic content to the depth of 90–100 cm is dominated by humic acids (Cga:Cfais 1.12–1.78). The general tendency of relative “pluralisation” of the arable lay eras a result of its agronomic exhaustion has been observed. In relation to the Cga to the general organic C, the chernozems soil of the study area is characterized by a high and very high degree of humification of organic matter. It is proved that the intensity of the migration processes of humic acids decreases in the direction of strengthening the hardness of the GTK territory, due to the tightening of calcium carbonates closer to the surface of the soil. Its middle and lower parts were formed, to a large extent, by infiltration of humic acids, moreover, mainly due to the calcium humates. In the case of the use of chernozems without the use of organic fertilizers, the processes of mineralization of plant residues and humus are more active, and the balance of humus is scarce. However, when applying a setoff measures, you cannot only prevent loss of humus but also increased their content. Such a complex should include the following measures: soil replenishment with organic substances, in particular, the planting of perennial grasses and sown crops, the abandonment of a higher grain of grain; minimizing cultivation; creation of optimal ratios of crops in crop rotation to reduce humus losses; the application of meliorants, which would ensure the strengthening of soil fixation of newly formed humus substances. Key words: Pre-Dnisterian Podolia, Haplic Chernozems, humus, humic acids, fulvic acids.

Predicting Soil Organic Carbon and Total Nitrogen in the Russian Chernozem from Depth and Wireless Color Sensor Measurements

Color sensor technologies offer opportunities for affordable and rapid assessment of soil organic carbon (SOC) and total nitrogen (TN) in the field, but the applicability of these technologies may vary by soil type. The objective of this study was to use an inexpensive color sensor to develop SOC and TN prediction models for the Russian Chernozem (Haplic Chernozem) in the Kursk region of Russia. Twenty-one dried soil samples were analyzed using a Nix Pro™ color sensor that is controlled through a mobile application and Bluetooth to collect CIEL*a*b* (darkness to lightness, green to red, and blue to yellow) color data. Eleven samples were randomly selected to be used to construct prediction models and the remaining ten samples were set aside for cross validation. The root mean squared error (RMSE) was calculated to determine each model’s prediction error. The data from the eleven soil samples were used to develop the natural log of SOC (lnSOC) and TN (lnTN) prediction models using depth, L*, a*, and b* for each sample as predictor variables in regression analyses. Resulting residual plots, root mean square errors (RMSE), mean squared prediction error (MSPE) and coefficients of determination (R2, adjusted R2) were used to assess model fit for each of the SOC and total N prediction models. Final models were fit using all soil samples, which included depth and color variables, for lnSOC (R2 = 0.987, Adj. R2 = 0.981, RMSE = 0.003, p-value < 0.001, MSPE = 0.182) and lnTN (R2 = 0.980 Adj. R2 = 0.972, RMSE = 0.004, p-value < 0.001, MSPE = 0.001). Additionally, final models were fit for all soil samples, which included only color variables, for lnSOC (R2 = 0.959 Adj. R2 = 0.949, RMSE = 0.007, p-value < 0.001, MSPE = 0.536) and lnTN (R2 = 0.912 Adj. R2 = 0.890, RMSE = 0.015, p-value < 0.001, MSPE = 0.001). The results suggest that soil color may be used for rapid assessment of SOC and TN in these agriculturally important soils.

Dynamics of the agrochemical fertility parameters of arable soils in the southwestern region of Central Chernozemic zone of Russia

Data of the agrochemical survey of arable soils in Belgorod oblast during the period from 1964 to 2014 have been analyzed. The soil cover mainly consists of typical chernozems (Haplic Chernozems) and leached chernozems (Luvic Chernozems) in the forest-steppe zone and ordinary chernozems (Calcic Chernozems) in the steppe zone. Under long-term agricultural use (from 1964 to 2014), the content of mobile phosphorus in arable soils of the region under study has increased from 55 to 137 mg/kg, and the content of mobile potassium has increased from 105 to 147 mg/kg. During the period of 1976–2014, the share of acid soils has increased from 22.8 to 45.8%, including medium-acid soils from 1.5 to 12.6%. No significant changes in the weighted average content of soil organic matter are revealed for the period from 1985 to 2014. The value of this parameter is within the range of 4.8–5.0%. In the 2010–2014, 95.0% of arable soils belonged to the category of low supplied with mobile sulfur; 99.2, 96.9, 94.1, and 54.4% of soils were poorly supplied with zinc, copper, cobalt, and manganese, respectively. During the same period, the maximum average productivity of the crop area (3710 f. u./ha) was noted at the application of 4.8 t/ha organic fertilizers and 97.9 kg/ha organic fertilizers on the average. The maximum long-term yields of sugar beet (36.8 t/ha) and corn grain (4.97 t/ha) were obtained at the application of relatively low fertilizer rates.

Микроагрегатный анализ почв методом лазерной дифракции: особенности пробоподготовки и интерпретации результатов

The opportunities of the laser diffraction method in the assessment of the microstructure condition of the soil are shown on the samples of humus layers of the following soils (agro soddy-podzolic (Eutric Albic Retisol (Loamic, Aric, Cutanic, Ochric)), Moscow oblast; gray (Luvic Greyzemic Phaeozem), Tulskie zaseky; migration micellar chernozem (Haplic Chernozem (Loamic, Pachic)), Kursk oblast; ferralitic (Rhodic Ferralsol), Norfolk island). The ways of samples preparation to the analysis are considered: boiling, stirring (80 min-1) of the attenuated water suspensions, intense stirring (2500 min-1) of the water suspensions, mixing of the suspension by the glass stick. The assessment of the preliminary saturation of samples by the distillated water before the samples preparation is given. The assessment of possibility of the implementation of soil micro structure indices, developed on the basis of sedimentation methods was made. The impossibility of the implementation of Kachinskiy dispersion coefficient to the results obtained by the method of laser diffraction was shown. The intense stirring (2500 min-1) of the water suspensions during the 10 minutes is recommended as the standard method of the soil samples preparation for the further microagregate analysis by the method of laser difraction. Such a way of soil samples preparation doesn’t lead to the modification of the properties of the solid body and provides the stability of the results. The results of the microagregate analysis by the method of laser diffraction, presented by the even distribution of particles by the size are characterized by the high informativity. The correlation of different ways of soil samples preparation along with the high accuracy of the method allow us to reveal the specificities of microstructure soil organization.

Bacteroidetes as a sensitive biological indicator of agricultural soil usage revealed by a culture-independent approach

The aim of the study was to determine the Bacteroidetes community structure in arable soils versus wastelands in order to assess their sensitivity to agricultural soil usage. Twelve arable soils (A) and the same number of wastelands, serving as controls (C), were grouped on the basis of the soil origin as: autogenic (AG) − formed from loess material, represented by Albic Luvisols, Haplic Luvisols, and Brunic Arenosols, hydrogenic (HG) − formed under the influence of stagnant water, represented by Haplic Chernozem, Mollic Gleysol, and Gleyic Umbrisol and lithogenic (LG) − formed from limestone, represented by Calcaric Cambisols. Additionally, the soils were classified into orders (Luvisols, Arenosols, Chernozems, Cambisols) according to the WRB classification rules. Statistical analyses were performed to gain the knowledge about soil chemical factors directly affecting the operational taxonomic units (OTUs) of Bacteroidetes in the soil environment. The composition of Bacteroidetes was analysed with the next generation sequencing Ion Torrent™ technology. The sequences were clustered into OTUs based on a 99% similarity threshold. An average of 2516 OTUs belonging to Bacteroidetes per C soil and 1568 OTUs per A soils were evidenced. It was found that Flavobacterium was the dominant genus in both C and A soils; however, its numbers significantly decreased in A soils, which proves its sensitivity to agricultural practices. Pedobacter and Mucilaginibacter were subdominants. Our results emphasised that, besides agricultural practices, soil genesis is an essential factor for the abundance of Bacteroidetes. They were found to prefer colonising the non-cultivated AG and HG soils rather than the LG soils. Importantly, the sensitivity to agricultural soil usage was similar irrespective of the soil classification system (genesis or orders), as reduction of Bacteroidetes OTUs in arable soils was revealed in both cases. Therefore, we recommend the Bacteroidetes phylum a sensitive biological indicator of agricultural soil usage.

The content and profile distribution of carbon and nitrogen fractions susceptible to acid hydrolysis in Haplic Chernozems and Mollic Fluvisols of western Slovakia

The content and profile distribution of carbon and nitrogen fractions susceptible to acid hydrolysis in Haplic Chernozems and Mollic Fluvisols of western Slovakia

Phytoaccumulation of Benzo[a]pyrene by the Barley in Artificially Contaminated Soil

ABSTRACTThe assessment of toxic effects of polycyclic aromatic hydrocarbons (PAHs) on Haplic chernozems soil was developed by using spring barley (Hordeum sativum distichum) bioaccumulation tendencies. Spring barley was used to estimate the negative effect of chernozemic soil contamination with benzo[a]pyrene (BaP), one the most carcinogenic and mutagenic PAHs compounds. The bioaccumulation tendencies were studied in soil spiking with BaP. Spiked doses were close to technogenic pressure level in studied area, 0–800 µg/kg of BaP. Condition and doses of BaP during 4 years of model experiment influenced morphometric characteristics of spring barley and rates of BaP uptake by plants. Exposure to the growth characteristics containing at least 20 µg/kg BaP promoted absorbing BaP by plants root system as well as increased roots length. Tendencies of phytotoxicity parameters inhibition were observed for all morphometric characteristics of spring barley as energy of germination, length of vegetation part, plant weight and ear height. Quantifiable levels of BaP uptake by spring barley roots exceeded vegetative part more than 2.5 times in all polluted variants. The constant of BaP semi-degradation in artificially polluted Haplic chernozems for 48 months of model experiment T50 reached 1.2–3.4 years. Thus, the BaP uptake by spring barley from chernozem soil contributes to the bioindication responses during environmental monitoring to assess the impact of BaP pollution.

Erratum to: Chemical contamination in upper horizon of Haplic Chernozem as a transformation factor of its physicochemical properties

The effect of Cu, Zn, and Pb high rates on the physical properties and organic matter of Haplic Chernozem (Clayic) (A1 horizon 0–20 cm) under model experimental conditions was studied. In a model experiment, soil samples of Haplic Chernozem (Clayic) were artificially contaminated with 2000 mg/kg of Cu, Zn, and Pb acetates added separately. The particle-size fraction, the microaggregates distribution, the structural status, the total content and fractional and group composition of organic matter, physico-mechanical properties were determined in soil without metals and soil contaminated with metals. At the soil contamination with Cu, Zn, and Pb, the content of organo-mineral colloids increased, which results to the increasing of the clay fraction content by 4.5% compared to the control. The analysis of the microaggregate size composition of the studied soil shows that the content of coarser aggregates (1–0.25 mm) increases and the content of finer (0.05–0.001 mm) aggregates decreases after the addition of HMs and correspond to the HMs series: Cu → Zn → Pb. A significant decrease in the coefficient of water stability in the control from 3.0 to 1.4–1.5 in the contaminated treatments. The structural status (estimated from total agronomically valuable aggregates) changes from excellent to good. The addition of Cu, Zn, and Pb to the soil affects the quantitative composition of organic matter. The contents of free and sesquioxide-bound humic acids and free fulvic acids increased. The contamination with Zn and Pb causes the aliphatization of organic matter. Under conditions of model experiment, the contamination of Haplic Chernozem (Clayic) with high rates of Cu, Zn, and Pb leads to changes of the microaggregates distribution, the structural status, and the qualitative composition of organic matter.

Modelling soil organic matter dynamics on a bare fallow Chernozem soil in Central Germany

Soil organic matter (SOM) can be characterised by soil organic carbon (SOC) and/or total nitrogen (TN). The observed dynamics of SOC and TN in the topsoil of a 28-year-old fallow experiment on Haplic Chernozem was modelled using the Candy Carbon Balance (CCB) model. This study selected two treatments from this experiment where the soil was kept bare with mechanical or chemical (herbicides) treatments. The CCB model was improved to include the SOC related change of soil physical parameters and dynamic handling of the physically stabilised SOM pool. Over 28years of bare fallow the top soil lost about 10t/ha of SOC and >1t/ha of TN. The results from observation and modelling reflected the increased SOM turnover due to soil tillage. The modelled size of the physically stabilised SOC pool was about 55% of total SOC and only reduced slowly during the almost three decades, but the implementation of this effect improved simulation results and reduced the relative RMSD (unitless) from 0.051 to 0.044 for SOC and from 0.053 to 0.049 for TN error level. From these results we conclude that the larger the SOM change the more important is the integration of the turnover of physically stabilised SOM within the modelling approach.

Chemical contamination in upper horizon of Haplic Chernozem as a transformation factor of its physicochemical properties

Chemical contamination in upper horizon of Haplic Chernozem as a transformation factor of its physicochemical properties

Comparing two methods of sequential fractionation in the study of copper compounds in Haplic chernozem under model experimental conditions

It is very important to obtain the information on the soils capacity to immobilize HMs and distribute them among soil components. The aim of this work was to study the fractional composition of Cu compounds in Haplic chernozem under model contamination conditions using different fractionation methods. The fractional composition of copper compounds in Haplic Chernozem artificially contaminated with copper acetate has been studied under model experimental conditions. General regularities and differences in the distribution of Cu forms in soils at the use of sequential fractionation by the Miller method modified by Berti and Jacobs (1996) and the Tessier method (Tessier et al. 1979) are revealed. The differences are related to the metal affinity for specific carrier phases, as well as to the selectivity and extraction capacity of the reagents used in these methods. A significant increase in the most mobile exchangeable Cu fraction is observed in contaminated soils. Aluminosilicates and soil organic matter make the largest contribution to the adsorption and retention of Cu. The Tessier method is more suitable for the separation of the total technogenic component from contaminated soils. The Miller method is more informative at the determination of loosely bound HM compounds because of the use of weaker extractants.

Minerals in the three-component combination of agrochernozems in the Kamennaya Steppe

Properties and mineralogy of fine fractions separated from agrochernozems forming a three-component noncontrasting soil combination in the Kamennaya Steppe have been characterized. The soil cover consists of zooturbated (Haplic Chernozems (Clayic, Aric, Pachic, Calcaric)), migrational-mycelial (Haplic Chernozems (Clayic, Aric, Pachic)), and clay-illuvial (Luvic Chernozems (Clayic, Aric, Pachic)) agrochernozems. All the soils are deeply quasi-gleyed because of periodical groundwater rise. The mineralogy of the fraction <1μm includes irregular mica–smectite interstratifications, di- and trioctahedral hydromicas, imperfect kaolinite, and magnesium–iron chlorite. The profile distribution of these minerals slightly varies depending on the subtype of spot-forming soils. A uniform distribution of clay minerals is observed in zooturbated agrochernozem; a poorly manifested eluvial–illuvial distribution of the smectite phase is observed in the clay-illuvial agrochernozem. The fractions of fine (1–5 μm) and medium (5–10 μm) silt consist of quartz, micas, potassium feldspars, plagioclases, kaolinite, and chlorite. There is no dominant mineral, because the share of each mineral is lower than 35–45%. The silt fractions differ in the quartz-to-mica ratio. The medium silt fraction contains more quartz, and the fine silt fraction contains more micas.

Current State of Haplic Chernozems in Specially Protected Natural Areas of the Steppe Zone

The current ecological state of Haplic Chernozems has been studied in three Specially Protected Natural Areas (SPNAs) of the Steppe zone in South of Russia. It has been found that the content of organic matter, texture and elements content of soils depend on the period and conditions of reservation in the SPNA. In accordance with the content and reserve of organic matter, the thickness of the humus-accumulative (A) and humus (A + B) horizons and the supply with macro- and micronutrients, the Haplic Chernozems of the SPNAs under study can be arranged in the following series: Persianovskaya Reserved Steppe > Botanical Garden of the Southern Federal University > Reserved Fallow land “Priazovskaya Steppe”, which corresponds to the duration of their reservation periods. The Botanical Garden, which is located in the center of a megalopolis (Rostov-on-Don, Russia), has higher contents of lead in the upper horizon of Haplic Chernozem than other soils on the plots considered.

Soil aggregation and soil organic matter in conventionally and organically farmed Austrian Chernozems / Bodenaggregation und organische Substanz in konventionell und biologisch bewirtschafteten österreichischen Tschernosemböden

Summary In order to study the soil aggregate distributions and soil organic matter (SOM), we sampled top- and subsoils in four intensively farmed croplands (two organic (Org-OB and Org-LA), and two conventional (Con-OB and Con-LA)) on Haplic Chernozems located in Marchfeld in the east of Vienna (Austria). Soil structure and SOM quantity, quality and distribution between free and occluded particulate organic matter and aggregate size fractions (&lt;20 µm, 20-250 µm, 250-5000 µm) were studied by following a density fractionation procedure with low-energy ultrasound treatment. The relation of the soil physicochemical (e.g., particle size distribution, pH, organic carbon, total nitrogen) and biological properties (e.g., fungal biomass, active fungi) with stable soil aggregate size fractions and SOM was studied. The mean weight diameter (MWD) showed no significant difference between all studied sites and was between 3.8 mm and 10.0 mm in topsoils and between 6.7 mm and 11.9 mm in subsoils. In topsoils, the contents of calcium-acetate-lactate (CAL)-extractable P, active fungal biomass, dithionite-extractable Fe and sand were significantly positively correlated with the amount of the macroaggregates and with the MWD. We observed that most soil organic carbon, depending on soil texture, was stored in the microaggregate size classes &lt;20 µm and 20-250 µm.

Simple but efficient signal pre-processing in soil organic carbon spectroscopic estimation

As there is no single (or combination of) signal pre-processing method that works best with all data sets, choosing the most feasible one is a key aspect in soil diffuse reflectance spectroscopy in the visible– and near infrared region (400–2500nm). The commonly used pre-processing methods include tools for spectra smoothing and/or noise reduction (e.g. Savitzky-Golay (SG) filtering or discrete wavelet transformation (DWT)), light scatter correction (multiplicative scatter correction (MSC), standard normal variate (SNV)), baseline normalization techniques to cope with vertical offset and/or slope effects (e.g. continuum removal (CR), first and second order derivative (FD and SD)), as well as other transformations (e.g. logarithmic-log(1/R)). All of these tools are aimed at eliminating or reducing unwanted side effects (artifacts) in the spectra and at enhancing the recognition of relevant information. For soil organic carbon content estimation using partial least square regression calibration technique, smoothing with SG filter and (or in combination with) CR usually ensures a reliable estimation. However, the common CR may suffer from a few shortcomings. An approximation is applied to connect the pivot points of the spectrum in order to derive a continuum, but more problematically, the CR procedure does not recognize the true essence of the vertical shift at the very beginning of the spectra (the CR value always equals one at that point). Therefore, we decided to modify the procedure in the way that the reflectance values at respective wavelengths were divided not by the continuum, but by the maximal reflectance value of the particular spectrum. This correction by the maximum reflectance (CMR) pre-processing was tested in comparison with eight other above mentioned methods at four different study sites that differ in the prevailing soil units. As a result, on site 1 (Haplic Chernozem), we achieved a significantly improved prediction accuracy using the CMR (R2cv=0.845) compared to raw (but smoothed) soil spectra (0.815). On site 2 (Rendzic Leptosol), the most accurate prediction was achieved equally with CMR, MSC, SNV, log(1/R), DWT and raw spectra (R2cv from 0.560 to 0.592), and on site 3 (Haplic Cambisol) equally with MSC and CMR (both R2cv=0.767), as only these two were significantly different from the raw spectra. On site 4 (Haplic Luvisol), the only one significantly more accurate prediction compared to raw spectra was achieved with FD (R2cv=0.611), while for the rest of the methods, except SD, there was no difference if either raw spectra or other transformations were used (R2cv from 0.499 to 0.591). Finally, using the whole data set the differences between pre-processing methods were even less pronounced, when there was no significant difference between raw spectra and other methods (except SD which was significantly worse), although all the predictions were more accurate in general (R2cv from 0.811 to 0.831).

Effect of Heavy Metals on the Enzymatic Activity of Haplic Chernozem under Model Experimental Conditions

The biological activity of soils is an essential parameter of their ecological status. The anthropogenic Heavy Metals (HMs) disturb the normal functioning of soil biota and, hence, the entire soil system. The aim of this work was to estimate the toxicity of loosely bound HM compounds in Haplic Chernozem using parameters of cellulose-degrading and urease activities. Contamination of Haplic Chernozem with Zn, Cd, Cu and Pb enlarged the group of mobile (loosely bound to soil) metal compounds, which includes exchangeable, complexed and specifically sorbed compounds of HMs. The increase of mobile HM forms content in soil inhibited the cellulose-degrading and urease activities after 30 days of the input of metal into the soil. A decrease in the toxic effect of metals on the studied parameters mainly occurred in the next 30 days. It was found that all HM forms similarly affected biological activity parameters. During two months from the moment of soil contamination with HMs, their toxic effect on cellulose-degrading and urease activities decreased. According to the degree of inhibition of biological activity in Haplic Chernozem, the studied metals formed the following series: Cd >Pb > Zn > Cu.

Structural state of migrational-mycelial (typical) agrochernozems of the Kamennaya Steppe on plowed fields of different ages

Changes in the structural state of migrational-mycelial (typical) chernozems (Haplic Chernozems (Clayic, Aric, Pachic)) as dependent on the duration of their cultivation (from 20 to 120 years) are considered. Field studies were performed in 2013 on the fields of the Dokuchaev Research Institute of Agriculture in the Central Chernozemic Region of Russia (the Kamennaya Steppe area) used for growing cereals and row crops in rotation. The study showed that the most intensive degradation of the structure of chernozems takes place during the first two decades of their agricultural use. The maximum transformation of the soil structure is observed in the upper 10 cm, as this layer is subjected to the most frequent and intense mechanical impacts. The rate of structural degradation decreases with time until the equilibrium between disaggregation and aggregation processes is reached. The time required for this largely depends on the applied crop rotation systems and agrotechnologies. In this context, flexible assessment scales for the structural state of agrochernozems under conditions of different farming systems should be developed in order to perform monitoring of the physical properties of cultivated chernozems for their long-term efficient and ecologically sustainable use. Despite general disintegration and destruction of granular aggregates, the structural state of agrochernozems in the Kamennaya Steppe area remains sufficiently good even on the old-cultivated (120 yrs.) fields.

Dynamics of benzo[α]pyrene accumulation in soils under the influence of aerotechnogenic emissions

The regularities of benzo[α]pyrene (BaP) accumulation and distribution in chernozems (Haplic Chernozems), meadow-chernozemic soils (Haplic Chernozems (Stagnic)), and alluvial soils (Fluvisols) affected by the aerotechnogenic emissions from the Novocherkasskaya Electric Power Station (NEPS) were studied on the basis of long-term (2002–2011) monitoring data. A 5-km-wide zone stretching to the northwest from the electric power station and coinciding with the predominant wind direction was found to be most contaminated, with the maximum accumulation of BaP at about 1.6 km from the source. The coefficients of vertical BaP distribution between the layers of 0–5 and 5–20 cm closely correlated with the contents of physical clay, clay, and humus, and with the cation exchange capacity. The content of BaP in soils was shown to be indicative of the level of technogenic loads related to the combustion products of hydrocarbon fuels.

Ecological and biological studies in the haplic chernozems pacnic soils area in the Central Caucasus (Kabardino-Balkaria)

The northern macroslope of the Central Caucasus and adjacent areas of the Middle Ciscaucasia belong to the Northeast Caucasian (semi-desert) type of vertical zonation. This type, which includes terskiy and elbrusskiy variants of vertical zonation, differs from the Northwest Caucasian vertical zonation by general xerophytization of landscapes. The Haplic Chernozems Pacnic soils of Kabardino-Balkaria formed within steppe zone of mentioned variants are almost entirely involved in agricultural use; natural ecosystems with characteristic species composition of natural vegetation and mesofauna were preserved only in small areas inconvenient for arable activity. Characteristics of the current ecological-biological state of the steppe ecosystem components from the Haplic Chernozems soils area (soil — vegetation — earthworms) is given. The values of synecological indices (Shannon’s, Simpson’s, Pielou’s, Hartley’s, and integral) characterize high floristic and phytocenosis diversity, and synantropization indices correspond to average levels. Earthworms are in abundance and represent the largest part of the mass of soil organisms in species composition, which corresponds to steppe zonal conditions and testifies to the dominance of the saprotrophic complex. The correlation and factor analysis by the principal components method shows wide ranges of interdependence in functioning of ecosystems components: between diversity of biotic communities and biological properties (humus content, microbial biomass carbon contents (Cmic), intensity of microbial respiration, enzymatic activity) and physicochemical properties (pH of soil solution, field moisture, soil density) of Haplic Chernozems.

Гумусовий стан чорноземів типових терсових місцевостей Західного Бугу та Стиру

Volyn Upland Haplic Chernozems are distributed mainly on the terrace landscapes of the Western Bug and the Styr and their tributaries (Chornohuzka, Luha, Lypa). Most of these soils are old ploughlands that have experienced various types of degradation. Haplic Chernozems are low-humus soils and they have low storages of humus substance in the 20 cm arable layer and middle storages of humus in 100 cm soil thickness. There is correlation of C humic acids to C fulvic acids within 1.2–3.3 in the humus profile. Among the various fractions of humic substances the 2nd fraction associated to Calcium dominates. A content of “free” humic acids (1rst fraction) is very low and the amount of humin is low. The optical density of humic acids ( 0,001% НА Е1 cm, 465 nm ) are high and very high. The organic matter of Volyn Upland Haplic Chernozems has some regional peculiarities. First, it caused by topographical conditions of its formation and evolution in the Holocene. Chernozems of the 1st terrace of the River Western Bug are extremely deep. They have progressive-accumulative type of humus distribution in profile, humate type of humus in upper 100 cm layer, a very high degree of organic matter humification and the same content of humic fraction associated to Calcium and lowmiddle content of 3rd fraction associated to clay minerals. The molecules of humic acids in the humus horizon of Chernozems of the 1rst terrace are better structured that indicates the older age of humus in these soils. Chernozems of the 2nd terrace above the floodplain of the River Styr are middle-deep soils. They are characterised by the regressive-accumulative type of humus distribution in profile, humate-fulvate type of humus and very high degree of organic matter humification only in 25–50 cm layer. The content of fractions associated to Calcium and clay minerals is predominantly high. Key words: Haplic Chernozems, humus, humic acids, fulvic acids, optical density, humus condition.