Leached Chernozem Research Articles

Change in the biochemical activity of leached chernozem during long application of fertilizers in a grain-sugar beet crop rotation

It is found that the 70-year application of fertilizers in a grain-sugar beet crop rotation in the forest steppe of the Central Chernozem Region changes considerably the biochemical indices of leached chernozem fertility and increases the activity of urease by 17.4–26.9%, catalase by 5.6–36.5%, protease by 23.2–54.2%, cellulose-decomposing activity by 96.2–154.2%; phosphatase activity decreased by 65.7–105.1%. The phytotoxicity of soil against a high fertilizer dose background increased 85.7%.

Biological properties of south Russian soils: Tolerance to oil pollution

Oil pollution of south Russian soils usually leads to reduction in the abundance of ammonifying bacteria, microscopic fungi, and bacteria of the genus Azotobacter, as well as in enzyme (catalase and invertase) and cellulolytic activities. By the criterion of biological tolerance to oil pollution, these soils can be arranged in the following series: ordinary chernozems >= soddy calcareous soils = southern chernozems >= leached chernozems > brown forest soils >= gray sand soils. A regional scheme of ecological safety standards for oil contents in these soil types is proposed.

Physicochemical properties and dynamics of humus content in leached chernozem during long application of fertilizers

The effect of long application of fertilizers in crop rotation on the physicochemical properties of leached chernozem and dynamics of the humus content in it is established.

Simulation of tridecane degradation under different soil water contents

A mathematical model for the degradation of n-tridecane in a leached chernozem with different water contents was developed on the basis of budget ratios and the Mono kinetic equations. In the course of the verification, the model equations were simplified and solved numerically. The cases of uniform and step-wise initial pollutant distributions in a soil-filled co lumn were considered. The model was refined in accordance with the experimental data on the decrease in the tridecane concentration during three months. A statistically significant positive effect of the moisture and the uncontaminated upper soil layer on the rate of the tridecane decrease was shown. It was found that the degradation of the tridecane stopped and then recommenced again. The tridecane concentration in the soil at which its decrease almost stopped was determined. It was supposed that the hydrocarbon-oxidizing microorganisms, in the course of their life activity, excrete products that are accumulated and inhibit the degradation of the hydrocarbon. The parameters of the microbial activity in the soil were determined in a numerical experiment.

Quantity and taxonomic composition of ultramicrobacteria in soils

The number, physiological state, and taxonomic composition of ultramicrobacteria and archaea in various soils (alluvial meadow, sod-podzolic, leached chernozem, and peat) were studied. In all of the tested soil samples, a large number of ultramicrobacteria (tens and hundreds of millions of cells per 1 g of soil) was revealed by fluorescence microscopy. The portion of cells with intact membranes was larger among ultra-microbacteria than among the ordinary-size cells (95–98 and 50%, respectively). Ultramicrobacteria were characterized by high taxonomic diversity and included representatives of the main phylogenetic groups widespread in soils, such as Archaea, Actinobacteria, Cytophaga, and Proteobacteria. The results indicate that ultramicrobacteria are widespread in soils in a viable state and are involved in soil processes.

Effect of weeds and some methods for their control in seed production stands of sainfoin (Onobrychis viciifolia Scop.)

During the 2007-2009 period in the experimental field of the Institute of Forage Crops a study was conducted with the purpose of investigating the effect of weeds and some methods for their control in seed production stands of sainfoin (Onobrychis viciifolia Scop.). The trial was carried out on a slightly leached chernozem on an area with a natural background of weed infestation. As a result of the study it was found: Establishment of very uniform and productive seed production stands of sainfoin required effective weed control concentrated mainly in the first year when the degree of weed infestation was the highest and reached to a number of 245 plants/m2 and the fresh weed biomass to 1311 g/m2. The chemical control method showed the highest efficacy had the highest efficiency when, in the year of stand establishment at the stage of second-fourth true leaf of sainfoin, the treatment was conducted with imazamox 40g/l (Pulsar 40) at the dose of 48 g a.i./ha or with the system of Bentazon 600 g/l (Basagran 600 SL) - 900 g a.i./ha - fluazifop-P-butyl g/l (Fusilad Forte) - 120 g a.i./ha. In the years of seed production in spring at the beginning of vegetation, the treatment was conducted with imazamox 40 g/l (Pulsar 40) at the dose of 20 g a.i./ha + adjuvant DESH at the dose of 1000 ml/ha. An alternative to the chemical method is to sow sainfoin under cover of spring barley achieving more complete use of the area in the first year, a weed suppressive and ecological effect, but some negative residual effect on the crop was also observed; The pure stands of sainfoin with chemical control of weeds had the highest seed productivity, exceeding the zero check by 24 to 28%, followed by the stands with spring barley as a cover crop with an increase of 12% and the mixed stands of sainfoin with crested wheatgrass had the lowest productivity.

Economic and energy evaluation of shallow tillage of leached chernozem for early cereal crops

The possibility of shallow tillage of leached chernozem to a depth of 8–10 cm for early cereal crops is established, provided that mineral fertilizers and herbicide tank mixtures are used.

Detoxification of heavy-metal contaminated leached chernozems and ancient alluvial soils with the use of sorption materials

It is shown that the use of sapropel and mixtures based on it is effective as sorbent-ameliorants for detoxification of heavy metal-contaminated leached and podzolized chernozems in the Ryazan oblast, and for ancient alluvial soils in Vietnam, the application of natural bentonite.

Dielectric characteristics of soils and categories of soil water

The complex permittivity of the Ap horizons of a leached chernozem, gray forest soil, and soddy-podzolic soil, as well as those of kaolin and its mixtures with sand, was studied by the capacitance method. The relationships between the characteristics of losses (the imaginary component ɛ″ and the loss tangent tan δ) and the water content (W) are more indicative of changes in the water categories than the analogous relationships of the real component (ɛ′), which characterizes the relaxation capacity of water molecules. The breakpoints on the curves tan ɛ′ = f(W) and ɛ″ = f(W) are more pronounced compared to the curve ɛ′ = f(W) and better agree with the soil-geological constants: tan δ = f(W) at the W value close to the wilting point (WP) for all soils and at the maximum water adsorption capacity (MWAC) and maximum capillary sorption capacity (MCSC) for kaolin and its mixtures; ɛ″ = f(W) at the MWAC, WP, and maximum molecular water capacity (MMWC) for the leached chernozem and soddy-podzolic soil. On the curve ɛ′ = f(W), breakpoints were observed only for the gray forest soil and sand-clay mixtures.

Fractional composition of humus in leached chernozems and gleyed podzolized chernozem-like soils of the northern forest-steppe zone

The composition of humus in leached chernozems differs from that in gleyed podzolized chernozem-like soils in the northern forest-steppe zone of European Russia. Leached chernozems have the fulvate-humate humus. Gleyed podzolized chernozem-like soils have the humate-fulvate humus. A more aggressive composition of humus in the latter soils is caused by their overwetting and the development of gley processes under conditions of a stagnant-percolative soil water regime.

Associations of segetal weed plants in the agrocenoses near the Ob River. Communication 2

Eight associations of weed vegetation in the cereal-fallow rotation and unchangeable wheat in leached chernozems of the areas near the Ob River have been revealed as a result of 17 years of study. Five of these associations were analyzed. The associations of segetal communities were largely affected by the long-term permanent agrocenotic factor.

Mineralization of organic matter and the carbon sequestration capacity of zonal soils

The susceptibility of soil organic matter (SOM) to mineralization decreases in the following sequence of zonal soils: tundra soil > soddy-podzolic soil > gray forest soil > chestnut soil > dark chestnut soil > chernozem. The content of potentially mineralizable organic matter in the plowed soils is 1.9–3.9 times lower than that in their virgin analogues. The highest soil carbon sequestration capacity (SCSC) is typical of the leached chernozems, and the lowest SCSC is typical of the tundra soil. Taking into account the real soil temperatures and the duration of the warm season, the SCSC values decrease in the following sequence: leached chernozem > dark chestnut soil > chestnut soil ≥ tundra soil > gray forest soil > soddy-podzolic soil. Arable soils are characterized by higher SCSC values in comparison with their virgin analogues.

Change in the fertility of leached chernozem and crop productivity in a cereal-sugar beet rotation in the Central Chernozem region during long-term use of fertilizers

It has been established that the 70-year use of fertilizers in a cereal-sugar beet crop rotation in the forest steppe of the Central Chernozem Zone changes considerably the fertility of leached chernozem and increases the productivity of sugar beet by 11.7–42.1%, barley by 66.5–105.2%, oats by 65.8–76.4%, and winter wheat by 54.0–73.1%. Pea productivity decreases by 30.2–55.4%.

Effect of oil contamination on the properties of leached chernozem under model experimental conditions

A model experiment was performed to study the effect of soil contamination with oil on the growth of wheat plants. Neither significant downward migration of oil or oil components, including the most mobile aromatic hydrocarbons, in a column with leached chernozem nor removal of these compounds from the column were observed when the initial oil concentration was below 0.75%. These data confirmed the previous results that oil at a concentration of 0.3% had no negative effect on the growth of wheat. The synergetic effect of oil, soluble salts, and exchangeable sodium should be taken into account in the determination of maximum permissible residual oil content in soils.

Effects of shepherd's purse (Capsella bursa pastoris (L.) Medic.) on the chemical composition of lucerne (Medicago sativa L.)

A study was conducted in a pure stand of lucerne (variety Viktoria) under natural weed infestation with shepherd's purse (Capsella bursa pastoris (L.) Medic.) on a slightly leached chernozem soil under nonirrigated conditions in the experimental field of the Institute of Forage Crops - Pleven during the 2006-2007 period. The effect of shepherd's purse Capsella bursa pastoris (L.) Medic. on the chemical composition of lucerne Medicago sativa (L.) was analyzed. Statistically significant (P<0.05) functional relations were found between the chemical characteristics and percentage of Capsella bursa pastoris (L.) Medic. participation in the lucerne sward, and forage quality. These relations indicated a multiple practical relevance and a necessity to control Capsella bursa pastoris (L.) Medic. in lucerne stands in order to decrease weed density and improve forage quality.

Specific surface area and wetting heat of different soil types in European Russia

The surface properties (specific surface area and wetting heat) of the solid phase were estimated for the main soil types of European Russia: soddy-podzolic, alluvial, and gray forest soils; typical, leached, ordinary, and vertic chernozems; and soils of the solonetzic complex. It was found that the values of the specific surface area and wetting heat are indicative of particular features of the genetic horizon of each soil type. Changes in these soil properties under the effect of different anthropogenic impacts were studied. The bonding strength between the adsorbed water and the soil solid phase was characterized. It was shown that the water content at the potential of the first wetting film layer is close to the content of strongly bound water calculated from the wetting heat of the soils.

Genesis, hydrology, and properties of soils in mesodepressions waterlogged by surface water in the northern Ryazan forest-steppe

On the interfluves and in small depressions of the Ryazan forest-steppe, under periodic stagnation of surface water, acid chernozem-like soils with a relatively thick humus horizon, podzolic horizons, and marble-colored gleyed B1 and B2 horizons are formed. The eluvial horizons of these soils contain Mn-Fe nodules, and dark humus coatings occur in the illuvial horizons. In the spring, the eluvial horizons of these soils are excessively moistened and gravitational water stagnates on the soil surface for 3–4 weeks. The formation of the acid light-colored eluvial horizons of the soils on leached rocks is related to gleying under the conditions of the stagnant-percolative regime. Their total thickness is 15–25 cm and more. According to the properties of their solid phase, these horizons are similar to the podzolic horizons of soddy-podzolic gleyed soils. These soils have not been represented in the classification systems of soils of the USSR and Russia. Based on the principles of the substantial-genetic classification, one of the authors of this article [9] referred this soil to gleyed podzolic chernozem-like soils, thus, considering it as an individual genetic soil type. The gleyed podzolic chernozem-like soils differ from the leached chernozems by their low productivity and difficulty of tillage. In humid and moderately moist years, the death of crops or a reduction in yield are probable because of the excess of moisture.

Heavy metals in the soil-crop system

Data on the bulk contents of heavy metals in polluted soils are not quite suitable to judge the ecological situation in an agrocenosis. According to the results of model experiments with artificial contamination of soil, the flux of zinc and lead from the starting point (from a medium loamy leached chernozem) to the final point (wheat grains) sharply decreases. It is possible to obtain an ecologically pure (uncontaminated) grain yield even on a strongly contaminated soil due to the buffering capacity of the latter and due to the self-protective capacity of agricultural crops. The ecological potential of the soil-crop system is formed mostly at the expense of the buffering capacity of soil to heavy metals; the barrier function of plants is less significant. It is argued that the existing ecological standards based on the total contents of heavy metals in soil are of little use for predicting the quality of crops.

The spatial heterogeneity of the fertility in a leached chernozem within a field

A methodology for studying the spatial heterogeneity of fertility was tested on a plowed area with a leached chernozem; it presumed identifying areas homogeneous in terms of the soil agrochemical parameters. The units identified were considered in relation to the relief and the Agropyron yield.

The effect of long-term irrigation on the properties of leached chernozems in the forest-steppe of the southern Cis-Ural region

The effect of long-term irrigation (more than 30 years) on the properties of leached chernozem under vegetable crops has been studied. It is shown that the agrophysical, chemical, and physicochemical properties of the soil have worsened. The accumulation of salts is revealed.