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A detailed study on soil resources characterization based on the understanding of the soil system is not available at Dugda district. With the cognizance of this fact, the present study was conducted to characterize the morphological and physicochemical properties of soils, classify the soils according to World Reference Base for Soil Resources (WRB) of Argo-Gedilala Subwatershed in Dugda District of Oromia Regional State, Central Rift Valley of Ethiopia. Four slope classes were considered and one pedon was opened for each and described in the field on a standard description sheet for each slope category. Soil samples were collected from genetic horizons of each pedon for laboratory analysis of the selected physicochemical properties of the soils. The soils were classified into different Reference Soil Groups following the (WRB).The organic carbon (OC) content of the study area ranged from low to medium/moderate (0.64 to 1.83%). Total nitrogen (TN),available.phosphorus (Av.P), cation exchange capacity (CEC) and percent base saturation (PBS) of the soils were in the range of (0.066-0.135%), (2.24-4.81 mgkg-1), (39.52-43.52) cmol(+)kg-1) and (77.57- 89.8%), respectively. Accordingly, they were rated as low to medium, very low to low, high to very high and high to very high, respectively. The soil classification revealed that pedon 1 and pedon 2 were Cambic Chernic Phaeozems (Pantoclayic, Humic, Hypereutric); and pedon 4, Cambic Chernic Phaeozem (Pantoclayic, Humic); whereas, pedon 3 is found to be a kind of Luvic Phaeozem (Abruptic, Albic, Clayic, Differentic, Hypereutric). The soils of the study area had low organic matter, available P and total nitrogen content, which can be seen as production constraints of all cultivated lands. To overcome the identified limitations, increasing the organic matter levels through continuous application of manure. Key words: Genetic horizons, morphological properties, pedon, physicochemical properties, slope.

The nitrogen mineralization capacity of soils characterizes the rate of organic nitrogen-containing compounds decomposition and reflects their ability to accumulate mobile mineral nitrogen, an objective indicator of the availability of this major nutrient to plants. We have studied gray forest soil (Luvic Greyzemic Phaeozem), widespread among Siberian crop fields, using laboratory (composting under optimal conditions) and field (fallow under natural conditions) techniques to get new agrochemical data on the quantitative and qualitative changes in soil nitrogen compounds and nitrogen-containing fertilizers. The decomposition kinetics of available nitrogen and its release from plant residues (melilot, rapeseed, winter rye, and straw) during the interaction with gray forest soil are determined. The CO2 emission, nitrogen content in microbial biomass, cellulolytic bacterial activity, and accumulation of mineral nitrogen species have been monitored. The role of plant biomass in maintaining the nitrogen status in field agrocenoses is experimentally shown.

Mineral and organic fertilizers have great potential to enhance crop yields in low fertility soils of the Buganda catena. However, the need for site-specific knowledge on use and yield of the two fertilizer types in a complex soil scape is acute among smallholder farmers exploiting any soil differences. This study evaluated on-farm grain yield response of common bean (Phaseolus vulgaris L.) to organic and mineral N and P fertilizers on three soils. Treatments included poultry manure at 0, 2.5 and 5.0 t ha-1, and N and P each at 0, 7.5, and 15 kg ha-1 in a complete factorial for two rainy seasons on each of the local farmers’ soils classified as Phaeozem, Cambisol, and Umbrisol. Fertilizer application resulted in 20, 25 and 36% maxima grain yield increase relative to soils (Phaeozem, Cambisol and Umbrisol soil, respectively) potentials when no nutrient inputs is applied. Mineral fertilizers applied separately reduced yield on the Cambisol while on Umbrisol soil, there was no particular increase; hence these were risky applications on highly degraded soils. Yield increases were greater with manure, with or without mineral fertilizers, but yield increase was not particularly fundamental on Phaeozem sites but was on Cambisol and marginal on the Umbrisol, resulting into positive and negative interaction effects, respectively. Thus, soil specific rates of manure nutrient ratios or with N and P mineral fertilizers are an effective strategy for targeting improved common bean yield under indigenous soil taxonomy of Buganda catena soils. Key words: Phaseolus vulgaris L, integrated soil fertility management, smallholder farming, soil type.

The spatiotemporal variability of CO2 emission from soils of Kursk under different land uses, pollution levels, and soil geneses has been assessed. Data on the seasonal dynamics of CO2 emissions in background (forested recreational areas) and urban soils under the anthropogenic impact are presented. Seasonal dynamics of soil СО2 emission depends on a number of factors: season, type of soil, organic matter content, anthropogenic modifications of soil profiles, hydrothermic conditions, and heavy metal pollution. Soil hydrothermic conditions to a greater extent determine the intensity and characteristics of the seasonal dynamics of soil CO2 emission with a maximum in summer. In anthropogenic soils, multidirectional transformation of soil CO2 emissions is noted. The intensity of CO2 emission from soils of various geneses is quite different. Heavy metal pollution of the soil has an ambiguous effect on the CO2 emission processes. The CO2 emission rate from Urbic Technosol increased by 16.4% in comparison with that from the background Luvic Chernozem (Loamic, Pachic), while for Technic Greyzemic Phaeozem (Loamic) this parameter decreased by 47% in comparison with the background Greyzemic Phaeozem (Loamic). In Carbic Podzols polluted by heavy metals, the averaged CO2 emissions are generally similar to those from the background soils unpolluted by heavy metals.

A new method of digital mapping of the soil cover pattern with calculation of the share of soils of different taxa and degree classes for soil erosion in the soil associations is proposed. A comparative analysis of soil maps obtained using different methods of construction (visual expert and digital) and with their different contents (displaying the dominant soil or soil associations) has been performed. In the case of mapping by the visual expert method (with the display of the dominant soil), a significant underestimation of the total area of moderately and strongly eroded soils in comparison with the digital mapping is noted. These differences are due to the underestimation of the area of small polygons with moderately and strongly eroded soils in the composition of soil associations on slopes of low steepness and in shallow hollows in the visual expert method of mapping. When the content of digital maps is generalized from soil associations to dominant soil categories, a significant change in information on the degree of soil degradation by erosion is also noted. Comparison of visual expert and digital methods for mapping soils of different taxa indicates a high degree of compliance between the spatial location and area of soil delineations with similar component content in both cases. The greatest differences between the soil maps created by these methods are noted for the soils with periodic overmoistening, namely, meadow-chernozemic (Luvic Chernic Phaeozem (Oxyaquic)) and chernozemic-meadow (Luvic Stagnic Chernic Phaeozem) soils because of the poor consideration for microtopography in traditional mapping. In general, it can be concluded that the creation of a digital map is more difficult in terms of the need to use specialized computer programs and mathematical models. However, the resulting digital databases contain information of a higher level of detail than traditional soil maps.

A comparative study of mountain-meadow and mountain-forest soils was performed within the entire Dolgorukovskaya Yayla—a plateau on the northern macroslope of the Main Ridge of the Crimean Mountains—in the altitudinal range from 560 to 975 m a.s.l. Soil morphology, texture, acidity, exchangeable cations, nonsilicate iron content, parameters of the humus status, and optical characteristics of soils were studied. Forest soils on the entire slope are assigned to acid and dark burozems (Cambisols, Luvisols); they are characterized by similar morphological properties and profile patterns of clay, humus, and nonsilicate iron. Mountain-meadow, mountain-meadow chernozem-like, and residual-carbonate soils (Phaeozems) are formed under meadow vegetation in the upper part of the plateau, and soils transitional to piedmont chernozems (Chernozems) are located in its lower part. Humus reserves in the 0- to 50-cm-thick soil layer varied from 16.6 to 42.2 kg/m2 under meadows and from 10.7 to 18.8 kg/m2 under forests. Soils under forest and meadow vegetation were characterized by an increase in acidity and a decrease in base saturation with the increase in the altitude. Acidity was generally higher in forest soils, while the difference in this parameter between forest and meadow soils in the upper part of the plateau was minimal. In soils under meadows, the content of oxalate-extractable iron also increased with the altitude, and its mean content in the A horizon (226 ± 67 mg/100) was higher than that in forest soils (183 ± 41 mg/100 g). More intense color of soils under grass vegetation as compared to soils under forests is mainly explained by the differences in the rate of organic matter humification and optical density of humic acids, the total humus content being similar in both groups of soils.

The postagrogenic dynamics of organic carbon (Corg), total nitrogen (Ntot), and density fractions of organic matter (OM) in the dark gray soil (Haplic Phaeozem, Belgorod oblast, Les na Vorskle (Forest on Vorskla) Reserve) and migrational–mycellary Chernozem (Haplic Chernozem, Kursk oblast, Streletskaya Steppe Reserve) were examined. The most significant postagrogenic changes in all the studied soil properties were observed in the top 0–5 cm layer. The contents of Corg and Ntot in this layer of the Phaeozem chronosequence increased by 1.2–1.3 times over 45 years after cessation of farming. The contents of Corg and Ntot in the top 0–5 cm layer of Chernozem chronosequence increased by 1.9–2.0 times over 60 years of the postagrogenic development. The accumulation of Corg took place in all density fractions. In both chronosequences, the free fraction of organic matter (density

This paper tests the hypothesis that the soil organic carbon (OC), total nitrogen (Nt), nitrate-N and ammonium-N in forests are significantly different from the same properties in arable soils, und...

Nitrate leaching through soil layers to groundwater may cause significant degradation of natural resources. The aims of this study were: (i) to estimate soil hydraulic properties (SHPs) of the similar soil type with same management on various locations, (ii) to determine annual water dynamics, and (iii) to estimate the impact of subsoil horizon properties on nitrate leaching. The final goal was to compare the influence of different SHPs and layering on water dynamics and nitrate leaching. The study was conducted in central Croatia (Zagreb), at four locations on Calcaric Phaeozem, Calcaric Regosol, and Calcaric Fluvic Phaeozem soil types. Soil hydraulic parameters were estimated using the HYPROP system and HYPROP-FIT software. Water dynamics and nitrate leaching were evaluated using HYDRUS 2D/3D during a period of 365 days. The amount of water in the soil under saturated conditions varied from 0.422 to 0.535 cm3 cm−3 while the hydraulic conductivity varied from 3 cm day−1 to 990.9 cm day−1. Even though all locations have the same land use and climatic conditions with similar physical properties, hydraulic parameters varied substantially. The amount and velocity of transported nitrate (HYDRUS 2D/3D) were affected by reduced hydraulic conductivity of the subsoil as nitrates are primarily transported via advective flux. Despite the large differences in SHPs of the topsoil layers, the deeper soil layers, having similar SHPs, imposed a buffering effect preventing faster nitrate downward transport. This contributed to a very similar distribution of nitrates through the soil profile at the end of simulation period. This case study indicated the importance of carefully selecting relevant parameters in multilayered soil systems when evaluating groundwater pollution risk.

The data have been presented on the microbial biomass content and on the abundances and taxonomic structure of bacterial and archaeal communities in the upper horizons of gray forest (Eutric Retisol (Loamic, Cutanic, Humic)) and alluvial-meadow (Fluvic Gleyic Phaeozem (Loamic, Pachic)) soils of the autonomous, transitional, and accumulative positions of the slope landscape, corresponding to the fallow, small-leaved forest, and meadow ecosystems. Soil microbial biomass was measured by DNA quantification and chloroform fumigation-extraction; the archaeal and bacterial abundances were estimated using the FISH method; and the structure of microbial communities was analyzed via high-throughput 16S rRNA gene amplicon sequencing (DNA metabarcoding). The microbial biomass and the abundances of metabolically active bacterial and archaeal cells correlated with the organic carbon (Corg) and total nitrogen (Ntot) contents, increasing along the slope from the autonomous to accumulative landscapes, and decreasing with depth throughout soil profiles. The alluvial-meadow soil of the accumulative landscape was characterized by a sharp decrease in the relative abundance of Verrucomicrobia, as well as by the increase in the relative abundance of Proteobacteria and Firmicutes compared to the gray forest soil of the autonomous and transitional positions. The number of operational taxonomic units and α-diversity indices correlated significantly with C/N, Corg, and Ntot and were almost independent of the soil pH. Thus, location in landscape (catena) determined not only the physicochemical but also the microbiological properties of soil, forming the spatial heterogeneity of the microbial community structure and abundance.

Urbanization is an important process that changes land use pattern and the sustainability of agroecosystems in the urban-rural transition zone. Through intensified anthropogenic activity, urbanization magnifies trace element (TE) inputs into soils and alters the balance of soil element fluxes. This study aims to investigate the effects of urbanization on the spatial dynamics of soil HMs in peri-urban zones and the distinct behaviors of TEs in response to urban sprawl. An area (15 km × 16 km) in the Chinese northeastern black soil region was selected to represent a typical urban-rural transition feature that received heavy impact by urbanization in last decade. Two hundred topsoil samples were taken from locations dominated by Phaeozem soils and analyzed for total Zn, Cu, As, Pb, Cd, Cr, Ni, and Hg. Principal component analysis (PCA) was used to distinguish the probable sources of TE inputs into the soils. The overall TE pollution of soils was evaluated by the Nemerow comprehensive pollution index. Inverse distance weighting algorithm combined with autocorrelation analysis was used to analyze the spatial patterns of soil TE distribution. The mean concentrations of the studied TEs, with the exception of Hg and As, were higher than their background values, and their concentrations were always higher in the part closer to the urbanized area. Soil pollution assessment shows that the overall pollution status was moderate, but for Cd and Cu, numerous hotspots were identified due to the overuse of agrochemicals. PCA showed that Cu, Zn, Pb, and Cd as the first component were due to urbanization and agronomic practices, whereas As, Ni, and Cr as a second group were primarily of lithogenic origin, partly due to urbanization, and Hg was related to the atmospheric deposition of industrial waste gas. Increasing urban sprawl in the study area resulted in higher TE concentrations in the southern part of the region than the northern part, confirming the positive effect of urbanization on excessive soil TE accumulation. Although the pollution status was not yet serious, with the current rate of urban growth, arable soils in the peri-urban area will continuously be contaminated and control measures must be taken to prevent the cumulative impact on human health.

A comparative analysis of organic matter in the mountainous soils under the main plant communities of the Crimea was performed. The humus state of burozems and mountainous meadow soils under natural meadow vegetation and planted forests was studied using traditional methods and 13C-NMR spectroscopy for the determination of the contents of total organic carbon, carbon of humic acids and optical density of humic acid solutions. The highest humus content in the A horizon was found in the dark burozem under the beech–hornbeam forest on the Chatyr-Dag Plateau. The meadow soils of the Ai-Petri Plateau were significantly inferior in terms of humus content than the dark burozem and meadow soils of other Crimean plateaus due to the intensive anthropogenic impact on these lands until the 1970s. The lowest humus content was found in the meadow soils of the forested Ai-Petri areas because of the strong degradation of the grass cover after planting trees. The investigation of humic acids using the 13C-NMR method showed that humic acids of Crimean mountainous soils were characterized by the elevated hydrogen content, which well agreed with the content of alkyl fragments. The structural molecular composition of humic acids was dominated by aliphatic components, aromatic components being weakly expressed. At the same time, the aromaticity was somewhat higher in the cases when the soil was formed in the meadow ecosystem; it was lower in the upper soil horizons of the forest ecosystems. The degree of aromaticity of humic acids is intermediate between that of podzolic and chernozem soils, which is typical for soils of semihumid regions. The substitution of herbaceous vegetation in the course of natural overgrowing or afforestation of areas with meadow soils has led to an increase in their acidity, but it had no noticeable effect on the elemental and structural composition of humic acids.

The objectives of this study are to test the penetration depth and determine the soil content in hydrocarbons’ components BTEX, PAHs, and TPH, after vertical movement of crude oil through undisturbed soils of different textures, and to assess their risk. The experiment simulates the fate of oil spills in the cold season. Three soil types were investigated: a sandy-textured eutric Arenosol, AR-eu; a loamy-textured haplic chernozem, CH-ha; and a clayey-textured, swell-shrink, Luvic Chernic Phaeozem, PH-ch-lv. Undisturbed small-scale lysimeters, 0.3 m in diameter and 1 m in length, were used. Crude oil was first applied and then water. TPH, BTEX, and PAH retention in the soils depends on soil texture. PH-ch-lv soil stored most of them in the upper horizons. TPH, BTEX, and PAH were found in different amounts as percentage from the applied ones, TPH as 48% (PH-ch-lv), and > 76% in the other two soils. BTEX was stored as 1.6% from the applied in PH-ch-lv, 5.1–5.1% in CH-ha and AR-eu soils, while PAH ranged from 15.1% in AR-eu soil to 24.8% in PH-ch-lv and 31% in CH-ha. Though subject to volatilization, chemical transformation, and bioremediation, TPH, BTEX, and PAH stored in soils present a health risk if they reach the groundwater. PH-ch-lv appears to be the most resilient soil to oil pollution. The results concern different soil textures and might be used in various countries. Future experimentation should focus on soil behavior in relation to crops, water, and certain crude oil types.

Newly-formed soils of wastewater disposal fields from two sugar refineries in forest-steppe zone (Kursk region, European Russia) were studied. Among factors of soil formation on sugar wastewater lagoons the geochemical influence of wastewater mixed with diluted filtration and transport-washing sludge stands out. We have revealed key physico-chemical and microbiological properties of such soils formed under different moisture regimes, substrates, vegetation, and duration of use. Compared to conditionally background soils (Luvic (Anthric) Chernozems), the newly formed soils show shift of pH values to alkaline ones, carbonation, increase of soil organic carbon, growth in mobile forms of phosphorus, potassium and nitrogen. Microflora in studied soils is identical in composition to background soils, but it differs significantly in structure. In soils formed in the decommissioned wastewater lagoons of an active sugar refinery, a higher number of bacteria with low participation of Micromycetes and Actinomycetes was noted, which indicates active destruction of organic matter. In soils of the recultivated and completely abandoned sugar wastewater lagoons indicated as Calcaric Someric Phaeozem, a higher number of Actinomycetes was noted than in the background soils.

Soils on riverine floodplains in temperate climate may be characterized by a mollic epipedon, i.e. by dark colour, enhanced content of soil organic matter (SOM), high ‘base’ saturation and developed structure in the topsoil. We studied 124 soil samples from ten central/east European countries to investigate whether SOM in mollic horizons has similar chemical features. We determined carbon contents with a thermal-gradient method to differentiate SOM with varying thermal stability, and carbonates. We characterized SOM by diffuse reflectance infrared Fourier-transform (DRIFT) spectroscopy. According to the World Reference Base for Soil Resources, 102 of the samples fulfilled all criteria of a mollic horizon. Mollic features were not restricted to the uppermost horizon but also detected in buried former surface horizons. Soil colour was mostly the criterion to exclude non-mollic samples. Mollic and adjacent non-mollic horizons contained thermostable SOM, indicating SOM stabilized by interaction with minerals or as black carbon (BC), to very similar extent, up to 20.4% of total soil organic carbon (SOC). However, the correlation between the contents of thermostable SOC and total SOC, the SOC:N ratios of the thermostable fraction, and the smaller extent of metal complexation of carboxyl groups, pointed to a larger contribution of BC to SOM of mollic samples than to SOM in non-mollic samples. Thus, like in mollic horizons in Chernozems and Phaeozems not affected by fluviatile dynamics, SOM in mollic horizons of floodplain soils seemed to consist of SOM affected by natural or anthropogenic fires, constituting a common chemical feature of SOM. Thus, BC may contribute to soil colour and SOM stability in mollic horizons of floodplain soils. However, apart from BC contribution, SOM in mollic horizons of floodplain soils may have further pathways of formation and development, as SOM may be inherited from deposited material or form/transform by degradative or constructive processes. Supplemenatry material: [http://aspace.agrif.bg.ac.rs/handle/123456789/5999]

Soil macrofauna are ecosystem engineers. They create soil structure. In the steppe zone, differences in soil macrofauna, the intensity of their activity and particular effects of individual invertebrate communities may be observed within different facets of the landscape. In Calcic chernozem, under herbaceous vegetation and forest plantations, the casts of various animals that feed on decaying organic matter are an important component of the structure of A horizons, and the droppings of insect larvae are prominent. In Luvic chernozem, Luvic chernic phaeozem and Pantofluvic fluvisol under native forest, worm casts are the predominant component of the soil structure. The ecology of macrofaunal communities is correlated with soil morphology and can be applied to reconstruct possible mechanisms of soil genesis.

The aim of the study. The aim of the study was to estimate heterogeneity of moisture-related soil physical properties in a sequence of degraded hillslope soils in the cis-Salair region. The main tasks were to examine spatial fluctuations and changes in morphological and agrophysical properties of soils, differing in erosion degree, and assess their variability. Location and time of the study. The study was conducted in the forest-steppe zone in the Bugotak Hills (Novosibirsk region, Russia). A sequence of arable soils located along the 411 m convex hillslope with south-eastern exposition was investigated since July 01 till August 15, 2016. Main results. The article describes the variation of soil density, moisture content and temperature in a sequence of hillslope soils. The variation in the ploughed layer was found to be quite high, depending on the sampling scale. Examination of the spatial variability of the soil hydrophysical properties showed that the non-eroded podzolised chernozem (Luvic Greyzemic Chernozem) and toeslope meadow soil (Gleyic Greyzemic Phaeozem, Colluvic)had the highest density. The lower temperatures were recorded in the slightly eroded dark-gray forest soil (Luvic Greyzemic Phaeozem) and in the toeslope meadow soil, accumulating soil material eroded from the topslope. The temperature difference range between the “cold” and “warm” soils was 1.8 °С. Conclusions. Such studies have important prospects in development and introduction of agricultural technologies that are landscape-adapted, especially in areas with diverse relief and eroded soils. The main focus of such research should be the anti-erosion landscaping. The problem needs to be further studied within the framework of targeting the anti-erosion measures to geographic regions and natural zones.

The implementation of a targeted, site-specific approach on reducing the nitrogen load from agriculture requires fine-scale assessment of soil heterogeneity. In this study, the soil heterogeneity was described through the spatial heterogeneity of the apparent electrical conductivity values (ECa) and its implications to the patterns of redox potential values (Eh) in an intensely tile drained agricultural area. Piezometers and platinum-tipped redox probes for water level and Eh measurements were installed in transects along the assumed subsurface lateral water flow direction at different depths overlying the tile drains. Water level and Eh were determined from February to August 2017. A statistical analysis of the average ECa and slope measurements of each transect showed that they could be classified into four operational soil combinations (SC): high ECa, low slope (SC-1), low ECa, low slope (SC-2), high ECa, high slope (SC-3), low ECa, high slope (SC-4). A significant correlation between the inverted electrical conductivity (EC) values, clay and soil organic carbon (SOC) content suggested that the EC correlates with clay content. The high clay percentage associated with high ECa is assumed to facilitate development of anoxic microsites which led to more reducing conditions. Due to the generally reducing conditions and higher occurrence of saturated piezometers, transects under SC-1 were considered to have the most potential for intense nitrate reduction. In a tile drained setting, classifications based on average ECa and slope values may be utilized as parameters for a simple mapping tool for improved fine scale prediction of potential hotspots for nitrate reduction.

The aim of the study was to evaluate the changes in glomalin-related soil proteins (GRSP) content, microbial diversity and soil physical quality depending on the type of soil measures of soil improvement and changes in soil health. The study was based on a 100-year stationary field microplot experiment where the soil profiles were collected with preserving the natural soil horizons. The microplot experiment was carried out on eight different soil types: Brunic Arenosol (Dystric I), Rendzic Leptosol, Fluvic Cambisol, Haplic Cambisol (Eutric), Gleyic Phaeozem, Brunic Arenosol (Dystric II), Haplic Cambisol (Eutric II) and Haplic Cambisol (Dystric). These soils are the most common types of agricultural soils in Poland. Relatively significant correlations with the soil quality, physical parameters and the glomalin-related soil proteins have been found. The study determined the total GRSP (T-GRSP) and easily extractable GRSP (EE-GRSP) levels in soils as well as the soil physical quality index and soil&rsquo, s microbial biodiversity. The GRSP depended on the type of soil and correlated with S-Index and also was responsible for the unique chemical and physical properties of soils. Soils characterized by the highest T-GRSP content belonged to the group of very good and good soil physical quality characterized also by high biological activity, for which there were strong correlations with such parameters as dehydrogenase activity (DHA), microbial biomass content (MBC), microbial nitrogen content (MBN) and total bacteria number (B). The highest T-GRSP content and higher microbial diversity were found in Gleyic Phaeozem, Rendzic Leptosol and Fluvic Cambisol. The T-GRSP and EE-GRSP content were additionally correlated with the number of AMF spores. Very poor and poor soil physical quality according to S-Index characterized Brunic Arenosol (Dystric I) and Haplic Cambisol (Dystric). This research indicates that a specific edaphone of soil microorganisms and GRSP content may be of great importance when assessing a soil&rsquo, s quality and improvements in soil health. The abundance of glomalin-producing fungi significantly affects the quality of the soil. This effect is particularly important for agricultural soils are threatened by ongoing land degradation.

The trends of enzyme activities and litter chemistry after abandonment of arable soil and succession of natural vegetation were studied in a deciduous forest zone (Moscow region, Russia). The Luvic Phaeozem chronosequence included an arable field, 3 fields with increasing abandonment periods (7, 11, 35 years), and the soil under natural forest as a reference site (never used for cropland). The activities of four hydrolytic enzymes (β-glucosidase, cellobiohydrolase, β-galactosidase, chitinase) in the topsoil (0–5 cm) were compared with chemical functional groups of plant litter identified by 13C NMR spectra. The total enzyme activity increased 5-fold during 35 years of postagricultural restoration of arable soil. The share of C-cycle enzymes with “narrower” substrate specificity (cellobiohydrolase and chitinase) increased during 35 years from 19% to 42% of the total enzyme pool. We explain this gain by the increase in the diversity and recalcitrance of organic compounds in the plant litter from cropland to natural forest. Aromaticity index of plant litter built up remarkably: from 0.11 in the young abandoned land to 0.14–0.15 in the 35-year abandoned land and the reference site. The share of enzymes with a “narrower” substrate specificity correlated closely with the portions of aryl C, O-aryl C, and carbonyl C functional groups in plant litter. Accordingly, the succession of natural vegetation on abandoned cropland leads to strong diversification of the plant litter composition and a corresponding production of soil enzymes with “narrower” substrate specificity.

Phaeozem is one kind of scarce resources on the earth. Due to the restrictions of natural factors and the influence of human activities over the years, phaeozem degradation has become increasingly serious. Based on images of the ASTER in 2006 and the ETM+ in 2000 in this paper, the phaeozem organic matter content which is greater than 2 ％ was obtained by using quantitative retrieval. Through the three-dimensional remote sensing image, terrain rendering and relevant information were analyzed. On the basis of the above, the spatial distribution characteristics of phaeozem in Songliao Plain were analyzed using DEM (digital elevation model) data. The results show that the total area of phaeozem in Songliao Plain is about 51360.15 km2, and the phaeozem organic matter content is gradually increasing along with the increasing latitude or longitude, and decreasing along with increasing slope. In addition, the soil organic matter content is lower in southern slopes than that in northern slopes.

In this paper, we studied the soils of recreational areas of Volgograd within three research areas. The survey found that in research area I the soils spatial distribution is mainly represented by the following soil group according to WRB: Urbic Technosols, Urbic Technosols (Mollic) and Gleyic Terric Phaeozem (Mollic, Prototechnic). Buried soils are represented by Gleic Cambisols (Protocalcic). In research area II, among natural soils, the largest areas are occupied by Calcaric Fluvisols (Loamic, Technic, Protovertic), Calcaric Fluvisols (Arenic, Salic), and Gleyic Calcisols (Sodic, Protocalcic, Technic, Salic). The anthropogenic-transformed soils include Urbic Technosols, and Ekranic Technosols are under buildings and road surfaces. In research area III, the natural soils spatial distribution is homogeneous and mainly represented by Gleyic Cambic Calcisols (Protocalcic), Gleyic Cambisols (Protocalcic, Prototechnic), and Calcaric Colluvic Regosols (Arenic, Prototechnic) in the bottoms of small flat-bottom valleys. In irrigation sites occur Urbic Technosols, and on hiking trails – Gleyic Cambisols (Prototechnic). Despite the presence of reclaimed horizons with a high content of phosphorus in the soils (average concentration of 82 mg kg−1), none of the profiles revealed Hortic horizon, but only some of its properties (colour, horizon thickness, zoogenic activity). The thickness of urbic-stratifying layer (Au) varies in a wide range from 10 to 135 cm, and the thickness of reclaimed horizons (A) also varies from 10 to 48 cm. The bulk density in Au horizons is 1.4 g cm−3, in the reclaimed horizons (A) – 1.39 g cm−3. The content of soil carbon in soil surface horizons varies from 0.85% to 4.58% in urbic horizons, and to 1.49% in reclaimed horizons. Chemical analysis of urbic (Au) and reclaimed (A) horizons revealed a low content of easily soluble salts (0.16%) and carbonates (1.5% and 1.7%, respectively).

The aim of the study. The aim of the study was to describe the fertility of Greyzemic Chernozems, Нaplic Chernozem and Greyzemic Phaeozems located on erosion-prone slopes; to evaluate the yield and grain quality of spring soft wheat. The location and time of the study. Research was conducted on soils of the three experimental plots. The study area was located in the southeastern part of West Siberia within the boundaries of the Bugotak Hills (called Cis-Salair region) on the right bank side of the Ob River in the Novosibirsk region in the south of West Siberia. Plot 1 was located in the Iskitim district of the Novosibirsk region on the slope of southern exposure with 0- 6o gradient and occupied by Greyzemic Chernozems with different degree of soil erosion. In the Toguchin district of the Novosibirsk region two plots were located. Plot 2 was located on the slope of southeastern exposure with 0- 6.5o gradient and occupied by Нaplic Chernozems and Greyzemic Phaeozems. Plot 3 was located on the slope of northwestern exposure with 0-4.5o gradient and occupied by the non-eroded, slightly and moderately eroded Greyzemic Phaeozems. Cereal crops were spring soft wheat of two cultivars: Novosibirskaya 29 (plot 1; 2010 and 2014) and Memory of Vavenkov (plots 2, 3; 2011). Metodology. Two replicate soil samples were collected from the soil profiles at the sites differing in soil erosion degree. Four wheat phytomass samples were taken by a special frame 50×50 cm. The main results. Content and stock of soil organic carbon and total nitrogen decreased due to the increased soil erosion of Greyzemic Chernozems, Нaplic Chernozems and Greyzemic Phaeozems (Luvic) with maximal values in the Greyzemic Phaeozem (Colluvic). The N-NO3 in soils was low; the content of easily available phosphorus varied from the moderate to the high level, whereas the content of exchangeable potassium varied from low to increased level. Under extensive land use and restricted water reserves the wheat yield varied from 0.5 to 5 t/ha on the non-eroded Greyzemic Chernozems located on the south-exposed slope (plot 1). On the eroded soils the yield was found to be the same as on the non-eroded soil or even had a tendency to increase on slightly and moderately eroded soils. The maximal wheat yield (3.3 t/ha) was obtained on the Greyzemic Phaeozem (Colluvic). Between the non-eroded Нaplic Chernozems, eroded and stratified soils of the southeastern exposure (plot 2) there were no statistically significant differences in the yield, which varied from 3.2 to 4.1 t/ha. On the non-eroded Greyzemic Phaeozems (Luvic) of the northwestern exposure of the slope (plot 3) the yield was 4.3 t/ha, while on the slightly and moderately eroded soils it decreased to 1.1 t/ha. The mass of 1000 grains of wheat indicated the group with high mass (>30 g). The nitrogen content in grain and straw was low; potassium content was below the moderate level, while the content of phosphorus in grain was found to be optimal, and in straw it varied from the high to the low level. The content of raw protein was low (5-8%. The grain accounted for 35-48% of the total aboveground wheat phytomass. Conclusion. Nutrient regime of eroded soils is determined by soil profile transformation due soil erosion process and its intensity, as well as due to anthropogenic factors. Potential and actual fertility of Нaplic Chernozems and Greyzemic Phaeozems are higher than that of Greyzemic Chernozems. The productivity of soft spring wheat depends on the quantity of atmospheric precipitation, type and degree of soil erosion and slope exposure.

Temporal changes in soils of forest landscapes of the forest-steppe zone—Haplic Luvisols and Greyzemic Phaeozems—under the impact of Holocene climate changes (natural factor) and long-term cultivation (anthropogenic factor) were studied on level interfluves of the Central Russian Upland. These soils were developed from covering loesslike loam of varying thickness. To study soil evolution under the impact of climate changes, soil chronosequences of archaeological sites—paleosols buried under ramparts of ancient settlements and background surface soils of adjacent areas—were analyzed. The time of the soil burying was determined via the 14C dating of charcoal from thin twigs sampled in the material of ramparts immediately above the surface of buried soils. According to 14C dates, the paleosols were buried in the interval from 2450±40 to 1150±110 BP. Before the Subatlantic period, these paleosols developed under grassland (steppe), which is proved by their properties typical of steppe soils and by the presence of paleokrotovinas—the features created by the burrowing activity of steppe animals (mole rats)—in the studied profiles. The 14C dates of the total organic carbon of humus in the dark gray filling of a paleokrotovina from a Phaeozem buried at the depth of 140–150 cm under the rampart of 1150±110 BP in age ranged from 6080±150 to 2810±60 BP. The evolution of steppe Chernozems into forest Phaeozems and Luvisols took place in the Late Holocene. The anthropogenic evolution of forest Luvisols and Phaeozems under the impact of long-term (more than 150–230 years) plowing was analyzed in the soil agrochronosequences that included background soils under native forest vegetation and their arable analogs with different durations of cultivation. It was concluded that this evolution is directed towards Chernozemic pedogenesis, i.e., it proceeds in the direction opposite to the natural trend of pedogenesis in the Late Holocene. This process takes place despite the traditional practice of limited application of organic fertilizers in arable farming in the studied region. A decrease in the mean residence time (MRT) of total organic carbon (TOC) in the old-arable soils is considered a consequence of the formation and accumulation of fresh humus material in the profiles of cultivated soils—one of the major processes in the transformation of arable forest soils into Chernozems. The accumulation of carbonates and an increase in their 14C age take place in the arable soils in comparison with their forest analogs. In the agrochronosequence from the Polyana site, the 14C age of carbonates at the depth of 170–180 cm reaches 8000±100, 8270±150, and 9150±100 BP under the forest, 100-year-old plowland, and 150-year-old plowland, respectively. This can be explained by the ascending migration of ancient carbonates from the parent material in suspensions. In the analogous Samarino agrochronosequence, the 14C age of carbonates from the depth of 90–100 cm comprised 6500±90, 7150±100, and 12,360±230 BP, respectively. Thus, the studied forest-steppe soils have a polygenetic nature specified by a complicated history of pedogenesis under the impact of both natural (climate-driven forest invasion into steppe) and anthropogenic (deforestation and land plowing) factors.

The postagrogenic dynamics of acidity and some parameters of humus status have been studied in relation to the restoration of zonal vegetation in southern taiga (podzolic and soddy-podzolic soils (Retisols)), coniferous-broadleaved (subtaiga) forest (gray forest soil (Luvic Phaeozem)), and forest-steppe (gray forest soil (Haplic Phaeozem)) subzones. The most significant transformation of the studied properties of soils under changing vegetation has been revealed for poor sandy soils of southern taiga. The degree of changes in the content and stocks of organic carbon, the enrichment of humus in nitrogen, and acidity in the 0- to 20-cm soil layer during the postagrogenic evolution decreases from north to south. The adequate reflection of soil physicochemical properties in changes of plant cover is determined by the climatic zone and the land use pattern. A correlation between the changes in the soil acidity and the portion of acidophilic species in the plant cover is revealed for the southern taiga subzone. A positive relationship is found between the content of organic carbon and the share of species preferring humus-rich soils in the forest-steppe zone.

Biochar amendment to soil has been proposed as a strategy for sequestering carbon, mitigating climate change and enhancing crop productivity. However, few studies have compared the general effect of different feedstock-derived biochars on the various gaseous reactive nitrogen emissions (GNrEs) of N2O, NO and NH3 simultaneously across the typical vegetable soils in China. A greenhouse pot experiment with five consecutive vegetable crops was conducted to investigate the effects of two contrasting biochars, namely wheat straw biochar (Bw) and swine manure biochar (Bm) on GNrEs, vegetable yield and gaseous reactive nitrogen intensity (GNrI) in four typical soils which are representative of the intensive vegetable cropping systems across mainland China: an Acrisol from Hunan Province, an Anthrosol from Shanxi Province, a Cambisol from Shandong Province and a Phaeozem from Heilongjiang Province. Results showed that remarkable GNrE mitigation induced by biochar occurred in Anthrosol and Phaeozem, whereas enhancement of yield occurred in Cambisol and Phaeozem. Additionally, both biochars decreased GNrI through reducing N2O and NO emissions by 36.4–59.1 and 37.0–49.5 % for Bw (except for Cambisol), respectively, and by improving yield by 13.5–30.5 % for Bm (except for Acrisol and Anthrosol). Biochar amendments generally stimulated the NH3 emissions with greater enhancement from Bm than Bw. We can infer that the biochar's effects on the GNrEs and vegetable yield strongly depend on the attributes of the soil and biochar. Therefore, in order to achieve the maximum benefits under intensive greenhouse vegetable agriculture, both soil type and biochar characteristics should be seriously considered before conducting large-scale biochar applications.

Organic manure application is a feasible approach to alleviate the deterioration of soil erosion on soil organic carbon (SOC). However, to what extent manure application can restore carbon contents in SOC fractions in the eroded Phaeozems remains unknown. A 5-year field experiment was conducted in an artificially eroded Phaeozem with up to 30 cm of topsoil being removed. Chemical fertiliser, or chemical fertiliser plus cattle manure was applied. The contents of SOC were 23.6, 21.6 and 15.1 g C kg−1 soil for non-soil removal control, 10 and 30 cm of topsoil removal, respectively. Compared with the chemical fertiliser-only treatment, the chemical fertiliser plus manure application markedly increased SOC contents by 30–45% and C sequestration rates by 7.1–9.0-fold, especially in the fraction of 53–250 μm particulate organic carbon. However, with manure applied, SOC content in the fraction of mineral associated organic carbon in the 30 cm topsoil-removed soil was 2.9 g kg−1, 14.7% less than control (3...

The aim of the study was to review indicators and propose grades of soil potassium availability to crops.. The need of assessing soil potassium status on the basis of combined use of several diagnostic indicators, characterizing soil potassium pool, both quantitative and qualitative, is substantiated; at the same time, it is indispensable to take into account some properties of a specific soil, such as particle size distribution and cation exchange capacity. The diagnostics of soil potassium status in the long-term field experiments conducted in the forest-steppe zone of West Siberia was carried out. Results and conclusions. It was found that over 40 years of the experiment on the meadow chernozemic soil (Gleyic Chernozem) with initially very high potassium supply the content of exchangeable potassium decreased from 60 to 30 mg/100 g soil; at the same time, the level of easily exchangeable potassium decreased from 4.0 to 1.1-1.2 mg/100 g soil, indicating a significant deterioration in soil desorption capacity in relation to potassium. In the gray forest soil (Phaeozem) that was initially supplied with potassium, the content of its exchangeable and easily exchangeable forms decreased in 5–7 years of experiments to a critical minimum level, i.e. from 12 and 2 to 6–7 and 0.4–0, 5 mg/100 g soil, respectively. During the subsequent years (25 years) this content remained unchanged. It is concluded that systematic application of potassium together combined with nitrogen and phosphorus background fertilization ensured optimization of potassium status of soils.

The aim of the study. To assess the potential of geophysical methods to investigate the structure and properties of chernozemic soils. Location and time of the study. The field work was carried out during June-October 2018 on the two arable soils, namely Luvic Greyzemic Chernozem (Siltic) and Haplic Phaeozem (Siltic, Colluvic, Pachic) over Haplic Phaeozem (Siltic, Luvic), in the Bugotak Hills, which is part of the Cis-Salair denudation-accumulation plain on the right side of the Ob River in the south-east of West Siberia. Methodology. Soils were studied by the standard soil and agrochemical techniques as well as by such geophysical methods as magnetometry, electrotomography and ground-penetrating radar. Soil morphology was described, and soil samples were collected from soil genetic horizons. Physical, physicochemical and chemical (altogether up to 28) properties, pertaining to soil potential and actual fertility were determined. Relationships between soil properties and geophysical parameters were studied using correlation and multiple regression analyses. Main results. The study showed that when underlying solid rock is rather close to the surface, the magnetometry cannot be used to solve urgent issues in soil science. When soil total carbon (STC) in humus-accumulating layer was high, the relationship of the decrease in electrical resistivity (ER) with the increase in STC did not work anymore. The ER was found to depend on soil texture, as the heavier soil granulomety resulted in decreased ER. This regularity allows establishing the depth of illuvial horizons in humus-accumulating soils and a fortiori texture-differentiated ones. The ER in the humus-accumulation layer of the Luvic Greyzemic Chernozem (Siltic) was estimated as 70 ohm·m, while the 0-10 cm thick soil layer after subsurface cultivator could be determined by the ER values decreased to 40-45 ohm·m. The combined use of electrotomography and ground-penetrating radar was found to be the most promising for soil studies as such combination allows estimating the thickness of the humus-accumulating layer and its lower boundary, as well as discriminating between agro-dark-humus (arable) and dark-humus horizons, establishing the depth of the illuvial horizon and the upper boundary of the carbonate horizon. Conclusion. We believe that geophysical methods can be beneficial for soil genesis research and large-scale soil mapping because of their ability to account for natural heterogeneity of spatial variation of soil potential fertility properties. Large scale soil maps provide a fortiori indispensable basis to solve many agricultural and environmental problems such as monitoring soil properties’ changes because of soil degradation due to erosion, estimating pollution degree, assessing soil nutrients’ content and calculating fertilization rates, etc. Establishing even empirical relationships between soil geophysical parameters and crop yields currently seems to be a rather ambitious task, as crop yields are mostly determined not by “basic’ soil characteristics (which may correlate with geophysical parameters), but by plant available mineral nutrients and such external factors as photosynthetically active solar radiation, precipitation, fertilizer and pesticide application.

Post-agricultural natural restoration is a worldwide strategy for eco-environmental sustainability. However, it is unclear how it affects soil organic carbon (SOC) pools and composition among soil types across climate gradient. Here, we investigated 23-year post-agricultural restorations of SOC in three soils: Luvic Phaeozem, Calcaric Cambisol and Ferralic Cambisol typical for mid-temperate, warm-temperate and subtropical zones, respectively. Six SOC fractions with different protection mechanisms (non-protected, physically, chemically, biochemically, physico-chemically and physico-biochemically) were separated. Compared with pre-restoration in 1990, post-agricultural restoration rebuilt SOC similarly (+68–+91%) among the three soils despite of different SOC background. Compared with continuous cultivation, post-agricultural restoration increased total SOC pools in all the three soils (+33–+60%) mainly because of the increments of non-protected pool (coarse particulate organic C, cPOC). However, the pure physically, chemically, and biochemically protected SOC fractions were less sensitive to post-agricultural restoration. The physico-biochemically protected SOC was hampered by restoration in the two temperate soils but remained stable in the subtropical soil, suggesting a divergent self-restoring trend. Positive correlations of the total SOC and most fractions with wetness (precipitation/temperature ratio) demonstrated the climate dependency of SOC. In conclusion, post-agricultural natural restoration builds up SOC pool mainly due to the cPOC increment and shifts SOC composition towards more easily available C in three soils across the climatic gradient.

Catch crop cultivation for green manure is considered to be a sustainable agricultural strategy whose main goal is to mitigate the negative effects of inappropriate plant sequent by increasing the soil biological activity, improving the nutrient content and reducing their loss from soil. Additionally, correct catch crop management is expected to improve the yield of consequent crops as well as their quality parameters. The effects of field pea when used as a catch crop, either incorporated in autumn or mulched and incorporated in spring vs. a control—without a catch crop on the soil chemical properties (total N, organic C, available forms of K and P) and the composition of spring barley grain and straw (total N, P, K, Ca) were studied for three years (2009 to 2011) in two-field, one-factor experiments, which were conducted on two different soil types (Luvisol and Phaeozem). The catch crop had no effect regarding the soil pH, soil organic C or total N content. In turn, applying a catch crop significantly affected the concentration of the available K (in both soils) and available P content (Phaeozem). The effect of a catch crop on the nutrients in the grain and straw of spring barley was associated with the soil type. In Luvisol, a catch crop, independent of its management, increased the total N and P in the grain and straw of spring barley. In Phaeozem, a catch crop that was incorporated in the autumn significantly increased the K content in grain.

In the presented study we estimated the effect of long-term application of (I) various systems of soil cultivation: (i) conventional tillage, (ii) reduced tillage and (iii) no-tillage, (II) wheat monoculture – spring and winter forms, and (III) crop rotation, on the basic physical properties of Rendzic Phaeozem. In the experiment soil physical properties were studied, such as particle density, bulk density, total porosity, air capacity (at -15.5 kPa), water content at sampling, field water capacity (at -15.5 kPa), available water content and the ratio of field water capacity and total porosity was calculated. The hypothesis that long-term wheat monoculture and/or reduced tillage have a negative effect on the soil physical condition has been verified. It should be emphasised that the long-term application of reduced tillage systems and wheat monoculture did not cause significant differences in the analysed parameters. The lowest compaction and the best conditions for gas exchange were noted in the soil on which conventional tillage was applied under spring wheat monoculture. The results of field water capacity and available water content showed that long-term application of reduced systems of soil tillage had a positive effect on the water properties of soil. Soil under the conventional tillage ensured significantly the smallest amount of water for the plants. It has been shown that long-term application of reduced tillage, as well as the form of wheat (spring or winter wheat), have a stronger impact on changes in the soil-water-air relations than long-term use of monoculture. We found out that both the use of reduced tillage and the abandonment of crop rotation in favour of monoculture can be put into safely use in agricultural practice. We believe that the application of such systems is especially valuable in emergency situations.

‘Machair’ describes a landscape form that is present along the Atlantic seaboard of Scotland and Ireland that is characterized by a gently sloping coastal plain developed from aeolian carbonate and quartzose sand. Three soil profiles were characterized along a coastal transect on Harris (Outer Hebrides, Scotland) by standard methods (colour, texture, pH, wet-chemical extractions), infrared spectroscopy, X-ray diffractometry, X-ray fluorescence spectrometry and differential scanning calorimetry. The aim was to understand chemical processes and properties of soils that have formed under the influence of sedimentation, erosion, weathering, accumulation of soil organic matter (SOM), and human impact. One of the profiles differed distinctly from the other two, in particular regarding depth, texture, contents of carbonate and SOM, and properties of SOM (relative content of rather labile permanganate-oxidizable SOM, oxidation, interaction with clay minerals). Thermally stable SOM was present in all soil samples, likely pointing to pyrogenic SOM, i.e. black carbon. The mineralogical composition differed among the profiles and reflected the intermediate character of the local rocks. Magnesium-hydroxy-interlayered minerals were identified in all surface Ah horizons. We suggest that sea spray was the likely source of intercalated Mg. The shallowest soil was classified as Hypereutric Leptosol and the others as a Cambic and Calcaric Phaeozem. Results warrant a more detailed survey on the yet less studied interplay of SOM properties and mineral (trans-) formation in highly diverse and dynamic coastal soils that are frequently affected by long-term agricultural use.

This experiment takes phaeozem paddy field as the object of study to research for the optimum water and fertilizer application scheme for mitigation of N2O emissions. The effects of nitrogen, phosphorus, potassium and irrigation rate on N2O emissions in growing season under controlled irrigation was analyzed by four-factor quadratic saturation D-optimum design scheme, using the method of static chamber-gas chromatographic techniques. The results showed that nitrogen had most significant effects for N2O emissions in growing season and the increase of nitrogen showed promotion effects for N2O emissions; the effects of phosphorus and potassium were not obvious; the increase of irrigation promoted N2O emissions at an earlier stage but inhibited it latter. In consideration of yield, an optimum management plan of water and fertilizer was suggested for N2O reduction by 0%~20%, that was 114.72 kg/hm 2 for nitrogen, 50.25 kg/hm 2 for potassium, 17.64 kg/hm 2 for phosphorus, 80% for relative soil water content at late tilling stage. Under this scheme, the yield was 79.23 g/pot, with an increase rate of about 19.6% (compared with the control group); the emission load was 0.095 g/m 2 in growing season, with an reduction rate of about 8% (compared with the

Perennialization and reducing tillage have increased soil organic matter (SOM) in both aggregate and particulate organic matter (POM) in short-term and small scale experiments, but there is a need for investigations into the long-term effects of agroecosystems on these dynamic pools of SOM. The objectives of this study were to investigate how management varying in crop rotation, tillage intensity and organic management from 1990 to 2013 has affected POM and aggregate C and N, and assess the relationship between these SOM fractions and biomass C inputs. We hypothesized that tillage, low biomass inputs, and annual crops in rotation would be associated with decreased POM and aggregate C and N. Soil from six systems from the Wisconsin Integrated Cropping Systems Trial (WICST) on a Phaeozem, or Mollisol, was sampled in 2013: Continuous Maize ( Zea mays L.), Maize–Soybean [ Glycine max (L.) Merr.], Organic Grain (including maize, soybean, and wheat [ Triticum aestivum L.] sequentially seeded with oats [ Avena sativa L.] and berseem clover [ Trifolium alexandrinum L.]), Conventional Forage (three years alfalfa [ Medicago sativa L.] followed by maize), Organic Forage (two years’ alfalfa with oats nurse crop followed by maize), and Pasture (rotationally grazed, seeded to a mixture of red clover [ Trifolium pratense L.], timothy [ Phleum pretense L.], smooth bromegrass [ Bromu sinermis L.] and orchardgrass [ Dactylis glomerata L.]). Among all systems at 0–25 cm depth, we found significantly greater concentrations of POM-C in the Pasture (4.4 g C kg −1 soil) and POM-N in Pasture (0.30 g N kg −1 soil) and Organic Forage (0.25 g N kg −1 soil). The Organic Grain system had lower concentrations of macroaggregates and lower stocks of C and N within macroaggregates. Across all systems, belowground biomass C input was significantly positively correlated with POM-C, POM-N, and aggregate C and N. The data supported our hypothesis in part, as results indicate that frequent cultivation in the form of tine weeding and rotary hoeing for weed control in Organic Grain rotation is likely disrupting formation of aggregates and storage of C and N therein. However, in systems that were chisel plowed every one to three years, high biomass C inputs maintain POM-C and POM-N and soil aggregation equivalent to the fully perennial system.

Carbon and nitrogen compounds and the emission of CO2, CH4, and N2O were studied in the ancient buried and modern background soils developed from different parent materials in the Arkaim Reserve of Chelyabinsk oblast. The studies were performed after an 18-year-long period of absence of anthropogenic loads on the local ecosystems. Element contents in the humus horizons of the chernozems of the former plowland and pastures and of the forest soil reach 28–45.6 g/kg for Corg, 2.5–4.5 g/kg for Ntot, 140–423 mg/kg for labile carbon (Cl), 32–73 mg/kg for labile nitrogen (Nl), 350–952 mg/kg for carbon of microbial biomass (Cmic), and 38–85 mg/kg for nitrogen of microbial biomass (Nmic). The contents of different forms of C and N depend on the soil type and texture and on the type of land use, including that before reservation of the territory. The emission of greenhouse gases was examined in this area for the first time. The production of CO2 by the soil buried about 4000 years ago is an order of magnitude lower than that by the modern soil. The emission and sink of N2O are small in both modern and ancient soils. The behavior of methane is clearly different in the automorphic and hydromorphic soils: the former serve as methane sinks, whereas the latter act as methane sources. The rate of the CO2 emission from the soils is controlled by many factors, including the soil type, texture, degree of hydromorphism, composition of parent materials, and type of land use.

Field shelterbelts as agroforestry practice provides numerous ecosystem services. Carbon capture and storage potential in biomass and soil is among regulating services shelterbelts provide. Designing shelterbelts to address the various demands and provide services, requests special attention to choosing structural and spatial characteristics of shelterbelts, and species selection for shelterbelts. This paper presents the research results of C storage in 20-years old shelterbelts established on Gleyic Phaeozem in the area of Backa Palanka (Serbia). Investigated shelterbelts were consisted of the most commonly used species for shelterbelt establishment in Serbia: Siberian elm (Ulmus pumila L.), poplar (Populus x euramericana (Dode) Guin. cv. „Serotina“) and black locust (Robinia pseudoacacia L.). The diameter at breast height (d) and the height (h) of all trees in studied shelterbelts were measured. Carbon stock in biomass was estimated according to IPCC (2003) methodology. Soil profiles were opened in studied shelterbelts with soil sampling carried out at fixed depths of 0-10 cm, 10-20 cm and 20-40 cm. Assessment of carbon storage in soil was performed according to IPCC (2003). According to the research results, living biomass C stock in 20-years old Siberian elm and poplar shelterbelts per tree is almost the same 0.333 t per tree and 0.300 t per tree, respectively. In black locust shelterbelt carbon stock is considerable less 0.111 t per tree. However, in species selection for shelterbelts some characteristics should take into account such as adaptability and suitability to the environmental conditions, longevity and their impact on crops that are grown in the sheltered fields, as well as the natural potential vegetation communities of the area. The results of this study indicate that the poplar is preferred species than the Siberian elm in given environmental conditions. The average carbon stock in the soil of studied shelterbelts in a layer 0-40 cm is 9.33 kg m-2 C.

Root growth is affected by soil features that could change after erosion. The goal of this study was to understand how root growth responded to water stress resulting from erosion. For this purpose a pot experiment was conducted combining three eroded soils (lightly, moderately, severely) and four soil water levels (relative to field capacity of 100%, 80%, 60%, 40%) using nondisturbed Luvic Phaeozem soil from field by electric drill. The results showed that the response of soybean root growth to soil water was different for the three eroded soils and varied with growth stages of the plant. Under an optimal water supply, roots grew best in moderately eroded soils. Response of soybean root growth to water stress degree was similar under deficit water situation for three eroded soils, and under excess water stress situation, the root growth of lightly eroded soils was restricted more seriously than that of moderately and severely eroded soils during the initial branching stage. Root growth was restricted onl...

Snowmelt erosion is one of the reasons for the decreasing soil fertility in the most valuable agricultural lands in the south of West Siberia. The aim of this study was to examine the influence of long term soil use and degree of soil erosion on the main fertility indicators of Greyzemic Phaeozem (30-year fallow, non-eroded, slightly eroded, moderately eroded and strongly eroded). Soils were analysed for organic carbon (SOC), pHw, cation-exchange capacity and total and available forms of nitrogen, phosphorus and potassium. Plants were analysed for sheaf and grain yield and NPK content of wheat. A decrease in the content of the total forms of carbon and nitrogen and an increase in the C/N ratio were observed with an increase in the degree of soil erosion. SOC losses in the ploughed layer of slightly, moderately and strongly eroded soils were 6.6, 13 and 27%, respectively, while the nitrogen losses were 5, 33, and 71%. The widest (37) C/N ratio was found in strongly eroded soil. The content of total phosphorus in the ploughed layer of slightly, moderately and strongly eroded soils decreased by 3.8, 23 and 15.4%, respectively, in comparison with non-eroded soil. Available forms of phosphorus and potassium increased with an increase in the degree of soil erosion, with the highest values found in moderately eroded soil. Exchangeable K/available K ratio, the overall mobility of potassium in the eroded soils also increased. The highest plant productivity was found on moderately eroded soil. A deterioration of the nitrogen regime led to a narrowing of the N/K ratio from 2.4 (grain) and 0.4 (straw) up to 1.9 (grain) and 0.3 (straw) for non-eroded and strongly eroded soils respectively. A critical decrease of soil fertility and plant productivity was found in strongly eroded soil.

The Phaeozem region is an important grain production base in China and soil fertility has declined under long-term cultivation. Studying soil organic carbon (SOC) change in the upland phaeozem of Northeast China under different tillage modes has great theoretical and practical significance for reducing greenhouse gases emissions, increasing soil carbon stocks, and ensuring food security. This study applied the DAYCENT model to simulate six long-term experimental sites in the phaeozem region, and through calibration and validation analysis, it concluded that the DAYCENT model could effectively simulate the dynamic change of SOC in the upland phaeozems; hence, the relevant parameters of each site were determined. Under future climate scenarios (Representative Concentration Pathway 4.5, RCP 4.5), SOC change in agricultural soils (0–20 cm topsoil) of four different management scenarios (fertilizer application, manure amendment, straw return, no-tillage) was simulated. The overall simulated trend was no-tillage > straw return > manure amendment > fertilizer application. Fertilizer had no evident effect on increasing SOC, but the effect would be better if combined with manure; both straw return and no-tillage had the general effect of improving SOC and the simulated values rose rapidly with a large increasing rate within a short period; however, the increasing rate became gentle after 2050, reached a relatively stable level after 2080, then gradually reached carbon saturation. Untill 2100, the SOC content of each site reached a relatively higher level by adopting the no-tillage treatment, where the SOC contents of Harbin, Hailun, Nehe, Dehui, Gongzhuling and Lishu were 2.36 g/100 g, 2.81 g/100 g, 2.22 g/100 g, 2.38 g/100 g, 1.97 g/100 g and 2.01 g/100 g, respectively. The SOC contents increased by 52.47% when compared with the initial value, and the simulated average annual increase of SOC for 84 years was 0.0082 g/100 g.

The effects of 20 years of potassium (K) fertilization (in two treatments: 113 and 225 kg K2O ha−1) on grain and stover yields, plant K concentrations, aboveground K uptake, K use efficiencies, soil K pools, and the K balance were examined in a Haplic Phaeozem soil under a rain-fed mono-cropped spring maize (Zea mays L.) system in the province of Jilin, northeast China. The indigenous K supply (zero K application) maintained an average grain yield of 7.0 t ha−1 per year, but the year-to-year variation was large. Application of K significantly (P

Abandonment of croplands ongoing on 220 million ha worldwide contributes strongly to soil restoration by improvement of degraded properties and medium- and long-term carbon (C) sequestration in post-agricultural ecosystems. Two interrelated processes – decomposition and stabilization of soil organic carbon (SOC) – govern SOC dynamics and affect the C source or sink functions of former croplands. We investigated how the abandonment of arable soils affects (i) accumulation of SOC, its composition, stability, and turnover during the post-agricultural restoration of soils, and (ii) microbial activity parameters. A chronosequence study was carried in two bioclimatic zones of European Russia: deciduous forest (Luvic Phaeozems, PH-chronosequence) and dry steppe (Calcic Chernozems, CH-chronosequence). Each chronosequence included an arable soil, 3–4 soils abandoned at increasing time periods (up to 35 years), and natural soil: never cropped Phaeozem and completely restored Chernozem. We combined the results of nuclear magnetic resonance (NMR), thermal analysis including Differential Scanning Calorimetry and Derivative Thermogravimetry, long-term incubation for SOC mineralization, and microbiological activity (basal respiration and microbial C content). Degraded Phaeozems with low SOC amount had much higher relative increase in SOC content (134%) during the post-agricultural restoration compared to SOC-rich Chernozems (38%). SOC gains were recorded in all organic compound classes identified by NMR and thermal analysis, but the increase of recalcitrant SOC was more pronounced in the post-agricultural Chernozems than in the Phaeozems. The post-agricultural Chernozems were characterized by higher SOC aliphaticity and aromaticity than Phaeozems. Microbial activity and biodegradable SOC increased gradually during post-agricultural restoration. Being mostly a function of climate and vegetation, the soil type was the primary factor explaining the greatest portion (54–88%) of the total variance for most soil and microbial parameters. Concluding, despite SOC content increased in both Chernozems and Phaeozems during the post-agricultural restoration, the mechanisms of C sequestration and stabilization were dependent on climate, vegetation, and on the degradation intensity during the agricultural use. The accumulation of organic compounds was specific for virgin soils dominating in deciduous forest and steppes, and had direct consequences for microbial activities, C turnover and sequestration.

Climate change is increasing the occurrence of extreme precipitation events and causing irregular precipitation patterns. This occurs in parallel with the degradation of crop fields, and triggers the occurrence of pluvial floods and droughts on the same field. Consequently, irrigation must be adapted to the changing soil properties. Detailed spatial and temporal measurements of changes in infiltration are required. This study aimed to quantify changes in infiltration for a subhumid irrigated cropland with various soil types (Phaeozem, Solonetz, Chernozem) and field conditions (seedbed and stubble) by simulating rainfall. As the soil structure determines hydrology, the aggregate stability/surface roughness was tested as a proxy of infiltration through photogrammetry. The soil losses caused by precipitation did not exhibit connections to changes in the surface roughness, and lower aggregate stability did not necessarily cause lower infiltration intensities, suggesting that sedimentation could only partly seal drainage pores. The final infiltration intensities varied within a wide range (0.2&ndash, 28.4 mm h&minus, 1). Seedbed preparation did not increase the volume of micropores (&lt, 10 &micro, m), which resulted in higher infiltration under stubble. Photogrammetry was found to be a potentially useful tool for measuring aggregate stability, however, further investigations on in situ soil surfaces are required for technical improvement.

In absence of commercial fertilizers prehistoric agriculture relied heavily on nutrient supply from soil. This study was designed to reconstruct the phosphorus (P) status of prehistoric arable soils in order to highlight the possible importance of soil P limitation in Neolithic (after the Early Neolithic, i.e. around 4400 until 2200 BC) and Bronze Age (2200 until 700 BC) agriculture. For this purpose, we sampled buried archaeological topsoil relicts that have been preserved in prehistoric pit fillings outside ancient settlements in the loess areas in Central and Western Germany. Adjacent subsoils and recent topsoils served as references. Samples were characterized using sequential P extraction and selected samples were characterized using 31 P NMR spectroscopy. Prehistoric topsoil relicts in the investigated regions showed larger contents of organic matter and extractable P (sum of all sequentially extracted inorganic and organic P fractions) than the adjacent subsoils. Sampling the soils at higher depth resolution did not provide any evidence of P-leaching. The P content in the topsoil relicts amounted to approximately 86% of the P content of the modern, fertilized topsoils. Most of the extractable P (> 80%) comprised inorganic P. Organic P fractions were dominated by monoester-P. Intriguingly, plant available P contents (sum of resin-P i , NaHCO 3 -P i and NaOH-P i ) in the prehistoric topsoils and the recent topsoils were similar (23% and 20% of extractable P, respectively), suggesting that even plant available P was maintained in the prehistoric topsoil relicts. Also the contents of Ca-associated P were large, but reflected differences in pedogenesis among the sampling sites (Chernozem, Phaeozem and Luvisol). Hence, we have to conclude that there was no significant P limitation in the prehistoric farmland of the two loess areas, either because the soils had been fertilized or because the inherent P stocks were sufficient to sustain ancient farm yields. In any case our data do not support the hypothesis that prehistoric P limitations may have reduced crop yields.

The enhancement of soil organic carbon (SOC) is important for sustainable agriculture, while changes in SOC depend on the balance between carbon (C) input and export. To investigate how chemical fertilizers contribute to C input (e.g. plant-derived C) and export (e.g. original SOC decomposition) in soil, a wheat (a C3 plant) pot experiment was conducted using a Phaeozem that had previously been used to cultivate maize (a C4 plant). The natural 13C abundance method was used to quantify wheat-derived SOC (WSC) and microbial respiration using the original SOC (Rmicrobial) during the wheat growing season. The wheat grain, WSC, wheat-derived C (WDC: including WSC, root and stubble biomass C) and Rmicrobial-derived CO2 emission (SCE) in fertilized treatments increased by 4.8–31.1%, 48.9–122.4%, 21.3–62.2% and 6.0–51.8%, respectively, when compared to unfertilized treatments. The total SOC in the post-experimental soil increased by 0.14–0.97% when compared to pre-experimental soil because the WSC input was larger than the SCE export, and it would be increased further if wheat root and stubble biomass C were included. Therefore, application of chemical fertilizer not only directly increases crop yield, but also indirectly contributes to C sequestration by favoring crop growth and crop-derived C input in soil.

The study was concerned with the physical properties of a soil which was under natural fallow for ten years (1996–2005). The experimental sites were situated on a Rendzic Phaeozem originating from cretaceous bedrock. Two adjoining arable plots (0.2 ha area of each) cultivated during the period were compared with the fallowed plot (0.1 ha area). The soil under study has been in use as arable land for over 100 years. The crops most frequently cultivated included cereals, sugar beet and potato. The primary soil tillage system applied was the conventional plough tillage system. An oat and barley mix was grown on this plot immediately before the fallowing started. The paper provides a presentation of results concerning the following physical properties of the soil: bulk density (BD), total porosity (TP), field air capacity (content of macropores Φ > 20 μm — FAC), field air permeability (FAP), moisture at the sampling moment (SM), field water capacity (FC), available water retention (AWC), unavailable water retention — wilting point (UWC), and the calculated ratio FC/TP. After the ten-year period of lying fallow the physical condition of the studied soil improved markedly. What should be noted as particularly valuable was the fact that after six years of exclusion from cultivation there was an improvement of soil compaction (BD) and an increase in total porosity (TP), field air permeability (FAP), field water capacity (FC) and available water retention (AWC). The ten-year (1996–2005) mean value of BD of the fallow soil was 1.11 Mg m − 3 , that of the soil from Field I — 1.17 Mg m − 3 , and from Field II — 1.15 Mg m − 3 ; TP: fallow — 0.550 m 3 m − 3 , Field I — 0.531 m 3 m − 3 , Field II — 0.543 m 3 m − 3 ; FAP: fallow — 104.1 × 10 − 8 m 2 Pa − 1 s − 1 , Field I — 47.9 × 10 − 8 m 2 Pa − 1 s − 1 , Field II — 66.9 × 10 − 8 m 2 Pa − 1 s − 1 ; FC: fallow — 0.374 kg kg − 1 , Field I — 0.353 kg kg − 1 , Field II — 0.354 kg kg − 1 ; AWC: fallow — 0.221 kg kg − 1 , Field — 0.202 kg kg − 1 , Field II — 0.201 kg kg − 1 . In view of the acquired data it should assumed that long-term fallow of arable fields is one of the methods leading to the physical regeneration of soil. Favourable changes in the physical structure of soil can be achieved through the application of reduced or no-till tillage systems.

Soil organic carbon (SOC) and total nitrogen (TN) stocks can be affected by soil erosion and this is of great significance in relation to global environmental concern about environmental change. This study investigated the spatial patterns of Cs-137, SOC and TN as well as their relationships for an agricultural catchment and presents a budget analysis of the redistributions of SOC and TN for the period 1954-2010. Cs-137, SOC and TN inventories were found to be significantly correlated, and the application of the(137)Cs technique proved to be useful for evaluating SOC and TN dynamics in the Luvic Phaeozem soil typical of the Chinese black soil region. Spatial patterns of soil, SOC and TN were greatly influenced by shelterbelts/windbreaks within the study catchment. Higher Cs-137, SOC and TN stocks were generally found upwind of the shelterbelts and at the study catchment outlet, whereas lower stocks of Cs-137, SOC and TN occurred behind the shelterbelts (i.e. in the lee). The total net losses of SOC and TN over the past 56 years were approximately 152 and 11 t respectively, with 47 and 38 per cent of the eroded SOC and TN in soils redeposited within the study catchment, respectively. Based on the relationships of soil, SOC and TN in the investigated catchment, erosion-induced SOC and TN losses per year are around 1.2 x 10(6) and 0.1 x 10(6) t for the typical black soil region of Northeast China. Copyright (C) 2012 John Wiley & Sons, Ltd.

Soybean ( Glycine max L.)–maize ( Zea mays L.) rotation has been recommended as a good cropping practice for soil quality improvement and crop productivity enhancement. However, its impacts on carbon sequestration in soil are not well documented. The main objective of this study was to learn whether soybean–maize rotation can promote soil organic carbon (SOC) sequestration. Based on a long-term field experiment (started in 1990) in Northeast China, we investigated the differences in soil organic carbon (SOC) and soil aggregate composition between cropping patterns. This experiment included four treatments: continuous maize cropping (CMC), maize–soybean rotation (MSR), continuous soybean cropping (CSC) and farmland fallow (FALL) in a Haplic Phaeozem soil. All treatments showed a sustained trend toward increasing SOC storage since 1990. The contents of SOC in the topsoil and in the profile to the 1 m depth were in the following order of CMC > MSR > CSC ≥ FALL, suggesting a greater potential of C sequestration under cropping with manure application than under the farmland fallow without any fertilizer application. In the 1 m soil profiles, SOC levels decreased with soil depth with a major part (around 60–71%) being distributed in the 0–40 cm layer, whereas different practices led to great differential of SOC distribution. The CMC had the highest SOC levels (47.3 Mg ha −1 ) in the topsoil (0–20 cm) among the four systems. Meanwhile, maize cropping system (e.g. CMC and MSR) promoted more SOC allocation in >40 cm soil layers. Moreover, cropping pattern also differently influenced the formation and transformation of soil aggregates and the distribution of SOC in the aggregates. Macro-sized aggregate and the associated C (18.6 Mg ha −1 ) dominated in the FALL, while the micro-sized fractions (44.0% and 52.5%, respectively) and corresponding associated C (14.8 Mg ha −1 and 19.2 Mg ha −1 , respectively) were maximized in the MSR and CSC. The CMC had the greatest silt + clay-sized aggregate fraction (42.0%) and associated C in the macro- (13.4 Mg ha −1 ) and silt + clay-sized aggregate (12.9 Mg ha −1 ) fractions when compared with the MSR and CSC. Thus, maize–soybean rotation may be not the best cropping practice for C sequestration in the rainfed farmland Mollisol (Cumulic Hapludoll) in Northeast China, and intensive cropping with manure application can sustain the soil fertility for a long-term with high crop yield.

The processes of the organic matter (OM) mineralization in forest soils developed under temperate continental (Moscow oblast, Russia), Mediterranean (the central and western parts of Spain), and tropical monsoon (southern Vietnam) climates were studied under laboratory conditions. The potential and specific rates of the OM mineralization (PR min and PR min/Corg, respectively), the ecophysiological parameters of the microbial communities status (Cmic, qCO2, and Cmic/Corg), and the sensitivity of the rate of the OM mineralization to the rise in temperature were evaluated by the temperature coefficients (Q 10) determined in the humus horizons (0–10 cm, without forest litter). The average values of PR min for the climatic zones decreased in the following order: Mediterranean (57.1 ± 10.6 mg C/kg per day) > temperate continental (23.8 ± 7.1 mg C/kg per day) > tropical monsoon (10.4 ± 1.6 mg C/kg per day). The lowest resistance of the soil OM to mineralization as evaluated by the PR min/Corg values was found in the Albeluvisol and Phaeozem of the temperate continental climate and in the Acrisol of the Mediterranean climate. The highest Q 10 coefficients were attributed to the OM mineralization in the forest soils of the temperate continental climate. This allowed us to conclude that the observed and expected climate changes with an increase in the mean annual air temperature should lead to the maximum intensification of the OM mineralization processes in the forest soils of northern regions.

It is difficult to analyse soil properties quantitatively with multispectral remote sensing data. An alternative solution is to determine the main spectral characteristic control points of soil hyperspectral reflectance curves by sensitivity analysis methods. Hyperspectral reflectance is simulated using the control points based on multispectral reflectance collected from satellites in this study. The laboratory hyperspectral reflectance and its continuum-removed curve of Phaeozem and the parent material (PM) of samples collected from Heilongjiang Province, China were analysed, and the spectral characteristic control points determined. Hyperspectral simulating linear and quadratic models based on laboratory reflectance were then built. Results show that montmorillonite and illite are the dominant minerals in Phaeozem PM. Organic matter content determines the spectral characteristics of Phaeozem and makes it suitable for reflectance simulation in the spectrum range of 1000 nm and less; the higher the organic matter content the greater the spectral absorption area. There are two absorption valleys at 500 and 660 nm, which determine the spectral characteristic control points of Phaeozem between 450 and 930 nm, namely 450, 500, 590, 660 and 930 nm. Both the linear and quadratic simulation models built with the characteristic control points accurately describe Phaeozem reflectance, which proves that the characteristic control points are selected reasonably and representatively. The hyperspectral simulation method based on multispectral reflectance closely represents the characteristics of Phaeozem hyperspectral reflectance, partly removes noise and improves the precision of predicting organic matter content. Therefore the method is feasible and useful for data compression of Phaeozem hyperspectral reflectance, soil and vegetation indices building, and quantitative remote sensing in the Phaeozem Zone, northeast China.