Indicators Of Soil Degradation Research Articles

Indicators of soil degradation on a pipeline footprint, Alberta, Canada

Indicators of soil degradation on a pipeline footprint, Alberta, Canada

A systematic benchmarking framework for future assessments of soil health: An example from Denmark

Based on current evidence and established critical thresholds for soil degradation indicators, it is concerning that over 60–70% of European soils are unhealthy due to unsustainable management and the impact of climate change. Despite European and national efforts to improve soil health, significant gaps remain. The proposal for a Soil Monitoring and Resilience Law, to be implemented by the European Union, seeks to establish a framework for soil monitoring and promote sustainable management practices to achieve healthy soils by 2050. This requires extensive data collection and soil monitoring systems to accurately estimate soil health across Europe, considering the diversity of soil types, climates, and land uses. To establish a framework for soil monitoring, we must understand the site-specific status of soil and the ranges of soil health indicators across specific pedoclimatic regions. In our study, we evaluated the soil status in agricultural areas in Denmark using soil health indicators and a site-specific benchmarking approach. We compiled nationally representative datasets, combining point and model-informed data of soil parameters such as organic carbon content, bulk density, pH, electrical conductivity, clay-to-soil organiccarbon ratio, water erosion, and nitrogen leaching. By categorizing Danish agricultural soils into monitoring units based on textural classes, landscape elements, and wetland types, we calculated benchmarks for these indicators, considering different cropping systems. Our approach provided detailed point-based results and a spatially explicit overview of the status of soil health indicators in Denmark. We identified areas where soil deviates from the benchmarks of different indicators. Such deviations might indicate soil functions operating outside the normal range, posing potential threats to soil health. This proposed framework could support the establishment of a baseline for assessing the directionality of future changes in soil health. Moreover, it is adaptable for implementation by other countries to support assessments of soil health.

Soil quality dynamics and degradation potentials as influenced by land use systems in humid tropical soil of Southeastern, Nigeria

An assessment of the effects of land use systems on soil quality dynamics and soil degradation potentials in Umuahia, Southeastern Nigeria was done in this study. Samples of soil were taken between 0 and 15 and between 15 and 30 cm. from coconut plantation (SSP1), palm plantation (SSP2), pineapple orchard (SSP3) and waste dump site (SSP4). The result revealed sand to be the dominant soil fraction in decreasing abundance: Waste dumpsite (WD)≥ Pineapple Orchard (PO) ≥ Coconut Plantation (CP)≥ Oil Palm Plantation (OPP), followed by silt :WD ≥ CP≥ PO ≥ OPP and clay: OPP≥CP≥PO≥WD. Land use systems recorded serious negative effects on soil physicochemical properties, with soil pH ranging between 3.43-7.20, waste dumpsite having neutral and others having less than 6.5-8.5 as the critical limit. The mean values of potentially toxic elements in soils as regard land use systems: Ni, Mn, Fe, Cr, Zn, Pb and Cu were all above the critical limits rendering the soil polluted. The effects of Land-use systems on biochemical indicators of soil degradation ranged from None to slightly (1) -Very highly degraded soils (4), with organic matter (OM) as biological indicator dominating the index. The effect of land use systems on soil degradation was in decreasing trend: WD > CP >OPP> PO constituting 32.5%, 26.7%, 20.8% and 20% respectively. Integrated waste management (IWM) and smart farming techniques should be encouraged for soil quality improvement.

Enhancing Soil Organic Carbon Content and Water Retention Using Polyvinyl Alcohol Cross-linked with Chitosan and Pectin

Soil organic carbon is considered a candidate without a substitute to be an important indicator of soil degradation by monitoring its amount and changes over time. Organic compounds such as chitosan (CS) and pectin (PC) can increase organic matter content in soils and provide a carbon source for microbes. Organic nanoparticles (NPs) were prepared by polymerization of CS and PC with polyvinyl alcohol (PVA), loaded with NPK nutrients, and evaluated by transmission electron microscope as well as zeta-potential (ZP). This study aims to test the effect of organic NPs on soil organic carbon (SOC) content, available water capacity (AWC), and growth of wheat plant. Thus, a pot experiment was conducted using clay soil. The treatments were NPK at two levels, viz., 50 and 85% of the recommended doses in combination with CS/PVA and PC/PVA as nano-carrier materials, as well as control treatment (85% NPK). Results showed that the loading of organic NPs with NPK nutrients obviously increases the solution stability and the positive as well as negative charges for CS/PVA (50.30 mV) and PC/PVA (− 17.80 mV), respectively. Furthermore, the using of NPK nano-fertilizers was significant for all the studied properties. Likewise, the addition of CS/PVA loaded with NPK decreased soil ZP at a range of − 13.00 to − 16.90 mV. Besides, it shows better carbon-cycling activity by increasing SOC at a range of 9.71 to 11.68 g kg−1. The PC/PVA loaded with 50%NPK not only increases AWC with a rate of 18.23% but also sustains water-release synchronization to meet wheat plant demands.

Comparative analysis of soil organic matter fractions, lability, stability ratios, and carbon management index in various land use types within bharatpur catchment, Chitwan District, Nepal

BackgroundLand use and land cover changes have a significant impact on the dynamics of soil organic matter (SOM) and its fractions, as well as on overall soil health. This study conducted in Bharatpur Catchment, Chitwan District, Nepal, aimed to assess and quantify variations in total soil organic matter (TSOMC), labile organic matter fraction (CL), stable organic matter fraction (CS), stability ratio (SR), and carbon management index (CMI) across seven land use types: pastureland, forestland, fruit orchards, small-scale conventional agricultural land, large-scale conventional agricultural land, large-scale alternative fallow and conventional agricultural land, and organic farming agricultural land. The study also explored the potential use of the Carbon Management Index (CMI) and stability ratio (SR) as indicators of soil degradation or improvement in response to land use changes.ResultsThe findings revealed significant differences in mean values of TSOMC, CL, and CS among the different land use types. Forestland and organic farming exhibited significantly higher TSOMC (3.24%, 3.12%) compared to fruit orchard lands (2.62%), small scale conventional farming (2.22%), alternative fallow and conventional farming (2.06%), large scale conventional farming (1.84%) and pastureland (1.20%). Organic farming and Forestland also had significantly higher CL (1.85%, 1.84%) and CS (1.27%, 1.39%) compared to all other land use types. Forest and organic farming lands showed higher CMI values, while pastures and forests exhibited higher SR values compared to the rest of the land use types.ConclusionsThis study highlights the influence of various land use types on soil organic matter pools and demonstrates the potential of CMI and SR as indicators for assessing soil degradation or improvement in response to land use and land cover changes.

Features of Soil Bacterial Communities of Varying Degree of Salinity on the Example of the Shaulder Irrigation Massif of the Turkestan Region of the Republic of Kazakhstan

A comparative assessment of bacterial communities of meadow-serozem soils of different degrees of salinity was carried out. Significant differences in the structure of microbiomes of arable horizons of weakly saline and highly saline meadow-serozem soil were revealed. A significant reduction in the diversity of the microbiome at the phylum level with an increase in the level of soil salinity was established (on the example of meadow-serozem soils of the Shaulder irrigation massif). The structure of bacterial communities of the meadow-serozem highly saline soil is represented by four bacterial phyla: (Actinobacteria, Bacteroidetes, Firmicutes, Proteobacteria), while 13 bacterial phyla were identified in weakly salinized soil (Proteobacteria, Actinobacteria, Bacteroidetes, Verrucomicrobia, Acidobacteria, Chloroflexi, Firmicutes, Gemmatimonadetes, Planctomycetes, Saccharibacteria, Cyanobacteria, Chlorobi, Nitrospirae). According to the Shannon index, the species diversity of the microbiome of the meadow-serozem soils of the Shaulder irrigation massif is about 20% higher on weakly saline soils compared to highly saline ones. The Chao1 index and the number of taxonomic units (OTUs) also indicate a roughly halving of alpha diversity in the highly saline soil microbiome. The ecological significance of the problem of secondary soil salinization was confirmed. With an increase of salt content in soils, the species diversity of the bacterial community decreases, which can be considered as one of the indicators of soil degradation.

Identification of Eroded and Erosion Risk Areas Using Remote Sensing and GIS in the Quebrada Seca watershed

The aim of this research was to identify eroded areas and areas at risk of erosion (EAER) as indicators of soil degradation by water erosion in a semiarid watershed of the Venezuelan Andes in 2017. To this effect, remote sensing techniques and geographic information systems (GIS) were used, focusing on spectral reflectance data from a satellite image, given the absence of continuous pluviographic information and data on soil properties in developing countries. This methodology involved estimating the potential water erosion risk (PWER) and mapping eroded and erosion risk areas (EAER) based on calculating the spectral Euclidean distance to bare soils and a remote sensing technique, which was selected via linear regression. Receiver operating characteristics (ROC) curves were determined to define classification thresholds, which were validated by means of a supervised classification and associated to PWER values. The main results indicate that EAER1 identified more eroded areas with bare soils (229,77 ha) as opposed to EAER2 (195,57 ha). Similarly, it was evident that the first alternative was more successful that the second (sum of the first three principal components). The PWER analysis, in addition to the erosion mapping developed and other data and criteria, such as mini-mum area size of interest, could help to consider necessary soil conservation measures.

Tamarugite, NaAl(SO4)2·6H2O, as a valuable indicator of soil degradation in a Spanish coastal wetland receiving acidic leachates from spilled mine waste

This paper documents the first occurrence of tamarugite in a Spanish coastal wetland registered as a UNESCO Biosphere Reserve, and discusses its origin and environmental significance. Tamarugite occurs as bladed crystals in efflorescent coatings on the topsoil of marshy areas, alongside an abandoned mining railroad. Tamarugite formation is described as a sequential process involving: (1) Oxidative dissolution of pyrite ore spilled on the former railway tracks and generation of acidic sulfate-rich waters; (2) decomposition of layer minerals under acidic conditions and release of Al3+ ions into solution; (3) interaction between acid discharges and estuarine water during flood tidal periods; and (4) precipitation of tamarugite and associated sulfate salts (sideronatrite, epsomite, pickeringite) under strongly evaporative conditions. These transient minerals have potential to release acid and associated major elements (Al, Fe, Mg, Na, S) and trace metals (e.g. Zn) into the solution causing detrimental effects. The occurrence of tamarugite is, therefore, a valuable indicator of environmental degradation in wetland ecosystems.

Oribatid mites in different Mediterranean crop rotations fertilized with animal droppings.

Unsustainable soil management is one of the drivers of soil degradation, but impact assessment requires the development of indicators. Oribatids might be considered as early indicators of disturbances due to the stability of their community. The aim of this study was to investigate the feasibility of oribatids as bioindicators of sustainable agricultural practices. Under a dry Mediterranean climate, three fertilization experiments - two under a two-crop rotation system and one under maize monoculture and established 12 years earlier - were sampled 3× for oribatid identification during the last annual cropping cycle. The hypothesis was that different nutrient and crop managements affect the number of oribatid species and individuals present, and these parameters could be used as indicators of soil degradation. In total, 18 oribatid species were identified, and 1974 adult individuals were recovered. Maximum abundance was found prior to sowing. Pig slurry (PS) vs. control, and dairy cattle manure (CM) vs. mineral fertilization increased oribatid abundance. This increase was evident when the average applied rates with PS were ca. 2 Mg of organic matter (OM) ha- 1 yr- 1, or higher than ca. 4 Mg OM ha- 1 yr- 1 for CM. When the preceding crop was wheat and PS or CM were used, Oribatula (Zygoribatula) excavata (which reproduces sexually) predominated. In maize monoculture fertilized with CM, Tectocepheus sarekensis and Acrotritia ardua americana (which can reproduce through parthenogenesis) prevailed vs. Oribatula, which indicated a heavily disturbed soil. Under this specific Mediterranean environment, the predominance of certain parthenogenic oribatid species and the number of individuals provide advanced warning on soil degradation.

Total organic carbon content as an early warning indicator of soil degradation

Total organic carbon content as an early warning indicator of soil degradation

Importance of soil labile organic carbon fractions in shaping microbial community after vegetation restoration

Studies have been increasingly focusing on soil carbon (C) pools to facilitate the sequestration and stabilisation of soil organic carbon (SOC). However, interactions between different SOC fractions and microbial communities have remained largely unexplored after vegetation restoration on the Loess Plateau. To address this gap, we analysed 16S and ITS rRNA gene sequencing, active SOC (Ca), slow SOC (Cs), passive SOC (Cp) and edaphic factors to decipher the importance of soil C fractions in shaping microbial communities after vegetation restoration. Compared to CK (Control, cropland), the average of SOC contents improved 70.52 % (p < 0.05), and the Ca, Cs and Cp improved 83.18 % (p < 0.05), 128.74 % (p < 0.05) and 18.69 % (p > 0.05). Under different land use types, the relative abundance of four bacterial phyla and two fungal phylum were > 80 % and 75 %, respectively. The Actinobacteria relative abundance in natural grassland and natural shrubland was higher than that in CK. The Shannon index, Chao index and OTUs of soil fungal and bacterial communities under CK were significantly lower than that of other land use types, except for artificial grassland (p < 0.05). The microbial communities transited from oligotrophic to copiotrophic groups according to the results of redundancy analysis (RDA), and the cumulative loads of two axes of RDA in bacterial and fungal communities approached 89.90 % and 88.19 %. The variation partitioning analysis showed that Ca and Cs exhibited large path coefficients in explaining the changes in soil microbial communities. And the microbial communities were mediated through change in labile organic C according to structural equation models, indicating that the structures and compositions of microbial communities were mainly under the control of labile SOC content after vegetation restoration. These results are referentially valuable for comprehending how to apply labile SOC in predicting variations of microbial communities and improving predictive ecosystem models for early-warning indicators of soil degradation.

Soil degradation and Cu, Cr, Ni, Pb and Zn contamination in dumpsites of humid and semiarid tropical regions in northeastern Brazil.

We investigated soil characteristics and heavy metal content changes in 12 inactive dumpsites in humid and semiarid tropical climates in Northeast Brazil. The metals Cu, Cr, Ni, Pb and Zn in soil samples were determined by atomic absorption spectrophotometry. Other parameters measured include pH, electric conductivity, soil texture, soil organic carbon, total porosity and available P. The soil contents of sand, clay, soil organic carbon, available P and heavy metals, and soil bulk density, total porosity and pH were efficient indicators of soil degradation. We found no influence of current use, soil class or climate on the soil response. The mean concentrations of heavy metals in the dumpsite soils followed the order Zn (49.96mgkg-1) > Cu (38.48mgkg-1) > Pb (24.64mgkg-1) > Cr (21.94mgkg-1) > Ni (7.77mgkg-1). They were 6- to 36-fold higher than the background values for the region and were above the Brazilian guideline values for metals. The four dumpsite soils that showed simultaneous contamination with two or more heavy metals were located in the semiarid region. This challenges the assumption that soil impacts in the semiarid region are minimal due to lower leaching and high evaporation. Soil changes increase with time under activity, size and decommission time of the dumpsite. These data are important for local authorities to establish more effective targeting policies for closure of dumps and control of the spread of contaminants in areas impacted by the disposal of municipal waste.

Microbial biomass and earthworms as indicators of soil quality under contrasting management practices in small-scale dairy systems

Objetive: To determine soil quality under two contrasting agricultural management practices, based on microbial biomass and earthworm density, as compared to untilled control soils in two seasons (dry and wet), in different production units of small-scale milk production systems. Methodology: The work was conducted in ten production units in the municipality of Aculco, Estado de México, Mexico. We analyzed physical, chemical, and biological soil indicators (microbial biomass and earthworm density). We conducted an ANOVA with a 3 x 2 factorial arrangement (three systems [maize, grassland, and control] and two seasons [dry and wet]). Results: Values for all quality indicators in maize-cultivated soils were low, but increased in the wet season. Parameters in pasture-cultivated soils were similar to control soils. Implications: These results determine the conditions of the soils used in milk production systems. Conclusions: Some of the parameters assessed can be used as indicators of soil degradation and to strengthen other indicators which lead to an improved assessment of these systems’ sustainability

Determination of Carbon, Nitrogen and Phosphorus Stocks and Stoichiometry in Broadleaf Mixed Forest Soil and Litterfall: A case study in Oltu district, Erzurum

It is necessary to provide plant nutrients in soil at optimal levels for the sustainability of forest ecosystems. The soil stoichiometry of total carbon (C), total nitrogen (N) and total phosphorus (P) allow monitoring and assessment of ecosystem structures and variations in nutrient cycle. Studies on determination of C-N-P stoichiometry in forest ecosystems, however, are somewhat inadequate. This study aims to determine change of C-N-P stoichiometry depending on litterfall condition and soil depth in broadleaf mixed forest (Europen Hophornbeam - Syspirensis Oak) soil and the C-N-P stocks in soil. In this context, we were determined both C-N-P stoichiometry and C-N-P stock in soil and litterfall by conducting field studied at 10 different points in the Broad Leaf Mixed Forest of Erzurum-Oltu district. The results indicated that as the depth of the soil increased, the C-N ratio decreased, whereas the N-P and the C-P ratios increased. Positive correlations were observed between C-N in all soil depths, but negative correlations between C-P and N-P. The correlation coefficients between C and N (r0-10= 0.58, r10-20= 0.52 and r20-30= 0.44) and between C and P (r0-10= 0.64, r10-20= 0.54 and r20-30= 0.42) and between N and P (r0-10= 0.52, r10-20= 0.35 and r20-30= 0.36) decreased as soil depth increased. The mean scores of the C-N-P stocks were determined as 5.9, 1.3, and 0.2 ton ha-1 in litterfall and 157.68, 24.60, and 2.68 tons ha-1 in soil, respectively. It is important to rehabilitate degraded forests and minimize the negative effects of erosion in order to increase the amount of carbon captured in forest soils. In addition, the variable C: N: P stoichiometry in forest ecosystems; It can be considered as a leading indicator of soil degradation and drought and climate changes.

Linking the past, present and future scenarios of soil erosion modeling in a river basin

BACKGROUND AND OBJECTIVE: Soil erosion is considered one of the major indicators of soil degradation in our environment. Extensive soil erosion process leads to erosion of nutrients in the topsoil and decreases in fertility and hence productivity. Moreover, creeping erosion leads to landslides in the hilly regions of the study area that affects the socio-economics of the inhabitants. The current study focuses on the estimation of soil erosion rate for the year 2011 to 2019 and projection for the years 2021, 2023 and 2025.METHODS: In this study, the Revised Universal Soil Loss Equation is used for estimation of soil erosion in the study area for the year 2011 to 2019. Using Artificial Neural Network-based Cellular Automata simulation, the Land Use Land Cover is projected for the future years 2021, 2023 and 2025. Using the projected layer as one of the spatial variables and applying the same model, Soil Erosion based on Revised Universal soil loss equation is projected for a corresponding years.FINDINGS: For both cases of projection, simulated layers of 2019 (land use land cover and soil erosion) are correlated with the estimated layer of 2019 using actual variables and validated. The agreement and accuracy of the model used in the case land use are 0.92 and 96.21% for the year 2019. The coefficient of determination of the model for both simulations is also observed to be 0.875 and 0.838. The simulated future soil erosion rate ranges from minimum of 0 t/ha/y to maximum of 524.271 t/ha/y, 1160.212 t/ha/y and 783.135 t/ha/y in the year 2021, 2023 and 2025, respectively.CONCLUSION: The study has emphasized the use of artificial neural network-based Cellular automata model for simulation of land use and land cover and subsequently estimation of soil erosion rate. With the simulation of future soil erosion rate, the study describes the trend in the erosion rate from past to future, passing through present scenario. With the scarcity of data, the methodology is found to be accurate and reliable for the region under study.

Soil degradation influences soil bacterial and fungal community diversity in overgrazed alpine meadows of the Qinghai-Tibet Plateau

Over half of the alpine meadows in the Qinghai-Tibet Plateau (QTP) are degraded due to human activities. Soil degradation from overgrazing is the most direct cause of grassland degradation. It is thus important to synthesize the effects of multiple soil degradation indicators on the belowground biomass of plants and soil microorganisms in the degraded QTP. We studied the diversities and structures of soil bacterial and fungal communities using soil bacterial 16S rRNA and the fungal ITS gene under four degradation gradients, D1: lightly degraded, D2: moderately degraded, D3: highly degraded, and a non-degraded control site (CK). The bacterial Shannon diversity in D3 was significantly lower than that in D1 (p < 0.001), and the bacterial richness index in D3 was significantly lower than that in D1 (p < 0.001). There was no difference in soil fungal diversity among the different degradation levels; however, soil fungal richness decreased significantly from CK to D3. The phyla Actinobacteria, Acidobacteria and the genus Mortierella were differed significantly under the four degradation gradients. Plant litter mass and root C/N ratio were important factors associated with bacterial and fungal diversity and richness. These results indicated that alpine meadow degradation can lead to variations in both microbial diversity and the potential functioning of micro-organisms in the QTP.

Changes in the hydrophobic-hydrophilic properties of the organic matter of the chernozems of the Kamennaya Steppe

Soil samples and physical size-density fractions isolated from them (silt particle size less than 1 µm, light fraction (LF) with a density of less than 2 g/cm3 and a fraction of the residue) of ordinary chernozem were studied in three contrasting variants of the experimental fields of the Kamennaya Steppe agrolandscape of the Voronezh region: mowed steppe, long-term permanent bare fallow and permanent corn – the main differences of which are in tillage (cultivated and not cultivated lands) and in the supply/absence of plant residues and root secretions. The LF content changes in the series: “mowed steppe” &gt; “permanent corn” &gt; “permanent bare fallow”, which corresponds to the direction of changes in the total carbon content of the soil and a decrease in the value of the contact angle of wetting (CA) of the surface of the solid phase of the studied chernozems. The determination of the total C and N content revealed the change in the qualitative and quantitative composition of the size-density fractions for different land use cases. Chromatographic fractionation of alkaline extractions of humus substances (HS) of chernozem samples and size-density fractions revealed an increase in the degree of hydrophilicity of HS while simultaneously increasing the hydrophobicity of the solid phase surface and the carbon content in the soil. HS of LF of the “mowed steppe” turned out to be by 63% more hydrophilic than HS of LF of “permanent bare fallow” and by 47% more hydrophilic than HS of LF of “permanent corn”. While the hydrophilicity of the HS silt differed by 16 and 27%, respectively. The hydrophilicity of the HS of the original soil in the plot of the “mowed steppe” was by 41% higher than the hydrophilicity of the HS in the soil in the plot of “permanent bare fallow” and by 24% higher than in the soil of the plot of “permanent corn”. In addition, changes in the hydrophilicity of HS of size-density fractions are more intense than the HS of the soil, so the change in the degree of hydrophilicity of HS of size-density fractions is an indicator of soil degradation under different agrogenic pressue.

Assessment of earthworms as an indicator of soil degradation: A case‐study on loess soils

AbstractSoil degradation restricts the development of agriculture, and the degree of soil degradation is related to land use type, and efficient evaluation methods are helpful for the timely implementation of remedial measures to ensure soil sustainability. Earthworms are directly affected by the deterioration of soil properties during the degradation process. The feasibility of using earthworms to assess soil degradation, however, still needs to be verified. In our Loess Plateau study, earthworm biomass, density, and diversity (Shannon‐Wiener, species richness, and Pielou's evenness) were investigated under nine different land use types (natural woodland, shrubland and grassland; planted woodland, shrubland and grassland; and cropland, orchard, abandoned land) and we analyzed their relationships with soil degradation. Our results showed earthworm biomass, density, and diversity associated with a low degree of degradation were significantly higher than those associated with a high degree of degradation. Earthworms can comprehensively characterize the physicochemical properties and biological characteristics of soils under different land use types. Linear correlations showed a significant relationship between the soil degradation index and the earthworm indices, indicating that the latter could be used to effectively evaluate and represent the degree of degradation of soils on the Loess Plateau over a certain degradation range. Nevertheless, this evaluation method requires further validation before wider use.

The quantity and quality of soil organic matter and humic substances following dry-farming and subsequent restoration in an upland pasture

Soil recovery, particularly soil organic matter (SOM), after land-use changes is crucial for the maintenance of ecosystem functioning and sustainability. The objective of this study was to investigate the influence of wheat dry-farming and subsequent abandonment of dry-farming on the quantity and quality of SOM and humic substances (HS) in a semi-humid upland pasture ecosystem. Soil samples were collected at 0–15 and 15–30 cm depths from cultivated pastures under dry-farming, restored pastures after dry-farming abandonment and never-cultivated pastures as a reference site. The samples were analyzed for total organic C (TOC), chemically labile organic C (LOC) and non-labile C (NLC) fractions; and further fractionated into conventional fulvic acid (FA), humic acid (HA) and humin (HU) components. Land-use changes in pastures altered both labile C and highly recalcitrant C fractions, depending on soil sampling depth. Long-term dry-farming reduced soil TOC (33%), LOC (64%) and NLC (29%) fractions, while dry-farming abandonment resulted in an increase in soil TOC (18–35%), LOC (45–65%) and NLC (17–33%), depending on the age of cultivation abandonment. The quantity of both FA and HU fractions decreased (40–43%) following dry-farming in pasture soils but increased (17–81%) after dry-farming abandonment when compared with cultivated pasture soils. Nevertheless, neither dry-farming nor abandonment of dry-farming affected the HA fraction. Although dry-farming practices increased the HA/FA ratio, (FA + HA)/TOC ratio and E4/E6 ratio of HA, the abandonment of dry-farming reduced these qualitative parameters of soil HS. Dry-farming abandonment in native pastures caused HA structure to be become more aromatic and stable. This study indicated that land-use changes in primary pastures can affect not only the quantity, but also the quality of SOM and its major fractions. Changes in both quantity and quality of SOM and HS could be used as sensitive indicators of soil degradation and ecological restoration in semi-humid pastures.

ВЛИЯНИЕ ФЕРТИГАЦИИ НА ЗАСОЛЕНИЕ ПОЧВЫ

The salt state has a noticeable effect on the physical and water properties of the soil. That is why the distribution of its water-physical properties along the profile and in space in territories with different soil-climatic, hydrological and hydrochemical conditions should be individual. This is due, on the one hand, to the fact that water is directly involved in the processes of transfer and distribution of salts. On the other hand, the main parameters of the processes of moisture and salt transfer directly depend on the physical properties of the soil, which change under the influence of soluble salts. We have assessed the effect of fertigation on the physicochemical properties of the soil. Four fertigations with different salinity levels were tested. The influence of precipitation on soil desalinization through salt leaching was controlled by comparing changes in soil electrical conductivity during and after the growing season. To measure the studied characteristics, sensors of the 5TE type were used, which independently determine three indicators - the volumetric water content (VWC) by measuring the dielectric constant of the medium based on capacitive / frequency technology, temperature and EC. The stability of soil aggregates was also measured as an indicator of soil degradation. The electrical conductivity of the soil during pre-sowing (or after sowing) treatment was higher than at the end of the growing season. Experimental studies were carried out in the western part of the city of Prague on the campus of the Czech University of Life Sciences with geographic coordinates 50 ° 8'N and 14 ° 23'E. The altitude is 286 m, the average annual air temperature is 9.1 ° C, the amount of precipitation is 495 mm. The soil is loamy chernozem with a content of 22.0 ... 32.5% sand, 39.5 ... 54.0% silt and 22.0 ... 28.0% clay. The limiting field moisture capacity of the soil and the moisture content of stable wilting are 34 and 21%, respectively. It was found that fertigation in the short term is not harmful to the soil in the presence of sufficient precipitation