Variability Of Soil Properties Research Articles

Mapping soil property variability in oil palm (Elaeis guineensis jacq.) plantationsof Krishna basin of Andhra Pradesh through geospatial technologies

Sixty seven soil samples were collected from oil palm growing regions of NTR District of Andhra Pradesh and were analysed for different soil properties. The data was subjected to descriptive analysis to find out the variability and then to geostatistical analysis to design best fit models having minimal error for developing prediction maps. Highest variation was observed in exch. Mg and the lowest in pH. The mean values of soil pH, EC (dS/m), OC (g/kg), Olsen-P (mg/kg), NH4OAc-K (mg/kg), Exch. Ca (mg/kg), Exch. Mg (mg/kg), CaCl2-S (mg/kg) and HWB (mg/kg) were 7.32 ± 0.08, 0.25 ± 0.02, 0.87 ± 0.03, 101.47 ± 6.95, 566.14 ± 42.97, 4.72 ± 0.24, 2.46 ± 0.27, 60.86 ± 2.6 and 5.98 ± 0.25 respectively in the surface layer (0-20 cm) of the soil. Geostatistical analysis revealed wider spatial variability in surface soil properties and they had circular, spherical, stable and exponential best fit semi variogram models for evaluating dependency. The wide spatial variability of soil properties warrants site specific nutrient management for higher oil palm production. Nutrient distribution maps could be developed through kriging interpolation to interpolate the nutrient levels in unsampled areas.

Analysis of tunneling-induced ground movements in spatially variable soil under the influence of existing building

Tunnel construction invariably results in ground movement, which is significantly impacted by the spatial variability of soil properties and proximity of existing buildings. However, few studies have examined the coupled effect of these two factors on tunneling-induced ground movement. This study establishes a stochastic finite element model that incorporates both the spatial variability of soil properties and influence of existing buildings. The model is used to perform a series of random analyses, studying the effects of story number, eccentricity, and building length on ground settlements induced by tunneling in soil with spatial variability of Young’s modulus. A probabilistic analysis is conducted to investigate the uncertainties associated with ground settlements. The results of the analysis indicate that the presence of the building enhances the influence of the spatial variability of soil, leading to an increase in the dispersion of ground settlement. For high-rise buildings, the reduction of building eccentricity and length will increase the uncertainty of surface settlement. Neglecting the influence of the existing building in the probability analysis of surface settlement can result in an overestimation of the failure probability.

Multi-property digital soil mapping at 30-m spatial resolution down to 1 m using extreme gradient boosting tree model and environmental covariates

Information on the variability of soil properties including clay, calcium carbonate equivalent (CCE) and acidity (pH) in space and depth play major role in sustainable agricultural development but scarce in many regions in the world, specifically in developing countries. Digital soil mapping technique has shown strong success in the prediction of soil properties both in space and depth from their relationship with environmental covariates. The aim of the study was to digitally map soil properties including clay, CCE and pH at multiple depths and identify the dominant factors controlling their variability using Minadoab region of Iran as a case study area due to its significance for agricultural production and economic development in the country. A total of 104 soil profiles were randomly selected and described in field during 15–30 July 2017, and 386 samples were collected from each genetic horizon with variable depths. A continuous spline function was fitted to the horizon data and properties were estimated at five standardized depths following GlobalSoilMap project. The soil layers were then grouped into three classes: i) H1: top (0–5 cm); ii) H2–H4: middle (5–15, 15–30 and 30–60 cm); and iii) H5: bottom (60–100 cm) for easy interpretation. A total of 17 static environmental covariates were derived from terrain-related attributes. Additionally, matching with the soil sampling date, a total of eight band ratios in addition to six individual bands were derived from Landsat-8 OLI (Product ID: LC08_L1TP_168034_20170721_20170728_01_T1) for the study area. Finally, all covariates were categorized in nine groups representing various factors controlling soil variations. The digital maps associated with uncertainties were prepared using extreme gradient boosting (XGBoost) Tree model and bootstrapping method, respectively. Overall, the highest accuracy using XGBoost Tree model was found for CCE (R2 = 0.73, on average), followed by pH (R2 = 0.72, on average) and clay (R2 = 0.70, on average). The highest amount of clay was observed for the bottom layer, followed by middle and top layers across the study area. H1 to H3 layers were subjected to tillage operations over the time and may have contributed to the redistribution of clays. A similar trend was also observed for CCE and pH as the location of the study area is underlain by massive limestone. The uncertainties helped quantify over- and under-estimation of the predictions and the factors with the highest variable importance was identified as the dominant factor. The information generated for the study area provides soil variability information that is critical for developing management strategies for sustainable production in the area.

Random analysis method for nonlinear interaction between shield tunnel and spatially variable soil

The spatial variability of soil properties is likely to have a remarkable influence on the longitudinal responses of shield tunnels. This paper proposes a one-dimensional random analysis method (RAM) for the interaction between the shield tunnel with circumferential joints and the spatially variable soil with nonlinear elastoplastic behaviors. A deterministic short beam-spring model with longitudinal variation in the initial subgrade reaction coefficient and the ultimate soil resistance is developed and solved by the finite difference method. The random field of the soil properties discretized by the Karhunen-Loeve expansion method is used to establish the RAM. A hypothetical example is further presented to demonstrate the applicability of the proposed method. The results imply that the soil nonlinearity may lead to a negative effect on the reliability control of the tunnel structure and should be considered to obtain more reasonable probabilistic evaluations of the tunnel deformations. The increasing joint rotational stiffness or shearing stiffness results in the lower variabilities of the maximum tunnel settlement, and reduces the probabilities of the maximum joint opening or joint dislocation exceeding the allowable value, respectively.

Soil fertility status, productivity challenges, and solutions in rice farming landscapes of Azerbaijan

Rice, a fundamental staple globally, plays a pivotal role in addressing food security and nutrition. This study explores the intricate interplay between soil characteristics, productivity challenges, and solutions in Azerbaijan's rice farming landscapes, acknowledging the agricultural importance of rice and its contribution to human nutrition. This study aims to assess the physical and chemical properties of soil samples from Azerbaijan's rice cultivation areas, with a focus on nutrient content and the identification of elements limiting productivity and plant nutrition. By synthesizing these perspectives, the study enriches the understanding of the complex relationship between soil fertility class and rice productivity, offering insights for sustainable rice farming. Soil samples were collected from representative rice fields across Azerbaijan and analyzed for various parameters, including soil texture, pH, electrical conductivity, organic matter, and nutrient content. The soil sampling and preparation process maintained the integrity of collected samples, providing a reliable basis for scientific analysis. The results reveal diverse soil properties, with clayey texture prevailing. Soil acidity, salinity, and nutrient deficiencies pose challenges, emphasizing the need for corrective measures. The majority of soils exhibit unsuitable pH levels and elevated sodium content, necessitating interventions such as soil acidification and sodicity remediation. Soil salinity issues highlight the importance of drainage and leaching practices. Low organic matter and nutrient deficiencies, particularly zinc and manganese, underscore the need for targeted interventions, including foliar applications. Overall, Azerbaijan's rice-cultivated areas face challenges related to soil fertility, salinity, and nutrient deficiencies, impacting productivity. Corrective measures, such as soil reclamation, proper fertilization, and foliar applications, are crucial for enhancing crop yields. The study contributes valuable insights for local practices and the broader global pursuit of sustainable rice farming, emphasizing the importance of tailored strategies in addressing specific regional challenges.

Delineation of Productive Zones in Eastern China Based on Multiple Soil Properties

Accurate soil management has long been the focus of research in agroecology. Crop productivity can be enhanced while reducing environmental threats from excessive fertilization by fully comprehending the spatial variability of soil properties and delineating management zones (MZs). A field investigation was carried out at experimental sites outside Hefei City’s administrative districts in China to study the spatial variability of soil properties and the delineation of MZs. A total of 9601 soil samples were collected in the study area. A variety of soil properties were analyzed, including the pH, organic matter, total nitrogen, alkali-hydrolyzable nitrogen, available phosphorus, available potassium, slowly released potassium, available sulfur, available boron, available copper, available zinc, available iron, and available manganese. The coefficient of variation for various soil properties exhibited a wide range, spanning from 12.2% to 100.5%. The geostatistical results show that most soil properties have moderate to strong spatial autocorrelation, and the ordinary kriging method is used to map the distribution of soil properties. The principal component analysis method was used to reduce the dimension of 13 soil properties to 4 principal components, and the fuzzy c-means clustering method was used to delineate MZs. The calculation results of the fuzzy performance index and normalized classification entropy show that the optimum number of MZs is five. In the study area, the western part exhibits the highest soil fertility, primarily attributed to its elevated organic matter content. Additionally, organic matter emerges as a key factor influencing sustainable agricultural production in this region. These results form the basis for soil managing areas outside the administrative districts of Hefei City.

Probabilistic analysis of ground settlement induced by tunnel excavation in multilayered soil considering spatial variability

Accurately evaluating and predicting the ground settlement during tunnel excavation are crucial for ensuring the stability of tunnel structures. However, the traditional methods always use representative (or average) values for deterministic analysis and rarely consider the spatial variability of soil properties. In this study, a probabilistic analysis of ground settlement under uncertain soil properties was performed based on random fields combined with the finite-difference method. The random fields of Young’s modulus and friction angle of multilayered soils were generated based on the Cholesky decomposition in a manner consistent with a specified numerical mesh. The effects of spatial variability and cross-correlation in random fields on the ground settlement were investigated in detail. The results demonstrate that spatially variable soils significantly influence the probability of failure, magnitude, and longitudinal profile of ground settlement in the vertical direction. It can be found that the allowable ground settlement of the limit state function also dominated the degree of the vertical scale of fluctuation on stability. Neglecting the cross-correlation between the two random fields results in an overestimation of the probability of failure compared with an independent analysis. Subsequently, the failure mechanisms of ground settlement in spatially random soils were discussed.

Trait–micro‐environment relationships of forest herb communities across Europe

AbstractAimThe microclimate and light conditions on the forest floor are strongly modified by tree canopies. Therefore, we need to better consider the micro‐environment when quantifying trait–environment relationships for forest understorey plants. Here, we quantify relationships between micro‐environmental conditions and plant functional traits at the community level, including intraspecific trait variation, and their relationship with microclimate air temperature, light and soil properties.LocationDeciduous temperate forests across Europe.Time period2018.Major taxa studiedHerbaceous vegetation.MethodsWe sampled 225 plots across 15 regions along four complementary gradients capturing both macro‐ and microclimatic conditions including latitude, elevation, forest management and distance to forest edges. We related the community‐weighted mean of five plant functional traits (plant height, specific leaf area [SLA], plant carbon [C], plant nitrogen [N] and plant C:N ratio) across 150 vascular plant species to variation in local microclimate air temperature, light and soil properties. We tested the effect of accounting for intraspecific variation in trait–environment relationships and performed variation partitioning to identify major drivers of trait variation.ResultsMicroclimate temperature, light availability and soil properties were all important predictors of community‐weighted mean functional traits. When light availability and variation in temperature were higher, the herb community often consisted of taller plants with a higher C:N ratio. In more productive environments (e.g. with high soil nitrogen availability), the community was dominated by individuals with resource‐acquisitive traits: high SLA and N but low C:N. Including intraspecific trait variation increased the strength of the trait–micro‐environment relationship, and increased the importance of light availability.Main conclusionsThe trait–environment relationships were much stronger when the micro‐environment and intraspecific trait variation were considered. By locally steering light availability and temperature, forest managers can potentially impact the functional signature of the forest herb‐layer community.

Investigation of topographic amplification on ground motions considering spatial variability of soil properties

Investigation of topographic amplification on ground motions considering spatial variability of soil properties

Multinational prediction of soil organic carbon and texture via proximal sensors

AbstractNovel technologies help to monitor the environmental impact of human activities, but tests involving datasets from several countries, encompassing a large variability of soil properties, are still scarce. This study utilized proximal sensors to predict soil organic carbon (OC) and soil texture of samples from Brazil, France, India, Mozambique, and United States. A total of 1749 samples were analyzed by portable X‐ray fluorescence (pXRF) spectrometry and visible near‐infrared diffuse reflectance spectroscopy. Sand (R2 = 0.89), silt (0.87), and clay (0.84) predictions were very accurate, despite contrasting climates, soil parent materials, and weathering degrees. Soil OC predictions were similarly successful (0.74) using samples from five countries. pXRF was the optimal sensor for soil texture predictions. The addition of international data may improve local models. Proximal soil sensing can be successfully used with a multinational soil database offering a clean, rapid, and accurate alternative to estimate soil texture and OC with international datasets.

Mechanism of seismic liquefaction for heterogeneous soil

In addition to inducing uncertainty in the predicted response, natural spatial variability of soil properties affects the mechanical response of geotechnical structures. When a failure surface is involved in the response, this surface can deviate from its theoretical location to pass through weaker zones of material. For the case of seismically induced soil liquefaction, it has been found that a larger amount of excess pore water pressure is generated in a soil exhibiting small-scale variability of its properties than in the corresponding uniform soil having geomechanical properties equal to the average properties of the heterogeneous soil. An explanation for this important phenomenon is provided in this paper based on the results of centrifuge experiments and numerical simulations of heterogeneous and homogeneous saturated soil deposits subjected to seismic loads. It is demonstrated, based on a detailed analysis of the results, that partial drainage during the earthquake, consisting of pore water inflow from loose soil zones that liquefy first toward surrounding dense areas, may trigger softening of dilative soils. The water inflow effects in terms of volumetric strains leading to reduced cyclic resistance of dense sands are compared with results of specially designed cyclic triaxial tests reported by other researchers.

Spatial variation in soil aggregate stability and erodibility at different slope positions in four hilly regions of northeast China

The spatial heterogeneity of erosion can affect soil properties in agricultural areas, which can in turn alter the soil aggregate stability and erodibility. However, it remains elusive how aggregate stability and soil erodibility vary at different positions in the Mollisol region of northeast China, and how soil properties drive these variations. This study selected different slope positions across a latitudinal gradient in four hilly regions from cold temperate (Jiusan, JS; Keshan, KS) to middle temperate (Hailun, HL; Binxian, BX) areas in northeast China. The spatial variations of soil properties, geometric mean diameter (GMD), mean weight diameter (MWD), soil erodibility (K), and soil structural stability index (SSI) were calculated at topsoils (0–20 cm) and subsoils (20–40 cm). Total nitrogen (TN) and soil organic carbon (SOC) decreased with increasing latitudes, and gradually declined and finally rose with decreasing slope positions. MWD, GMD, and SSI were the highest in JS, and first obviously decreased from the top position to lower position, and then increased at the bottom position. The K followed an order of BX > HL > KS > JS, and decreased in the bottom position compared with that in the middle and lower positions across the four regions, which could be ascribed to the new aggregate formation promoted by fine soil particle deposition at the slope bottom. Redundancy analysis and variance decomposition analysis indicated that SOC, TN, and bulk density had higher vector values, and region (interpretation rate = 57.97 %) had the greatest influence on aggregate stability and soil erodibility. Available potassium (AK), saturated conductivity (KS), SOC, TN and soil texture were the main factors driving the variation of MWD and K. These findings highlight the spatial variations in soil aggregate stability and erodibility in Mollisol regions, providing a scientific basis for soil restoration in eroded farmland.

Efficient slope reliability analysis under soil spatial variability using maximum entropy distribution with fractional moments

Spatial variability of soil properties imposes a challenge for practical analysis and design in geotechnical engineering. The latter is particularly true for slope stability assessment, where the effects of uncertainty are synthesized in the so-called probability of failure. This probability quantifies the reliability of a slope and its numerical calculation is usually quite involved from a numerical viewpoint. In view of this issue, this paper proposes an approach for failure probability assessment based on Latinized partially stratified sampling and maximum entropy distribution with fractional moments. The spatial variability of geotechnical properties is represented by means of random fields and the Karhunen-Loève expansion. Then, failure probabilities are estimated employing maximum entropy distribution with fractional moments. The application of the proposed approach is examined with two examples: a case study of an undrained slope and a case study of a slope with cross-correlated random fields of strength parameters under a drained slope. The results show that the proposed approach has excellent accuracy and high efficiency, and it can be applied straightforwardly to similar geotechnical engineering problems.

Stability of soil bacteria in undisturbed soil and continuous maize cultivation in Northern Thailand.

Rotational shifting cultivation (RSC) in Northern Thailand serves the dual purpose of ensuring food security and meeting economic goals through maize cultivation. However, the research question remains: Does the dynamics of soil bacterial communities differ between maize monoculture and RSC fields with continuous fallow throughout the season? Therefore, the objective of this study was to investigate and compare the variation of soil bacterial communities in maize monoculture and fallow RSC fields. A continuous 5-year fallow field (undisturbed soil; CF-5Y) and a continuous 5-year maize cultivation field (M-5Y) in Mae Chaem District, Chiang Mai Province, Northern Thailand, were selected due to their similarities in microclimate, topography, and the 5-year duration of different field activities. Over the span of a year, we collected soil samples from the surface layer (0-2 cm depth) at both sites. These collections occurred at 3-month intervals, starting from March 2022 (summer season) and followed by June (rainy season), September (rainy season), December (winter season), and March 2023 (summer season). Soil bacterial diversity and composition were analyzed using 16S rRNA gene-based metagenomic analysis. The results found that undisturbed soil over a 5-year period exhibited more stability in the richness and diversity of bacteria across seasons compared with M-5Y. Notably, fertilizer application and tillage practices in M-5Y can enhance both the diversity and richness of soil bacteria. In terms of bacterial abundance, Proteobacteria prevailed in CF-5Y, while Actinobacteria dominated in M-5Y. At the genus level, Candidatus Udaeobacter dominated during the summer and winter seasons in both CF-5Y and M-5Y sites. Interestingly, during the rainy season, the dominant genus shifted to Bacillus in both CF-5Y and M-5Y fields. The soil bacterial community in M-5Y was strongly influenced by organic matter (OM) and organic carbon (OC). In contrast, in CF-5Y, there was no correlation between soil properties and the soil bacterial community, likely due to the lower variation in soil properties across seasons. β-Glucosidase was the dominant enzyme in both CF-5Y and M-5Y sites, and it showed a positive correlation with OM and OC. Further studies should continue to investigate soil bacteria dynamics, considering the changes in land management practices.

Effects of microtopography on within-field spatial variation of inherent soil properties in Andosols of Tokachi district, Hokkaido

ABSTRACT In large-scale upland cropping systems, understanding the magnitude of soil property variations and mapping the distribution are essential to improve soil nutrient management. The Tokachi district of Hokkaido has large-scale upland fields, and the soils are dominated by Andosols that inherently have characteristic clay minerals and high soil organic carbon content. In the region, microtopography is known to exist that can affect soil formation and within-field variation of the inherent soil properties. However, limited information exists about the relationship between microtopography and the spatial variation of inherent soil properties that are important for nutrient dynamics. Therefore, this study aimed to assess the effect of microtopography on the within-field variation of inherent soil properties in Andosols of Tokachi district, Hokkaido. Within a 6.6-ha field with an elevation difference of 3.2 m, four soil profiles were surveyed at different topographical positions, and 530 surface soil samples were collected at 12-m intervals. Samples were analyzed for total carbon (TC), acid-oxalate extractable Al, Fe, and Si (Alo, Feo, and Sio), pyrophosphate extractable Al and Fe (Alp and Fep), cation exchange capacity (CEC), and phosphate absorption coefficient (PAC). Geostatistical analysis was applied to understand the spatial structure of the surface soil properties. All soil profiles were dominated by volcanic parent materials, and they were classified into different types of Andosols. An exceptional variation of inherent soil properties was found in the surface soil, with TC content ranging from 35.2 to 124 g kg−1 and CEC from 20.3 to 55.7 cmolc kg−1. Geostatistical analysis showed that TC content varied over a large distance (range: 226 m) while allophane content varied at a shorter distance (range: 118 m). Our findings revealed that microtopography affected the soil water dynamics and erosion of the surface soil particles which caused the variation of TC, CEC, and allophane. Further studies must be conducted to understand the effects of the variation of these inherent soil properties on soil nutrient availability and crop productivity.

Variation and dynamics of soil properties of ordinary chernozem in the Saratov region

Based on data from an agrochemical survey using GIS technologies at test site No. 2 in 2009-2016 within the framework of the general scheme of soil-ecological monitoring of the Saratov region, an assessment was made of the dynamics and spatial variation of soil properties of ordinary chernozem, depending on the steepness and exposure of the slope. Soil and agrochemical characteristics in conditions of a pronounced relief demonstrate a certain dependence on the location and are very variable over time. Soil sampling on an area of more than 2000 hectares using navigation equipment made it possible to obtain agrochemical cartograms in GIS and analyze them using zonal statistics, taking into account a digital elevation model. The spatial variability of soil properties is often lower in leveled areas or short transition sections of the slope, while the maximum variability is noted on steeper slopes. The highest values of indicators are typical for flat watershed surfaces, which are the most fertile, however, the closest relationship between humus and other agrochemical indicators was noted just on steeper slopes. The variability of fertility indicators on differently directed slopes was within 28–36 % for P2O5, 20 % for K2O, and 4–6 % for pH. The greatest differences in the variability of the polar slopes along the survey tours are noted for the content of humus in the soil. In 2009, the coefficient of variation was 19 and 30 %, and in 2016, 11 and 24 % on the slope of the northern and southern exposure, respectively. A retrospective analysis showed that the highest rates of decline were noted for the content of humus in the soil and the reaction of the environment on gently sloping slopes (by 2 and 1.5 times, respectively) relative to the average change in the massif. For mobile forms of phosphorus and potassium, the maximum decrease was noted on gentle slopes.

Effects of different soil and water conservation measures on plant diversity and productivity in Loess Plateau

Many soil and water conservation measures (SWCM) have been implemented in the Loess Plateau of China, and they have an impact on ecosystems all levels and involve complicated mechanisms. Previously, studies typically focused on a single factor's effect on diversity or productivity. With this background, the current investigation embarked on an extensive study, with vegetation survey conducted in the no measure plots (NM), vegetation measure plots (VM) and engineering measure plots (EM) in the Loess Plateau of China. We used structural equation models (SEM) to explain the mechanism by which SWCM affects plant productivity and diversity. VM have direct effects on plant diversity, and EM have direct effects on soil properties and community structure. The two measures also had indirect effects on plant functional traits and community structure. The results show that the changes in plant functional traits and community structure by SWCM decreased plant diversity, whereas the increase of productivity was primarily dominated by improvements in community structure, and we conclude that variability in plant diversity and productivity across different measures on the Loess Plateau was primarily due to the responses of different plants to variable soil properties and the community responses. It was also emphasized that vegetation measures were beneficial to the increase of biomass per plant, while engineering measures were more beneficial to the growth of dominant species. These findings provide a theoretical foundation for vegetation management and restoration after the application of different SWCM.

Distinct dynamics of plant- and microbial-derived soil organic matter in relation to varying climate and soil properties in temperate agroecosystems

Global environmental change can substantively alter soil carbon storage and dynamics in agroecosystems. However, investigations of soil organic matter (OM) composition associated with various environmental factors are still limited, and this hinders the understanding of soil carbon biogeochemistry in agricultural settings. Soil samples were collected at two times (time 0 and 8 or 10 years) from 10 agricultural sites across Canada and New Zealand with varying soil properties (i.e., soil texture, pH) and climates (MAT, mean annual temperature; MAP, mean annual precipitation). The soils were analyzed for organic carbon, nitrogen and soil OM composition using molecular-level techniques that included targeted compound-specific and solid-state 13C nuclear magnetic resonance analyses. Soil carbon contents were similar over time and were not correlated with environmental factors. Molecular-level characterization of soils found that the preservation and degradation of specific soil OM components differed. Simple sugars and microbial-derived compounds (i.e., fungi-derived ergosterol and microbial-derived lipids) persist less with time in soils compared to other OM components. However, the increased cutin- and suberin-derived compounds at most sites and similar alkyl carbon contents with time suggested that cutin- and suberin-derived compounds were longer-lived compared to other soil OM compounds. Correlation analyses indicated that temporal differences in fungal-derived ergosterol were positively correlated with silt content (r = 0.78). An inverse correlation was observed between lignin degradation and silt content (r = −0.75). Cutin- and suberin-derived compounds were negatively correlated with MAT (r = −0.69); when the analysis was restricted to only Canadian sites, cutin- and suberin-derived compounds and their degradation were correlated with MAP and MAT (climate variables). Further, partial correlation analysis revealed that the correlations between soil texture and the temporal shifts in soil OM composition were indirectly regulated by MAP but not MAT. Overall, distinct environmental constraints were observed for specific OM components in agroecosystems, suggesting that the preservation mechanisms are not uniform across a wide range of soils under different climates and soil properties.

Infiltration Measurements during Dry Conditions in an Urban Park in Ljubljana, Slovenia

A thorough understanding of the hydrologic mechanisms that control the movement of water through the soil is essential for developing effective stormwater management strategies. Infiltration is critical for determining the amount of water entering the soil and controlling surface runoff. Spatial and temporal variations in soil properties strongly affect infiltration rates, which underscores the importance of evaluating field-specific values for hydraulic conductivity, which are also highly dependent on the chosen measurement and evaluation methods. The objective of this study is to determine and compare soil hydraulic conductivity under dry conditions using two field measurement techniques, namely the double-ring infiltrometer (DRI) and the mini-disk infiltrometer (MDI). The results demonstrate the importance of performing multiple replicates of infiltration tests, especially during the dry season, as the initial dry surface caused deviations in hydraulic conductivity estimates for both methods used (DRI and MDI). Significant spatial variability was observed within the radius of the test replicates over short distances (<1 m). In addition, experimental infiltration curves for a selected site were used to evaluate and compare soil hydraulic parameters through infiltration modeling. In general, the Philip, Green-Ampt, and Smith-Parlange theoretical models showed a better fit to the experimental DRI data than the semi-empirical Horton model.

Increased soil penetration resistance drives degrees of hemeroby in vegetation of urban parks

Urban parks provide a variety of ecosystem services, and a range of management practices promote their maximisation. The species diversity of plant communities is a factor in the maintenance of ecosystem services. The reconstruction of parks is one of the management practices, but the environmental impact of such activities is not clear. The reconstruction of parks affects vegetation and soil cover, and the interconnection of these components of the urban park ecosystem has not been studied before. The study revealed the features of variability of physical properties of soil and vegetation cover and identified their interconnection in the conditions of urban park reconstruction. The study was conducted in the recreational area of the Botanical Garden of Oles Honchar Dnipro National University (Ukraine). The park was studied in the area where reconstruction activities had previously been carried out. During the reconstruction process, walkways were restored, shrubs were removed, old or damaged trees were excavated, and tree crowns were trimmed. Young trees were planted in place of the removed old trees. Old outbuildings that significantly impaired the aesthetic impression of the park were also dismantled. The reconstruction involved transport and construction equipment. Samples were collected within transects, two of which were located in the reconstruction area, and two other transects were located in a similar area of the park where no reconstruction was carried out. The plant community was found to consist of 65 species. The mean level of alpha diversity was 11.5 species and beta diversity was 5.7. The alpha diversity was higher in the reconstructed park. The principal component analysis of the variability of soil properties extracted four principal components with eigenvalues greater than one. The principal components 1 and 3 reflect the variability of soil properties induced by the park's reconstruction, while the principal components 2 and 4 reflect variability that may be caused by other anthropogenic factors unrelated to the park's reconstruction, or may be due to natural variability of the soil cover. The principal component 1 indicates a uniform increase in the soil penetration resistance as a result of the application of technological processes during the reconstruction. This effect may be the result of the direct technological impact of the mechanisms employed and the large number of employees involved in the park's reconstruction. The condition of the crown space of the park plantation can explain the variation in soil penetration resistance. The increase in the height and projective cover of the grass vegetation is due to a decrease in the closure of the stand crowns, but the effect of such coordinated stand and grass dynamics on soil penetration resistance is observed only at a depth of 25–55 cm. This effect can be explained by the influence of the plant root system on the physical state of the soil. The root system of herbaceous plants is capable of loosening the soil and reducing its soil penetration resistance. The reconstruction of the park led to an increase in the hemeroby of the plant community. The criterion for the success of the reconstruction may be an increase in the attractiveness of the park for visitors without the risk of increasing hemeroby. The trend of increasing hemeroby clearly coincides with the direction of transformation of soil conditions, which are indicated by the principal component 1. The increase in the soil penetration resistance is a driver of the growth of vegetation cover hemeroby. The physical environment of the soil cover acts as an important environmental filter that affects the structure of the vegetation cover and the species composition of plant species complexes.