Search Results (27)

Livestock production systems can negatively affect soil structure, resulting in negative changes in physical–hydraulic properties, compromising soil functioning and productivity. This research aimed to evaluate the effects of rotational silvopastoral systems on soil physical–hydraulic functioning in their second year of implementation. The study was performed under Oxisol soil with a loamy sand texture in Southeast Brazil. We considered four grazing systems: an intensive silvopastoral system with Panicum maximum in consortium with Leucaena leucocephala (ISPS + L), an intensive silvopastoral system with Panicum maximum in consortium with Tithonia diversifolia (ISPS + T), an silvopastoral system with Panicum maximum (SPS) with tree row (TRs), and open pasture under a rotational grazing system with Panicum maximum (OP). The treatments ISPS + L, ISPS + T, and SPS had tree rows (TRs) every 20 m composed of Khaya ivorenses, Leucaena leucocephala, Eucalyptus urograndis, Acacia mangium, and Gliricidia sepium. Nine physical–hydraulic indicators were evaluated in the first 0.40 m of depth: bulk density (Bd), total porosity (TP), macroporosity (MaP), microporosity (MiP), field capacity (FC), permanent wilting point (PWP), available water content (AWC), total soil aeration capacity (ACt), and S-index. The soil physical–hydraulic properties were sensitive to the effects of the livestock systems. The use of silvopastoral systems in consortium with grass (ISPS + L and ISPS + T) allowed for better soil water retention, resulting in higher FC and AWC than the OP, SPS, and TR. The indicators Bd, ACt, MaP, FC, MiP, and S-index presented the greatest variance; however, FC, ACt, MaP, and MiP enabled the greatest differentiation among systems. Therefore, these properties are important in studies on soil physical quality since they provide information about the soil porous status and its ability to retain water and exchange soil air and gases. Therefore, enhancing the physical–hydraulic attributes of the soil in silvopastoral systems with shrub species is crucial for ensuring long-term productive sustainability and strengthening environmental resilience against future climate challenges. Full article

Agricultural drought poses a severe threat to food security in the North China Plain, necessitating accurate and timely monitoring approaches. This study presents a novel drought assessment framework that innovatively integrates multiple remote sensing indices through an optimized random forest algorithm, achieving unprecedented accuracy in regional drought monitoring. The framework introduces three key innovations: (1) a systematic integration of six drought-related factors including vegetation condition index (VCI), temperature condition index (TCI), precipitation condition index (PCI), land cover type (LC), aspect (ASPECT), and available water capacity (AWC); (2) an optimized random forest algorithm configuration with 100 decision trees and enhanced feature extraction capability; and (3) a robust triple-validation strategy combining standardized precipitation evapotranspiration index (SPEI), comprehensive meteorological drought index (CI), and soil moisture verification. The framework demonstrates exceptional performance with R² values consistently above 0.80 for monthly assessments, reaching 0.86 during autumn and 0.73 during summer seasons. Particularly, it achieves 87% accuracy in mild drought (−1.0 < SPEI ≤ −0.5) and 85% in moderate drought (−1.5 < SPEI ≤ −1.0) detection. The 20-year (2000–2019) spatiotemporal analysis reveals that moderate drought events dominated the region (23.7% of total occurrences), with significant intensification during the 2010–2012 and 2014–2016 periods. Summer drought frequency peaked at 12–15 months in south-central Shandong (37°N, 117°E) and eastern Henan (34°N, 114°E). The framework’s high spatial resolution (1 km) and comprehensive validation protocol establish a reliable foundation for agricultural drought monitoring and water resource management, offering a transferable methodology for regional drought assessment worldwide. Full article

Water availability, a vital factor in agriculture, is being threatened by shortages caused by droughts, desertification, and climate change. In this context, hydrogels, polymers with high water absorption and retention capacity, emerge as key solutions to improve water use efficiency in irrigation. This study investigated the effect of a natural superabsorbent hydrogel (TG) at different concentrations (0.3%, 0.5%, 0.8%, and 1.0%) on the water retention capacity in three coarse-textured soils and one medium-textured soil. Results are compared to an existing commercial polymer (COM). The evaluation shows that both polymers increase the values of the water retention curve; however, higher values were observed with TG. The addition of both hydrogels was compared in the increase of the available water capacity (AWC). For sand soil, the TG obtained a statistically significant difference of a 26% greater AWC when compared to the COM superabsorbent. Soils with a higher percentage of sand tend to obtain a greater improvement in the AWC. There is a proportional relationship of the increase in the AWC when increasing hydrogel concentration ($R^2$ = 0.74). Sand soil with a concentration of 0.5% of the TG showed 17.8% of the AWC, while for a concentration of 1.0% of this hydrogel, a value of 35.8% of the AWC was obtained. However, in soils with higher clay content, such as silt loam, the effect was smaller. Finally, the time required to reach a permanent wilting point (PWP) was compared. The loam sand soil increased the time to reach the PWP by more than three times using the TG or COM when compared to the same soil without any hydrogel concentration. In conclusion, the TG significantly improves water retention in coarse and medium-textured soils, making it a promising solution for improving water efficiency in agriculture, especially in drought-affected regions. However, additional field studies are needed to evaluate its long-term durability and environmental compatibility, ensuring its applicability under real agricultural conditions. Full article

In recent years, products containing humic acids have been increasingly used in agriculture to improve soil parameters. Quantifying their impact on soil quality is, therefore, of key importance. This study seeks to evaluate the impact of the commercial humic acid product (HA) on the hydrophysical parameters of sandy and clayey soils sampled from different sites in Slovakia. Specifically, the study hypothesizes that humic amendment will enhance particle density (ρ_s), dry bulk density (ρ_d), porosity (Φ), saturated hydraulic conductivity (K_s), soil water repellency (SWR), and water retention capacity in sandy and clayey soils. The results of the laboratory measurements were analyzed using NCSS statistical software at a statistical significance of p < 0.05. In sandy soil, there was a statistically significant decrease in ρ_d and K_s and an increase in Φ and a contact angle (CA) after the application of 1 g/100 cm³ HA. At a dose of 6 g/100 cm³ HA, the values of ρ_s, ρ_d, and K_s decreased, and the Φ and CA values increased. In clayey soil, the K_s value significantly decreased by −35.5% only after the application of 6 g/100 cm³ HA. The addition of HA increased the full water capacity (FWC) and available water capacity (AWC) of clayey and sandy soils. The positive influence of HA on the studied soil parameters was experimentally confirmed, which can be beneficial, especially for their use in agricultural production. Full article

Sandy areas occupy a huge amount of land worldwide, but due to their characteristics, they are mostly low in fertility and low in organic matter. Sandy soils have coarse texture, high saturated hydraulic conductivity, low soil organic carbon, and poor aggregate stability and water retention capacity; therefore, it is necessary to add organic additives to them. The objective of this study was to assess the effect of particle size and application rate of biochar (BC) produced under different pyrolysis temperatures on the porosity P, available water content for plants AWC, saturated hydraulic conductivity Ks, and contact angle CA of sandy soil. The results show that an application of BC to sandy soil significantly increased AWC by 76–168%, CA by 252–489%, P by 6–11%, and significantly reduced Ks by 37–90%. Statistical analysis of the effect of three examined factors (BC application rate, particle size, and pyrolysis temperature) revealed that P, AWC, and Ks were affected by all three factors, while CA was affected only by BC application rate and particle size. The statistically significant interaction between the two factors was found for P (temperature × rate and size × rate), AWC (temperature × size), and Ks (size × rate). Statistically significant interaction among the three factors was not found for any hydrophysical parameter. The application of BC to amend sandy soils can be seen as a strategy to mitigate drought conditions and to reduce the amount of irrigation, saving water. Further investigations are needed with regard to the BC application under climate conditions with long hot and dry periods, which may promote soil water repellency. Full article

Soil water availability during the vine growth cycle can affect yield and grape quality. The objective was to evaluate the effect of soil water holding capacity (AWC) and available soil water (ASW) throughout the growing cycle on the nutritional status, vigor, production, and composition of grapes and wine. The study was conducted in the municipality of Uruñuela in the DOCa Rioja (Spain). The soils of four rainfed vineyard plots were characterized to determine AWC and its impacts on vine, grape, and wine composition. The N, P, and K foliar content, vigor, grape yield, berry weight, and composition of must and wine were analyzed in those vineyard plots during the period 2010–2014. The ASW was simulated in each plot and each year analyzed, considering the soil properties and the weather conditions, after model calibration in one plot in which soil water content was registered. The results showed that AWC influenced ASW along the growing cycle, so vines suffered from water stress in some periods of the vegetative cycle. Plots with higher AWC had higher ASW from fruit set to ripening and lower water stress during this period, which explains the higher N, P, and K foliar content, vigor and grape yield, and lower polyphenol and anthocyanin content in grapes and wines. The period where water availability had the most influence on the quality of the grapes was from veraison to ripening, during which ASW increased berry weight and acidity and decreased anthocyanins and polyphenolic compounds. Full article

Soil quality is a very important indicator used to assess ecosystem restoration states in terms of vegetation recovery and establishment. Evaluating the soil quality of different vegetation restoration types in mountainous areas of Beijing and identifying their influencing factors would provide a scientific basis and be helpful for vegetation restoration in the future. Six vegetation types (or communities), including Platycladus orientalis (L.) Franco pure forest (POP), Pinus tabulaeformis Carr. pure forest (PTP), Platycladus orientalis–Pinus tabulaeformis mixed forest (PPM), Platycladus orientalis coniferous and broadleaved mixed forest (POCB), Pinus tabulaeformis coniferous and broadleaved mixed forest (PTCB), deciduous broadleaved mixed forest (DBMF), and one area of non-afforested land (NF), with similar stand conditions were selected and fourteen factors of soil physical and chemical characteristics were measured and used to establish a total data set (TDS), while a minimum data set (MDS) was obtained by using the principal component analysis (PCA) and Pearson correlation analysis methods. Two scoring methods, linear (L) and non-linear (NL), were used to calculate the soil quality index (SQI), and the key factors influencing soil quality by vegetation were identified by a general linear model (GLM), PCA, and correlation analysis. The results showed that: (1) The screened MDS indicators which showed good relationships with the SQIs in the study areas were total nitrogen (TN), sand content, total potassium (TK), pH, and available water capacity (AWC). The SQI–NLM method has better applicability. (2) The contribution rates of vegetation to different soil factors accounted for 28.644% (TN), 21.398% (sand content), 24.551% (TK), 16.075% (pH), and 9.332% (AWC). (3) TN showed a positive relationship with all vegetation types; the content of TN in PTCB and DBMF was obviously larger than in the other types in the 0–10 cm layer; PPM, PTCB, and POCB affected the sand content, which showed negative correlativity; and DBMF showed positive correlativity with AWC. The mechanism of how different species affect TN, sand content, and AWC should be focused on and taken into consideration in further studies. Full article

Soils enriched with biochar are recommended as a cultivation grounds, especially in case they contain significant amount of sand. However, the interactions between biochar and plants, as well as the influence of the biochar on water retention, cultivation and air properties of soils, are still not obvious. The present study aimed to determine the impact of various biochar doses on soils used for soya cultivation, in comparison to soils maintained as black fallow soil, on their water retention and productivity, for the period of two years. Sunflower husk biochar (BC1) and biochar of leafy trees (BC2), in doses of 0, 40, 60, 80 t·ha⁻¹, were used for field experiments. The water retention was investigated with porous boards in pressure chambers by a drying method. No differences in the hydrological properties of the soils that were differently managed (black fallow soil, crop) were observed following biochar application. Addition of BC1, in the amounts of 40, 60, and 80 t·ha⁻¹, caused an increase in the plant available water capacity (AWC) by 15.3%, 18.7%, and 13.3%, respectively, whereas the field capacity (FC) increased by 7.4%, 9.4%, and 8.6% for soils without biochar. Application of BC2 analogously resulted in higher AWC, by 8.97, 17.2%, and 33.1%, respectively, and higher FC by 3.75, 7.5%, and 18.3%, respectively. Increasing the doses of BC1 and BC2, both on black fallow soils and soils enriched with soya, caused a rise in total porosity (TP) and drainage porosity (DP), and a decrease in soil bulk density (SBD). Biochar with a higher total area and higher porosity (BC1) applied to soils with soya cultivation resulted in lower reductions in AW and FC than BC2 in the second year of investigation. Full article

This paper shows the changes in soil properties in the fourth year after the application of two kinds of environmentally burdensome wastes. One of the wastes was mineral—carboniferous rock from a coal mine, and the other one was organic—post-fermentation sludge from an agricultural biogas plant. The wastes were applied once to a soil of poor quality—a Podzol. The hypothesis to be verified was that one-time application of waste carboniferous rock and/or post-fermentation sludge to a soil has a beneficial effect on the physical status of the soil, and the changes in the soil properties have a permanent character. Also, based on the experiment results, we suggested how these types of waste should be applied to soil. For that purpose, an assessment was performed of the durability, range, and character of changes in soil properties, inter alia: soil texture (PSD), total organic carbon content (TOC), particle density (PD), bulk density (BD), total porosity (TP), air capacity (FAC), air permeability (FAP), sampling moisture (SM), field water capacity (FC), available water (AWC), unavailable water (UWC), and hydraulic conductivity (Ks). Some soil properties have been improved by the use of post-fermentation sludge and the combined application of the two wastes. These were the following soil properties: PSD, TOC, BD, TP, and SM. However, changes to the soil air-water properties (FAC, FAP, FC, AWC, UWC, and Ks) were unfavorable. The effect of the waste’s application was permanent, as differences in soil properties were still visible in the fourth year after their addition. The observations made in the course of the experiment indicate that natural utilization of wastes requires a lot of consideration and should be focused on keeping the balance in the relations between the environmental functions of the soil. Full article

The deterioration of soil physical properties had led to a decrease in soil–water availability in facility agriculture. Thus, an experiment was set up with five soil treatments of 0% (CK, No additives), 3% biochar (BA₃, Mass ratio), 3% earthworm manure (QA₃), 5% biochar (BA₅), and 5% earthworm manure (QA₅) to investigate the effects on soil physical properties and hydraulic characteristics under greenhouse conditions. The physical properties of soil including the soil bulk density (BD) and total porosity (TP) were measured; the results showed that BA₅ provided the lowest soil BD (1.24 g·cm⁻³) and the highest TP (53.09%) and was 13.8% higher than CK. More importantly, the saturated hydraulic conductivity (K_S), field capacity (FC), permanent wilting point (PWP), and available water content (AWC) of the soils treated with biochar and earthworm manure were significantly higher than those of CK. At the same application rate, the effect of biochar on soil–water permeability and water-retention capacity was significantly higher than that of earthworm manure, in which the soil–water-characteristic curve (SWCC) showed that as BA₅ > BA₃ > QA₅ > QA₃ > CK, the FC and AWC increased from 28.90% and 14.13% under CK, respectively, to 40.73% and 21.91% under BA₅, respectively; and the K_S, FC, PWP and AWC of BA₅ increased by 45.93%, 40.91%, 27.46% and 54.96% compared with CK, respectively. The results revealed that the improvement of the soil TP was conducive to the enhancement of the soil K_S and FC, enhanced the soil–water permeability and the water-retention capacity, and ultimately increased the AWC. From the perspective of improving the facility soil and economic benefits, the application of 5% biochar is considered to be the most beneficial. Full article

Parameter sensitivity analysis is a significant part of quantifying model uncertainty, effectively identifying key parameters, and improving the efficiency of parameter optimization. The Soil and Water Assessment Tool (SWAT) model was applied to the upper Heihe River basin (UHRB) in China to simulate the monthly runoff for 11 years (1990–2000). Four typical sensitivity analyses, namely, the Morris screening, Sobol analysis, Fourier amplitude sensitivity test (FAST), and extended Fourier amplitude sensitivity test (EFAST), were used to determine the critical parameters affecting hydrological processes. The results show that the sensitivity parameters defined by the four methods were significantly different, resulting in a specific difference in the simulation effect of the SWAT model. The reason may be the different sampling process, sensitivity index, and calculation principle of each method. The snow-melt base temperature (SMTMP) and snowfall temperature (SFTMP) related to the snow-melt process, the available water capacity of the soil layer (SOL_AWC), saturated hydraulic conductivity (SOL_K), depth from the soil surface to the bottom of the layer (SOL_Z), moist bulk density (SOL_BD), deep aquifer percolation fraction (RCHRG_DP), and threshold depth of water in the shallow aquifer required for return flow to occur (GWQMN) related to the soil water and groundwater movement, baseflow alpha factor for bank storage (ALPHA_BNK) related to the base flow regression, and average slope steepness (HRU_SLP) are all very sensitive parameters. The 10 key parameters were optimized 100 times with the sequential uncertainty fitting procedure version 2 (SUFI-2). The Nash–Sutcliffe efficiency coefficient (NSE), Kling–Gupta efficiency coefficient (KGE), mean square error (MSE), and percentage bias (PBIAS) were 0.89, 200, 8.60, and 0.90, respectively. The simulation results are better than optimizing the sensitive parameters defined by the single method and all the selected parameters. The differences illustrate the rationality and importance of parameter sensitivity analysis for hydrological models and the synthesis of multiple approaches to define sensitive parameters. These conclusions have reference significance in the parameter optimization of the SWAT model when studying alpine rivers by constructing the SWAT model. Full article

Water retention is an important hydrological ecosystem service of active floodplain soils. The aim of the study was to evaluate the soil chemical, physical, and hydrological properties in Fluvisols in three different ecosystems that have an impact on water retention hydrological ecosystem services (WRHESs). We selected 16 localities along the Štiavnica River in Central Slovakia, 8 located in riparian zones (RZ), 5 in arable lands (AL), and 3 in grasslands (GL). Soil samples were collected from two layers (0–10 and 20–30 cm). In the laboratory, the soil physical (soil texture) and soil chemical properties (pH, soil organic carbon content, humic and fulvic acid ratio) were determined. Using undisturbed soil samples, the soil physical characteristics (particle density, bulk density, porosity, and actual soil moisture–SMa) were measured. With the help of pedotransfer functions, hydrological soil properties (field water capacity–FWC, wilting point–WP, available water capacity–AWC) were estimated. The recorded properties differed between the localities, ecosystems, and two layers. The SMa values showed a higher soil water retention potential of extensively used ecosystems, such as GL and RZ. However, the hydrological properties estimated by pedotransfer functions (FWC, WP, AWC) showed a higher soil water retention potential in AL localities. This indicated that for calculations, selected pedotransfer functions (particle size fractions, organic matter, and bulk density) and other soil or ecosystem properties (e.g., vegetation cover, meteorological conditions) have an impact on WRHESs. One such soil factor can be the quality of organic matter. On the basis of the results of the ANOVA, significant differences emerged between the different ecosystems for selected basic chemical, physical, and hydrological properties. The effect of the soil layer on the soil properties was revealed only in the case of SOC. The results indicated the effect of different ecosystems on soil WRHES and the importance of extensively managed ecosystems, such as RZ and GL. From this point of view, the reduction in the RZ and GL areas during a period of the last 70 years is negative. The findings should be taken into account in future sustainable floodplain management and landscape architecture. Full article

Efficient water resource management requires accurate analyses of hydrological components and water balance. The Hydrological Simulation Program—FORTRAN (HSPF) model serves this purpose at the watershed scale. It has limited accuracy in calculating runoff and infiltration because the model simulates hydrological processes using one representative parameter for each land use in the watershed. Accuracy requires field-scale analysis of hydrological components. We calculated the lower zone storage nominal parameter, which markedly affects runoff in HSPF, from effective moisture content and depth of each soil layer. Analysis of hydrological components suggested re-calculating the parameters reflecting soil characteristics. We investigated two scenarios through simulations: Scenario 1 used the existing method. Scenario 2 used parameters that reflected soil properties. Total flows for each sub-catchment were identical, but proportions of direct and intermediate runoff were larger in Scenario 1. Ratios of baseflow, evapotranspiration, and infiltration were larger in Scenario 2, reflecting soil characteristics. Comparing the baseflow ratio to total flow, Scenario 2 values were similar to observed values. Comparisons of R² and Nash–Sutcliffe Efficiency (NSE) at the end of the watershed were well matched (R² and NSE are higher than 0.9) in both scenarios, but proportions of each hydrological component differed. It is important to consider soil characteristics when applying water quantity and quality analyses in an HSPF simulation. Full article

Smallholder agriculture is a major source of income and food for developing nations. With more frequent drought and increasing scarcity of arable land, more accurate land-use planning tools are needed to allocate land resources to support regional agricultural activity. To address this need, we created Land Capability Classification (LCC) system maps using data from two digital soil maps, which were compared with measurements from 1305 field sites in the Dosso region of Niger. Based on these, we developed 250 m gridded maps of LCC values across the region. Across the region, land is severely limited for agricultural use because of low available water-holding capacity (AWC) that limits dry season agricultural potential, especially without irrigation, and requires more frequent irrigation where supplemental water is available. If the AWC limitation is removed in the LCC algorithm (i.e., simulating the use of sufficient irrigation or a much higher and more evenly distributed rainfall), the dominant limitations become less severe and more spatially varied. Finally, we used additional soil fertility data from the field samples to illustrate the value of collecting contemporary data for dynamic soil properties that are critical for crop production, including soil organic carbon, phosphorus and nitrogen. Full article

European beech (Fagus sylvatica L.) trees are becoming vulnerable to drought, with a warming climate. Existing studies disagree on how radial growth varies in European beech in response to droughts. We aimed to find the impact of multiple droughts on beech trees’ annual radial growth at their ecological drought limit created by soil water availability in the forest. Besides, we quantified the influence of competition and canopy openness on the mean basal area growth of beech trees. We carried out this study in five near-natural temperate forests in three localities of Germany and Switzerland. We quantified available soil water storage capacity (AWC) in plots laid in the transition zone from oak to beech dominated forests. The plots were classified as ‘dry’ (AWC < 60 mL) and ‘less-dry’ (AWC > 60 mL). We performed dendroecological analyses starting from 1951 in continuous and discontinuous series to study the influence of climatic drought (i.e., precipitation-potential evapotranspiration) on the radial growth of beech trees in dry and less-dry plots. We used observed values for this analysis and did not use interpolated values from interpolated historical records in this study. We selected six drought events to study the resistance, recovery, and resilience of beech trees to drought at a discontinuous level. The radial growth was significantly higher in less-dry plots than dry plots. The increase in drought had reduced tree growth. Frequent climatic drought events resulted in more significant correlations, hence, increased the dependency of tree growth on AWC. We showed that the recovery and resilience to climatic drought were higher in trees in less-dry plots than dry plots, but it was the opposite for resistance. The resistance, recovery, and resilience of the trees were heterogeneous between the events of drought. Mean growth of beech trees (basal area increment) were negatively impacted by neighborhood competition and positively influenced by canopy openness. We emphasized that beech trees growing on soil with low AWC are at higher risk of growth decline. We concluded that changes in soil water conditions even at the microsite level could influence beech trees’ growth in their drought limit under the changing climate. Along with drought, neighborhood competition and lack of light can also reduce beech trees’ growth. This study will enrich the state of knowledge about the ongoing debate on the vulnerability of beech trees to drought in Europe. Full article