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To optimise the under-membrane fertiliser application of "one film for two years" technology, this paper established the model of T1 and T2 roller hole applicators and adopted discrete element method - multi-body dynamics (DEM-MBD) coupling technology to simulate the under-membrane fertiliser application process and to optimise water and fertiliser application using transport laws under the whole-membrane double-rowed furrow. The coupling results showed that when the roller hole applicator advances at 1 m s−1, the hole application volume of T1 and T2 models is 14.43 g and 15.02 g, respectively, the particle velocity of the membrane pore is 0.2–0.8 m s−1 and 0.2–0.96 m s−1, respectively, the resistance of the hole tying is 21.67 N and 21.41 N, respectively, and the soil disturbance velocity is respectively 1.54 m s−1 and 1.31 m s−1. The HYDRUS-2D/3D was used to simulate the under-membrane fertiliser application process. The results of HYDRUS-2D/3D showed that the water content of the soil in the furrow was 12.7–13.5%, the water absorption rate of the crop root system was 0.2 cm d−1, and the concentration value at the centre point of the fertiliser application in the furrow was 0.72–0.88 mg cm−3. The results of the study showed that the roller hole applicator meets the requirements of the "one-membrane-two-use" under-membrane fertiliser application of full-film dual-monopoly furrow. The results provide a theoretical basis for the optimisation and enhancement of water and fertiliser transport in full film two monopoly furrow. [Display omitted] • Simulation of fertilizer application using coupled DEM-MBD technique. • Particle modelling of full-film duopoly films using the discrete element approach. • HYDRUS-2D/3D simulation of soil water and fertilizer transport. • Integration of agro-mechanical and agronomic technologies. • Modelling two types of roller hole fertiliser applicators. [ABSTRACT FROM AUTHOR]

Thermal desorption is a preferred technology for site remediation due to its various advantages. To ensure the effective removal of different pollutants in practical applications, it is necessary to understand the kinetic behaviors and removal mechanisms of pollutants in thermal desorption process. This paper explored the thermal desorption processes of five organic pollutants (nitrobenzene, naphthalene, n-dodecane, 1-nitronaphthalene, and phenanthrene) at 50–350 °C in two different subsoils with 6–18% moisture content. The results suggested that the thermal desorption process was well-fitted by the exponential decay model (R 2 = 0.972–0.999) and could be divided into two distinct stages. The first stage was relatively fast and highly influenced by soil moisture, while the second stage showed a slower desorption rate due to the constraints imposed by the soil texture and structure. The influence of soil moisture on thermal desorption depended on the octanol/water partition coefficient (K OW) of pollutants. Pollutants with log K OW values lower than the critical value exhibited enhanced thermal desorption, while those with log K OW values higher than the critical value were inhibited. The critical value of log K OW might be between 3.33 and 4.46. Changes in soil texture and structure caused by heating promoted thermal desorption, especially for naphthalene, 1-nitronaphthalene and phenanthrene. The differences in texture and structure between the two soils diminished as the temperature increased. Finally, an extended kinetic model under changing temperature conditions was derived, and the simulation results for the two subsoils were very close to the actual thermogravimetric results, with the differences ranging from −1.28% to 0.94% and from −0.67% to 1.35%, respectively. These findings propose new insights into the influencing mechanisms of soil moisture and structure on the thermal desorption of organic pollutants. The extended kinetic model can provide reference for future kinetic research and guide practical site remediation. [Display omitted] • The thermal desorption process of pollutants was divided into two distinct stages. • Specific influence of moisture on desorption is related to the log K OW of pollutants. • Heating makes different soils become similar, which promotes thermal desorption. • An extended kinetic model under changing temperatures was derived and validated. [ABSTRACT FROM AUTHOR]

Accurate and efficient numerical simulations of soil water movement, as described by the highly nonlinear Richards' equation, often require local refinement near recharge or sink/source terms. In this paper, we present a novel numerical scheme for solving Richards' equation. Our approach is based on the vertex-centered finite volume method (VCFVM) and can be easily adapted to locally refined meshes. The proposed scheme offers some key features, including the definition of all unknowns over vertices of the primary mesh, expression of flux crossing dual edges as combinations of hydraulic heads at the vertices of the primary cell, and the capability to handle nonmatching meshes in the presence of local mesh refinement. For performance evaluation, soil water content and soil water potential simulated by the proposed scheme are benchmarked against results produced from HYDRUS (a widely used soil water numerical model) and the observed values in four test cases, including a convergence test case, a synthetic case, a laboratory experiment case and a field experiment case. The comparison results demonstrate the effectiveness and applicability of our scheme across a wide range of soil parameters and boundary conditions. [ABSTRACT FROM AUTHOR]

In the Tibetan Plateau (TP) soil water and heat transfer process, soil organic carbon (SOC) and gravel content are considered as the most influential soil texture factors. However, the issues of underestimating SOC and neglecting gravel effect affected the simulation performance of CLM5.0 on soil moisture (SM) and soil temperature (ST). This paper proposed a new parameterization scheme, the organic carbon-gravel (OC-G) scheme, to simulate ST and SM from 1990 to 2018. The results showed that correlation between the simulated and observed ST or SM was higher, and the error was smaller, after the modification of the parameterization scheme. This improvement justifies the applicability of the scheme for soil hydrothermal simulations on the TP. The experiment described that ST and SM were more sensitive to changes in SOC content. And changes in gravel or SOC content had the "Same-Frequency" effect in the northeast and southeast TP. When the SOC and gravel content changed at the same time, the effects on ST and SM were a "cumulative" effect. The change directly affected the memory time of ST and SM in summer. Specifically, when the SOC content was increased, the memory time of SM increased in the northwest and decreased in the southeast. When gravel content was increased, the memory time of SM decreased in the northwest but increased in the southeast, but the memory time of ST remained largely unchanged. Changes to the abnormal duration may alter summer weather and climate in Eastern China. • Proposed the OC – G parameterization scheme in CLM5.0 to improve simulation performance. • Verified the applicability for soil hydrothermal simulations on the TP by observations. • Discussing the impact of changes in SOC and gravel content on the TP's hydrothermal distributions. • Effects of changes in SOC and gravel contents on soil moisture/temperature memory time. [ABSTRACT FROM AUTHOR]

This paper explored the drought propagation phenomenon based on meteorological, hydrological, and agricultural aspects in the Yangtze River basin (YRB), China. To evaluate meteorological, hydrological, and agricultural droughts, this paper used three drought indices, standardized precipitation evapotranspiration index (SPEI), standardized runoff index (SRI), and standardized soil moisture index (SSMI), respectively. The community land model (CLM) in the YRB to generate the monthly evapotranspiration, soil moisture, runoff data, which are required for the estimation of drought index, were applied. Different mean durations (6-and 12-month) were used for drought estimation, and propagations of meteorological to hydrological and meteorological and agricultural droughts were investigated for different durations as SPEI6-SRI6, SPEI6-SSMI6, SPEI12-SRI12, SPEI12-SSMI12. The average drought propagation between 1950 and 2010 presented the highest autocorrelation and correlation with one-month lags in four combinations of drought indices in SPEI6-SRI6, SPEI6-SSMI6, SPEI12-SRI12, and SPEI12-SSMI12. Additionally, this paper estimated the optimal lags of SPEI-SRI and SPEI-SSMI drought propagations using mean 6-and 12-month lag times for six representative drought periods. Therefore, the propagation phenomenon of meteorological to hydrological and to agricultural droughts were confirmed in the YRB. • SPEI, SRI, and SSMI indices have been applied to the Yangtze River basin (YRB). • Propagation analysis of SPEI-SRI and SPEI-SSMI have extended to 1951–2010. • Mean 12-month duration shows clearer drought propagation than mean 6-month duration. • SPEI-SSMI presents 1–7 months propagation time. • SPEI-SRI presents 1–2 months propagation time. [ABSTRACT FROM AUTHOR]

One of the greatest challenges in the 21st century is the question of how humanity will adapt to a changing climate to continue producing food at the production levels that will be necessary to feed an increasing global population while conserving soil and water resources. While there are political, social and economic factors that impact agricultural development, this paper will not be focusing on those factors, instead focusing on the potential use of cover crops as a nutrient management tool, a soil and water conservation practice, and a good approach to adapting to a changing climate. The potential of using cover crops for climate change adaptation and mitigation will be reviewed. Cover crops are a key tool that could contribute to increased yields, conservation of surface and groundwater quality, reduced erosion potential, sequestration of atmospheric carbon (C), and improved soil quality and health across the tropics. However, there are a lot of research gaps, and there is a need for additional research about the potential use of cover crops for soil, human, and animal health, as well as a need for an open-access data information system about research on cover crops in the tropics. While cover crops show a lot of promise, they are not a silver bullet, and in some circumstances, they can also contribute to reduced yields. We evaluated the use of cover crops and we ranked the different ways that cover crops can contribute to climate change adaptation, on a scale ranging from very low potential to contribute to climate change adaptation to very high potential. For example, cover crops have very high potential to reduce erosion generated by a changing climate in humid systems. On average, cover crops appear to be a good practice for climate change adaptation and mitigation across the tropics, and nutrient managers, agronomists, and soil and water conservation practitioners could add them to their management toolbox for different regions of the tropics. The 4 Rs of cover crops should be applied when using this tool (the right cover crop, the right timing of placement, the right timing of killing, and the right management). [ABSTRACT FROM AUTHOR]

More than 50 years after the first comprehensively designed projects, the significance of research on past societies and their interactions with landscapes has even increased: Studying arid landscapes opens many areas of general interest about adapted lifestyles and livelihoods, since aridity touches upon problems of desertification and climate change, decentral water and food security. This synoptical paper sheds light onto the premises, functionalities and questions of water harvesting systems in antiquity and asks about the implications of runoff-based economies and societies in the Old World Dry Belt. By comparing results and considerations of the individual contributions to this special issue on ancient water management in general, and water and soil harvesting in particular and other relevant studies, it aims at extracting commonalities and differences between the interlinkages of environmental conditions and human intervention. Moreover, it embeds the various approaches, methods and results of the special issue's authors into overarching considerations oriented towards achieved results, application-oriented aspects and towards focal open questions. Differential analysis of the studied cases, i.e. systematic evaluation of the differences and similarities increases the understanding of the complex issues of runoff agriculture under various environmental and socio-economic conditions. The relevance of the models of ancient water-harvesting based systems evolved during the last decades for modern challenges is given special regard. • Interdisciplinary research in drylands models ancient resource management and livelihoods on a local and regional scale. • Potentials and dynamics of agro-ecosystems are outlined on basis of ancient water harvesting systems. • Studies of ancient resource management are relevant for actual development, sustainability and resilience objectives. • Comparative and complementary analysis of different studies and regions enhances understanding of issues at question. [ABSTRACT FROM AUTHOR]

Soil nitrogen (N) is an essential nutrient for tree growth, and excessive N is a source of pollution. This paper aims to define the effects of plant diversity and forest structure on various aspects of soil N cycling. Herein, we collected soils from 720 plots to measure total N content (TN), alkali-hydrolyzed N (AN), nitrate N (NO 3 −-N), ammonium N (NH 4 +-N) in a 7.2 ha experimental forest in northeast China. Four plant diversity indices, seven structural metrics, four soil properties, and in situ N 2 O efflux were also measured. We found that: 1) high tree diversity had 1.3–1.4-fold NO 3 −-N, 1.1-fold NH 4 +-N, and 1.5–1.8-fold N 2 O efflux (p < 0.05). 2) Tree growth decreased soil TN, AN, and NO 3 −-N by more than 13%, and tree mixing and un-uniform distribution increased TN, AN, and NH 4 +-N by 11–22%. 3) Soil organic carbon (SOC) explained 34.3% of the N variations, followed by soil water content (1.5%), tree diameter (1.5%) and pH (1%), and soil bulk density (0.5%). SOC had the most robust linear relations to TN (R2 = 0.59) and AN (R2 = 0.5). 4) The partial least squares path model revealed that the tree diversity directly increased NO 3 −-N, NH 4 +-N, and N 2 O efflux, and they were strengthened indirectly from soil properties by 1%–4%. The effects of tree size-density (−0.24) and spatial structure (0.16) were mainly achieved via their soil interaction and thus indirectly decreased NH 4 +-N, AN, and TN. Overall, high tree diversity forests improved soil N availability and N 2 O efflux, and un-uniform spatial tree assemblages could partially balance the soil N consumed by tree growth. Our data support soil N management in high northern hemisphere temperate forests from tree diversity and forest structural regulations. We found that plant diversity directly increased NO 3 −-N, NH 4 +-N and N 2 O efflux in soil. Soil physicochemical properties played a strong mediating role in the effect of forest structure on soil nitrogen availability. Tree size-density indirectly decreased the soil N availability via soil physicochemical properties, but the forest spatial distribution (mixing and un-uniform distribution) balanced part of the negative effect on soil N. Our results provide new insights into forest management and deepen our understanding of plant diversity and forest structure on the N cycle. [Display omitted] • Four soil N parameters from 720 soils, and 18054 trees were measured in 720 plots in NE China. • High tree diversity accompanied with 1.3–1.4-fold nitrate-N, 1.1-fold ammonium-N, and 1.5–1.8-fold N 2 O efflux. • The best predictors for soil N were soil organic carbon, water content, and diameter at breast height. • Tree growth decreased soil N availability, and tree mixing and distribution patterns balance part of these declines. • Tree size-density and spatial distribution contrarily affect soil N availability via soil properties. [ABSTRACT FROM AUTHOR]

• This paper proposes a networking stress wave communication method that can be implemented on pipelines. • The proposed method uses orthogonal variable spreading factor (OVSF) codes and correlation features to realize multiple-access channels. • The experimental results verify the feasibility of the proposed networking stress wave based communication method. Stress waves are increasingly employed in structural health monitoring (SHM) systems of pipelines based on sensor networks. Data transmission among sensors is crucial for the overall stress waves based SHM system. Since conventional communications are hampered by limited transmission ranges when in some environments, such as in soil and water, it is essential to develop an alternative approach to deal with the issues. This paper proposes a stress wave communication networking method that can be implemented among multiple sensors. The proposed work introduces Orthogonal Variable Spreading Factor (OVSF) codes to achieve multiple-access stress wave channels by using piezoelectric transducers. In this paper, both frequency-domain and time-domain channel responses are estimated, and communication schemes are thereby designed to achieve data transmission among multiple sensors based on the features of multiple channels. The experiments are conducted on a T-shape pipeline structure in the laboratory environment, and the results verify the feasibility of the method. Experimental results show that the data rate of each single channel reaches 250 bps. [ABSTRACT FROM AUTHOR]

Abstract This paper investigates estimation of root zone soil moisture using two passive microwave remote sensing datasets, Advanced Microwave Scattering Radiometer – 2 and Soil Moisture Active Passive satellites sensors. The study is focused on two crops, namely rice and wheat for the Indo-Gangetic basin, India, having a dynamic crop and soil type and land use land cover. A total of 21 rice crop and 23 wheat crop locations are chosen from the states of Uttar Pradesh, Madhya Pradesh and Bihar falling in the basin. The root zone soil moisture information is derived by estimating soil wetness index from surface soil moisture at 10 and 40 cm depths using a recursive exponential filter. The soil wetness index based algorithm is implementable even in the absence of ground information for a basin level study. The reference soil moisture dataset is obtained from the Global Land Database Assimilation System – NOAH at 10 and 40 cm depth. The research has also demonstrated significant potential of GLDAS-NOAH soil moisture data in the absence of ground (in-situ) soil moisture data. Of the various factors affecting surface and root zone soil moisture, this work evaluates the control of soil constituents on root zone soil moisture. The Spearman rank correlation coefficient is estimated for characteristic time delay with sand, silt and clay percentage at different locations. Coupling between and trends of surface and root zone soil moisture for rice and wheat crop locations are studied. The accuracy of estimated soil wetness index at 10 and 40 cm from two different satellite sensors at two different acquisition times (ascending and descending passes) is investigated by calculating the coefficient of determination, mean absolute error and mean biased error. This work highlights the significant difference in surface soil moisture estimation by two satellite sensors to derive root zone soil moisture for rice and wheat crops. Coefficient of determination is more (∼0.9) for SMAP derived soil wetness index whereas it is lower (∼0.65) for AMSR-2 derived soil wetness index for both crops. Characteristic time delay variation is observed at two different times and at both the depths, with characteristic time delay increasing with depth. Also, at the descending pass characteristic time delay is lower as compared to the ascending pass. A strong relationship between root zone soil moisture and soil texture is observed. For rice crop, a positive correlation with sand and clay is observed for Uttar Pradesh, Madhya Pradesh and Bihar locations having loam and sandy loam as the major soil class. And, for wheat locations, a positive correlation is observed for silt and clay for Uttar Pradesh locations and sand for Madhya Pradesh locations having loam and clay (light) soil texture. This work delivers essential information in understanding sustainable irrigation scheduling and increasing irrigation potential for rice and wheat crop locations. Having the knowledge of all the factors influencing crop cultivation and the derived root zone soil moisture, crop production can be optimized. Graphical abstract Image 10347690 Highlights • Estimating root zone soil moisture from AMSR-2 and SMAP surface soil moisture data. • Correlation between derived root zone soil moisture and soil texture for rice and wheat crops. • Error of estimated soil moisture is higher at morning times than afternoon. • Precise root zone soil moisture estimation (higher R2) from SMAP than AMSR-2 sensor. • Understanding the potential of GLDAS-NOAH as the reference data in absence of in-situ data. [ABSTRACT FROM AUTHOR]

Abstract The indiscriminate use of pesticides due to modern agricultural practices has received special attention from the scientific community to address the persistence, recalcitrance and multi-faceted toxicity of several pesticides. Pesticides are hazardous/toxic and can accumulate easily into non-target organisms including humans and other life forms. Several studies have been performed to investigate the effect of biochar addition for pesticide remediation. This review provides a comprehensive information on biochar amendment for the remediation of persistent organic pollutants such as pesticides. The types of pesticides and their hazards to life forms are briefly introduced before detailing biochar production, its characteristics and applications. Biochar addition in pesticide polluted environment offers the following advantages: (a) increases the soil water holding capacity, (b) improves aeration conditions in soil, and (c) provides habitat for the growth of microorganisms, thereby facilitating microbial community for metabolic activities and pesticide degradation. This paper also provides an up-to-date review on remediation of pesticides using biochar, the knowledge gaps and the future research directions in this field to evaluate the effect of biochar addition on agricultural and environmental performances. Graphical abstract Image Highlights • Recent findings published on pesticides remediation using biochar have been narrated. • Feedstock and pyrolysis conditions play vital role in case of biochar properties. • Long-term impacts regarding biochar application for remediation of pesticide(s) is essential. • Detailed studies are required to fill existing knowledge gaps prior to engineering application. [ABSTRACT FROM AUTHOR]

This paper introduces a discrete element method (DEM) model for studying soil-sweep interaction, where the investigated microscopic parameters were the viscous damping which was utilised for energy dissipation and parallel bonds for simulating the effect of moisture in the particle assembly. The aims were to improve the DEM model with the appropriate set of viscous damping to simulate the effect of the tool's working speed on draught and investigating the set of bond radius multiplier of the parallel bonds for modelling the soil's moisture content (mc) with the spherical particles used. For verification of the DEM model's input parameters, two laboratory soil bin studies were made. The first test confirmed that the draught forces were comparable with the viscous damping used, where the particle assemblies were overdamped at low speeds (0.5–2.8 m s −1 ) and underdamped at higher working speeds (2.8–4.1 m s −1 ). The second soil bin test proved that the appropriate set of parallel bonds enable the simulation of the soil volumetric moisture content over the range 2, 15, 30, 35%. The draught was lower in the simulation using radius multiplier of 0.0, 0.2 in the same manner as 2, 15% mc in the laboratory test. The draught was highest in the model at radius multiplier of 0.5, similarly to the 30% mc in the soil bin study. When the bond radius multiplier was set to 0.8, the DEM model able to simulate lower draught similarly to soil with 35% mc. [ABSTRACT FROM AUTHOR]

The benefits of closed-loop irrigation control have been demonstrated in grower trials which show the potential for improved crop yields and resource usage. Managing water use, by controlling irrigation in response to soil or substrate moisture changes, to meet crop water demands is a popular approach but requires substrate specific moisture sensor calibrations and knowledge of the moisture levels that result in water deficit or over-watering. The use of water tension sensors removes the need for substrate specific calibration and enables a more direct relationship with hydraulic conductivity. In this paper, we present a novel dielectric tensiometer that has been designed specifically for use in soil-free substrates such as coir, peat and Rockwool with a water tension measurement range of −0.7 kPa to −2.5 kPa. This new sensor design has also been integrated with a precision PID-based (drip) irrigation controller in a small-scale coir substrate strawberry growing trial: 32 strawberry plants in 4 coir growbags under a polytunnel. The data illustrates that excellent regulation of water tension in coir can be achieved which delivers robust and precise irrigation control - matching water delivery to the demands of the plants. During a 30-day growing period vapour pressure deficit (VPD) and daily water use data was collected and the irrigation controller set to maintain coir water tension at the following levels: −0.90 kPa, −0.95 kPa and −1 kPa for at least 7 consecutive days at each level. For each set-point the coir water tension was maintained by the irrigation controller to within ±0.05 kPa. Meanwhile the polytunnel VPD varied diurnally from 0 to a maximum of 5 kPa over the trial period. Furthermore, the combination of the dielectric tensiometer and the method of PID-based irrigation control resulted in a linear relationship between daily average VPD and daily water use over 10 days during the cropping period. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) are ubiquitous in the environment and more abundant in the marine environment. Consequently, increasing focus has been put on MPs in oceans and seas, while little importance has been attached to their presence in freshwaters and soils. Therefore, this paper aimed to provide a comprehensive review of the occurrence, analysis and ecotoxicology of MPs. The abundance and distribution of MPs in several typical freshwater systems of China were summarized. It suggested that the surface water of Poyang Lake contained the highest concentration of 34 items/L MPs among all the 8 freshwater systems, and the content of MPs in sediments were higher than that of the surface water. Net-based zooplankton sampling methods are the most frequently utilized sampling methods for MPs, and density separation, elutriation and digestion are three major pretreatment methods. Fourier transform infrared spectroscopy, Raman spectroscopy and pyrolysis-gas chromatography coupled to mass spectrometry are often used to identify the polymer types of MPs. Besides, MPs might damage the digestive tract of various organisms and negatively inhibit their growth, feeding and reproduction. The ways of human exposure to MPs are by ingestion, inhalation and dermal exposure, digestive and respiratory system might be adversely influenced. However, potential health risks of MPs to humans are remained insufficiently researched. Overall, by showing the presence of MPs in freshwaters and soils as well as possible ecotoxicological effects on the environment and humans, this paper provided a framework for future research in this field. Image 1 • Occurrence and distribution of microplastics in freshwater systems were discussed. • Sampling and analytical methods of microplastics in soils and waters were reviewed. • Ecological effects of microplastics on organisms and humans were summarized. • Research gaps were revealed and future research recommendations were proposed. [ABSTRACT FROM AUTHOR]

Conservation agriculture (CA) practices of reduced soil tillage, permanent organic soil coverage and intercropping/crop rotation, are being advocated globally, based on perceived benefits for crop yields, soil carbon storage, weed suppression, reduced soil erosion and improved soil water retention. However, some have questioned their efficacy due to uncertainty around the performance and trade-offs associated with CA practices, and their compatibility with the diverse livelihood strategies and varied agro-ecological conditions across African smallholder systems. This paper assesses the role of key institutions in Malawi in shaping pathways towards more sustainable land management based on CA by outlining their impact on national policy-making and the design and implementation of agricultural development projects. It draws on interviews at national, district and project levels and a multi-stakeholder workshop that mapped the institutional landscape of decision-making for agricultural land management practices. Findings identify knowledge gaps and institutional barriers that influence land management decision-making and constrain CA uptake. We use our findings to set out an integrated roadmap of research needs and policy options aimed at supporting CA as a route to enhanced sustainable land management in Malawi. Findings offer lessons that can inform design, planning and implementation of CA projects, and identify the multi-level institutional support structures required for mainstreaming sustainable land management in sub-Saharan Africa. [ABSTRACT FROM AUTHOR]

The Soil and Water Assessment Tool (SWAT) is a well-established eco-hydrological model that has been extensively applied to watersheds across the globe. This work reviews over two decades (2002–2022) of SWAT studies conducted on Mediterranean watersheds. A total of 260 articles have been identified since the earliest documented use of the model in a Mediterranean catchment back in 2002; of which 62% were carried out in Greece, Italy, or Spain. SWAT applications increased significantly in recent years since 86% of the reviewed papers were published in the past decade. A major objective for most of the reviewed works was to check the applicability of SWAT to specific watersheds. A great number of publications included procedures of calibration and validation and reported performance results. SWAT applications in the Mediterranean region mainly cover water resources quantity and quality assessment and hydrologic and environmental impacts evaluation of land use and climate changes. Nevertheless, a tendency towards a multi-purpose use of SWAT is revealed. The numerous examples of SWAT combined with other tools and techniques outline the model's flexibility. Several studies performed constructive comparisons between Mediterranean watersheds' responses or compared SWAT to other models or methods. The effects of inputs on SWAT outputs and innovative model modifications and improvements were also the focus of some of the surveyed articles. However, a significant number of studies reported difficulties regarding data availability, as these are either scarce, have poor resolution or are not freely available. Therefore, it is highly recommended to identify and develop accurate model inputs and testing data to optimize the SWAT performance. [Display omitted] • SWAT review on Mediterranean hydro-climatic studies. • Lack of SWAT assessment on Mediterranean catchments. • A comparison of data from different Mediterranean basins. • Enhancing data availability for SWAT applications. • Developing a comprehensive knowledge of Mediterranean watersheds. [ABSTRACT FROM AUTHOR]

In 2009, a low-volume gravel road in Sweden was stabilised using fly ash from a local paper mill. The objective was to examine whether fly ash could be used to enhance the stability of the road and how the nearby environment would be affected. The technical and environmental properties of the road have been monitored for two, six, and eleven years. Because the construction costs are higher for ash upgrading than for conventional upgrading, knowing for how long the improved properties will remain is relevant. Strength development was studied using a falling weight deflectometer and compressive strength tests. Environmental properties were studied by chemical analysis of road samples, soil, soil pore water, and vegetation. The results showed that the ash sections had higher stiffness than the reference sections. Leaching tests of road samples showed that the mobility of potassium, sodium, chloride, and sulfate decreased with time. Trace element concentrations in soil samples, except barium, were below the Swedish guideline values for sensitive land use. Chromium, lead, and copper were as high or even higher along the reference section than along the ash section. After 11 years, the pH closest to the ash section was slightly enhanced. Concentrations of zinc and cadmium in the soil pore water were the lowest closest to the ash road, although the total concentrations in the soil were at their highest at the same distance. No toxic levels of trace elements were found in the vegetation close to the road, although a clear difference was observed between plants from the ash section and the reference section, using multivariate data analysis. The positive effects on the geotechnical road properties from ash stabilisation remained after 11 years. The environmental impacts on nearby soil and vegetation can be considered low and acceptable. This study demonstrates that the use of biofuel fly ash in infrastructure projects can contribute to the circular economy and effective use of resources because the demand for pristine materials will be reduced. • Technical and environmental properties of gravel road upgraded with fly ash. • Higher stiffness in ash section than in reference sections after eleven years. • No toxic levels of trace elements in the vegetation close to the ash road. • Environmental impact on nearby soil and vegetation can be considered low. • Biofuel fly ash in infrastructure projects can contribute to circular economy. [ABSTRACT FROM AUTHOR]

Biochar has caught great attention over the last decade with the loose and porous structure, and carbon stability provides suitable living conditions for the growth and activity of microorganisms. This review provided a comprehensive summary of biochar immobilization microbe (BIM) in water and soil decontamination. Firstly, the bacterial immobilization techniques including adsorption, entrapping, and covalence methods were exhibited. Secondly, the applications of BIM in water and soil environmental remediation were introduced, mainly including the treatment of organic pollutants, heavy metals, and N/P, among which the most frequently immobilized microorganism was Bacillus. Then, the mechanisms of adsorption, redox, and degradation were analyzed. Finally, pertinent questions for future research of BIM technology were proposed. The purpose of this paper is to provide useful background information for the selection of better biochar fixation microorganisms for water and soil remediation. • Biochar immobilization microbe (BIM) is promising for environmental remediation. • Biochar applied as shelters can provide living conditions for microorganisms. • Biochar can promote electron transfer between pollutants and microorganisms. • BIM is capable of eliminating pollutants through adsorption and biotransformation. [ABSTRACT FROM AUTHOR]

Over the past decade, biochar-supported nZVI composites (nZVI/biochar) have been developed and applied to treat various pollutants due to their excellent physical and chemical properties, especially in the field of chromium (VI) removal. This paper reviewed the factors influencing the preparation and experiments of nZVI/biochar composites, optimization methods, column experimental studies and the mechanism of Cr(VI) removal. The results showed that the difference in raw materials and preparation temperature led to the difference in functional groups and electron transfer capabilities of nZVI/biochar materials. In the experimental process, pH and test temperature can affect the surface chemical properties of materials and involve the electron transfer efficiency. Elemental doping and microbial coupling can effectively improve the performance of nZVI/biochar composites. In conclusion, biochar can stabilize nZVI and enhance electron transfer in nZVI/biochar materials, enabling the composite materials to remove Cr(VI) efficiently. The study of column experiments provides a theoretical basis for applying nZVI/biochar composites in engineering. Finally, the future work prospects of nZVI/biochar composites for heavy metal removal are introduced, and the main challenges and further research directions are proposed. [Display omitted] • NZVI/biochar is a highly efficient Cr(VI) removal composite. • Pyrolysis temperature and feedstock affect functional groups and electron transfer ability. • More efficient and stable effects can be achieved by adding stabilizer and element doping. • Flow rate is the key factor affecting removal efficiency in column experiment. • Multiple removal mechanisms coexist in nZVI/biochar Cr(VI) removal. [ABSTRACT FROM AUTHOR]

The partitioning of volatile organic compounds (VOCs) in soil multiphase system is a critical process for vapour intrusion, however, the importance of vapour-solid interface adsorption doesn't receive the due attention, which causes the exposure assessment too conservative particularly in arid conditions. This paper proposed a multiphase partitioning equilibrium (MPE) model establishing the quantitative relationship between VOCs and its various partitioning phases in soil, including solid-liquid interface adsorption phase, vapour phase and dissolved phase and vapour-solid interface adsorption phase. Taking benzene as the targeted pollutant, the model was found in good agreement with the experimental data while the errors were within one magnitude basically. The role of vapour-solid interface adsorption under different soil moisture conditions was also investigated by the model. The results reveals that a) soil moisture is the conspicuous controlling factor that affects the benzene partitioning in soil; b) vapour-solid interface adsorption dominates benzene uptake when soil relative saturation (RS) is under 20% among three typical soils; c) as adsorption by soil minerals (vapour-solid interface adsorption) is reduced by increasing amounts of humidity (RS > 20%), uptake by partitioning into the soil organic matter (OM) increasingly becomes a controlling factor; d) the common sense that vapour concentration of benzene is particularly high with low level of RS may not occur since the vapour-solid interface adsorption dominates benzene uptake in arid environment. The MPE model is suitable for prediction of VOCs partitioning and vapour exposure risk assessment of contaminated soil in arid area. [Display omitted] • A more actuate prediction model of soil VOCs multiphase partitioning is proposed. • Organic matter plays only a minor role in sorption at low soil moisture contents. • Vapour-solid interface adsorption dominates benzene uptake in arid soil. • Vapour-solid interface adsorption greatly reduce the vapour exposure in arid environment. [ABSTRACT FROM AUTHOR]

Problems with lowering of water table are common all over the world. Intensive pumping of water from aquifers for consumption, irrigation, industrial or mining purposes often causes groundwater depletion and results in the formation of cone of depression. This can severely decrease water pressure, even over vast areas, and can create severe problems such as degradation of agriculture or natural environment sometimes depriving people and animals of water supply. In this paper, the authors present a method for determining the area of influence of a groundwater depression cone resulting from prolonged drainage, by means of satellite images in optical, near infrared and thermal infrared bands from TM sensor (Thematic Mapper) and ETM+ sensor (Enhanced Thematic Mapper +) placed on Landsat 5 and Landsat 7 satellites. The research area was Szczercowska Valley (Pol. Kotlina Szczercowska), Central Poland, located within a range of influence of a groundwater drainage system of the lignite coal mine in Belchatow. It is the biggest lignite coal mine in Poland and one of the largest in Europe exerting an enormous impact on the environment. The main method of satellite data analysis for determining soil moisture, was the so-called triangle method. This method, based on TVDI (Temperature Vegetation Dryness Index) was supported by additional spatial analysis including ordinary kriging used in order to combine fragmentary information obtained from areas covered by meadows. The results obtained are encouraging and confirm the usefulness of the triangle method not only for soil moisture determination but also for assessment of the temporal and spatial changes in the area influenced by the groundwater depression cone. The range of impact of the groundwater depression cone determined by means of above-described remote sensing analysis shows good agreement with that determined by ground measurements. The developed satellite method is much faster and cheaper than in-situ measurements, and allows for systematic monitoring of the vast area in the vicinity of Belchatow lignite mine. Besides, this method could be useful as a helper in in-situ measurement allowing a significant reduction of the number of in-situ measurements by performing them only within problematic areas. Hence, the triangle method can be used as an effective supplement to field measurements. Although the research area is located in Poland, in the vicinity of lignite mine, the method of observation of depression cones provided in this study is universal and effective, and therefore could also be useful to an international audience. [ABSTRACT FROM AUTHOR]

Understanding the impact of climate change on terrestrial wet and dry changes and the relationship between the two is of great significance to the sustainable development of terrestrial ecosystems. The farming-pastoral ecotone of northern China (FPENC) is an area that is sensitive to climate change, suffering from perennial drought and a clear aridification trend. Unlike previous single-factor, single-timescale studies, we identified aridification in the region based on a dataset established by remote sensing and ground-based monitoring stations from a combination of two perspectives: climate and soil. The results show that, in terms of climate, the period from 2000 to 2019 was the driest in the region during the last 120 years , and the summer drought was the most severe and shifted from a summer to spring drought; in terms of soil, the soil aridification trend in the region was severe, with 16.1% of the areas becoming significantly drier (P < 0.1) among the years and 41.6% in spring, respectively. Similar to climate change, soils exhibited recessive aridification due to the counterbalancing effect of the dry and wet seasons within the year. Then the coupling relationship between climate change and soil aridification was established in time and space. Moreover, the spatiotemporal response patterns of both were obtained. The results showed that the frequency of soil drought under meteorological drought conditions showed an increasing trend and that the sensitivity of soil drought occurrence increased. Among them, the effect of precipitation on relative soil moisture (RSM) was immediate, and the effect of prolonged warming on RSM is greater. The area of soil aridification that was caused by climatic aridification in spring accounted for 13.7% of the entire area. The regional aridification research mode proposed in this paper can provide ideas for subsequent studies. [Display omitted] • A comprehensive judgment mode of the regional aridification combining climate elements, soil moisture was established. • Over the last 20 years, the central part of the FPENC showed overall warming and wetting of the climate. • Over the last 20 years, the trend of the soil aridification in the central part of the FPENC remained severe. • The counterbalancing effect of the dry and wet seasons leads to recessive aridification. • The sensitivity of the occurrences of soil drought to the climate drought anomalies continuously became stronger. [ABSTRACT FROM AUTHOR]

Natural vegetation restoration (NVR) highly relates to the development of gully erosion, and is mainly determined by both the soil properties and species competition in the gullies. However, it is still not clear what are the key factors influencing on the vegetation restoration in the gullies with the poor soil properties (e.g. low soil organic matter and nutrients) under the special hydrological process (e.g. high runoff intensity and long flow duration). In this study, soil total organic carbon (SOC), total nitrogen (TN), available nitrogen (AN), ammonium nitrogen (NH 4 +-N), nitrate nitrogen (NO 3 −-N), total phosphorus (TP), available phosphorus (AP), pH, soil moisture (SM) were investigated, and both regression and structural equation model analysis were used for detecting how soil properties and species competition influence the herbaceous plants restoration in the poor quality of Mollisols in gullies of Northeast China. The results show that, (1) influence of NH 4 +-N, AN, TN, pH on biomass was stronger in 0–10 cm than that in 10–20 cm soil depth, opposite was stronger in 10–20 cm than that in 0–10 cm soil depth for NO 3 −-N, SOC and SM (P < 0.05). (2) NH 4 +-N, NO 3 −-N, AN, TN, SOC, pH, C:N were all negative, while SM was positive to plant biodiversity in soil layers (P < 0.05). (3) SOM mainly mediates the TN and NH 4 +-N and then directly or indirectly influences on biodiversity and biomass, and P changed the species richness when AP >20 mg kg−1 in 10–20 cm soil depth. (4) Vegetation restoration was mainly determined by the dynamics of Elymus dahuricus Turcz. firstly, and then by Leymus chinensis (Trin.) Tzvel. at the early of vegetation restoration. Generally, the heterogeneity of SOC and SM in soil layers and AP in deep soil layer was the key factors determining NVR in the gullies of Mollisols watershed. At the end of paper, the NVR process in Moillosols in gullies was classified as four stages, and each stage was depicted in detail. [Display omitted] • Influence of N, SOC and SM on plant biomass differed from plant biodiversity. • SOM mediates the N form and content and then influences on biomass and biodiversity. • SOC and SM in 0–20 cm soil layers mainly determine natural vegetation restoration. • P changed the species richness when AP >20 mg kg−1 in 10–20 cm soil depth. • Increasing Poaceae could be optimal method to accelerate early vegetation restoration. [ABSTRACT FROM AUTHOR]

Soil erosion is significantly increased and accelerated by unsustainable agricultural activities, resulting in one of the major threats to soil health and water quality worldwide. Quantifying soil erosion under different conservation practices is important for watershed management and a framework that can capture the spatio-temporal dynamics of soil erosion by water is required. In this paper, a modeling framework that coupled physically based models, Water Erosion Prediction Project (WEPP) and MIKE SHE/MIKE 11, was presented. Daily soil loss at a grid-scale resolution was determined using WEPP and the transport processes were simulated using a generic advection dispersion equation in MIKE SHE/MIKE 11 models. The framework facilitated the physical simulation of sediment production at the field scale and transport processes across the watershed. The coupled model was tested using an intensively managed agricultural watershed in Illinois. The impacts of no-till practice on both sediment production and sediment yield were evaluated using scenario-based simulations with different fractions of no-till and conventional tillage combinations. The results showed that if no-till were implemented for all fields throughout the watershed, 76% and 72% reductions in total soil loss and sediment yield, respectively, can be achieved. In addition, if no-till practice were implemented in the most vulnerable areas to sediment production across the watershed, a 40% no-till implementation can achieve almost the same reduction as 100% no-till implementation. Based on the simulation results, the impacts of no-till practice are more prominent if implemented where it is most needed. • A modeling framework for estimating soil loss and sediment transport was presented. • The impacts of no-till on soil loss and sediment yield were examined. • Implementing no-till in areas of high soil loss was key in reducing soil erosion. [ABSTRACT FROM AUTHOR]

The ecotoxicity of arsenic (As) contamination toward small soil fauna living in soil pore water such as soil enchytraeids has rarely been studied but is important in the assessment of soil pollution. Here, the endpoints of As ecotoxicity to Enchytraeus crypticus were studied at three biological levels, i.e., individual (morphology and body tissue As concentrations), population (survival, reproduction and growth) and cell biochemistry (antioxidant enzymes CAT, POD and SOD and peroxidation malondialdehyde MDA). Contact filter paper tests without soil and single species tests with OECD artificial and field soils were conducted. Arsenic contamination resulted in severe morphological pathologies in E. crypticus and the symptoms and degree of damage increased gradually with increasing As concentration and exposure time up to 48 h. The abnormal morphological effects occurred before the impairment of fecundity. The population endpoints responded to the As concentration and the EC50 values increased in the following sequence: reproduction, juvenile body weight, adult body weight, juvenile length and adult length. Changes in biochemistry parameters were induced rapidly and changed with increasing As concentration and exposure time. The activity peak values of enzymes were 3–5 times higher and the activity maximum values of MDA were 1–3 time higher than their controls. The sensitivity of enzyme activities was generally much higher than that of MDA and CAT generally showed the highest enzyme activity. The results indicate that As contamination can be very harmful to soil enchytraeids and the endpoints of the ecotoxicity tests of soil enchytraeids can be used to complement existing soil As assessment systems or may be used alone for the assessment of soil As pollution. Image 1 • E. crypticus was studied at endpoints of different biological levels. • Arsenic contamination can be very harmful to soil enchytraeids. • Abnormal morphological parameters occurred before fecundity damage. • Sensitivity of CAT to As was generally higher than that of POD or SOD. [ABSTRACT FROM AUTHOR]

In ecological restoration, one of the main challenges is to develop new methods, techniques, and incentives that both favour and reduce maintenance costs in restoration projects. Besides, post-planting maintenance is often neglected hampering seedling survival over time owing to alien grasses, which compete strongly with native plants for resources. To solve these issues, recently, an innovative technology called Nucleário has been developed in Brazil. Aiming to hinder alien competition filters, the Nucleário also attempts to condition a better microenvironment, reducing drought stress through the water storage tank, decreasing temperatures, which facilitates the survival and growth of seedlings in areas under restoration. Another method used to decrease alien grasses, which is inexpensive, is seedling crowning using cardboard lowing maintenance needs in restored areas. Cardboard has similar functions to Nucleário , such as protecting soil against loss of water and nutrients and reducing competition with invasive exotic grasses. Therefore, comparing them also with traditional manual weeding (i.e., clean-weeded crown by hoe), we aimed to verify which technique is most cost-efficient for seedling crown maintenance of Dipteryx alata Vog., which is an indigenous tree species with high economic value owing to its nuts. We tested three techniques in areas under restoration in the Cerrado, in the Environmental Protection Area "Córrego Guariroba" located in Campo Grande, Mato Grosso do Sul, Brazil. We monitored seedlings submitted to the three methods in the wet and the dry periods for biotic (competition with exotic grasses, herbivory, and growth) and abiotic (moisture and soil temperature) indicators. We observed that the Nucleário was the treatment that maintained the highest soil moisture, resulting in a larger canopy area. However, these effects do not reflect increases in the survival rate, diameter, and height of the seedlings. None of the treatments was effective in reducing herbivory. Nucleário was the most effective treatment in reducing the competition of seedlings with invasive grasses. Cardboard presented an implementation value 21.5 times lower than Nucleário and 1.2 times than manual crowning. Given the high purchase price, the Nucleário 's cost-benefit ratio was very high compared to the crowning of cardboard and the manual weeding, which discourages us from recommending it for this species with high survival rates. Its project can be revised to decrease herbivory rates, as well as its efficiency tested in the short and long term in different ecosystems and species, particularly species susceptible to water stress. • Dipteryx alata is a Cerrado native tree appreciated for its nuts and had high rates of seedling survival in all treatments. • Nucleário enhanced soil moisture content in dry season, enlarged D. alata crown area, and reduced alien grass competition. • Cardboard was the most cost-effective maitenance technique and presented an implementation value 21.5 times lower than Nucleário and 1.2 times than manual crowning. [ABSTRACT FROM AUTHOR]

This paper reports the mobility and total balance of chlorotoluron (CTL), flufenacet (FNC) and bromide ion (Br−) throughout a sandy soil profile after the application of spent mushroom substrate (SMS) and green compost (GC). Obtaining mobility dataset is crucial to simulate the herbicides' fate under amended soil scenarios by application pesticide leaching models with regulatory application (FOCUS models). The application of organic residues is nowadays increased to improve the crop yields and there is a gap in the simulations of this kind of amended scenarios. A two-year field experiment involving unamended soil (S) and SMS- or GC-amended soil plots was conducted. CTL, FNC, and Br− were annually applied and their residual concentrations were determined in soil profiles (0–100 cm) regularly sampled. In all the treatments the order of mobility is followed as FNC < CTL < Br−. SMS and GC increased herbicide retention in the top 10 cm by the higher organic carbon (OC) content than the unamended soil, and their ability to increase the soil's water-holding capacity and to decrease water percolation. Simultaneously dissolved organic carbon (DOC) content facilitated herbicide transport being it favoured by the initial soil moisture content and the rainfall shortly after the chemicals' initial application. Over the first year, residual amounts (<2.6%) of Br−, CTL and FNC were leached down to 90–100 cm depth in the three treatments. However, over the second year low CTL and FNC amounts (<1.0%) reached the bottom layer only in S + SMS although high Br− concentrations did so in the three treatments (<20%). According to the total balance of Br−, CTL, and FNC in the soil profiles other processes (degradation, mineralisation, bound residues formation, and/or crop uptake) different from leaching below 1 m depth might play a key role in their dissipation especially in the amended soil profiles. SMS and GC are likely to be used as organic amendments to preserve the soil and water quality but in the case of SMS, its higher DOC content could imply a higher potential risk for groundwater contamination than GC. • Herbicide concentrations were evaluated in soil profiles for 2 years along with Br− tracer ion and water content. • Organic residues increased the soil's water-holding capacity and the herbicide adsorption by topsoil. • Herbicide transport increased by soluble organic carbon, initial soil moisture and rainfall. • Leaching, degradation and other processes could be involved in the chemicals' dissipation in soils. • The data set obtained is needed to simulate pesticide environmental fate with leaching models. [ABSTRACT FROM AUTHOR]

South Africa has always been subject to an arid climate, receiving only slightly more than half of the world's average precipitation. This precarious situation is further exacerbated by very high potential evapotranspiration and an extremely rapid population growth. This paper aims to evaluate the threats to the soil and water resources of South Africa. These resources are vital in ensuring sustainable food production. Physically, wind and water erosion, structural decay, subsoil compaction and soil surface crusting are of great concern. Chemically, acidification, salinization, and pollution are the main concerns; with acidification mainly limited to the humid eastern parts and salinization to the arid western parts of South Africa. Biological degradation is mainly driven by organic matter decline, reducing the already low soil organic carbon content of South African soils. The extent of organism decline and the concomitant pathogen increase is not that well-known. Water resources in South Africa are very limited and of variable certainty. Water use efficiency, especially in agriculture and forestry, should receive urgent attention, since these are the main consumers of this valuable resource. Sedimentation, salinization, and pollution constitute the main impacts on water quality. Water pollution arises mainly from point sources such as municipal effluent, with smaller impacts from industry and feedlots. Given the varied nature of institutions and role-players involved in soil and water degradation, it is vital that one or more national institutions take responsibility to monitor and at least attempt to rectify and/or manage the degradation of South Africa's soil and water resources. In this regard substantial financial support from the private sector would also be imperative. [ABSTRACT FROM AUTHOR]