Water Infiltration Rate Research Articles

Characterization and identification of elemental sulphur, iron pyrite, mineral gypsum, phospho gypsum and marine gypsum using SEM-EDAX

India has 6.73 million ha of salt-affected soils, of which 3.77 million ha is sodic soil. Sodicity is a serious issue in agriculture, and it prevents to meet the properties of fertile soil. Sodicity alters its physical and chemical properties, including soil structure and hydraulic conductivity. High exchangeable sodium and pH decrease soil permeability, available water capacity and infiltration rates through swelling and dispersion of clays as well as slaking of soil aggregates. Gypsum is one of the sources used for sodic soil reclamation, and the cheaper and alternative source is marine gypsum which is recovered from salt pans during production of common salt in coastal region, particularly in Gujarat and Tamil Nadu. The recovery of by-product gypsum and marine gypsum together is substantial and is comparable with the production of mineral gypsum.The amendments generally used for sodic soil reclamation should be a source of sulphates such as elemental sulphur, iron pyrite, mineral gypsum, phospho gypsum and marine gypsum. Characterization of sources by SEM–EDAX is rapid and elementary. The elemental composition revealed by the spectra of the bentonite sulphur for weight percentage and atomic percentage of sulphur is quantified as 34.04% and 18.59%, respectively, in the ZAF matrix. In iron pyrite spectra the weight percentage and atomic percentage of sulphur are 4.89% and 2.31%,respectively, in the ZAF matrix, while in mineral gypsum, the calcium weight percentage is 10.14% and atomic percentage is 04.04% while sulphur weight percentage is 6.52%, atomic percentage is 3.50%. The calcium composition in phosphogypsum is weight percentage is 14.69%; Atomic percentage is 34%, and the sulphur composition in phosphogypsum is weight percentage 10.40%, atomic percentage 5.60%, whereas in marine gypsum the calcium (weight percentage 09.10%, atomic percentage 03.58%) and sulphur (weight percentage 06.28%, atomic percentage 03.09%) proportions dominate as like two other above-mentioned gypsums, the element which makes difference in the marine gypsum from others is sodium (Weight percentage 00.18%, atomic percentage 00.12%). This helps to confirm that marine gypsum is an economic and alternate source available for sodic soil reclamation.

Date Palm Waste-Derived Biochar for Improving Hydrological Properties of Sandy Soil Under Saturated and Unsaturated Conditions

Water conservation and effective irrigation management are vital for sustainable agriculture in arid regions. While organic soil amendments have been widely used to enhance water retention in sandy soils, research on the use of date palm waste-derived biochar remains limited. Thus, this study aimed to explore the innovative application of biochar produced from date palm waste, focusing on its effects on the hydrological properties of sandy soil. Biochars of varying particle sizes (0.5, 1, and 2 mm) and pyrolysis temperatures (300 °C, 450 °C, and 600 °C) were produced and their impacts were assessed under both saturated and unsaturated conditions on soil hydrological properties. The biochar was incorporated into soil columns at application rates of 0%, 1%, 3%, and 5% (w/w) within a 10 cm layer on top of 35 cm deep soil columns. The soil columns were placed vertically into water basins for saturation. Evaporation, infiltration, and saturated hydraulic conductivity were measured. The findings revealed that the application of 1%, 3%, and 5% biochar significantly increased soil water retention by 36.80%, 34.18%, and 29.66%, while cumulative evaporation decreased by 7.30%, 2.00%, and 1.35%, respectively, as compared to the control. Water retained at the end of the experiment was increased by 100.63%, 112.29%, and 101.68%, while unsaturated hydraulic conductivity decreased by 21.27%, 26.15%, and 26.17% after amending the soil with 1%, 3%, and 5% biochar, respectively, as compared to the control. The water retention ranged between 30.34 and 42.51%, 22.59 and 43.20%, and 22.48 and 38.81% for biochar produced at 300 °C, 450 °C, and 600 °C, respectively. Water infiltration rate and pore size was decreased with the increased pyrolysis temperature. Overall, the application rates of 3% and 5% with particle sizes of 1 and 0.5 mm and low pyrolysis temperature were most efficient for improving soil properties such as water retention, reducing unsaturated hydraulic conductivity, reducing the rate and volume of infiltration, and enhancing the micro-porosity reduction of sandy soils. In a nutshell, this study highlights the potential of date palm waste-derived biochar as an effective soil amendment, significantly enhancing water retention by up to 112.29% and reducing evaporation. By optimizing irrigation management in sandy soils, these findings contribute to more sustainable agricultural practices.

Specific cation effects on soil water infiltration and soil aggregate stability–Comparison study on variably and permanently charged soils

Improving soil hydraulic properties is one of important purposes of soil tillage. Recent studies on permanently charged soil have shown specific cation effect on soil water infiltration. In this study, specific cation effects on soil water infiltration and soil aggregate stability of both variably and permanently charged soils were comparatively examined. It was found that, specific cation effects on soil water infiltration and soil aggregate stability are quite different for permanently and variably charged soils. For the permanently charged soil, the sequence of specific cation effects on soil water infiltration was Li+ << K+ < Cs+, which was in accordance with the cation polarizability sequence of Li+ (0.029 Å3) << K+ (0.88 Å3) < Cs+ (2.56Å3); but for the variably charged soil, the sequence changed to Cs+ > Li+ > K+. Moreover, the sequence of cation concentration effect on permanently charged soil water infiltration rate (SWIR) was SWIR (0.0001 mol/L) < SWIR (0.001 mol/L) < SWIR (0.01 mol/L) < SWIR (0.1 mol/L) whereas that for the variably charged soil changed to SWIR (0.1 mol/L) < SWIR (0.0001 mol/L) ≈ SWIR (0.01 mol/L) < SWIR (0.001 mol/L). The differences of specific cation and cation concentration effects on soil water infiltration for the two soils came from those on soil aggregate stability. For permanently charged soils, soil electric field determined soil aggregate stability. However, for variably charged soils, besides soil electric field, osmotic pressure, positively charged colloids and surface reaction of metal cation may possibly play critical role in soil aggregate stability.

A decade of conservation agriculture in intensive cereal systems: Transitioning to soil resilience and stable yield trends in a climate crisis

Climate change jeopardizes the food security gains achieved in India since the Green Revolution, especially by impacting the productivity of the rice-wheat system in the Indo-Gangetic Plain, a region that serves as the ‘breadbasket’ of South Asia. In this study, we characterized the potential of long-term conservation agriculture (CA) based management practices (i.e., no-tillage, residue retention, and diversified rotations) to stabilize and enhance crop yields in Northwest India. The study consisted of six different production scenarios (Sc) namely Sc I: conventional rice-wheat system; Sc II: partial CA-puddled transplanted rice-zero till wheat-zero till mung bean (TPR-ZTWMb); Sc III: CA-based zero-till direct seeded rice-zero till wheat-zero till mung bean (ZTDSR-ZTWMb); Sc IV: CA-based zero till maize-zero till wheat-zero till mung bean (ZTM-ZTWMb); Sc V: Sc III + subsurface drip irrigation (SSDI); and Sc VI: Sc IV + SSDI. Long-term yield analysis indicated that the CA-based maize-wheat-mung bean system with SSDI (Sc VI) produced approximately 12%, 27% and 35% higher rice equivalent yield (REY), wheat yield and overall system yield, respectively, over to Sc I. Our study examines Wricke's ecovalence index (Wi2) and the sustainability yield index (SYI) to gauge long-term yield stability and sustainability. Consistently higher wheat yields with lower Wi2 and higher SYI were recorded in CA-based scenarios (Sc V: Wi2 = 0.82, SYI = 0.81; Sc VI: Wi2 = 0.85 and SYI = 0.82). CA-based scenarios also demonstrated stable REY over time. The soil physical properties were influenced by CA systems and compared to Sc I, bulk density was −5.89% in Sc V, followed by −3.62% in Sc III and −1.73% in Sc VI. Moreover, CA systems, Sc IV, Sc VI, and Sc V exhibited positive responses by +106%, +99 % and +72%, respectively for water infiltration rates. Overall, soil organic carbon was +83% and +69% with Sc VI and Sc V, respectively than in Sc I. By substantially enhancing soil health and crop productivity, as well as boosting resilience, CA emerges as a promising solution for meeting the increasing food demand in Northwest India and beyond.

Steady infiltration rate: Relation to antecedent soil moisture, soil permeability, and measurement method and period

ABSTRACT Soil steady water infiltration rate (SIR) is a key variable in hydrological modeling, but its relationship to antecedent soil moisture is not yet well understood. We tested the hypothesis that the SIR decreases with the increase in antecedent moisture, and that this relationship depends on permeability to water on the soil surface, the measurement method, and the measurement period. We conducted an experiment in an Argissolo Vermelho-Amarelo Distrófico abrúptico (Psammentic Paleudult – Soil Taxonomy), measuring infiltration in up to 14 antecedent moisture conditions under two soil structural conditions (no-till and no-till with subsoiling), with two measurement methods (double ring and Cornell infiltrometers), and for up to 48 h, with ten replications. In addition, vertical effective hydraulic conductivity of the saturated profile (Kef) was determined with Darcy’s equation for N layers. Crop succession used in the area was black oats and ryegrass in the winter and soybean in the summer. The SIR decreased to as little as 7.7 % of its original value with the increase in antecedent moisture; it was ~200 % greater in the treatment with subsoiling compared to no-till alone, and ~80 % greater when measured with the Cornell infiltrometer than with the double ring infiltrometer. Nevertheless, the effects of the method and the soil structural condition declined with the increase in antecedent moisture, confirming our hypothesis. In soil initially nearly saturated (degree of saturation ~90 %), the SIR drew near Kef (12.7 mm h -1 ) under the two soil structural conditions, especially when measured with the double ring infiltrometer. In contrast, increasing the time for measuring infiltration (&gt;2 h) did not generate a new lower SIR level. The SIR decreases with the increase in antecedent soil moisture, and this relationship depends on the permeability to water of the surface layers and the measurement method. The SIR determined with infiltrometers better corresponds to vertical infiltration the nearer the soil is to saturation before beginning measurement.

Historical memory in remotely sensed soil moisture can enhance flash flood modeling for headwater catchments in Germany

The wetness precondition of a catchment affects available soil water storage capacity and infiltration rate, thus influences flash flood generation. Remotely sensed (RS) soil moisture (SM) can provide valuable information on catchment wetness, but typically only represents the top 5 cm of the land surface. However, hydrological models for flash flood simulation need to consider deeper layers to calculate the total soil water storage. Therefore, a key challenge is to link RS SM to total soil water storage and assimilate RS SM into flash flood models to correctly describe initial catchment wetness. In this study, we developed an approach to combine present and antecedent RS SM to infer present soil water storage based on four regression models. The inferred soil water storage from SMAP (soil moisture active passive) SM was assimilated into the operational LARSIM (Large Area Runoff Simulation Model) hydrological model. We tested this new approach with 12 events in the headwater catchments Körsch, Adenauer Bach and Fischbach in Germany. Results show that random forest regression performs the best among the four regression models. The BIC (Bayesian Information Criterion) score suggests that regressions considering antecedent RS SM can well infer soil water storage, resulting in R2 of 0.85, 0.94 and 0.93 for the Körsch, Adenauer Bach and Fischbach catchments, respectively. Compared to the open loop (without data assimilation) simulations, our approach enhanced the general performance of event simulations with average KGE increases of 0.09, 0.24 and 0.33 for the Körsch, Adenauer Bach and Fischbach, respectively; and the mean error in the 12 simulated event peaks is reduced 15 %. Moreover, the simulation uncertainty is reduced, too. The transferability of the proposed approach to other RS products is also discussed. Although assimilating RS SM can enhance flash flood modeling, it is primarily affected by the uncertainty in precipitation. In the future, the proposed approach should be tested with more catchments and events to verify its general validity.

Water provision benefits from karst ecosystems: An example for Watuputih groundwater basin, North Kendeng Mountain, Indonesia

Karst ecosystems offer a wealth of ecosystem services, but their protection is increasingly challenging due to degradation and land-use conversion, including limestone mining. This study investigates the water provision service derived from karst ecosystems threatened by limestone mining in the Watuputih groundwater basin, Central Java, Indonesia. Water supply was quantified by measuring water discharge rates from major springs around the basin. Water usage was quantified for household consumption, agriculture, and recreation. This study also measured water infiltration rates in mining and non-mining areas to indicate the effects of limestone mining to hydrological processes. This study identified three primary springs around the basin: Sumber Seribu spring, Brubulan spring, and Kalutan spring, with discharge rates of 1080 L per second, 85 L per second, and 0.76 L per second, respectively. A local water company extracts water from Sumber Seribu spring at a rate of 80 L per second to supply approximately 57,600 individuals. The water supply from the three springs can irrigate approximately 1594 ha of rice fields. Water from Sumber Seribu spring also supports recreational activities in Sumber Semen recreation park, attracting an average of 19,173 visitors per year. This study revealed a complete impairment of soil's water infiltration capacity in limestone mining areas. These findings underscore the pressing need to safeguard the Watuputih groundwater basin and to mitigate the detrimental effects of limestone mining on hydrological processes. This involves designating the Watuputih karst ecosystem as a protected area, implementing Payment for Ecosystem Services (PES) programs, and restoring degraded post-mining sites.

Impact of textural layers in soils on irrigation infiltration processes in an oasis farmland, northwestern China

AbstractThe Hexi Corridor Oasis in China is an important agricultural area supported by extensive irrigation. The sandy soil in the area exhibits textural layering, which has marked effects on its properties. Textural layered soils play an important role in distributing and regulating water regimes in irrigated fields. However, little is known about the textural layering‐dependent variability in soil water infiltration characteristics following irrigation and the potential effects on soil hydrology and water regimes in these soils. The objective of this study was to determine water infiltration processes and their influencing factors for six soil profile types in an oasis farmland. Six in situ constant‐head infiltration measurements (with three replications in each of six sites) were conducted with a single‐ring infiltrometer in different soil texture configurations, and Hydrus‐2D model was applied to evaluate soil water distribution. The results showed that the wetting front depth for all treatments was in the following order: ST‐1 &gt; ST‐5 &gt; ST‐6 &gt; ST‐3 &gt; ST‐2 &gt; ST‐4; the stable infiltration rate ranged from 1.2 to 3.3 cm/min during the investigation period in all treatments. The presence of a finer‐textured soil layer decreased water infiltration rates through the profiles, and the thickness and burial depth of textured layers had obvious effects on infiltration, compared with homogeneous sand profiles. Presence of a medium‐textured layer affected the infiltration characteristics and soil water spatial variability; driven by increased field capacity and the wilting point, hydraulic conductivity was correlated with soil variables that were related to soil structure, such as wilting point and field capacity, and less so with variables that were related to soil texture, such as the clay fractions (p &lt; 0.001). These results suggested that textural layering altered the soil structure and caused heterogeneous infiltration of water, with implications for the distribution of irrigation water and prevention of deep percolation in this oasis farmland. The result of this study offers a new analysis of ponded single‐ring water infiltrometer data that the soil water infiltration is also influenced by the type of textural layered than just the irrigation system, which supports crop irrigation management in study area and other regions with similar soil regimes.

Evaluation of Infiltrated Water Volume in the Liang Anggang Protected Forest Block 1

The Liang Anggang Protection Forest is an area formed from peat soil. Peat soils have a role to play in conserving water resources, reducing flooding, preventing seawater seepage, and so on. Damage to the water system in peat soils is often caused by individual activities that are not well controlled. This is thought to have resulted in the depletion of water in peat soils, causing the soil to become dry and flammable in the dry season. The purpose of this research is to examine the rate of water infiltration in Liang Anggang Protected Forest Block 1. In this study, the method used in analyzing the infiltration rate was the Horton method by measuring the infiltration rate using a double-ring infiltrometer (turf-tec infiltrometer). According to the study's findings, the average decrease in infiltration rate of test 1 on bare or low-density land is 12.4 cm/hour, medium-density land is 2.7 cm/hour, very dense, closed, or forested land is 3.6 cm/hour, and test 2 on barren land is 2.4 cm/hour, medium density land is 2.7 cm/hour, and very dense, closed, or forested land is 4.7 cm/hour. Keywords: Double ring infiltrometer, Infiltration Rate, Horton Method, Liang Anggang Protection Forest

Novel drainage pipeline breakages detection based on MEMS inertial sensor: From mechanism to application

Urban water environment pollution is a global concern, in developing countries, sewage infiltration resulting from urban drainage pipelines breakage is an essential element in the urban groundwater pollution and the recurrence of black odor water bodies, it is crucial to accurately and efficiently detection and localisation of urban drainage pipelines breakage to protect the urban water resources. In this paper, a device for detecting defects in drainage pipelines was developed and assembled using microelectromechanical systems (MEMS) inertial sensors as the core components, and the improved cumulative sum (CUSUM) model was used for anomalous detection of the pitch angle of the device's movement along the course of the pipeline as a method of detecting pipeline breakage. In the laboratory simulation of drainage pipeline tests, the CUSUM peaks (0.709, 1.102, 3.038, 7.990) for the case of external water infiltration rates into the pipeline at the point of pipe breakage (2.9%, 4.6%, 5.8%, 9.2%), and for the cases of sewer exfiltration rates in the pipeline of 4.2% and 6.4% (0.760, 1.382). CFD simulations of the water flow in the laboratory pipeline show a high degree of overlap between the trend of the water surface near the point of breakage and the anomalous fluctuations in the pitch angle of the device motion in the laboratory tests. Finally, the authors tested the device on municipal drains in the city of A. The results demonstrated the reliability and high accuracy of the device. The device enables to improve the ecological quality of urban water environment by accelerating the rate of defect detection in urban drainage pipelines and reducing the detection expenses.

Tillage influence on agrophysical soil properties and crop productivity in the irrigated conditions of the steppe zone of Ukraine

The main goal of the study was to establish the influence of various tillage systems on the agrophysical properties of dark-chestnut soil under short-grain crop rotation in the irrigated conditions of southern Ukraine. The research was carried out during 2021-2022 in a stationary experiment on a four-field crop rotation: grain maize – winter rapeseed – winter wheat – soybeans. The experimental field was in the semi-arid steppe climate zone at the Institute of Climate-Smart Agriculture of the National Academy of Agrarian Sciences of Ukraine. Three tillage systems were studied for their influence on soil bulk density, porosity, and water permeability, namely: mouldboard-differentiated ploughing tillage; differentiated chisel tillage; and differentiated ploughless tillage with soil slitting. Soil bulk density was determined using the core method. Soil porosity was calculated as the ratio of total bulk density to solid fraction bulk density. Water infiltration rates, established through the water absorption test method, were used to measure soil water permeability. The results of the study were statistically analysed using the common ANOVA procedure with Fisher’s least significant difference test at P&lt;0.05. In addition to the agrophysical parameters of the soil, the energy output of the crop rotation was assessed. It was established that mouldboard tillage did not provide significant benefits in terms of bulk density and soil porosity. However, ploughing showed the best results for soil water permeability across all crops in the rotation. The highest energy output of crop rotation (119.1 GJ/ha) was recorded for the ploughless-differentiated tillage system with soil slitting, whereas the mouldboard ploughing and chisel tillage systems produced somewhat lower energy yields of 112.0 and 108.6 GJ/ha, respectively. Therefore, ploughless-differentiated tillage with soil slitting is the most effective option for short-grain crop rotations in irrigated conditions of southern Ukraine, in terms of creating optimal soil agrophysical properties and achieving the highest crop productivity

Grasslands and flood mitigation – Contrasting forages improve surface water infiltration rates

Grasslands globally deliver many ecosystem services, including water management to alleviate flood risk reduction. Two replicated field experiments were conducted to study how agricultural forage species with diverse rooting systems, sown as single species, affected rooting, soil structure and earthworm populations, and consequently water infiltration to understand how they each might influence flood risk from grasslands. Experiment One showed soils under red clover (Trifolium pratense), white clover (Trifolium repens) and chicory (Cichorium intybus) had higher infiltration rates three years after establishment, compared to perennial ryegrass (Lolium perenne). Higher red clover and chicory root biomass or increased earthworm abundance under white clover may have caused these effects. Experiment Two monitored infiltration at intervals over several years post establishment to understand the timeframe for changes in rates; plantain (Plantago lanceolata) was sown as an additional forage. Infiltration declined post establishment, the timing and extent of decline varying with forages; forage effects were significant after 27 months (P < 0.05). Infiltration rates were higher under red and white clover compared to ryegrass, with chicory and plantain intermediate (P < 0.05). Forages again differed in likely mechanisms delivering higher water infiltration, notably between the two clover species. White clover had higher earthworm biomass (P < 0.05), whereas red clover had a higher average root diameter compared to the other forages (P < 0.05). Drivers of intermediate benefits of chicory and plantain also differed: chicory had higher earthworm abundance (month 38) compared to plantain, which had higher average root diameter compared to ryegrass (month 41); 30 months post-establishment soil bulk density was lower under both forages compared to ryegrass and red clover, with white clover intermediate (P < 0.05); bulk density and penetration resistance did not relate to infiltration. Findings demonstrate that a shift from perennial ryegrass-dominated pastures to swards with more contrasting forages provides an ecohydrological approach to mitigating flood risk and climate adaptation.

Seasonal soil health dynamics in soy-wheat relay intercropping

There is growing interest in intercropping as a practice to increase productivity per unit area and ecosystem functioning in agricultural systems. Relay intercropping with soy and winter wheat may benefit soil health due to increased diversity and longer undisturbed soil cover, yet this remains largely unstudied. Using a field experiment in Eastern Germany, we studied the temporal dynamics of chemical, biological, and physical indicators of soil health in the topsoil over a year of cultivation to detect early effects of soy-wheat relay intercropping compared to sole cropping. Indicators included microbial abundance, permanganate-oxidizable carbon, carbon fractions, pH, and water infiltration. Relay intercropping showed no unique soil health benefits compared to sole cropping, likely affected by drought that stressed intercropped soy. Relay intercropping did, however, maintain several properties of both sole crops including an increased MAOM C:N ratio and higher soil water infiltration. The MAOM C:N ratio increased by 4.2 and 6.2% in intercropping and sole soy and decreased by 5% in sole wheat. Average near-saturated soil water infiltration rates were 12.6, 14.9, and 6.0 cm hr−1 for intercropping, sole wheat, and sole soy, respectively. Cropping system did not consistently affect other indicators but we found temporal patterns of these indicators, showing their sensitivity to external changes.

Determination of Sustainable Factory Locations for the Lemon Agroindustry using AHP, Mapping and Water Management

This research was conducted in Suntenjaya Village, Lembang, and West Bandung Regency, focusing on lemon agro-industrial development. Research was conducted using the Analytical Hierarchy Process (AHP) approach, area mapping, and water management to determine a sustainable factory location. The main objective is the selection of factory sites by integrating lemon production, considering sustainable agriculture aspects, product aspects, and water conservation programs. The results of this study provide a strong foundation for sustainable agro-industrial development that will support sustainable agriculture, local economy, and environmental protection. The research also combined qualitative and quantitative elements with a mixed approach that included Focus Group Discussion (FGD) and AHP, and the results showed that integrated drainage management was the top priority, followed by sanitation, clean water, reforestation, and sustainable agriculture. Mapping of areas based on geographical characteristics, such as rainfall, slope, and soil type, provided a map of water infiltration rates, which became a key guide in planning water conservation programs. The ultimate location for the lemon agroindustry is half of Desa Suntenjaya, mostly from the center to the northern area, which needs to consider proximity to markets in Bandung Regency and City, easy access to sources of raw materials for lemons, water availability, adequate transportation infrastructure, access to energy sources, suitable climate for lemon growth, and the availability of adequate labor in the region.

Deep-root respiration: The unknown CO2 removed from the atmosphere

Carbon (C) sequestration in soils is a promising CO2 removal approach. So far, the focus has been on how to increase the content of soil organic C (SOC), while the management soil inorganic C (SIC), i.e. carbonate minerals, has received little attention, because SIC is thought to be much less involved in biotic C cycling than SOC. However, in principle SIC management potentially provides a long-term solution, with a much greater capacity for C sequestration than SOC. The forgotten link is the dissolved inorganic carbon (DIC), i.e. CO2 species dissolved in soil solution, and its fate throughout the unsaturated zone (USZ). The return of CO2 respired by deep roots to the atmosphere, either directly through CO2 degassing or indirectly through DIC leaching, may not necessarily take place over decades or centuries. CO2 diffusion decreases sharply with depth due to reduced porosity of the subsoil and more water-filled pores. The downward water percolation rate is often only a few centimeters per year, and the large amount of respired CO2 compared to the leached DIC results in a relatively small amount of CO2 being transferred to the groundwater. Therefore, respired CO2 at deeper soil depth can be defined as a hitherto unknown ecosystem service of deep-rooted plants i.e. providing a net C sink as inorganic C in the USZ. A conservative estimation suggests a C sink as SIC of at least 80 kg C ha−1 y−1, comparable to reported annual C sequestration as SOC in temperate grasslands.

Electrothermal mineralization of per- and polyfluoroalkyl substances for soil remediation

Per- and polyfluoroalkyl substances (PFAS) are persistent and bioaccumulative pollutants that can easily accumulate in soil, posing a threat to environment and human health. Current PFAS degradation processes often suffer from low efficiency, high energy and water consumption, or lack of generality. Here, we develop a rapid electrothermal mineralization (REM) process to remediate PFAS-contaminated soil. With environmentally compatible biochar as the conductive additive, the soil temperature increases to >1000 °C within seconds by current pulse input, converting PFAS to calcium fluoride with inherent calcium compounds in soil. This process is applicable for remediating various PFAS contaminants in soil, with high removal efficiencies ( >99%) and mineralization ratios ( >90%). While retaining soil particle size, composition, water infiltration rate, and cation exchange capacity, REM facilitates an increase of exchangeable nutrient supply and arthropod survival in soil, rendering it superior to the time-consuming calcination approach that severely degrades soil properties. REM is scaled up to remediate soil at two kilograms per batch and promising for large-scale, on-site soil remediation. Life-cycle assessment and techno-economic analysis demonstrate REM as an environmentally friendly and economic process, with a significant reduction of energy consumption, greenhouse gas emission, water consumption, and operation cost, when compared to existing soil remediation practices.

Evaluation and comparison of infiltration models for estimating infiltration capacity of different textures of irrigated soils

Accurate estimation of infiltration rates is crucial for effective irrigation system design and evaluation by optimizing irrigation scheduling, preventing soil erosion, and enhancing water use efficiency. This study evaluates and compares selected infiltration models for estimating water infiltration rates in the Shillanat-iv irrigation scheme in northern Ethiopia. Soil samples were collected to determine textural classes using hydrometer soil texture analysis and the United States Department of Agriculture (USDA) textural triangle. The soil textural map of the study was created using the inverse distance weight interpolation technique in ArcGIS version 10.4. Infiltration rates were measured using the double-ring infiltrometer for five soil textures: clay loam, loam, sandy clay loam, clay, and sandy loam. Six infiltration models (Kostiakov, Modified Kostiakov, Revised Modified Kostiakov, Philip, Horton, and Novel) were employed and evaluated using statistical parameters. Model calibration and validation were conducted using data from 38 points within the study area. The parameter values of the infiltration models were optimized using SPSS statistical software using least-squares errors. The results showed that, Revised Modified Kostiakov, Modified Kostiakov, and Novel infiltration models demonstrated superior capability in estimating infiltration rates for clay loam, loam, and sandy loam soil textures, respectively. Horton's model outperformed other models in estimating infiltration rates for both sandy clay loam and clay soil textures. The appropriately fitted infiltration models can be utilized in designing the irrigation system to estimate the infiltration rate of soil textures within the selected irrigation scheme and at similar sites with comparable soil textures.

Hydrological Response of Bamboo Plantations on Soil–Water Dynamics in Humid and Semi-Arid Coastal Region of Kenya

Soils and water are major resources that drive a country’s economy, and therefore should be conserved and utilized sustainably. However, in Kenya, these two resources are facing huge depletion and degradation due to anthropogenic factors and climate change. Bamboo species, especially on large plantations, can significantly alter ecological, hydrological, and biogeochemical processes in the long term. This study aimed to evaluate the effects of different species of bamboo and tree plantations on important soil–water processes like infiltration, bulk density, runoff, and soil loss in Kenya. The research was conducted at two sites (Gede in Arabuko Sokoke forest and at Baolala, in Kilifi County) managed by the Kenya Forestry Research Institute (KEFRI). The Arabuko Sokoke forest has a hot–humid coastal climate, while Baolala is a hot semi-arid area with little precipitation. The study involved measurement of soil–water infiltration rates using infiltrometers, installing runoff plots to quantify surface runoff and sediment loss, and analyzing soil properties like bulk density for growing periods for different bamboo and tree species. At the Gede forest site, the 30-year-old Thyrsostachys siamensis and Bambusa bambos plantations recorded the highest infiltration rates. Mature bamboo plantations of T. siamensis and B. bambos recorded higher infiltration rates compared to mature plantations of E. camaldulensis and G. arborea. It was observed that the bamboo plantations manifested lower soil bulk density compared to bare land, which recorded the highest bulk density. At Boalala, infiltration rates were significantly higher in the bamboo species compared to grassland and bare land. The painted bamboo (B. vulgaris vittata) had a slightly higher water infiltration rate compared to B. vulgaris. Runoff and erosion patterns reinforced the benefits of more mature bamboo plantations as well. There was a significant correlation between amount of runoff and collected soil loss through erosion. The data showed reductions in surface runoff volumes and sediment loss as the bamboo plantations aged compared to younger species. Therefore, by enhancing infiltration and reducing runoff and erosion, well-managed bamboo plantations can protect valuable soil resources, improve water recharge, and support sustainable land use over the long term. In conclusion, this study showed the strong potential of bamboo as a soil and water conservation tool in Kenya.

Water infiltration rate in fine glass beads under micro- and partial gravities

The applicability of the theory of water infiltration in porous media under low gravities is controversial. We evaluated the hypothesis that infiltration under low gravities can be simulated from horizontal infiltration experiments under 1G. Parabolic flights provided low gravity conditions, assuming in the space station (µG), on the moon (0.19 G), and Mars (0.38 G). We measured infiltration rates in uniform particle-size porous media. No significant differences existed between infiltration rates under low gravities and ground-based predictions, i.e. the 1G condition. The air was entrapped little in this study, which may have prevented the infiltration rate reduction reported in previous studies. We concluded that the current infiltration theory adequately simulated water infiltration in fine uniform porous media under low gravity conditions.

The Relationship between the Time Difference of Formation Water Infiltration Rate, Tectonic Movement, and the Formation Pressure Coefficient

The study of formation pressure holds great significance for both exploration and development. The formation pressure coefficient is a crucial parameter in geology, encompassing various aspects. Numerous models exist to explore its influencing factors, yet they remain highly controversial. Our research has gathered data on formation pressure states and tectonic movement rates from dozens of large sedimentary basins worldwide. We delved into the patterns of formation pressure changes during basin deposition, subsidence, and tectonic uplift, taking into account the permeability of formation water. The findings reveal that during the Neogene and beyond, rapid deposition or tectonic uplift can cause the infiltration of formation water to lag behind tectonic movements, resulting in overpressure. Conversely, if recent tectonic movements are slow, formation water will complete its infiltration process ahead of tectonic changes, bringing the formation pressure to a hydrostatic state. Consequently, we have concluded that abnormal formation pressure primarily depends on the rate of tectonic movements during the Neogene and Quaternary periods. This study also proposes four formation pressure models, paving the way for a comprehensive understanding of formation pressure within a unified theoretical framework.