Moisture Characteristic Curve Research Articles

Consideration of Vadose Zone Moisture Dynamics in Remediation of PFAS‐Impacted Soils

AbstractOilfield brines are soluble, non‐volatile, and recalcitrant contaminants that are vulnerable to capillary effects and evapoconcentration and have been known to recontaminate clean fill soils emplaced after excavations. This problem may also occur for some poly‐ and perfluoroalkyl substances (PFAS) at PFAS sites. In this paper, we consider the soil moisture characteristic curve, wetting front dynamics, and the moisture redistribution cycle to understand the potential behavior of different PFAS in the vadose zone. Drawing on experience with remediation of soils impacted by brine spills, we provide recommendations on the design and implementation of soil excavation and cover remedies such as capillary barriers to prevent recontamination.

Influence of peatmoss and polymer on moisture characteristic curve of soils with different gypsum and clay contents

To determine the hydraulic properties of several soils with varying clay and gypsum contents and treatments with peat moss and polymer, a laboratory experiment was done. Gypsum ratios varied from 410 g kg-1 to 46 g kg-1, while clay ratios ranged from 0 to 435 g kg-1. Two soils were employed, one having 410 g kg-1 of gypsum and the other containing 435 g kg-1 of clay. Peat moss and a polymer were used to treat the five soils. Three soaking and drying cycles were performed on soil that had been treated with conditioners by packing it into plastic columns that were 5 cm in diameter and 25 cm high with a bulk density of 1.3 mcg m3. The experiment's goal was to improve the ability of gypsiferous soils to retain water. The moisture characteristic curves were computed using the connection between the volumetric moisture content () and the matric tension, which ranged between 0.1 and 1500 kPa. The results revealed that the values of for the study's soil and treatment methods decreased as matric tension increased, and the discrepancies were more pronounced at low tensions. With rising gypsum and falling clay, the values of decreased. As gypsum was raised from 46 to 410 g kg-1, the values of the available water reduced from 0.276 cm3 cm-3 to 0.191 cm3 cm-3. The addition of peat moss (1%), polymer 1 (2%), and a combination of the two clearly increased the amount of water that was accessible while also changing the amounts of clay and gypsum in all treatments.

Soil-Matric-Potential-Based Irrigation Scheduling to Increase Yield and Water Productivity of Okra

A field experiment was conducted on okra (Abelmoschus esculentus L.) for assessing the sustainability of yield with optimum irrigation schedule based on soil moisture depletion. Four irrigation treatments: Irrigation at I1:20%, I2:30%, I3:40% and I4:50% of soil moisture depletion rate in main plots and three fertilizer treatments: Fertigation at F1:100%, F2:80% and F3:60% of recommended NPK (100:25:40 kg/ha) in subplots were tested. Soil matric potential was recorded continuously using electronic tensiometers. The soil moisture characteristics curve was derived for various soil matric potential value sand the soil water content. The irrigation controller triggered solenoid valves for irrigation when soil moisture depletion reached a prespecified level in each treatment. Soil moisture depletion values were significantly predicted based on a regression model calibrated for each treatment over the crop growing period. The model gave minimum prediction error (PE) for I1, followed by I2, I3 and I4, respectively. Plant growth and yield parameters were significantly influenced by the soil moisture availability under each treatment. It is recommended that irrigation be scheduled at 20% soil moisture depletion rate together with 100% NPK fertilizer application for attaining sustainable yield of okra (12.3 t/ha), apart from maximum WUE (3.5 kg/m3) and plant growth parameters under semiarid inceptisols.

Assessment of the soil structure stability focusing on the high-energy moisture characteristic curve in pasture and arable land uses in semi-arid areas, northeastern Iran

Assessment of the soil structure stability focusing on the high-energy moisture characteristic curve in pasture and arable land uses in semi-arid areas, northeastern Iran

Assessing the effects of agricultural waste returning on soil moisture characteristics

AbstractAgricultural waste is an emerging and promising resource due to its abundant organic compounds and high water‐holding capacity. It plays a crucial role in improving soil water use efficiency and contributing to sustainable agricultural development. This study aimed to investigate the impact of returning agricultural waste on soil moisture characteristics. Different volume ratios (4:5:1:0, 3:5:1:1, 2:5:1:2, 1:5:1:3, and 0:5:1:4) of agricultural waste blend (AWB) consisting of cattle manure, yellow loam soil, wheat straw, and distiller's grains were examined, and the water‐holding performance of the five AWB ratios under various suction forces was compared. The analysis confirmed the suitability of the Van Genuchten‐Mualem model for fitting soil moisture characteristic curves at different ratios. The study also examined the influences of AWB ratios on soil‐specific water capacity, hydraulic parameters, and equivalent pore size. The results showed that agricultural waste effectively increased soil‐specific water capacity, available water content, soil WHC(Water‐holding capacity), and soil pore count. Furthermore, reducing cattle manure and increasing distiller's grains enhanced these effects. For instance, when the AWB ratio was 0:5:1:4, soil‐specific water capacity increased by 47.7%, while field WHC and available water content increased by 9.9% and 3.8%, respectively. Additionally, the number of extremely small and small pores increased by 1.4% and 0.77%, respectively. These findings provide valuable theoretical guidance for agricultural waste treatment and improving soil WHC. Based on the results, it is recommended to increase the proportion of distiller's grains and reduce organic fertilizer when using agricultural waste for improving soil WHC.

Mechanical Analysis of Road Graben Slopes Based on Saturated-Unsaturated Seepage Theory

As the construction of mountainous highways continues to heat up, the stability analysis of road graben slopes becomes one of the current research hotspots. In this paper, based on the saturated-unsaturated seepage theory, the force analysis of the road graben slope under rainfall conditions and its laws are studied. Firstly, the damage mode of the road graben slope and its three damage stages of creeping deformation, sliding damage and tendency to stability are summarized according to the engineering practice and literature survey, and the right side of the road graben slope from K316+439 to K316+859 of Longlian Expressway is monitored, so as to amend the next theoretical analysis. The three stages of rainfall infiltration were analyzed, the state variables and material variables of soil water were selected according to the continuous medium theory and the soil water suction analysis was carried out. Based on the saturated-unsaturated seepage theory, the fluid-structure interaction mathematical model and soil moisture characteristic curve (SWCC) model under rainfall infiltration conditions were established, and the stress of the cutting slope under saturation conditions was analyzed. The experimental results show that for the soil at the foot of the slope, the infiltration depth of rainfall is limited due to the low permeability coefficient, and the change of seepage field is not obvious; the longer the rainfall is held, the deeper the infiltration depth is, and the rainfall will continuously replenish the groundwater, so the force on the slope of the road graben will increase continuously and finally reach the limit of damage. When the rainfall intensity is 5mm-h-1, the decline of stability coefficient for 48 h is 0.121; the initial stability coefficient of the slope is the largest when the dip angle of the weak interlayer is equal to 25∘, and the stability coefficient decreases rapidly with the rainfall time, and when the rainfall reaches 60 h, the stability coefficient tends to be stable and the equilibrium of the slope force no longer changes.

Simultaneous enhancement of soil properties along with water-holding and restriction of Pb–Cd mobility in a soil-plant system by the addition of a phosphorus-modified biochar to the soil

Soil quality deterioration and heavy metal contamination have greatly limited soil productivity in mining areas. As soil is a complex system with various properties and interactions, it is imperative to conduct a comprehensive investigation to understand the amendment's mechanisms at work in the soil in mining areas as well as effective ways to address its deteriorating quality. In this study, a potassium dihydrogen phosphate-modified maize straw-cow dung biochar (PBC) was applied as a soil amendment. Various physicochemical properties of the soil including organic matter, total nitrogen, available phosphorus, and pore characteristics were analyzed. This study also assessed soil-saturated water content and soil moisture characteristic curve. Lettuce biomass was measured and changes in various speciation of Pb and Cd in the soil, and the accumulation of Pb and Cd in lettuce were examined. Results showed that the addition of PBC increased soil organic matter, total nitrogen, and available phosphorus while reducing soil bulk density, it also increased soil porosity, saturated water content, and capillary water capacity. Soil structure analysis using CT scanning revealed that 3% PBC increased the macrospores volume fraction while 5% PBC made the pores more uniform. Lettuce biomass increased by 53.3%. 5% PBC resulted in a 56.79% and 38.30% reduction in Pb and a 44.56% and 16.60% reduction in Cd in roots and shoots of lettuce respectively. PBC facilitated the transformation of Pb and Cd from unstable fractions to stable fractions through complexation and precipitation. Overall, the addition of PBC effectively improved soil nutrients, porosity, and water-holding capacity, promoted plant growth, immobilized Pb and Cd, as well as reduced the bioavailability in contaminated-soil from mining areas. This study provides an effective strategy and a new perspective for the remediation of Pb–Cd-contaminated soils.

The Thermal Conductivity and Matric Potential (Moisture Tension) Relationships for Soils of Different Gypsum Content

The soil samples have been taken from a soil profile at the Research Station of College of Agriculture in the University of Tikrit at a longitude of 430 38- 23= in the east and at a latitude of 340 48- 40= in the north. The samples were taken from the surface horizon with a gypsum content of 62 g.kg-1 (G1) and also from the subsurface horizon of 443g.kg-1 (G7) gypsum content. Different gypsum content samples were prepared as G2, G3, G4, G5, and G6 that have Gypsum contents of 106, 153, 202, 245, and 337 g.kg-1 respectively. These samples were prepared by mixing the surface soil samples with the soil of gypsic horizon. The prepared soil samples were wetted by water spraying to two thirds the field capacity levels (0.25 kg.kg-1). Then they incubated for two months in order to make soils homogeneity in addition to moisture distribution in soil. The plastic rings of 10.4 cm diameter and 10 cm heights were drilled from the middle to fix the sensor of heat flux of thermometer plug. The size and height of the soil to be placed in the plastic ring was calculated based on the area A and height h of ring and then the mass of the soil (m) was calculated based on the value of the bulk density. The samples were oven dried at 70° degree until the weight of samples were fixed to obtain the completely dry soils. The amount of water to be added per sample was calculated based on the moisture characteristics curve and by the tensions specified in this study (0.1, 5, 15, 33 and 100) kPa. The moisture was converted to a depth of water and then soil samples were wetted in a light spraying manner with continuous flipping and the thermometer sensors were fixed up and down the heat flux sensor and then six readings per replication were recorded. The time from one reading to another was 60 seconds and their rate was extracted. Based on the results of the experiment, it can be concluded that by the fixation of moisture tension, the thermal conductivity values of the soil decreased with the increased soil content of gypsum, as the G3 treatment with gypsum content 15% gave the highest significant value while the least significant average value of thermal conductivity values at the G7 treatment with gypsum content was 43%. The increase in gypsum from 25% at G5 to 30% and 44% in G6 and G7 successive treatments did not significantly affect the values of the soil’s thermal conductivity averages. The overlap point of the relationship between soil gypsum content and thermal conductivity was found at G3 and G4 that have gypsum content of 15% and 25% respectively. The average of gypsum decreases the thermal conductivity values of the soil with increased moisture tension values, as the tension gave 0.1 kPa a significant increase in the values of the average thermal conductivity from the rest of the tensions and for all treatments while the least significant average of thermal conductivity values at tension was 100 kPa.

Effect of unsaturated flow on groundwater-river interactions induced by flood event in riparian zone

A coupled unsaturated–saturated model for groundwater flow in a riparian zone is established to evaluate the impacts of unsaturated zone on groundwater flow and aquifer-river interactions during a flood event. The semi-analytical solutions for hydraulic head and discharge are obtained by the Laplace-Fourier transform and verified with COMSOL Multiphysics. The results show that the groundwater flow induced by a flood wave is significantly influenced by the dimensionless constitutive exponent κD in the moisture characteristic curve: the larger the value of κD, the stronger the water storage capacity of unsaturated zones, leading to smaller fluctuations of the hydraulic head and higher water amount exchanging between an aquifer and river. The present solution approaches to the solution for an unconfined aquifer when κD=100, and approaches to the solution of confined aquifers when κD=0.01. A thicker unsaturated zone causes less hydraulic head change and slower head recession after a flood wave passes. The traditional solution for an unconfined aquifer tends to underestimate the hydraulic head and overestimate the water exchange between the aquifer and river because it neglects the water retention of the unsaturated zone. The solution is applied to field data, and it improves the prediction of hydraulic heads over a previous solution.

Effects of five years conservation tillage for hedging against drought, stabilizing maize yield, and improving soil environment in the drylands of northern China.

Continuous tillage cultivation positioning trials can provide the basis for maintaining soil health, improving resource utilization efficiency and crop productivity, and achieving sustainable agricultural development. In this study, changes in soil stability and water-holding capacity characteristics were measured under different tillage cultivations from a multi-year microscopic perspective and analyzed to evaluate selected key indicators. Continuous monitoring of rainfall utilization efficiency and yield was carried out for five years. Here, we discuss the role of conservation tillage in buffering and stabilizing rainfall precipitation pattern on the fluctuation and uncertainty of soil water retention and water supply capacity and soil quality. The study was carried out on dryland areas of the Loess Plateau in northern China with eight tillage systems established in 2016: no-tillage (NT); no-tillage and straw (NTS); subsoiling (SU); subsoiling and straw (SUS); rotary tillage (RT); rotary tillage and straw (RTS); conventional tillage (CT); and conventional tillage and straw (CTS). All treatments were applied in conjunction with continuous cropping for five years. The evaluated soil parameters were mean weight diameter (MWD), geometric mean diameter (GMD), >0.25 mm aggregate content (R0.25) of water-stable aggregates (WSAs), soil moisture characteristic curve (SMCC), specific soil water capacity (Cθ), soil organic matter (SOM), rainfall utilization efficiency (RUE), and maize yields for five consecutive years. The MWD, GMD, and R0.25 of SUS were 27.38%, 17.57%, and 7.68% more than CTS (control), respectively. Overall, SOM, average annual RUE, and average annual yields increased by 14.64%, 11.89%, and 9.59%, respectively, compared with 2016. Our results strongly suggest that conservation tillage can considerably improve these characterization indicators. SUS was more effective than CTS in the 0-40 cm soil layer at hedging against drought in the area, stabilizing crop production, and achieving sustainable agricultural development.

The ecosystem wilting point defines drought response and recovery of a Quercus-Carya forest.

Soil and atmospheric droughts increasingly threaten plant survival and productivity around the world. Yet, conceptual gaps constrain our ability to predict ecosystem-scale drought impacts under climate change. Here, we introduce the ecosystem wilting point (ΨEWP ), a property that integrates the drought response of an ecosystem's plant community across the soil-plant-atmosphere continuum. Specifically, ΨEWP defines a threshold below which the capacity of the root system to extract soil water and the ability of the leaves to maintain stomatal function are strongly diminished. We combined ecosystem flux and leaf water potential measurements to derive the ΨEWP of a Quercus-Carya forest from an "ecosystem pressure-volume (PV) curve," which is analogous to the tissue-level technique. When community predawn leaf water potential (Ψpd ) was above ΨEWP (=-2.0MPa), the forest was highly responsive to environmental dynamics. When Ψpd fell below ΨEWP , the forest became insensitive to environmental variation and was a net source of carbon dioxide for nearly 2 months. Thus, ΨEWP is a threshold defining marked shifts in ecosystem functional state. Though there was rainfall-induced recovery of ecosystem gas exchange following soaking rains, a legacy of structural and physiological damage inhibited canopy photosynthetic capacity. Although over 16 growing seasons, only 10% of Ψpd observations fell below ΨEWP , the forest is commonly only 2-4 weeks of intense drought away from reaching ΨEWP , and thus highly reliant on frequent rainfall to replenish the soil water supply. We propose, based on a bottom-up analysis of root density profiles and soil moisture characteristic curves, that soil water acquisition capacity is the major determinant of ΨEWP , and species in an ecosystem require compatible leaf-level traits such as turgor loss point so that leaf wilting is coordinated with the inability to extract further water from the soil.

The impact of cyanobacteria inoculation on soil hydraulic properties at the lab-scale experiment

Ecosystem-based approaches, including soil inoculation, have been considered to improve the soil water behavior, for the purpose of ensuring better irrigation management on farms. This study was, therefore, conducted to assess the responses of the moisture characteristic curve (MCC) and saturated hydraulic conductivity (SHC) to soil inoculation with cyanobacteria. To this end, the most suitable existing cyanobacteria (i.e., Nostoc sp. and Oscillatoria sp.) from the original soil were inoculated on clay, loam and sand textures at a small cylinder scale. After 35 days, the MCC and SHC of the treatments (six control and inoculation treatments in three repetitions) were measured using the sandbox and pressure plate, and constant head method, respectively. The results showed that, in the control treatment, the volumetric water content of the clay, loam and sand textures was 38–69%, 28–58% and 8–24%, respectively. Meanwhile, the inoculation of cyanobacteria led to a significant (P < 0.05) increase in the MCC of the loam and sand soils; their values were 36–65% and 16–31%, respectively. In the control, the SHC of the clay, loam and sand textures was 0.42, 0.54 and 1.21 cm min−1, respectively; meanwhile, this was 0.37, 0.50 and 0.67 cm min−1 for the inoculated treatments, respectively. On the other hand, the inoculated cyanobacteria reduced the SHC of the sand soils by 44%. We also found that the inoculated cyanobacteria perceptibly improved the soil surface physical and chemical properties, which could play a key role in determining the soil hydraulic and hydrologic behavior. Overall, we found that soil inoculation with cyanobacteria could be an effective approach in improving the soil water behavior, especially in coarse texture soils; thus, it could serve as a suitable irrigation and drainage management method in agricultural lands.

Physical and hydrological characteristics and modelling of the soil water retention curve in the brazilian semi-arid region

Semiarid regions are characterised by water scarcity, a limiting factor on plant growth and development. The Sertão Canal was built in the semiarid region of Brazil, more specifically in the state of Alagoas, with the aim of making year-round irrigation possible. However, for the best water management, a physical and hydrological knowledge of the soils is necessary. As such, the aim of this study was to determine the physical and hydrological characteristics of three different types of soil (Argisol, Quartzarenic Neossol and Regolithic Neossol) under native vegetation (Caatinga) and agricultural systems in the semiarid region of Alagoas, as well as to adjust the soil water retention characteristic curves. Soil samples were collected at depths of 0-10, 10-20 and 20-30 cm in the municipalities of Inhapi, Delmiro Gouveia and Pariconha, in the state of Alagoas. The points of the moisture characteristic curve were determined by the Richards method, at pressures of 33, 100, 500, 1000 and 1500 kPa. Retention curves were modelled using the exponential decay equation and compared using the van Genuchten equation, modelled with the help of the RETC computer software. Particle size varied according to the textural classification of the different soils, from Sand to a Sandy Clay Loam. The retention curve fluctuated due to the particle size of the soil, with the Red-Yellow Argisol (Inhapi) having a greater capacity for water retention. Extremely sandy soils, such as those in the Delmiro Gouveia region, had a low capacity for retaining water. For each soil sample, the exponential decay equation gave the best fit, with values for R2adjust of greater than 0.93. When the measured soil moisture levels were compared with the levels estimated by the RETC model, some of the treatments were unable to estimate accurately the moisture levels obtained with the soil water retention curves.

Measurement of the hydraulic properties of chalk using centrifuge permeameter; the study of chalk hydraulic properties under accelerated gravitational force

In this study, a geotechnical centrifuge has been used to study the unsaturated hydraulic properties of rock samples from the chalk aquifer, SE England. This method allows rapid measurement of hydraulic properties in a controlled environment, in contrast to previous studies on the chalk unsaturated zone, which required either an extended period (years) of data monitoring in the field or extended experimental periods (weeks) in the laboratory. Three types of specially built sensors were used to monitor water flow through chalk samples: a water pressure transducer to measure matric potential, frequency domain reflectometry probes to measure the volumetric water content and pressure transducers to measure the volume of water passing through the sample. Chalk samples were tested during wetting and draining processes to understand any hysteresis occurring during periodic recharge of the aquifer. Before undertaking physical tests of chalk samples in the centrifuge, a theoretical model of chalk hydraulic behaviour under centrifugal force was developed. This model was used to define and justify the instrumentation plan of the physical model and predict the shape of the soil moisture characteristic (SMC) curve and unsaturated hydraulic conductivity (Ku) function. The results were then evaluated and compared with the experimental results. These results show that chalk samples can be successfully tested under centrifuge conditions and hydraulic properties can be measured, including soil moisture characteristic curves and hydraulic conductivity.Supplementary material:Calculation spread sheets are available athttps://doi.org/10.17033/DATA.00000283

Retraction Note: Prediction of soil moisture characteristic curve based on Internet of Things and enterprise e-commerce operation

E-commerce has an important influence on China’s economic and social development. The rapidly emerging Internet of Things and other emerging information technologies can promote the revolutionary innovation and development of e-commerce products and industries. Online direct sales channels fully apply the Internet of Things technology and e-commerce. The operations and channels have more power to apply the Internet of Things technology. If offline business operations have stronger advantages than online e-commerce operations, the Internet of Things technology and the diffusion process are incorporated into the database model; when the proliferation of the Internet of Things remains local, e-commerce operations can only obtain higher efficiency and benefits after applying the Internet of Things technology online, to closely integrate the new generation of information technology with traditional operating strategies. At the same time, government support policies have played an important role in promoting the application of a new generation of information technology. The particle gradation, stress status, dry density, etc., in the soil moisture characteristic curve prediction system may change with the operation of the soil in the atmosphere, and these influencing factors are important measurements that affect soil permeability and land water quality characteristics. The prediction of soil moisture characteristic curve, soil permeability, and soil erosion resistance are linked together, and the study of the influence of these influencing factors on soil permeability and soil moisture characteristics on soil water retention is useful for exploring the mechanism of soil erosion and soil erosion. Sexual control measures have very important guiding significance. Therefore, this paper uses the Internet of Things technology to conduct a detailed study on the prediction content of the soil moisture characteristic curve and the process of enterprise e-commerce operations.

Experimental study of hydraulic properties in grain packs: Effects of particle shape and size distribution

Uniform and multi-dispersed grain packs have been frequently used to conceptually study flow in porous media. Numerical simulations were previously used to address the effect of particle shape on characteristics, such as pore space fractal dimension, moisture characteristic curve (MCC) and saturated hydraulic conductivity (SHC) of grain packs. However, experimental observations are still required since fractal-based approaches have been extensively proposed to model various properties in porous media. In this study, 16 angular sand and 16 spherical glass bead samples with different particle size distributions (PSDs) from well- to poorly-sorted were packed. The MCC was measured using the combination of sandbox and pressure plates methods. The pore space fractal dimension (DMCC), calculated from the measured MCC, ranged from 0.80 to 2.86 in sand and from ‐0.18 to 2.81 in glass bead packs, which indicated that DMCC may be negative in homogeneous media (e.g., glass bead packs) consistent with several studies in the literature. Results showed greater DMCC for the sand packs than the glass bead packs with the same geometric mean diameter values and PSDs. This clearly demonstrated the effect of particle shape on DMCC in the studied packs. The critical path analysis (CPA) approach was used to estimate the SHC measured using the constant-head method. We found that the CPA estimated the SHC accurately, within a factor of four of the measurements on average. Although the CPA is theoretically known to be accurate in media with broad pore size distributions, we experimentally found that it estimated the SHC in various types of grain packs reasonably well.

English

The hydraulic properties of soil are very important to determine the soil relationship with water. The Soil Hydraulic Properties (SHP) are used to determine the soil water relationship as it is very crucial for estimation of water holding capacity of soil. In real field conditions, most widely used model for soil moisture retention curves is van Genuchten model. The soil samples were taken randomly from five different depths with three replications of each depth. Moreover, two samples at the depth of 5-35cm and 35-155cm were selected for evaluation of integrated approach to find soil characteristic curves. Soil moisture characteristic curves calculated by integral approach were compared with, soil moisture curves measured by pressure plate apparatus, and Soil Plant Air Water (SPAW) hydrology a computer based Model. The accuracy of results were evaluated by determination of Root Mean Square Error (RMSE), Normalize Root Mean Square Error (NRMSE) and Willmott’s index of agreement (£). A good agreement was observed between integrated approach, high-pressure technique and SPAW model results. In case of integrated method versus high-pressure technique the RMSE was 9.51×10-3 for 5-30cm depth and 8.32×10- 3 for 30-155cm depth. The NRMSEs was 6.52 ×10-2 for 5-30cm depth and 6.1×10-2 for 30-155cm depth, similarly £ was 0.881 and 0.893 for both depths 5-30cm and 30-155cm respectively. Regression coefficient (R2 ) for 5-35cm depth for sorptivity (s) and wetting distance (d) were 0.991 and 0.988 respectively and at depth of 35-155cm, R2 for (s) was 0.990 and for wetting distance (d) was 0.994. In case of integrated method versus SPAW hydrology the RMSEs was 1.3×10-2 for 5-30cm depth and 1.15×10-2 for 30-155cm depth. The NRMSEs for was 9.33 ×10-2 for 5-30cm depth and 7.15×10-2 for 30-155cm depth and similarly £ was 0.852 and 0.863 for both depths respectively. Results indicated a good relationship between high-pressure technique, SPAW hydrology results and integral method. However, integrated approach is best approach to determine the soil moisture characteristics curves of undisturbed and unsaturated soils

Relationship of soil moisture characteristic curve and mechanical properties in Entisols and Inceptisols of Iran

The objective of this research was to investigate the relationship between soil moisture characteristic curve (SMCC) and confined compression curve (CCC), and the ability to estimate the SMCC from the CCC. Five provinces of Iran have been chosen as sampling sites and soil samples (150) were collected from these areas, and some properties of the soil samples were determined. The Gardner model has been fitted to the measured SMCC and CCC. The Gardner model's stress-void ratio coefficients, as well as the CCC properties, were used to estimate the soil moisture at five levels (five classes of variables) through the Gardner model using artificial neural networks (ANNs). A more accurate estimation of the water content was obtained by combining the basic soil properties, and three key properties of soil compression. In addition, the integral root mean square error (IRMSE) in the training and testing steps was reduced from 0.107 and 0.111 to 0.095 and 0.096, respectively. In conclusion, the use of CCC data to estimate the SMCC at all levels of the input variables indicated very favorable results with an increase in the accuracy of the water content estimation between 4% and 16% in both training and testing steps.

RETRACTED ARTICLE: Prediction of soil moisture characteristic curve based on Internet of Things and enterprise e-commerce operation

E-commerce has an important influence on China’s economic and social development. The rapidly emerging Internet of Things and other emerging information technologies can promote the revolutionary innovation and development of e-commerce products and industries. Online direct sales channels fully apply the Internet of Things technology and e-commerce. The operations and channels have more power to apply the Internet of Things technology. If offline business operations have stronger advantages than online e-commerce operations, the Internet of Things technology and the diffusion process are incorporated into the database model; when the proliferation of the Internet of Things remains local, e-commerce operations can only obtain higher efficiency and benefits after applying the Internet of Things technology online, to closely integrate the new generation of information technology with traditional operating strategies. At the same time, government support policies have played an important role in promoting the application of a new generation of information technology. The particle gradation, stress status, dry density, etc., in the soil moisture characteristic curve prediction system may change with the operation of the soil in the atmosphere, and these influencing factors are important measurements that affect soil permeability and land water quality characteristics. The prediction of soil moisture characteristic curve, soil permeability, and soil erosion resistance are linked together, and the study of the influence of these influencing factors on soil permeability and soil moisture characteristics on soil water retention is useful for exploring the mechanism of soil erosion and soil erosion. Sexual control measures have very important guiding significance. Therefore, this paper uses the Internet of Things technology to conduct a detailed study on the prediction content of the soil moisture characteristic curve and the process of enterprise e-commerce operations.

Application of Differential Evolution Cuckoo Search Algorithm in Parameter Optimization of VG Equation

Van Genuchten (VG) equation is the most commonly used equation of soil moisture characteristic curve, and the accuracy of its parameters directly affects the calculation accuracy of soil moisture motion equation. In order to obtain the parameters of the equation more accurately, this paper establishes an optimization model of the VG equation parameters. This optimization model uses the advantages of the cuckoo search algorithm and the differential evolution algorithm to combine the two into a new hybrid cuckoo search algorithm, namely DECS algorithm, and uses this algorithm to solve the parameter optimization problem of VG equation of soil moisture characteristic curve. By collecting and analyzing the relevant experimental data of various soil qualities, the dehumidification and moisture absorption curves of three different soil qualities were selected for simulation calculation. The results show that in the experiment of solving the parameter estimation problem of the VG equation, the DECS hybrid algorithm has better exploration and development capabilities than the cuckoo search algorithm. The hybrid algorithm has relatively significant performance in terms of calculation accuracy and convergence.