Initial Soil Moisture Content Research Articles

Effect of Soil Compaction due to Organic Matter and 4-Wheel Tractor Traffic on Sugarcane Growth

Background: Soil compaction can occur due to the intensity of tractor traffic in the tillage process. The objective of this study was to determine the changes in physical, mechanical properties of the soil and plant growth that occurred due to tractor traffic and how it would affect if the addition of organic matter (compost) was added to the soil. Methods: The experimental work was conducted at the Sugarcane Plantation of PTPN II Klumpang at an initial soil moisture content of 24.69% and a bulk density of 1.08 gr/cm3 with compost and no compost then the land is traversed by the tractor with 2,4 and 6 passes. Result: The results of indicate that the tractor trajectory and the addition of compost have a significant effect on soil compaction. The highest values for water content, bulk density, particle density and penetration resistance were obtained at 6 times tractor traffic with soil without compost sowing respectively 35.36%, 1.31 gr/cm3, 1.87 gr/cm3, 9.61 kgf/cm2, while in soil with compost, the values obtained were 33.62%, 1.23 gr/cm3, 1.82 gr/cm3, 9.04 kgf/cm2, respectively. These findings indicated that the application of compost can reduce the level of soil density so that plant growth becomes better and more even rate of plant growth is obtained than without compost.

Influence of Hydraulic Response Time of Tensiometer in Hydraulic Characteristics Estimation for Riverbank Sand

The knowledge of the continuous evolution of soil hydraulic characteristics is required for several environmental geotechnical applications such as capillary barrier systems and river bank slope stability analysis. Such data are obtained in the field by embedding suction sensors in slopes for stability analysis. The hydraulic equilibrium time and other limitations of sensors in establishing the hydraulic characteristics are not available for the compacted soils. Thus the influence of initial soil moisture content, initial wetting condition of the suction sensor, and soil compaction density on the hydraulic equilibrium time of the tensiometer was studied on riverbank sand. A laboratory method considering the equilibrium data at each saturation/drying state was proposed for establishing the equilibrium-SWCC data. The hydraulic equilibrium time of the tensiometer for the studied soil was found to vary from a few hours to several days depending upon the magnitude of suction and state of the sensor. The conventional method for estimating the instantaneous SWCC severely overestimated the suction values at a given water content. The sensor response time was found to be the single most influencing factor in the estimation of soil hydraulic characteristics. The in-situ tensiometer application should be replaced with the moisture sensor readings combined with the lab-based proposed equilibrium SWCC approach.

How much raindrop energy is used for transportation of the two-phase splashed material?

The ejection of a mixture of solid (soil) and liquid (water) phases is one of the aspects of the energy dissipation of the impacting drop during the soil splash phenomenon. All calculations to date have only been taking into account the ejection of solid phase material and were based on significant simplifications of the measured quantities. Therefore, the aim of the study was an improved calculation of the falling drop energy transferred to the ejected material, while considering that such material was a mixture of solid soil particles and water droplets and therefore, “two-phase”. Experimental variants included combinations of soils with different textures and initial moisture contents as well as various falling water-drop energies. Two complementary methods of i)splash cup measurements and ii) image analysis based on high-speed cameras were used for the calculation of quantities i.e. the number of ejected particles, their mass, and their ejection velocity. Based on the obtained results, it was stated that the kinetic energy of ejected particles, expressed as a percentage of falling drop energy, ranged from 1 % to 14 %. This percentage depended strongly on soil texture as well as initial moisture content. The highest values were obtained for soil with the largest amount of sand fraction and the lowest for the soil with the largest amount of finer fractions. All tested soils showed a trend of a higher drop energy transferred to the splashed particles with increasing initial soil moisture content. Taking into account the varied energy of the falling drop variants, the amount of energy transferred to ejected particles was constant.

Experimental Investigation of Relationship between Infiltration Rate and Soil Moisture under Rainfall Conditions

In this study, a mathematical expression describing the relationship between infiltration rate and soil moisture content was deduced based on the Horton equation in order to study the relationship between infiltration rate and soil moisture content during the rainfall infiltration process. Specific experimental data on infiltration processes were used to verify the validity of the equations and to analyze the main factors affecting the infiltration rate. The results indicate the following: (1) The experimental data demonstrated a high degree of accuracy. The volumetric error of soil moisture increase and cumulative infiltration was 3.5% and the coefficient of determination (R2) was 0.87 in the 42 tests. (2) The equation obtained in this paper can well describe the relationship between infiltration rate and soil moisture content; the R2 of the fitted results was greater than 0.80 in more than 80% of the experiments. (3) The relationship between infiltration rate and soil moisture content is mainly influenced by initial soil moisture content; the higher the initial soil moisture content, the lower the initial infiltration rate, the faster the infiltration rate decreases with soil moisture content, and the lower the “relative stable infiltration rate” in the process of infiltration.

Influence of Rainfall Events and Surface Inclination on Overland and Subsurface Runoff Formation on Low-Permeable Soil

This paper presents the results of laboratory tests that allowed us to determine the effect of the soil surface inclination and its initial moisture content on the formation of overland and subsurface runoff. The experiments were carried out for the soil that is commonly present in the southern part of Poland, including the Outer Carpathians. The results of these measurements served as a reference for overland runoff calculations using the Richards model, simplified Green–Ampt model, and the empirical model (MSME). The results of the measurements showed that, for low-permeable soil, overland runoff is the dominant form. It was shown that a slope in the range of 2.5–5.0% does not have a significant effect on the amount of overland runoff, but affects its dynamics. The measurements also showed that the starting time and amount of overland runoff are strictly associated with the initial soil moisture content. High soil moisture content in the period preceding the onset of rainfall causes faster generation and an increase in overland runoff, which is caused by the saturation of the surface layer of the soil. This mechanism was confirmed by the results of calculations using the Richards model and measurements of the electrical resistance of the soil. Theoretical calculations showed that the results of the runoff calculations using the Richards and Green–Ampt models are strongly dependent on the hydraulic properties of the soil adopted for the analysis. It was also demonstrated that the modified MSME model satisfactorily estimates the amount of overland and subsurface runoff, but requires parameter calibration based on existing hydrological data.

Effects of rock fragment coverage on soil erosion: Differ among rock fragment sizes?

The presence of rock fragments can change land cover and thus profoundly perturb soil erosion process. This study aimed to identify the effects of rock coverage on soil erosion, and how such effects were influenced by rock fragment sizes. A series of simulated rainfall experiments were applied to erosion plots with two initial soil moisture contents (dry run and wet run), under rock fragment coverage (15%, 30%, 45%, 60%) composed of eight different fragment sizes (0.7, 1.1, 3.0, 5.5, 12.0, 18.8, 26.4, 36.0 cm) from May to September in 2021. The results show that total runoff and sediment concentration increased with rock fragment size. When rock fragments with the sizes were less than 12.0 cm, the total runoff and sediment concentration were respectively 0.81–16.02% and 16.45–50.88% lower than the bare soil. Consequently, the soil loss decreased exponentially with rock fragment coverage. When rock fragment with the sizes were large than 12.0 cm, they decreased sediment concentration by 7.91–33.32% in the dry run, but increased the total runoff by 0.26–10.28% and sediment concentration by 9.33–82.91% in the wet run. As a result, the soil loss ratio firstly enhanced as rock fragment coverage up to 45% and then declined at the rock fragment coverage of 60%. Our findings demonstrate that the effects of rock fragment coverage on soil erosion are rock fragment size dependent. This can help to better parameterize the effects of rock fragment coverage in current soil erosion models, in turn providing guiding information for soil erosion control in stony regions.

Estimating groundwater recharge in the assiniboine delta aquifer using HYDRUS-1D

Unconfined aquifers are often directly impacted by high irrigation demands. Therefore, accurate recharge estimates are crucial for sustainable groundwater management. It is important over time to re-examine the existing hydrologic understanding of aquifers, taking into account developments in knowledge and changing climate conditions. The last in depth study into the Assiniboine Delta Aquifer located in Manitoba, Canada, that gave a recharge estimate was conducted in the 1980s (Render, 1988). This work re-examined the Assiniboine Delta Aquifer, employing new methods and data to estimate recharge rates. Twelve one-dimensional models were created in the software HYDRUS-1D to model the soil water fluxes in the unsaturated zone to analyze the historic recharge from 1996 to 2019. Remote weather station data, measured hydraulic conductivity, soil texture distribution, soil moisture content, and soil temperature data were used to initialize and run the models. Inverse calibration used the measured moisture contents to calibrate the models, which resulted in Root Mean Square Error in the calibration and validation periods averaging 0.034 and 0.051 m3/m3, respectively, above the 0.025 m3/m3 sensor measurement error. Rough estimates of soil texture distribution across the aquifer was determined to assist in the final recharge estimate. The historical regional recharge average was estimated to be 68 mm/year, double the previous estimate for the aquifer (Render, 1988). Modelled periods were limited to less than a year due to limitations in the general HYDRUS-1D software model code under frozen soil conditions, which the Assiniboine Delta Aquifer experiences during the winter months. Assumptions on initial soil moisture contents, snowpack heights, and model start dates were best estimated for historical years. Results show these estimates can have significant impacts on the resulting recharge. Suggested future work includes implementing the HYDRUS-1D freeze-thaw code to allow for model spin-up and multi-year simulations to enhance the reliability of model results.

Analysis of urea nitrogen leaching under high-intensity rainfall using HYDRUS-1D

The leaching of nitrogen in farmland could lead to groundwater nitrogen pollution, while precipitation is the driving factor. Nevertheless, the influences of extreme precipitation on soil organic nitrogen leaching, such as urea, is not clear. In this study, we used soil column experimental data to construct a nitrogen migration and transformation model. The constructed model was applied to unsaturated zones in farmlands in the Dagu River Basin of China. Three rainfall scenarios, namely rainstorms, heavy rainstorms, and extreme rainstorms, were simulated to analyze the variation in urea nitrogen leaching to groundwater. As the rainfall intensity increased, the quantity of urea nitrogen leaching increased from 0.04% to 18.09%. The cumulative urea nitrogen leaching flux is related to the initial soil moisture content. The time interval between fertilization inversely influenced the urea nitrogen leaching flux. Applying urea-based fertilizers shortly before high-intensity rainfall significantly increases the soil-crop system urea leaching loss and decreases crop nitrogen utilization. These findings imply that urea leaching under extreme rainstorms should not be ignored, and based on weather forecasting, fertilizer application in farmland should be avoided before high-intensity rainfall.

Mixed Effects of Soil Compaction on the Nitrogen Cycle Under Pea and Wheat.

Soil compaction caused by highly mechanized agriculture can constrain soil microbial diversity and functioning. Physical pressure on the soil decreases macropores and thereby limits oxygen diffusion. The associated shift from aerobic to anaerobic conditions can reduce nitrification and promote denitrification processes, leading to nitrogen (N) losses and N depletion that affect plant productivity. High soil moisture content during trafficking can exacerbate the negative effects of soil compaction. However, the extent to which soil moisture amplifies the effects of compaction on the soil microbiome and its control over N cycling is not well understood. Using a controlled greenhouse experiment with two different crops (pea and wheat), we compared the effects of compaction at three different soil moisture levels on soil physicochemical properties, microbial diversity, and the abundance of specific N species and quantification of associated microbial functional groups in the N cycle. Soil compaction increased bulk density from 15% (light compaction) to 25% (severe compaction). Compaction delayed germination in both crops and reduced yield by up to 60% for pea and 40% for wheat. Compaction further induced crop-specific shifts in microbial community structures. After compaction, the relative abundance of denitrifiers increased along with increased nitrate (NO3–) consumption and elevated nitrous oxide (N2O) concentrations in the soil pores. Conversely, the relative abundance of nitrifiers remained stable under compaction, but potentially decelerated nitrification rates, resulting in ammonium (NH4+) accumulation in the soil. This study showed that soil compaction effects are proportional to the initial soil moisture content, which could serve as a good indicator of compaction severity on agricultural fields. However, the impact of soil compaction on crop performance and on microbial communities and functions associated with the N cycle were not necessarily aligned. These findings demonstrate that not only the soil physical properties but also various biological indicators need to be considered in order to provide more precise recommendations for developing sustainable farming systems.

Hydrologic‐land surface modelling of the Canadian sporadic‐discontinuous permafrost: Initialization and uncertainty propagation

AbstractPermafrost thaw has been observed in recent decades in the Northern Hemisphere and is expected to accelerate with continued global warming. Predicting the future of permafrost requires proper representation of the interrelated surface/subsurface thermal and hydrologic regimes. Land surface models (LSMs) are well suited for such predictions, as they couple heat and water interactions across soil‐vegetation‐atmosphere interfaces and can be applied over large scales. LSMs, however, are challenged by the long‐term thermal and hydraulic memories of permafrost and the paucity of historical records to represent permafrost dynamics under transient climate conditions. In this study, we aim to understand better how LSMs function under different spin‐up states, which facilitates addressing the challenge of model initialization by characterizing the impact of initial climate conditions and initial soil frozen and liquid water contents on the simulation length required to reach equilibrium. Further, we quantify how the uncertainty in model initialization propagates to simulated permafrost dynamics. Modelling experiments are conducted with the Modélisation Environmentale Communautaire—Surface and Hydrology (MESH) framework and its embedded Canadian land surface scheme (CLASS). The study area is in the Liard River basin in the Northwest Territories of Canada with sporadic and discontinuous regions. Results show that uncertainty in model initialization controls various attributes of simulated permafrost, especially the active layer thickness, which could change by 0.5–1.5 m depending on the initial condition chosen. The least number of spin‐up cycles is achieved with near field capacity condition, but the number of cycles varies depending on the spin‐up year climate. We advise an extended spin‐up of 200–1000 cycles to ensure proper model initialization under different climatic conditions and initial soil moisture contents.

Impact of Drying and Wetting Cycles on Vegetation Cement-soil Physical and Mechanical Properties

The physical and mechanical properties of the ecological slope protection substrate will be affected by long-term variation of the meteorological condition, resulting in the stability of the substrate being reduced. So an artificial substrate of vegetation cement-soil was selected as the research object to prepare specimens with the different initial moisture content of 13%, 19%, 25%, 31%, 37%, and 43%. And a series of tests are conducted to investigate the evolution of the physical and mechanical properties under drying-wetting cycling conditions. Typical results of the vegetation cement-soil evolution can be divided into three stages: cement hydration stage, shrinkage stage, and stabilization stage. In terms of different initial moisture content, the shrinkage cracks number, cracks length, crack width, and cracks surface area are increased first and then stabilize with the increase of the number of drying-wetting cycles. In contrast, the cohesion and internal friction angle of the vegetation cement-soil is reduced with the increase of the number of cycles. Comprehensive analysis shows that the initial moisture content of vegetation cement soil ranges from 25% to 31% is the optimal choice to ensure substrate stability in production practice.

A model for soil moisture content prediction based on the change in ultrasonic velocity and bulk density of tillage soil under alternating drying and wetting conditions

The feasibility of introducing soil bulk density as a factor to distinguish different levels of soil compactness for the predictive modeling of soil moisture content was verified. Outdoor rainfall was simulated to set different initial soil moisture contents, after which the soil was allowed to air dry in a natural environment. Four drying and wetting (D-W) cycles were simulated in the experiment. An ultrasonic detection device was employed to measure the soil ultrasonic velocity and calculate the corresponding soil bulk density.An adaptive weighted data fusion algorithm was adopted to integrate the soil ultrasonic velocity and bulk density results, and a bivariate linear regression model was established to describe the relationships of soil ultrasonic velocity and bulk density with soil moisture content over D-W cycles. The model suitably described the soil moisture content in a given cultivated layer as a function of soil ultrasonic velocity and bulk density.

Efficient Removal of Copper and Cadmium from Contaminated Soil Utilizing Electrokinetic Process

Present manuscript demonstrates the efficient removal of copper and cadmium from contaminated soil utilizing electrokinetic process. The results of systematic bench-scale study on improved extraction of copper and cadmium shows the suitability of process to decontaminate low permeable soil. The influence of operating parameters such as electrode material, soil pH, current density, soil temperature, inter-electrode spacing and initial soil moisture content on the decontamination performance is investigated. Study revealed that, removal of copper and cadmium reached to 89.4% and 62.7% respectively while using titanium electrodes. Removal efficiency improved with the increase in current density, soil temperature and initial soil moisture content. About 74.5% of copper removal achieved within 20 hours at soil temperature of 35°C and current density was kept at 9.3 mA/cm2. During this study, soil pH decreased from 6.7 to 2.4 near anode and reached up to 12.3 near cathode resulting in augmented metal removal. An improvement of 33% in removal efficiency observed when moisture content increased from 45% to 73%. Rate of metal removal increased as the inter-electrode spacing decreased to 15 cm, which demonstrated the highest copper removal at a current density of 9.3 mA/cm2. The maximum energy consumption found to be 5.2 kWh/m3 of soil volume demonstrated the economy of process, which can be scaled up at cleanup sites.

Exploring the Impacts of Genotype-Management-Environment Interactions on Wheat Productivity, Water Use Efficiency, and Nitrogen Use Efficiency under Rainfed Conditions.

Wheat production under rainfed conditions is restrained by water scarcity, elevated temperatures, and lower nutrient uptake due to possible drought. The complex genotype, management, and environment (G × M × E) interactions can obstruct the selection of suitable high yielding wheat cultivars and nitrogen (N) management practices prerequisite to ensure food security and environmental sustainability in arid regions. The agronomic traits, water use efficiency (WUE), and N use efficiencies were evaluated under favorable and unfavorable weather conditions to explore the impacts of G × M × E on wheat growth and productivity. The multi-N rate (0, 70, 140, 210, and 280 kg N ha−1) field experiment was conducted under two weather conditions (favorable and unfavorable) using three wheat cultivars (AUR-809, CHK-50, and FSD-2008) in the Pothowar region of Pakistan. The experiments were laid out in randomized complete block design (RCBD), with split plot arrangements having cultivars in the main plot and N levels in the subplot. The results revealed a significant decrease in aboveground biomass, grain yield, crop N-uptake, WUE, and N use efficiency (NUE) by 15%, 22%, 21%, 18%, and 8%, respectively in the unfavorable growing season (2014–2015) as compared to favorable growing season (2013–2014) as a consequence of less rainfall and heat stress during the vegetative and reproductive growth phases, respectively. FSD-2008 showed a significantly higher aboveground biomass, grain yield, crop N-uptake, WUE, and NUE as compared to other wheat cultivars in both years. Besides, N140 appeared as the most suitable dose for wheat cultivars during the favorable growing season. However, any further increase in N application rates beyond N140 showed a non-significant effect on yield and yield components. Conversely, the wheat yield increased significantly up to 74% from N0 to N70 during the unfavorable growing season, and there was no substantial difference between N70–N280. The findings provide opportunities for maximizing yield while avoiding excessive N loss by selecting suitable cultivars and N application rates for rainfed areas of Pothowar Plateau by using meteorological forecasting, amount of summer rainfall, and initial soil moisture content.

A method to compute the effect of vertical mulching on the reduction of surface runoff

Six plots (three as controls) were established in southern Brazil to assess the reduction in runoff by vertical mulching (vm). In the other three, ditches (0.08-m wide, 0.4-m deep) were cut perpendicular to the slope, 2-m and 12-m upslope from the bottom of the plot where a flume was installed to measure runoff. Three simulated rainfalls (80mmh-1 for 120min, 80mmh-1 for 65min, 97mmh-1 for 65min) were applied with a sprinkler system to generate runoff. Compared to the controls, vm delayed its beginning by 10 to 20min and reduced its volume by 34 to 39%, because initially all and later some runoff was caught in the ditches from where it infiltrated into the surrounding soil. Based on the experimental results, we derived a method to compute the runoff reduction by vm as influenced by ditch spacing (ds), initial soil moisture content (θi), and rainfall rate and duration. Computations for a combination of four ds (5 to 20m), five θi (16 to 32%-vol), and three rainfall regimes (124mmh-1 for 20min, 66mmh-1 for 60min, and 42mmh-1 for 120min) showed an increasing runoff reduction as ds or θi decreased. In some cases, runoff was even completely prevented. The reductions were larger in the 60-min than in the 20-min rainfall. For the 120-min rainfall, there was no runoff with any combination of ds and θi.

Effects of initial soil moisture content on soil water and nitrogen transport under muddy water film hole infiltration

Film hole irrigation has been widely adopted as an effective water-saving irrigation technology in the arid and semiarid areas of China. To investigate the effects of initial soil moisture content (θ0) on soil water and nitrogen transport characteristics under muddy water film hole infiltration, the laboratory experiments were conducted with muddy water film hole infiltration, using five initial soil moisture content treatments. The models for describing the relationships between the cumulative infiltration (I(t)) and infiltration duration (t); the relationship among the horizontal and vertical migration distances of the wetting front (Fx, Fz), θ0 and t, were established. The results showed that the initial soil moisture content had a significant effect on I(t), Fx, Fz and moisture content distribution in the wetted body. The change of I(t) over t conformed to Kostiakov model. With the increase of θ0, the infiltration coefficient (K) gradually decreased. NO–3-N was mainly distributed in the range of the wetting radius of 15 cm, while NH +4-N was mainly distributed in the range of the wetting radius of 8 cm. This study can provide a theoretical basis and technical support for film hole irrigation. Keywords: film hole irrigation, muddy water, initial soil moisture content, water and nitrogen transport, water redistribution DOI: 10.25165/j.ijabe.20211404.6024 Citation: Liu L H, Fei L J, Chen L, Hao K, Zhang Q J. Effects of initial soil moisture content on soil water and nitrogen transport under muddy water film hole infiltration. Int J Agric & Biol Eng, 2021; 14(4): 182–189.

Application of bio-cementation to enhance shear strength parameters of soil-steel interface

In this study, the microbially induced calcite precipitation process is introduced to a sandy soil-steel interface. A series of modified direct shear tests designed based on the Taguchi design of experiments method are conducted to examine the bio-cemented soil-steel interface strength parameters. The primary test results are analyzed using the ANOM and ANOVA approaches, and the predictions of the Taguchi method are compared with the test results. The effects of the initial soil moisture content, density ratio of urea/CaCl2, and rate of injection of the cementation solution on the response of the bio-cemented sand-steel interface are scrutinized. Both the ANOM and ANOVA show that the density of the cementation solution is the most influential parameter, while the initial soil moisture content is the least influential factor in the bio-cementation process of the sand-steel interface. The test results show that introducing bio-cementation process to the soil-steel interface is an effective approach in enhancing the interface properties, increasing the sand-steel interface shear strength 3 to 7 times, depending on the normal stress used in the tests. The results also show that the initial moisture content that yields the highest gain in the interface shear strength due to bio-cementation is near the optimum moisture content of the soil obtained from the modified compaction test.

Experimental study on moisture migration in soil during coupled heat storage and release processes

The soil around ground heat exchanger is the heat source or heat sink of ground source heat pump system. Most scholars had analyzed the soil heat and moisture migration in heat storage or release process, respectively. In this paper, the coupled heat storage and release experiments were conducted in saturated and unsaturated fine-grained sand under the same excess temperature. The comparison on the soil moisture migration and the temperature and humidity recovery characteristics were analyzed. Results showed that the amount of soil moisture migration is almost symmetrical for the test soil sample during heat storage and release processes under the same excess temperature, the relative difference of moisture migration is within 10%. For a certain initial moisture content, the phenomenon of moisture migration could not occur until the excess temperature reaches a certain value. Similarly, for a certain excess temperature, the phenomenon of moisture migration could not occur until the initial moisture content of soil reaches a certain value. The phenomenon of maximum moisture content exists in heat storage process, but not exists in heat release process. The time required to restore to the initial soil temperature is the same, while the time required to restore to the initial moisture content is different between soil heat storage and release processes. With the increase of the initial moisture content, the humidity recovery time increases.

Experimental Study on Critical Moisture Content of Octadecylamine Modified Expansive Soil

Taking weak expansive soil as the research object, octadecyl primary amine (octadecylamine) was mixed into remolded expansive soil as a water repellent, and modified samples with different octadecylamine content and initial moisture content were configured. The dripping water penetration time method was used to determine the water repellency grade of the modified expansive soil, and the critical moisture content test of the modified expansive soil was carried out to analyze the relationship between different octadecylamine content and the initial moisture content of the expansive soil. The results show that with the increase of the initial moisture content, the water repellency of the modified expansive soil first increases and then decreases. When the octadecylamine content is 0.8%, the limit moisture content is 33.33%, and the peak moisture content is 29.51%. The bottom water content is 0%, and its interval value is 3.78 times larger than when the octadecylamine content is 0.2%.he above research results can provide a test basis for the engineering application of modified expansive soils.

Numerical Simulation of Water Distribution with Uptake Root in Drip Irrigation using Different Soil Hydraulic Models

Surface drip irrigation is one of the most conservative irrigation techniques that help control providing water directly on the soil through the emitters. It can supply fertilizer and providing water directly to plant roots by drippers. One of the essential needs for trickle irrigation nowadays is to obtain more knowledge about the moisture pattern under the trickling source for various types of soil with various discharge levels with trickle irrigation. Simulation numerical using HYDRUS-2D software, version 2.04 was used to estimate an equation for the wetted area from a single surface drip irrigation in unsaturated soil is taking into account water uptake by roots. In this paper, using two soil types were used, namely sandy loam and clay loam, with three types of plants; (corn, tomato, and sweet sorghum). The soil wetting pattern was analyzed each half an hour for three hours of irrigation time and three initial soil moisture content. Equations for wetted radius and wetted depth were predicted and evaluated by utilizing the statistical parameters for the different hydraulic soil models (Model Efficiency (EF) and Root Mean Squares Error (RMSE)). The values RMSE does not exceed 0.40 cm, and EF is greater than 0.96 for all types of soil. These values were between the values obtained from program HYDRUS-2D and the values obtained from formulas. This shows that evolved formula can be utilized to describe the soil wetting pattern from the surface drip irrigation system. The relative error for the different hydraulic soil models was calculated and compared with Brooks and Corey's model, 1964. There was good agreement compared with different models. RMSE was 0.23 cm, while the relative error -1% and 1 for EF for wetted radius.