JWSS - Journal of Water and Soil Science

In order to optimize the irrigation system performance, it is essential to get information about water balance components in the farm. So, the objective of this study was evaluating the performance of the WFD device in determining water penetrated fate in the soil at each irrigation occurrence as one of the important components in evaluating the irrigation water efficiency. By having the water amount infiltrated in the root zone and the deep percolation amount collected and determined by WFD device, contribution of surface losses related to every irrigation occurrence can be determined by the employing water balance equation. This research was carried out in the form of completely randomized design blocks in three replications and under the treatments of 60, 80, 100 and 120% of the irrigation requirement supply of a potato plant in the research farm of Shahr-e Kord University in 2014. To gather the growing season data, before the planting operation, various WFD devices were installed at different depths and locations along furrow. In addition to WFD data, input discharge (using counter), output discharge (measured by flume type 1) and values of soil moisture (theta-probe device) were collected during the harvesting season. The results showed that the mean Nash–Satcliffe coefficient of comparison between the  values of calculated and measured surface losses corresponding to it, and also comparison of  the values of the calculated and measured residual moisture before each irrigation occurrence were obtained to be 0.87 and 0.98, respectively. Quantity of this indicator in the two conducted comparisons represented the correct and exact performance of the WFD device in the farm operation evaluation. During the farm evaluation process under the experimental furrow, distribution uniformity averages in the experimental treatments were acquired to be 75.56, 83.78, 88.06, and 90.34%, respectively. Likewise, water amount average percolation of root zone (depth losses) in experimental treatments at each irrigation occurrence was measured to be 0.02, 0.07, 0.27 and 0.47m³ for each furrow.

Due to the water scarcity in Iran, it is important to provide strategies to reduce water consumption in the agriculture sector. Zycosil is a nanotechnology material that makes a great hydrophobe in the soil. This study was conducted based on completely randomized block design within microlysimeter with the height of 15 cm and the diameter of 8 cm to investigate the hydrophobic effect on the amount of consumed water in pepper. Sweet pepper seedlings were planted in them; then the treatments were applied. The Z25, Z50 and Z75 treatments consisted of  covering 25, 50 and 75 % of the soil surface by Zycosil; these were compared with  the control (Ctrl- no Zycosil application) in three replications. The results showed that Z75 treatment reduced 27% water consumption and increased the fresh yield by approximately 62 %. The increased yield of Z25 and Z50 was 5 and 26 %, respectively. Dry pepper yield was increased in Z25, Z50 and Z75 treatments by 22, 19 and 80%, respectively, as compared to Ctrl treatment. The amount of water consumed was decreased by 10 % per 25% coverage level. The least amount of water use efficiency was observed in the control treatment (1.28 gr/cm3). The Z75 had the highest water use efficiency (2.96 gr/cm3). Hence, the application of hydrophobic material such as Zycosil in the soil surface reduced water evaporation and increased water retention. This increased the yield and water use efficiency.

To determine the potential for groundwater contamination, vulnerability should be evaluated in different areas susceptible to contamination should be investigated. Aquifer (carbonate) karst or part of it is karst aquifer in the western region of Iran; due to the natural conditions of the region and human activities, they are susceptible to contamination by carbonate aquifer through holes devourer and feeding point leading to pollution. The aim of this study was to analyze aquifer vulnerability zoning map karst plain elster by using COP. This model uses three parameters including lining (O) the concentra flow(C) and precipitation regime (P) to assess the vulnerability of groundwater against pollution GIS software. The results showed that the plain with an area 7.8 km² was dominated in terms of vulnerability, being in the middle class. Other classes, respectively, were low with the area 18.69 km², high with the  area 0.65 km² as part of the northeast plain, and much less with the  area of  0.6 km^{2 ,} The results of the sensitivity analysis  also showed that at the factorization (P) due to appropriate rainfall area, the  maximum impact was in determining the vulnerability  of the area. And the factor (C) minimum has impact on determining the vulnerability of the area. Due to the small size of the mature karst area, the wide extent of non-karst region was shown for the verification of results related to electrical conductivity data (EC) against discharge wells in the region with the high vulnerability and moderate. A comparison was made too.

Creating a mulch layer on the sand dunes surface has long been applied to reduce their mobility. However, application of oil mulch in some countries, in addition to high costs, has many environmental problems. In this research, the hydrated lime slurry was used as a protective cover on the sand dunes. The slurry was prepared in three treatments with 3, 5 and 7% lime and sprayed uniformly on 2×5 m plots on the sand dunes surface. The average thickness of different types of mulch was measured by a caliper and then their abrasions were calculated in two-month intervals for three calcareous and controlling treatments at three locations. Statistical analysis was performed by using SPSS and the Excel software. The results showed that the 3% lime slurry layer had no resistance to wind abrasion and was comparable to the controlling sites. The results obtained for the 5 and 7% lime slurry mulch layers indicated that the increase in lime percentage raised the mulch resistance against the wind abrasion. The 7% lime slurry layer with a 6.3 mm thickness showed the highest abrasion resistance in the natural conditions.

Creation and conservation of urban parks is challenging in arid environments where daily thermal extremes, water scarcity, air pollution and shortage of natural green spaces are more conspicuous. Water scarcity in the arid regions of Iran is major challenge for water managers. Accurate estimation of urban landscape evapotranspiration is therefore critically important for cities located in naturally dry environments, to appropriately manage irrigation practices. This study investigated two factor-based approaches, Water Use Classifications of Landscape Species (WUCOLS) and Landscape Irrigation Management Program (LIMP), to measure the water demand in a botanic garden. The irrigation water volume applied was compared with the gross water demand for the period from 2011 to 2013. On average, WUCOLS estimated an average annual irrigation need of 1164 mm which is 15% less than the applied value of 1366 mm while the LIMP estimate of 1239 mm was 9% less than the applied value. Comparison of estimated and applied irrigation showed that a water saving of 9% can be made by the LIMP method. The outcomes of this research stressed the need to modify the irrigation requirements based on effective rainfall throughout the year, rather relying on long-term average data.

Soil water content is the most effective factor associated with the hydrophobic and hydrophilic changes in a soil. Water repellency in soils, is not a permanent feature; it can be reached in the dry season and reduced or eliminated in the wet season It can be said that in terms of moisture, there is a critical region that is defined as the threshold moisture content, where in lower moisture, the soil is repellent and in higher moisture, the soil is wet able. The purpose of this study was to investigate soil moisture variations on degree of hydrophobicity and determine the amount of threshold water content in soil samples of wetland around Shahr-e-Kord. In this study, some samples of Shahr- e-Kord wetland were investigated. After determining the initial moisture content of the soil, the soil hydrophobicity conditions were determined by determining the time of water droplet penetration (WDPT). Soil moisture variations were carried out using soil wetting and drying method, and in each step the soil hydrophobicity conditions were tested. Reducing water content in soil samples, led to a change in the degree of hydrophobicity in hydrophobic samples, in one soil hydrophilic soil sample, Reducing water content changed hydrophilic soil to hydrophobic soil. The threshold water content was also observed up to a maximum of 54% volumetric water content at a given point. Based on this, the higher moisture content of the threshold at this point indicates the higher soil potential for runoff generation. Soil analysis showed that soil organic matter had a positive correlation with threshold water content.

The Plant Water Resistance Index (CWSI) is a tool that can be used for the rapid monitoring of plant water status, which is a key requirement for the accurate product irrigation management.The purpose of this study was to calculate the CWSI index for bean hares in the Khorramabad region for two methods of surface irrigation and drip tape ‎irrigation. For this purpose, a design was implemented in the form of randomized complete block design and split plot experiment. The main factors included drip tape irrigation (T) and surface irrigation (F), and the cultivars of Chibi cultivars including COS16 (C), Sadri (S) and diluted (K) served as sub-plots. By using the field measurements, the position of the upper and lower base lines was estimated for each treatment in different months and used to calculate the CWSI index. The results showed that CWSI values calculated in the surface irrigation during plant growth period were always higher than those in the drip tape irrigation. The highest value of CWSI index was obtained for the Sadri variety, which was equal to 0.20 and 0.26, for the type and surface method, respectively. Statistical analysis showed that the effect of irrigation method on the amount of water stress index was significant at 5% level, but there was no significant difference between different cultivars. According to the results of this study, the threshold values for CWSI were considered to be 0.19 and 0.24 for surface and drip tape ‎irrigation respectively, and relationships were presented based on the differences in vegetation and air temperature to determine the irrigation time.

The contact angle is a numerical index of differentiation between hydrophilic and hydrophobic soils. The objectives of this research are: 1) assessing different methods such as capillary rise, the molarity of ethanol droplet, repellency index, and sessile drop, and 2) Determining the most efficient method in a typical soil with sandy loam texture. In this study, hydrophobic soil was hydrophobized artificially using stearic acid and according to the water drop penetration time classification method. Calculated contact angles of hydrophilic soil with capillary rise method, the molarity of ethanol droplet method, repellency index (two methods of calculation), and sessile drop method were 89.9, 75.41, (57.81), 56.28, and 58.91, respectively. Using the contact angle measuring device, the contact angle of five hydrophobic levels were 58.91, 104.92, 120.48, 129.96, and 173.07, respectively. According to the precession of the device where the operator is capable to control data and processes and there is no limitation in usage, therefore, the sessile drop method is the most suitable method to measure contact angle. The contact angle of the late method and water drop penetration data are positively correlated (R² = 0.975).

Using a rough bed for spillway compare to common dissipation methods such as stilling basins, stepped spillways, ski jumps, and bed elements may be more efficient to boost energy dissipation. In this research, the impact of spillway continuous bed roughness on energy dissipation was investigated. For this purpose, a non-dimensional relationship was developed, and by calibrating the numerical model based on the present experimental study, energy dissipation over the spillway for three slopes of 15, 22.5, and 30 (degree) with six roughness sizes of 0.0, 0.005, 0.0072, 0.0111, 0.016, and 0.022 (m) and three discharges of 170, 110, and 90 (lit/s) was investigated. Based on the present results, using a rough bed spillway will increase energy dissipation. Also, the ratio of energy lost per meter length of rough bed spillway to that of smooth spillway increases by chute slope. The results showed that the highest amount of relative energy consumption in the presence of roughness was related to the slope of 22.5 degrees and 22.2 mm for roughness (85%), and the lowest relative energy consumption was observed in the control state (25%). As a result of the present study, a natural rough bed without concrete coating has befitted in terms of environmental aspects, construction cost, and energy loss.