Samira mesry; Shoja Ghorbani; Hossin Shirani; Abolghasem Kamkar; hamidreza motaghian
Abstract
Soil water is an important factor in the growth of the plant. There are different methods for soil moisture estimation. It is time-consuming to obtain volumetric soil moisture in a laboratory. This study was performed to evaluate estimate of soil moisture by different in situ methods including the electrical ...
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Soil water is an important factor in the growth of the plant. There are different methods for soil moisture estimation. It is time-consuming to obtain volumetric soil moisture in a laboratory. This study was performed to evaluate estimate of soil moisture by different in situ methods including the electrical resistance of Werner electrode arrangement and ground penetration radar (GPR) from 700 MHz antenna, and two humidity sensors, namely, thetaml2 and sm300. These were used in 72 soil samples with different textures (loam, sandy clay loam and silty loam, silty clay, silty clay loam, clay loam) in parts of Shahrekord Watershed.The results showed that the coefficient of correlation between soil moisture and electrical resistance was 0.85. Also, the correlation coefficient between the values obtained from subsurface radar method, sm300 sensor and thetaml2 with the results obtained from laboratory measurements were 0.86, 0.94, 0.86, with CRM index values of -0.52, -0.75 and –1.22. By comparing the results of electrical resistivity, moisture from the GPR and the sm300 and thetaml2 sensors with volumetric moisture, the Root Mean Squared Error (RMSE) values were 8.41, 4, 5.3 and 8.6; and RRMSE were 10, 31, 29, and 26, respectively. Duncan test of moisture content showed that the difference between the sensors and the laboratory moisture content was significant at 5% level (p<0.05). According to the value of RRMSE All sensors had a good estimate of soil moisture. In conclusion, electrical resistivity and GPR method, due to higher sampling density, could be used as a rapid, cost effective, and non-destructive technique to estimate profile of soil water content at scales of field to sub-watershed.
Sina Fallah; m ghobadinia; m shokrgozar; sh ghorbani
Abstract
Population growth has resulted in increase in water use, which in turn has led to a decline in quantity and quality of groundwaters. Therefore, quantitative and qualitative assessment of groundwater resources is crucial for sustainable agriculture. This research was conducted to evaluate the spatio-temporal ...
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Population growth has resulted in increase in water use, which in turn has led to a decline in quantity and quality of groundwaters. Therefore, quantitative and qualitative assessment of groundwater resources is crucial for sustainable agriculture. This research was conducted to evaluate the spatio-temporal variation (18 years) of groundwater table and the quality of groundwater resources of Darab plain. To this end, data of 39 piezometers in the plain were selected to evaluate the groundwater table fluctuations during an 18-year period, while qualitative characteristics were determined for 2008-2012. Results showed that the mean groundwater level depletion was 27.23 m during the studied period. Also, qualitative dynamics indices of water showed that EC, pH, and nitrate of the groundwater increased annually during the study period. Overall, the water budget of the region, the lowering of water table, and the increase in water salinity and acidity indicate the unsustainability risk of the ground water of the studied region.