8
Jamal Mohammadi Moalezade; saeid hamzeh; Abdali Naseri
Abstract
Soil moisture is one of the most important parameters in water, soil and plant resources management. Therefore, the present study was conducted to evaluate the efficiency of thermal and optical remote sensing data in order to estimate soil moisture and irrigation planning in sugarcane fields of Khuzestan ...
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Soil moisture is one of the most important parameters in water, soil and plant resources management. Therefore, the present study was conducted to evaluate the efficiency of thermal and optical remote sensing data in order to estimate soil moisture and irrigation planning in sugarcane fields of Khuzestan Province, Iran. For this purpose, soil moisture content for 9 passes of Landsat 8 and Sentinel 2 satellites was calculated using thermal and optical trapezoidal methods from April to October 2020 in Amirkabir Sugarcane Agro-industry fields. To validate the results, the measured soil moisture content data of 337 ground control points located in 18 sugarcane-growing fields measured by TDR350 dehumidifier were used simultaneously with the passage of the satellites. The results showed that TOTRAM model with a determination coefficient of 0.82 and error rate of RMSE and NRMSE as 4.45% and 12.9%, and OPTRAM model with an explanation coefficient of 0.93 and RMSE and NRMSE error of 3.14% and 12.1% were able to properly estimate soil surface moisture in sugarcane fields. Also, the results of evaluation of soil moisture maps for irrigation planning of sugarcane fields showed that these data could be used for irrigation planning with average NRMSE error of 16% and 9% in relation to ground irrigation time data for TOTRAM and OPTRAM models, respectively. In this regard, OPTRAM model data were more efficient compared to thermal data, due to better spatial resolution of optical data and less effect by environmental factors such as temperature and relative humidity of air and also the effect of adjacent pixels.
2
mohammad amin khandan barani; Peyman Afrasiab; mehdi akbari; Masoomeh Delbari
Abstract
In this research, the status of water productivity for wheat production and strategies to increase water productivity in different quantitative conditions of water was determined and analyzed in the irrigation district of Sistan Dam. In this regard, the SWAP simulation model was calibrated and validated ...
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In this research, the status of water productivity for wheat production and strategies to increase water productivity in different quantitative conditions of water was determined and analyzed in the irrigation district of Sistan Dam. In this regard, the SWAP simulation model was calibrated and validated by considering the current water resources operation, various quantities of irrigation water, and use of field information. Water production functions were used to determine the irrigation schedule (time and depth) for wheat crop. The results of field measurements in the crop year 2016-2017 in the irrigation district showed that farmers irrigate wheat on average four times in the current conditions. Farmers' average crop yield and water productivity were about 1450 kg/ha and 0.41 kg/m3, respectively. These results show that available water is not appropriately used and should be addressed with practical solutions to improve water productivity. The validation and calibration results of the SWAP model also showed the high accuracy of the model in the case study. The results of different management scenarios of eliminating some irrigation shifts compared to the existing conditions indicated that, although there was no significant difference in water productivity, crop yield decreases about 37%. The results of evaluating the scenarios of reducing the depth and frequency of irrigation (using 640 mm per season and applying 40 mm at each shift) showed that, with reliable and timely water supply and more frequent irrigation, water productivity could be increased by 30% compared to the baseline scenario; and crop yield can be doubled. In these scenarios, the presence of adequate moisture in the plant's root zone increases the yield, and the amount of deep percolation is greatly reduced. The amount of water used by farmers is excessive for various reasons. Therefore, it is recommended to train farmers on how to improve irrigation and crop management according to the water available in the irrigation district, so that they can distribute water according to the real needs of the plant and irrigate at the right time and sufficient quantity.
7
fatemeh keykhaei; ghasem zareai; Naser Ganji Khorramdel; sadegh sadeghi
Abstract
One of the strategies to reduce water losses in agriculture is proper irrigation scheduling, which is based on accurate estimation of crop water requirement. In order to determine the evapotranspiration rate of three rose varieties, a one-year study was conducted in a hydroponic greenhouse equipped with ...
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One of the strategies to reduce water losses in agriculture is proper irrigation scheduling, which is based on accurate estimation of crop water requirement. In order to determine the evapotranspiration rate of three rose varieties, a one-year study was conducted in a hydroponic greenhouse equipped with drip irrigation system in Arak Plain using drainage type lysimeters. Reference evapotranspiration was also determined using a drained micro-lysimeter with grass. The results showed that the total amount of reference evapotranspiration in the greenhouse was 1608 mm. Also, the total evapotranspiration value of Utopia rose during this growth period was 1423 mm, Dolcevita rose 1480 mm and White rose 1313 mm. The annual average of daily evapotranspiration of rose varieties was 3.8 mm/day. Due to rose bushes being perennial, the crop coefficients did not have four growth stages and, therefore, the average coefficients varied between 0.7 and 0.96 in 10-day intervals. The results also indicated that the average crop coefficient of rose varieties was 0.81 over a year and the average amount of applied irrigation water was 20573 m3.ha-1.year-1 for approximately 75000 rose plant /ha.