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Reza Mohammadikia; ali ashraf sadraddini; amir hossein nazemi; Reza delearhasannia; ajdar onnabi milani
Abstract
This study aimed to determine the crop coefficient of sugar beet using canopy cover extracted from digital images under different irrigation managements. The crop coefficient and canopy cover were directly measured by water balance and image processing methods, respectively, in 10 days intervals during ...
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This study aimed to determine the crop coefficient of sugar beet using canopy cover extracted from digital images under different irrigation managements. The crop coefficient and canopy cover were directly measured by water balance and image processing methods, respectively, in 10 days intervals during the growing season. The crop coefficient of sugar beet in three irrigation managements with maximum allowable depletion (MAD) of 40%, 60%, and 80%, was estimated using its regression equation with canopy cover. This was modeled for potential conditions and then validated by using the average measurements in two years. The findings showed that the estimated crop coefficients were in good agreement with the observations in irrigation managements that had MAD of 40% and 60%. The coefficient of determination (R2), normalized Root Mean Square Error (nRMSE), and model efficiency (EF) were 0.95, 0.11 and 0.95, for 40% MAD, 0.9, 0.13 and 0.85 for 60% MAD, respectively. The results illustrate that the crop coefficient of sugar beet, within the moisture range between field capacity to a MAD of 60%, can be reliably estimated by this approach. The values of determination coefficient (R2), normalized Root Mean Square Error (nRMSE) and model efficiency (EF) decreased to 0.49, 0.37 and 0.63, respectively, for 80% MAD, indicating poor performance of the model under severe drought stress conditions. The proposed method has some advantages including easy and fast data collection, greater accuracy and lower cost, the ability to provide the desired number of images, and no need for meteorological data. Therefore, this can be applied to study the plant growth and crop coefficient variations during the growth period.
Amir Hossin Nazemi; Mohammad Amin Parandin; aliashraf sadraddini; Hooshang Ghamarnia
Abstract
Some experiments were performed around the Agricultural and Natural Resources Research Station of Islamabad-Gharb in order to determine The effect of surge irrigation on yield of water productivity(WP) and water use efficiency of maize in that area. The statistical design of the research was randomized ...
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Some experiments were performed around the Agricultural and Natural Resources Research Station of Islamabad-Gharb in order to determine The effect of surge irrigation on yield of water productivity(WP) and water use efficiency of maize in that area. The statistical design of the research was randomized complete block with 4 treatments in 3 replication, as a composite analysis in two years (2015 and 2016). The treatments were continuous irrigation method (c), surge irrigation method with 1 to 1 on and off flow ratio (S1-1), surge irrigation method with 1 to 2 on and off flow ratio (S1-2), surge irrigation method with 1 to 3 on and off flow ratio (S1-3). Corn variety SC704 was used for planting. The results showed that in 2015 and 2016, savings in the consumption of water compared to continuous irrigation was respectively, 10.8% and 10.4% in S1-1 treatment. 10.4% and 10.5% in S1-2 and (S1-3) treatment, respectively 11% and 10.5%. Combined analysis of variance (ANOVA) showed that performance parameters had no significant difference between treatments during different years. The results indicated that the water productivity values for total yield and grain yield were higher in surge irrigation treatment than in the continuous irrigation. WP based on total corn ear weight was 0.69 kg/m3 and based on grain weight, it was 0.54 kg/m3. These values represent 0.07 and 0.06 kg/m3 higher WP compared to continuous irrigation. The average water use efficiency was 32.3% for continuous irrigation and it was 36% for surge irrigation which was 3.7% more than continuous irrigation. Generally, the results showed that surge irrigation with a cycle ratio of 1 to 2 was more suitable for irrigation.
aliashraf sadraddini; mohammadamin parandin; Amir hossin nazemi
Abstract
Some experiments were performed around the Agricultural and Natural Resources Research Station of Islamabad-Gharb city in order to determine the reaction of corn crop to deficit irrigation strategy and its effects on yield, yield components and water productivity (WP) under furrow irrigation. The research ...
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Some experiments were performed around the Agricultural and Natural Resources Research Station of Islamabad-Gharb city in order to determine the reaction of corn crop to deficit irrigation strategy and its effects on yield, yield components and water productivity (WP) under furrow irrigation. The research used randomized complete block design (as a composite analysis in two years (2015 and 2016)). The treatments included irrigation with 100%, 75%, 50% and 25% water requirement with three replications. The SC704 Variety was used for planting corn. To compare the treatments, the 7 parameters of the performance components were considered, using analysis of variance (ANOVA). The results showed that the weight of corns in the first treatment was significantly superior to other treatments. Nevertheless, there was no significant difference in total weight of ears, ears length, seeds number per row, number of ear rows, wood weight and the weight of 1000 corns between treatments of 100% and 75% water requirement. However, in all measured attributes, there were significant differences between the other two treatments and the first and second treatments. Regarding water productivity in terms of total weight and grain weight of ears, the 75% treatment was superior to other treatments and had significant differences with the other treatments. In the treatment with 75% water requirement, WP was 0.8 kg/m3 based on the total weight of the grains, and based on the seed weight, it was 0.62 kg/m3, which were, respectively, 17% and 13% higher than the full irrigation treatment. The results showed that the highest water productivity was observed with about 30% deficit irrigation. It is to be noted that deficit irrigation may increase salinity of the root zone.
m b; a s; a n; r d
Abstract
Reduction of water losses due to increase in the applicationuniformity in sprinkler irrigation systems needs appropriate selection of the sprinklers spacing and arrangement. In the present study, to evaluate the impact of spacing and arrangement of sprinklers on uniformity coefficient (UC) of the irrigation ...
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Reduction of water losses due to increase in the applicationuniformity in sprinkler irrigation systems needs appropriate selection of the sprinklers spacing and arrangement. In the present study, to evaluate the impact of spacing and arrangement of sprinklers on uniformity coefficient (UC) of the irrigation system and to investigatethequalitative and quantitative changes of UC due to changes in the parameters of the area covered by the sprinkler and wind speed, the test of distribution pattern of a single sprinkler was performed. The test was conducted according to ISO 8026, ASAE S398.1and ISO 7749, 2 standards on three VYR 35, IRILINE 30, and RAINBIRD 40B sprinklers. In this study, the square shaped arrangement had the highest UC and lowest sensitivity to decreasing coefficient of uniformity with an average of 5.3% and 5.5 percent for the average increasing of 59.4% and 98.3 percent in the covered area and wind speed, respectively. The least sensitivity of the UC were obtained for the IRILINE sprinkler with the mean reduction values of 3.4% and 5.48 percent for the average increasing of 37% and 117.8 percent in the covered area and wind speed, respectively. Results showed that to achieve the desired coefficient of uniformity, the maximum sprinkler spacing should be considered as 40 percent of the nominal application diameter of the sprinkler with a square arrangement when wind speed exceeds 4 meters per second.