H J; P A; M D; M T
Abstract
Evapotranspiration of orchard crops is often determined by indirect method and based on meteorological data due to the difficulties inherent in direct measurement instruments such as installation of large lysimeters or precision equipment, and long growing seasons of tree crops. Evapotranspiration estimation ...
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Evapotranspiration of orchard crops is often determined by indirect method and based on meteorological data due to the difficulties inherent in direct measurement instruments such as installation of large lysimeters or precision equipment, and long growing seasons of tree crops. Evapotranspiration estimation with sufficient accuracy is not feasible due to spatial variability of meteorological parameters and, sometimes, due to inappropriate distribution of meteorological stations. Therefore, using methods based on remote sensing, which account for these variations, is much more desirable. In this research, evapotranspiration of olive trees at different phonologic stages was measured using direct and indirect methods in Tarom district of Zanjan Province. In the direct method, actual evapotranspiration was determined by measuring moisture balance components, whilst in the indirect one, it was specified with the help of satellite imagery, the SEBAL algorithms, and Penman-Monteith equation. Olive crop coefficient was subsequently calculated and evaluated by determining reference crop evapotranspiration. The results indicated that evapotranspiration calculated by the remote sensing method at different stages of the growth had acceptable conformity with soil moisture balance data and evapotranspiration values obtained from the Penman–Monteith equation (the respective correlation coefficients were 0.95 and 0.88) and both evapotranspiration curves along the growing season had a similar increasing and decreasing trend. Moreover, crop coefficient obtained by the SEBAL algorithm and the water balance methods were well correlated (R2=0.86) and the remote sensing method with the aforementioned advantages can be used in predicting evapotranspiration.
m t; m a; n d; n e
Abstract
This study was carried out to investigate the effects of different irrigation regimes and planting methods on yield, yield components, morphological traits, and storage characteristics of a local onion cultivar, namely, Goli Ghesse. The experiment was conducted as a factorial split plot design with RCBD ...
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This study was carried out to investigate the effects of different irrigation regimes and planting methods on yield, yield components, morphological traits, and storage characteristics of a local onion cultivar, namely, Goli Ghesse. The experiment was conducted as a factorial split plot design with RCBD arrangement in four replications and for three years at Kheirabad Research Station. Irrigation intervals were allocated to the main plots and planting methods were studied in the sub plots. Irrigations were initiated after 40, 70, 100 and 130 mm cumulative evaporation in treatment E1, E2, E3 and E4, respectively. Two planting methods consisting of direct seeding and transplanting were used in this experiment. Seasonal and combined analysis of variance was done and means were compared using Duncan's multiples rang tests. Combined analysis showed that there was significant difference at 5% confidence level among treatments. Assessing effect of different irrigation intervals on average yield revealed that bulb yield in direct planting was 45.54 t/ha, which was 0.6 t/ha more than transplanting method, but this was not significant. Also, results showed that the highest bulb yield (60.8 t/ha) was obtained from E1. In comparison, treatments E2 to E4 had 48.88, 40.23, and 32.21 t/ha bulb yield and were in statistical groups of b, c, and d, respectively. But, cultivation method had no significant effect on yield at 5% probability level. .Effect of planting method on water use efficiency was significant at 5% level and the highest amount was obtained from transplanting method with 10.295 kg onion bulb/m3. Thus, irrigation interval after 70 mm evaporation from Class A pan and transplanting are recommended for Zanjan and other regions with similar climate and soil conditions.
Jaefar Nikbakht; Marzieh Khadehrouyan; Afshin Tavakoli; Mehdi Taheri
Abstract
The purpose of this study was to evaluate the effect of deficit irrigation with magnetized water on yield and water productivity of maize. The research was carried out as factorial with 2 factors arranged in complete randomized blocks design with 4 replications in the greenhouse of Zanjan Agricultural ...
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The purpose of this study was to evaluate the effect of deficit irrigation with magnetized water on yield and water productivity of maize. The research was carried out as factorial with 2 factors arranged in complete randomized blocks design with 4 replications in the greenhouse of Zanjan Agricultural and Natural Resources Research Center from July to September 2011. The factors were the amount of irrigation water consisting of 100%, 80%, 60% and 40% of crop water requirement (T1 (control treatment), T2, T3, T4) and water type consisting of magnetized and tap water. Based on the results, passing the tap water through a magnetic field reduced the amount of calcium and chlorine ions by 41.11 and 35.5 mg/lit, respectively. Leaf area, leaf chlorophyll content, total wet and dry mass, and water productivity of plants irrigated with magnetized water increased by 9.5%, 10.68%, 8.31%, 17.41%, and 9% compared to plants irrigated with tap water. These differences were statistically significant. The results showed that deficit irrigation caused significant difference at 4 levels in leaf area, leaf chlorophyll content and total wet and dry mass. Total wet weight and water productivity (based on total wet weight) in the magnetized and tap water treatments were 31.56 ton/ha and 14.22 kg/m3, and 28.94 ton/ha and 12.94 kg/m3, respectively.
j nikbakht; m taheri; m sakaki
Abstract
To evaluate deficit irrigation effect on quantity and quality characteristics of olive fruit (Olea europaea L. cv. Koronaiki), this study was carried out in 2009 in Gilvan (49o 5¢ E longitude, 36o 47¢ N latitude, and elevation 330 m above sea level) located in Tarom region in Zanjan province, ...
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To evaluate deficit irrigation effect on quantity and quality characteristics of olive fruit (Olea europaea L. cv. Koronaiki), this study was carried out in 2009 in Gilvan (49o 5¢ E longitude, 36o 47¢ N latitude, and elevation 330 m above sea level) located in Tarom region in Zanjan province, Iran. Soil texture of the farm was loam. The experimental design was randomized complete blocks with 4 replications. The irrigation treatments were T1, =100% (control treatment), T2= 75%, T3= 50%, and T4= 25 % of olive water requirement (OWR). Trees were watered by drip irrigation system with loop layout. OWR was calculated based on Gilvan synoptic weather station data and FAO Penman-Monteith equation and the FAO-56 recommended crop coefficient.
Based on the results, the effect of deficit irrigation on percentage of fruit oil, ratio of fruit length to diameter, percentage of complete flowers, and percentage of secondary fruits were significant at 1% probability, while the effects on percentage of primary fruits produced were significant at 5% probability. However, deficit irrigation effects on the percentage of fruits dry mass and pulp/pit ratio were not significant. The results showed that the percentage of complete flower produced in T4 was the least (42%). Deficit irrigation caused significant difference (P=5%) between T1 and the other treatments in terms of percentage of primary fruits produced (about 31% difference). Also, deficit irrigation caused differences between percentage of the primary and secondary fruits in T4. Based on the results, difference in ratio of fruit length to diameter between T1 and deficit irrigation treatments were significant (P=5%). Therefore, deficit irrigation was not suggested for cannery objectives. The maximum content of fruit oil (28.49%) and the least content (22.73 %) were obtained from 75% and 25% OWR treatments, respectively. Therefore, in the research site, to irrigate olive trees cv. Koroneiki, 25% continuous deficit irrigation (irrigation with 75% OWR) is suggested in order to save on water use.