جستجوی مقالات مرتبط با کلیدواژه "آبیاری" در نشریات گروه "اقتصاد کشاورزی"

In order to study the effect of irrigation cycle and size of mother corms on flower yield and daughter corms in saffron, an experiment was conducted in Ghaen region in 2016 crop year using a split plot design. The main factor was irrigation cycles (2, 3 and 4 weeks) and the secondary factor was the size of corm (less than 4 g, 4 to 8 g, 8 to 12 and 12 to 16 g). The interaction effect of irrigation cycle and pistachio size on flower-related traits was insignificant and on female pistachio-related traits was significant. In mother corms less than 4 g and 4 to 8 g, irrigation cycle had no effect on the dry weight of daughter corms produced per square meter. Irrigation of mother corms 8 to 12 g and 12 to 18 g every two weeks, respectively, produced 3689 g and 4230 g of female corm per square meter, which increased by 7.5 and 9, respectively, compared to the four-week irrigation cycle. / 4% of this adjective. In mother corms less than 4 g, the two-week irrigation cycle increased the number of female corms per square by 7.5% compared to the four-week irrigation period and decreased the diameter of female corms by 9.5%, but in other sizes of mother corms There was no difference between irrigation cycles in terms of number of female corms per square meter and diameter of female corms.

The aim of this study was to investigate the effects of using different combinations of waste water and well water with the approach of using unconventional water on some physical and chemical properties of soil. For this purpose، a factorial experiment was conducted in a completely randomized design with three factors. The main factors include irrigation with waste water to well water ratio in 5 levels including I1 (control: irrigation with well water)، I2 (75% well water and 25% waste water)، I3 (50% well water and 50% waste water)، I4 (25% well water and 75% waste water) and I5 (irrigation with 100% waste water)، the second factor includes two soil depths (0-30 and 30-60 cm) and the third factor includes the duration of irrigation in 5 levels (zero، 1، 2، 3 and 4 months). The results showed that soil salinity، pH and organic carbon increased with increasing irrigation time. The highest increase in salinity was observed after 4 months in I5 treatment with about 37% increase compared to the control treatment. The amount of organic carbon in treatments I4 and I5 in the surface layer increased by about 60% compared to the subsurface layer. However، waste water consumption improved hydraulic conductivity compared to well water، so that its amount increased in I5 treatment، at surface and subsurface depth by 76.7% and 80%، respectively، compared to the control treatment. The findings of this study showed that the use of treated wastewater as one of the unconventional water sources، despite increasing soil salinity، can increase organic carbon and improve soil permeability.

The aim of this study was to determine the role of different irrigation regimes on flag leaf and other leaves , stem length, stem weight, average leaf length and width of aerobic rice genotypes was carried out during 2014 and 2015 in Shavoor Agricultural Research Station in northern of Khuzestan. Four irrigation regimes (1, 3, 5 and 7 days) in main plots and twelve rice genotypes in subplots with three replications. The results of combined analysis showed that there was a significant difference between genotypes, irrigation regimes and their interactions in all traits. One-day and three-day irrigation regimes had the highest and the seven-day irrigation regimen the lowest in terms of less time in nutrient accumulation in all traits. Grain yield, while having the highest positive and significant correlation (0.486 **) with flag leaf weight in terms of providing the most photosynthetic material for the main reservoir in the All genotypes tended to produce the most grain yield in the second irrigation regime (the three-day irrigation interval); genotype IR 81025-B-327-3, with 6555.10 kg ha-1 of grain yield, out-performed the remaining genotypes in this level of irrigation regime. Examination of the growth index showed that all genotypes reached their maximum growth by reducing the irrigation cycle in a shorter period of time, while more resistant genotypes maintained their growth process in the conditions of better irrigation cycle reduction, which can be due to breeding and Corrected figures used.

This experiment was conducted to study the effect of drought stress using four different tillage methods on yield and yield components of hullessbarley in Gorgan, Iran region. The experiment was laid out in randomized complete block design with split plot arrangement with three replications was carried during 2012-13 growing season. The main factor for different methods of tillage was including moldboard plow, chisel plow, disc plow and no-tillage and sub- factor was including irrigation at ear emergence stage amount 100, 75 and 50 percent of field capacity and no irrigation. Results showed that drought stress caused a delay in the occurrence of phenological stages and reduces plant height, spike length, grain weight, grain and biological yield and harvest index. Tillage with chisel reduces days to the occurrence of phenological stages. This treatment also resulted in increasing yield per spike, number of grains per spike and number of grains per square meter. Plant height was significantly lower in disc plow and no-tillage treatments than chisel and moldboard plow. Conservation tillage reduced thousand green weights but this reduction was not significant. Biological and grain yield and harvest index was maximized chisel plow treatment and its difference with other methods was significant.

In this study the effect of irrigation systems and variety diversification on risk and productivity of wheat farms have been investigated. Data were collected from field survey in Shahrekord district in the south west of Iran in 2008-2009. Then stochastic production function was estimated to evaluate the effect of variables on the mean and variance of wheat yields. To perform this work, several form of production functions with several estimation procedures were used, and finally quadratic production function was selected. After that estimated coefficients were used to simulate the effects of variable. Econometric evidence shows that variety diversification increases farm productivity. Variety richness also reduces yield variability but only for high levels of genetic diversity. Results also show the same relation with respect to irrigation systems and improved seeds; however, deficit irrigation tends to reduce the mean wheat production and increase risk. Simulations with estimated parameters illustrate planting more diverse wheat varieties contribute to reduce production risk and to improving farmer’s productivity and welfare.

In order to study of regression coeficient for irrigation periods and traits of castor plants this fiels experiment was done in 2010 at Damghan Islamic Azad University research farms. The experiment model was randomized complete block design with three replications. Irrigation periods intervals were every 5، 10 and 15 days. Plant densities were 5 plants per square meter. After data harvesting we used from SAS statistical software and mean comparition was calculate by Duncan''s multiple range test at 5%. the correlation coeficient between plant characteristics irrigation periods were stimated too. All traits studied showed significant differences for the period of irrigation and the highest yield and lowest yield in a period of 5 days of irrigation in the irrigation period was 15 days I attribute 15 percent oil and protein content in irrigation water during the 10 days had the highest. Attributes associated with the irrigation effect was linear (r =0/95**) and the correlation with oil yield significant and negative r=0. 65*، % protein and significant and negative relationship was -0. 85**Percent of the oil with the water cycle has a positive slope of the line that represents.

This research was done to investigate the effect of nitrogen fertilizer and furrow irrigation methods on quantity and quality yield of tobacco، Coker 347 cultivar. It was done at research farm of Rasht tobacco research center during 2008-2009. The experiment was conducted on a split plot design based on CRBD with 3 replications. Major factor was considered nitrogen fertilizer (45، 55، 65 Kg/ha) and minor factor was considered as irrigation (one way، two ways and no irrigation). Irrigation time was determined by tans meter device and in each turn soil irrigation was performed to the extent of field capacity. Tobacco product has been harvested in 5 sorts. Results showed that leaf length، dry leaf weight، sugar، chlorophyll، plant height were significant (P<1%) and leaf width and nicotine were significant (P<5%). Generally applying irrigation caused to increase of tobacco yield while two ways irrigation method had more effects. Applying 45 kg nitrogen/ha caused to maximum yield in major factors.

In this research، The effect of different levels of nitrogen fertilizer and irrigation was evaluated on morphological characteristics. In order to obtain the best irrigation and nitrogen levels، the research was conducted in pot and greenhouse system in Zahedan. The treatments included three amounts of nitrogen fertilizer (20، 40 and 60 kg/ha) and three irrigation regimes (2 mm per week، 4mm per 2 weeks and 2 mm per 2 weeks). The studied factors were flower yield، plant height، flowering time، and anthodia height and anthodia diameter. The results indicated that the increase of nitrogen fertilizer from 20 to 60 kg/ha improved plant height، early flowering، anthodia height and diameter significantly. Highest amount of flower dry yield is obtained in 40 kg/ha nitrogen fertilizer but highest amount of flower wet yield is obtained in 60 kg/ha and the lowest amount of flower wet yield is obtained in 40 kg/ha nitrogen fertilizer. Irrigation also affects flower dry weight، anthodia diameter and flowering time in 2mm irrigation per week and 4 mm irrigation per two weeks increased plant height and flower wet weight significantly. The interactions between nitrogen fertilizer and irrigation was significant as plant height (31. 89 cm)، flowers wet weight (8. 78 gr per pot) and flowering time (41 days) as concerned and the best treatments was 60 kg/ha nitrogen fertilizer and irrigation 4 mm per two weeks. According to the results، it appears that 60 kg/ha nitrogen fertilizer plus 4 mm irrigation per two weeks was the best treatment to produce the flower yield in German chamomile in organic system.

In order to investigate of manure consumption on used efficiency in corn (SC704) an experiment was conducted in agricultural researches center of Hajiabad in Hormozgan. The experimental design was CRBD with four replications. Main plots were considered as four irrigation methods (irrigation of one side of hills to full growth, one side of hills Till steming and then from Two sides, one side of hills Till flowering then from Two sides irrigation) and four amounts of manure (0, 10, 20 and 30 ton/ha) were considered as subplots. Results showded that irrigation method and using manure have significant effects on water used efficiency, yield, 1000 cernel weight, biomass, number of grain per row and stem diameter (p<0.01). Maximum grain yield was related to Two side irrigation by 10070 kg/ha when 30 ton/ha manure. Also Maximum dry matter was related to notice trait.

In order to investigation of planting dates and irrigation regimes on physiological traits of two spring sufflower cultivars a field experiment was conducted in 2002.The experimental design was a split-split plot with four replications. Treatments were planting dates as main plots, irrigation regimes as sub-plots and safflower cultivars (Arak-2811, Esfahan Local) as sub-sub plots. The result showed that late planting and low irrigation decrease the physiological traits such as LAI, CGR, and LAR. NAR and LWR were not shown any significant differences between two considered cultivars, because those had similar growth period. Maximum LAI in first planting date and better irrigation was 4.75 and maximum LAI in third planting date and low irrigation was 3.89, which needed 1340 GDD. Highest CGR obtained between 1400-1500 GDD when LAI started to decline.Relative growth rate (RGR) showed net assimilation rate (NAR) also declining trend. NAR also decreased with time. LAR and LWR also showed a declining trend.