JWSS - Journal of Water and Soil Science

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In order to compare the effect of drip and furrow irrigation methods with different quantities of water (50%, 75%, and 100% of the amount of water evaporated from class A pan evaporation during irrigation intervals) on yield and quality of tomato, an experiment was conducted on a silty loam soil in Mashhad Agricultural Research Station. The experimental design was a factorial trial with completely randomized blocks and. four replications.

The results showed that the highest yield (51 t/ha) was obtained from the treatment of drip irrigation with 100% water application. This amount was 4.5 tons higher than the yield from furrow irrigation treatment. Deficit irrigation by 25 and 50 percent decreased total yield by 34.7% and 67.95% in the drip irrigation method and by 27.57% and 64.29% in the furrow irrigation, respectively. Water use efficiency in drip irrigation was two times higher than that in the furrow treatment. Quality and chemical composition of the fruits were not significantly different in the two irrigation methods. Increasing the water deficit, however, increased the amount of soluble solids of the fruits.

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In order to investigate the effects of different nitrogen fertilizer levels and water stress during milky and dough stages on grain yield, yield components and water use efficiency of corn hybrid SC 704 (late maturing, non prolific and dent type), a field study was conducted. The factorial design of the study comprised of a randomized complete block with four replications. Four levels of nitrogen fertilizer (0, 92, 184 and 276 kg/ha nitrogen) along with three levels of irrigation (water stress imposed at milky stage, dough stage and a season-long optimum irrigation) were used as treatments. Results showed that water stress during milky and dough stages significantly decreased grain yield and thousand kernel weight. Also, effect of nitrogen fertilizer on grain yield, kernel number per ear, kernel weight per ear and thousand kernel weight was significant. Maximum grain yield was produced with 276 kg/ha nitrogen, although no significant differences were found among 92, 184 and 276 kg/ha nitrogen levels. Regarding water use efficiency during water stress, maximum efficiency was observed at milky stage but, as water stress declined with optimum irrigation, water use efficiency decreased.

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This study was conducted to evaluate the effects of four levels of irrigation (irrigation of plants after I₁ = 40, I₂ =60, I₃ = 80 , and I₄ = 100mm of evaporation from class A pan) and four plant densities(D₁ = 30, D₂ = 40, D₃ = 50 and D₄ = 60 plants/m²) on the seed yield and seed quality in three soybean cultivars(V₁=Hobit, V₂=Williams and V₃=Hill) in a split factorial design, based on the completely randomized blocks, with three replication for two years(2001 and 2002). The Irrigation treatments were assigned to the main plots, and the plant densities and cultivars to the sub plots. Results indicated that soybean seed yield was influenced by the different irrigation and plant density levels in the both years. Irrigation levels I₂ produced the highest and I₄ the lowest seed yield. It was also revealed that the plant density D₃ produced the highest and D₁ the lowest seed yields. Among the cultivars under investigation, V₂ produced the highest and V₃ the lowest seed yield . Seed oil and its protein contents both were affected significantly by the irrigation levels, plant densities and cultivars in both years. The plants receiving I₁ treatment had the highest and those having I₄, the lowest percentages of seed oil. Changes in the plant densities also affected seed oil and protein content. The plant density of D₁ caused the seeds to have the highest oil and lowest protein percentages. However, D₄ decreased oil and increased protein percentages. The highest water use efficiency was obtained from I₃ and that of the lowest value from I₁. The results also indicated that D₄ had the highest and D₁ the lowest water use efficiencies. Therefore, it could be concluded that the water use efficiency can be increased by increasing the plant density per unit area. The highest efficiency for biological and grain yield belonged to V₂ and V₁ respectively where as the lowest efficiency for those two mentioned characters belonged to V₁ and V₃, respectively. However, the treatment I₂V₂D₂ is recommended for higer the seed yield production per unit area.

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In order to examine the responses of proso millet (Panicum miliaceum) to drought stress at different growth stages, four breeded genotypes and a local one of proso millet were selected and planted in a split-plot design with five irrigation treatments and three replications.This experiment was conducted in two locations, Birjand and Sarbisheh. Irrigation treatments included well - watered, drought stress at vegetative stage, ear emergence stage, seed filling stage and vegetative and seed filling stages which were considered as main- plots. The first five mentioned genotypes were considered as sub-plots. Drought stress. caused a great reduction in grain yield and WUE at ear emergence stage. This reduction represented itself in the number of seed per ear and the weight of seeds, but it didn’t have any effects on the number of ear. At ear emergence stage, the drought stress increased the floret death and loss of weight of seeds which resulted in the reduction in the harvest index of both ear per plant and seed per plant. Comparison of genotypes indicated that since K-C-M.4 had a greater number of ears and K-C-M.9 had heavier seeds that had higher grain yield. These two genotypes had the highest WUE and their harvest indices were relatively higher. Due to the salinity of water and infertility of soil in Birjand, the grain yield was lower compared with Sarbisheh. In summary, it can be said that genotype K-C-M.4 proved to be more suitable for both areas.

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To investigate yield and water use efficiency (WUE) of potato with tape and furrow irrigations, an experiment was performed at Hamadan Agricultural and Natural Resources Research Center (Ekbatan station) in 2004. The experiment was arranged in a split-plot experimental design based on completely randomized block with 3 replications of irrigation water amount as the main factor (75%, 100%, 125% of cumulative evaporation from class A pan) and sub-factor of irrigation method [including tapes in the middle of furrow ridge on soil surface (T_D0), tapes in the middle of furrow ridge at the depth of 5 cm (T_D5), tapes on the sides of furrow ridge on soil surface (T_S0), and furrow irrigation (F)]. The results indicated that yield of potato increased with increasing water use. Regardless of irrigation method, maximum (32.51 ton/ha) and minimum (19.33 ton/ha) yield of potatoes was achieved with 125% and 75% irrigation water treatments, respectively. The lowest yield (21.35 ton/ha) was obtained in furrow irrigation and the highest yield (28.91 ton/ha) belonged to tape irrigation (T_D5 treatment). The highest WUE (4.68 kg/m³) belonged to tape irrigation (T_D5 treatment) and the lowest WUE (3.32 kg/m³) belonged to furrow irrigation (F). The difference in WUE between 75% and 100% irrigation water treatments was not significant. The highest WUE (4.49 kg/m³) was achieved in treatment 125%. Also, it is more economical to use irrigation water treatment of 125%, as compared with other irrigation water treatments.

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  Effect of change from the conventional (flooding) to subsurface irrigation system was studied on mature pistachio trees (Cultivar Ohadi) in Kerman pistachio research station for four years. This experiment was carried out in a randomized complete block design including 7 treatments and 3 replications. The experiment also used two irrigation intervals (7&14 days) and three water rates according to pan coefficient (20%, 40%& 60% evaporation from surface of class A pan) for subsurface irrigation system with 6 treatments the conventional (flooding) irrigation system was tested as control. The pipes of subsurface irrigation system were installed at 90cm distance from trees trunk at each side of trees, and 50cm from soil surface. Mean of pressure and discharge in the pipes was 0.8 to 1 atmosphere and 5.4 Lh^-1m^-1, respectively. Different factors of quantity and quality pistachio yield, current vegetative growth, water use efficiency and soil electrical conductivity were measured. The results showed that change of conventional (flooding) to subsurface irrigation system is possible and the best treatment can have water rate of 7174 m³ha^-1y^-1 with 14 days irrigation interval. In comparison with other treatments, this treatment has better quantity and quality pistachio yield. Water use efficiency (WUE) of this treatment was 164g dry yield per cubic meter. Nevertheless, application of water rate of 4783 m³ha^-1y^-1 can result in the deficiency of irrigation water. At this water rate, WUE was 177g dry yield per cubic meter. However, it was found that the application of lower water rate (<4783 m³ha^-1y^-1) produced severe effects on the treated pistachio trees, e.g. decreasing the growth rate, yield and increasing the early splitting in pistachio fruits. Finally, it is concluded that 14-day interval irrigation is the preferred treatment for pistachio trees. Also, soil salinity showed considerable change in subsurface irrigation treatments after irrigation system was changed, especially in the first year.

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In tea plantation regions of northern part of the country, application of supplemental irrigation during dry periods (lacking rainfalls) in conjuction with proper nitrogen fertilizer application can significantly improve tea yield per unit of plantation area. In order to quantify the effectiveness of proper irrigation and nitrogen management on tea, the response of tea to various levels of irrigation and nitrogen applications was studied in Fouman suburb of Guilan province. Tea crop production function and its crop coefficient (K_C) were determined. A line source sprinkler irrigation was used for creatiating a variable irrigation application and a split-split-plot statistical design was used. Irrigation treatments consisted of full irrigation (I₄), deficit irrigation (I₃, I₂ and I₁) and no irrigation(I₀). Nitrogen application treatments were N₁, N₂ and N₃ (100, 180 and 360 kg/ha) in three replications randomly arranged as main plots, while irrigation treatments as sub plots were not randomized. During the growing period, soil moisture up to the depth of 90 cm was determined gravimetrically and actual crop water use was calculated from mass balance equation weekly. Reference evapotranspiration (ETo) was estimated by Penman-Montieth equation and was used to estimate tea crop coefficient. During growing period, the actual tea water use of I₄ and I₀ were computed to be 457 and 256 mm. Tea crop coefficient during dry period (June, July and Augest) ranged from 0.8 to 0.9. Crop resistance factor (K_y) for tea was found to be 1.37. Results indicated that optimum rate of nitrogen (180 kg/ha) along with supplemental irrigation, increased yield and water use efficiency (WUE). Futhermore, supplemental irrigation increased yield and WUE more than nitrogen application. In I₀ and I₁ treatments, application of 100 kg/ha nitrogen resulted the highest yield and WUE.

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Sugarcane has been cultivated in an extensive area in Khuzestan and irrigated by hydro-flume or siphon and furrow. In a field experiment during 2005-6 at Amir Kabir Agro-Industry, Khuzestan, the effect of every other-furrow irrigation method was studied on sugarcane in regard to irrigation water volume, water use efficiency and quality and quantity of sugarcane. The experiment was conducted in a completely randomized design with three irrigation treatments, including conventional method (blank), variable every other furrow(alternative furrow) and fixed every other furrow. This experiment was conducted by cv. Cp69-1062 sugarcane. The results showed that water use efficiency rates were 0.41, 0.58 and 0.7 kg/m3 for conventional, fixing furrow and alternative, respectively. However, water use efficiency rates were not significantly different in treatments. It had minimum amount of water use efficiency in every other furrow treatments. Maximum water use efficiency, quality and quantity of sugarcane were obtained every other irrigation. Maximum irrigation water was used in conventional treatment and resulted in minimum irrigation, quality sugarcane and water use efficiency. It produced 14.5 ton/ha sugar for 20604 m3/ha application of irrigation. Sugarcane quality and quantity characteristics in variable treatments, except for length number per hectare, were not significant.

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In order to study the effect of deficit irrigation at reproductive growth stages on water use efficiency and drought tolerance of four sunflower cultivars, including Azargol, Allstar, Alison and Euroflor, an experiment was conducted during 2007 growing season at experimental field of Agricultural Faculty of Bu-Ali Sina University, Hamadan, Iran. The experiment was a split plot based on randomized complete block design with three replications. The irrigation levels included full irrigation, deficit irrigation at heading, deficit irrigation at flowering, deficit irrigation at seed filling, deficit irrigation at heading and seed filling and deficit irrigation at flowering and seed filling stages. The biological and economic yield (BY and EY), harvest index (HI), water used, water use efficiency (WUE) and water stress indexes were measured. The results indicated that the highest BY (11681.7 kg.ha-1), EY (4854.0 kg.ha-1) and HI (42%) were obtained from full irrigation treatment. The lowest negative effects in cultivars belonged to deficit irrigation at seed filling stage. Euroflor obtained the highest of these parameters with 10127.1 Kg.ha-1, 4081.5 Kg.ha-1 and 40% respectively. Highest WUE was related to twice cutoff of irrigation in flowering and seed formation stages and then without irrigation in seed formation stage by 1.09 and 0.96 Kg.m-3. Allstar and then Euroflor had highest WUE among sunflower cultivars by 1.01 and 0.94 Kg.m-3 respectively. Results also indicated that Euroflor was a tolerant cultivar and STI (Stress Tolerant Index) and GMP (Geometric Mean Productivity) were acceptable indexes for selection. Finally, deficit irrigation at seed formation stage had the lowest negative effect on yield and HI with suitable WUE. In addition, Euroflor showed the highest yield, drought tolerance and HI with suitable WUE.

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Deficit irrigation is one of the irrigation management methods that is used to increase Water Use Efficiency. Considering the internal plant adaptability characteristic to water shortage, Partial Root Drying method has been introduced in recent years. In this field research improvement of Water Use Efficiency for Soybean was determined. This experiment which was conducted at four furrow irrigation treatments at the Research Field of Tehran University in Karaj in 2008, consists of full irrigation (100% soil moisture deficit compensation), conventional deficit irrigation at 50 and 75 percent soil moisture deficit compensation and Partial Root Drying at 50 percent soil moisture deficit compensation with three replications. The amounts of irrigation used were exactly compensation level (negligible loss). Results indicated that Water Use Efficiency according to Duncan's Multiple Range Test at the five percent level of probability there was a significant difference between partial root drying treatment (PRD50%) and conventional deficit irrigation treatment at fifty percent soil moisture deficit compensation (DI50%),. Water Use Efficiency in PRD50% compared with DI50%, DI75% and full irrigation increased by 48.3%, 61.9% and 70.1% respectively.

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The positive and beneficial effects of mycorrhizal symbiosis on the growth of various plants have already been documented. Most arable crops can mutually establish symbiosis with endo-mycorrhizal fungi, however, mycorrhizal associations with almond (prunus amygdalus), particularly in calcareous soils of arid and semi-arid regions, have not been studied. Thus, to realize the symbiotic association between mycorrhiza fungi and economically important native almond genotypes in Chaharmahal va Bakhtiary province, an experiment consisting of a randomized complete factorial design with three factors: almond genotypes (Mamaei, Rabee, Talkh, Sefid), soil phosphorus levels (0 and 150 kg P ha-1) and mycorrhizal treatments (almond inoculated with Glomus intraradices, Glomus mosseae and without inoculation) with three replications was conducted under greenhouse conditions by 4 months. Results showed that physiological traits including chlorophyll concentration, net photosynthetic rate and water use efficiency, were significantly increased for 20%, 300% and 300%, respectively in mycorrhizal almond plants, while transpiration rate was decreased (8-10%). Although the genotype of almond and soil P were dependent on these factors, mycorrhiza species had the same effects. Increased available P in the soil enhanced the growth in all treatments and photosynthesis of nonmycorrhizal almonds.

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Modification of irrigation scheduling and management improvement of irrigation systems are two essential factors that have significant impact on agricultural water use efficiency. Therefore, a field experiment was conducted to evaluate the effect of tape drip irrigation (T) and furrow irrigation systems (S) under different irrigation regimes on yield and yield components of soybean in growing season of 2006-2007 at Gorgan Agricultural Research Station in north part of Iran. The experiment was laid out in a split plot design in a randomized complete form where each treatment was replicated three times. The main plots were irrigation systems of tape and furrow, and three irrigation regimes 100 (I100) , 75 (I75) and 50 (I50) percent of total irrigation requirement were chosen as secondary plots. Results showed that thousandgrain weight (gr) and plant height (cm) in furrow irrigation were significantly more than the tape drip irrigation method. Also significant differences between different irrigation regimes in terms of plant height, node numbers and yield were observed. So, I100 and I50 had highest and lowest values, respectively. In terms of irrigation system, 63 percent of water consumption was reduced in tape drip irrigation method. Also, the results indicated that higher and lower water use efficiencies were obtained from tape drip irrigation method with I50 treatment (1.09 kg m-3) and furrow irrigation with I100 treatment (0.50 kg m3), respectively.

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Application of the modern irrigation systems such as T-Tape irrigation system is one of the ways to achieve aptimal irrigation The present study deals with the effect of surface and subsurface drip irrigation systems on the cotton yield For this purpose, a field experiment was conducted in the Agricultural and Natural Resource Research Institute of Orzoueyeh, located in the Kerman province. The experiments were conducted in a split plot design based on the Randomized Complete Block Design (RCBD) with three replications. The treatments were comprised of three levels of the crop water requirements (i.e. irrigation based on 100, 80 and 60 percent of crop water requirement) in main plot and with the two irrigation systems, surface one and subsurface one. The results showed that the yield resulting from treatments with 60 and 80 percent crop water requirement was respectively 981 and 413 kg/ha lower than that of treatment with 100 percent crop water requirement. In addition, the obtained yield due to subsurface system was 248 kg/ha greater than that of the surface pattern. The interaction of treatments on the yield of the crop also indicates that the treatment with subsurface system and 100 percent crop water requirement produces the maximum yield. Despite equal water consumption in each sub plots, the WUE in subsurface system was 14 percent higher than that of surface system. From the economical point of view, benefit to cost ratio in the subsurface system is 8 percent less than surface system. Considering the results obtained in this study in the light of water saving as the main objective in deficit irrigation and water use efficiency (WUE) for cotton cultivation in Orzoueyeh, the 80% of crop water requirement is preferred

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Four partial root zone drying (FULL, 1PRD50, 2PRD50, 3PRD50) treatments were investigated on tomato characteristics and water use efficiency using completely randomized design with five replications. In the control treatment (Full irrigation), all water requirement of plant was met in the root area equally during the growing season. Roots in 1PRD50, 2PRD50 and 3PRD50 treatments were divided into two equal parts and each side of root was irrigated one, two and three times, respectively. Results showed that the highest (44.43 g) and lowest (24.57g) tomato mean weights were obtained at full irrigation and 3PRD50, respectively. Maximum of diameter (43.1 ml) and fruit number (46 No) was observed in the control and minimum of these traits (15.6 ml and 20 No, respectively) was observed in 3PRD50 treatment. There was a highly significant difference between fruit number in all treatments. Highest yield and marketable yield was obtained in the control and 1PRD50 treatment, respectively. The highest irrigation water use efficiency was obtained in 1PRD50 (48 percent more than the control) and the lowest value was in 3PRD50 (27 percent lower than the control). Based on results of this study, partial intermittent irrigation (1PRD50) is recommendable for tomato production.

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efficiency was investigated during a 2-year period (2009-2010) in a silty clay loam soil in Tajarak Research Station (Kaboudarahang Township), Hamedan. The experimental design was a strip-plot within a randomized complete blocks design. The horizontal band, the irrigation water rate after flowering, included full and deficit irrigation (100% and 75% potato water requirement) and the vertical band, kind of inter-planting row tillage including 1- subsoiling to 30-35 cm soil depth, 2- chiseling to 20-25 cm soil depth, 3- sweeping to 5 cm soil depth and 4- no-till. During the growing season, soil mechanical resistance (cone index) in two stages and water infiltration into the soil were measured. At the end of the growth season (harvesting time), potato yield quantity and quality were measured. Result showed that the effect of inter-row tillage on soil mechanical resistance was significant. Subsoiling and chiseling had lower soil mechanical resistance and higher water permeability between treatments, respectively. The effect of inter-row tillage on potato yield was significant so subsoiling and chiseling had a higher potato yield between treatments, respectively. The effect of irrigation water rate on potato yield was not significant. The effect of inter-row tillage on water use efficiency wasn’t significant.

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An experiment was performed at the Miyandoab Agricultural Research Station to study yield and water use efficiency of furrow and tape irrigation systems in one-row and two-row planting patterns, and to investigate density of grain corn SC704. The experimental design was a completely randomized block arranged in Strip Split Plots with three replications in 2010. Irrigation treatments were applied in vertical plots, and planting arrays of different densities were applied in horizontal plots in the form of split plots. The vertical plots were comprised of four irrigation treatments, including three levels (80%, 100% and 120%) of water requirement by use of drip tape irrigation and 100% of water requirement in furrow irrigation, and the horizontal factor was a planting array in the form of single-row and two-row planting patterns and the sub factor was comprised of three levels: 75, 90 and 105 thousand plants per hectare. The results showed that furrow irrigation had the highest rate of grain yield, about 18.6 ton per hectare, and the treatments of tape irrigation of 120%, 100% and 80% had 18.4, 18.2 and 14.9 tons per hectare, respectively. Although the furrow irrigation treatment had higher yield than the rest, there was no significant difference between treatments except for the 80% of tape irrigation. Thus, by utilizing tape irrigation without a great decrease in the yield, water use efficiency improved. The comparison between treatments of tape irrigation of 80%, 100%, 120% and furrow irrigation led to grain yields of 2.3, 2.2, 1.9 and 1.4 kg/m3, respectively. Also, the highest water use efficiency and maximum yield were obtained from 90000 plants per hectare.

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In order to investigate the effects of furrow irrigation and amount of irrigation water on yield and water use efficiency of corn, an experiment was conducted as a split plot based on a randomized complete block design with three replications for a period of two years at Agriculture Center of Mazandaran. Treatments included three levels of 100, 80 and 60 percent water requirement as the main treatments, and three irrigation methods included fixed every-other- furrow, alternative every-other- furrow and every-furrow irrigation as the subsidiary treatments. Statistical analysis of the results of two years' data showed that treatment with 100% water requirement with every-furrow irrigation and treatment with 60% irrigation water requirement with fixed every-other-furrow had the highest and lowest yield, respectively. The highest water use efficiency was in 60 percent irrigation water requirement with a fixed every-other- furrow treatment and the lowest water use efficiency was related to the treatment with 100 percent irrigation water requirement with alternative every-other- furrow. The value of ky was obtained 0.8 for the total growth stage.

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In order to investigate the effect of different levels of irrigation on qualitative and quantitative yield and determine the corn's optimum depth of Irrigation in sShahrekord, a randomized complete block design experiment was done with 7 treatments including 40, 55, 70, 85, 100, 115 and 130 percent of soil moisture deficit and three replications in furrow irrigation. Effects of irrigation levels on yield, water use efficiency, weight of dry matter, plant height, stem diameter, median diameter, length and weight of corn were significant. Different levels of irrigation had no significant effect on seed oil and protein content, but their impact on plant fiber content was significant. With increasing depth of irrigation, stem length, grain weight and plant fiber content increased. The minimum and maximum corn yield were related to 40 and 130% of full irrigation with the yield of 43.1 and 88.1 tons per hectare, respectively. The maximum and minimum use efficiencies were 55 and 130% of full irrigation treatments with values ​​of 16.17 and 10.1 Kg per cubic meter, respectively. The result of economic analysis showed that the water consumption is 5/582 mm, equivalent to 86% full irrigation depth.

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