Irrigation
M. Zokaee Khosroshahi; K. Parvizi
Abstract
IntroductionWater is a critical factor for the growth and fruiting of the grapevines. Considering the water scarcity crisis in Iran and most parts of the world in recent years, it is necessary to apply methods such as deficit irrigation for the optimal management of water use in agriculture. It has been ...
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IntroductionWater is a critical factor for the growth and fruiting of the grapevines. Considering the water scarcity crisis in Iran and most parts of the world in recent years, it is necessary to apply methods such as deficit irrigation for the optimal management of water use in agriculture. It has been determined that by deliberately reducing water consumption in vineyards, it is possible to preserve the existing water resources and improve the water use efficiency. Materials and MethodsA research was carried out in summer 2023 in a randomized complete block design with three replications on 8-year-old vines of the Turkmen-4 variety, to investigate the effect of deficit irrigation levels on the quantitative and qualitative traits and water use efficiency of grapevines. The vines were planted with 2 x 4 meter intervals, were trained as a vertical trellis on a bilateral cordon system, and the vineyard was irrigated by drip irrigation. The experimental treatments included full irrigation (providing 100% of vine water requirement; as control), 25% deficit irrigation (providing 75% of vine water requirement) and 50% deficit irrigation (providing 50% of vine water requirement). Irrigation of the vineyard started from May 22 and continued until November 6 at 7-day intervals, according to the conventional procedure. The water requirement of each vine in non-stressed condition was calculated by a class A evaporation pan based on reference crop evapotranspiration (ETo) and crop coefficient (Kc) throughout the season. Then, the amount of water for each treatment was determined according to the irrigation levels in the treatments and applied in volume form. Results and DiscussionThe amounts of water consumption of control, 25% and 50% deficit irrigation treatments were 5140, 3855 and 2570 m3 per hectare, respectively. The results showed that irrigation levels had a significant effect on the berries length, berries diameter, cluster length, cluster width, berries weight, cluster weight, sugar percentage, chlorophyll index, relative water content, midday leaf water potential, vegetative growth, vine yield, yield index and water use efficiency. The 25% and 50% deficit irrigation treatments caused a decrease of 7.2% and 14.2% of the berry length compared to full irrigation, respectively. Also, these treatments caused a reduction of 8.3% and 13.9% of the berry diameter, respectively. While the 25% deficit irrigation treatment had no significant effect on the berries sugar content (°Brix), the 50% deficit irrigation treatment caused a significant decrease (5%) in sugar content compared to the control. Both relative water content and midday water potential of the leaves decreased significantly with the reduction of irrigation levels. Reducing the level of irrigation led to a significant decrease in the SPAD index and vine vegetative growth. Increasing the intensity of deficit irrigation had a significant negative effect on yield components including berry weight, cluster weight, vine yield and yield index. The highest and lowest yields were obtained from full irrigation and 50% deficit irrigation, respectively but the effect of 25% deficit irrigation on yield reduction was not significant. Although the 25% and 50% deficit irrigation treatments caused a 5.8% and 27.5% decrease in vine yield, respectively but these treatments increased water use efficiency by 34% and 44.5%, respectively compared to the control. The lowest water use efficiency was related to the control (3.53 kg of fresh fruit per cubic meter of water used), while the water use efficiency of vines under 25% and 50% deficit irrigation was 4.73 and 5.10 kg of fruit per cubic meter of water, respectively. The 25% and 50% deficit irrigation treatments had a statistically significant difference with the control in terms of water use efficiency, but the difference between the two was not significant. ConclusionIn the present study, reducing the volume of irrigation water led to a decrease in vine yield, but what is important is the low yield reduction rate compared to the amount of water consumption. The decrease in vine yield was 5.8% and 27.5%, respectively with a 25% and 50% decrease in water consumption. Also, with 25% and 50% reduction in water consumption, the yield index decreased by 6.1% and 27.3%, respectively. Meanwhile, the water use efficiency of vines increased by 34% and 44.5% in response to 25% and 50% deficit irrigation treatments, respectively. It is recommended to apply 25% deficit irrigation to increase the water use efficiency of Turkmen-4 grapes in climatic conditions of Malayer, but 50% deficit irrigation leads to a decrease in quality of grapes.
rasoul asadi; farzad hasanpour; mitra mehrabani; Amin Baghizadeh; Fateme karandish
Abstract
Introduction: In arid and semi-arid areas, water can be a limiting factor for plant growth and agricultural yields. Considering limited water resources in arid and semi-arid climate of Iran, deficit irrigation is one of the strategies for efficient use of water and increasing water use efficiency ...
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Introduction: In arid and semi-arid areas, water can be a limiting factor for plant growth and agricultural yields. Considering limited water resources in arid and semi-arid climate of Iran, deficit irrigation is one of the strategies for efficient use of water and increasing water use efficiency in agricultural lands. Deficit irrigation (DI) is a suitable solution to gain acceptable and economic performance by using minimum amount of water. The Partial Root- zone Drying (PRD) irrigation is a new improvement in deficit irrigation in which the half of the root zone is irrigated alternatively in scheduled irrigation events. The plants with PRD irrigation method can, therefore, have different root system in comparison with other irrigation methods. At this method the plant’s condition would be OK by withdrawing water from wet side, and the roots at the dry side can release abscisic acid hormone which decrease the stomatal conductance and consequently the water use efficiency would increase. Also, by using proper irrigation management in farm, we are able to utilize water, soil and fertilizer to produce high yield and quality products. Drip irrigation is considered one of the most efficient irrigation methods. One of the major advantages is its ability to apply water to the soil as often as desired and in smaller quantity than the other irrigation methods. Drip irrigation has been practiced for many years for its effectiveness in reducing soil surface evaporation and it has been widely used in horticultural crops in both greenhouse and open field.
Materials and Methods: In order to compare two deficit irrigation methods on plant growth characteristics of Rosmarinus officinalis L., a field experiment was carried out during 2016 growing season at an experimental farm in Kerman Municipality seedling production station. The experimental treatments were arranged as randomized complete block design with three replications. The irrigation regimes consisted of full irrigation (FI-100), regulated deficit (RDI75 and RDI55) and partial root zone drying irrigation (PRD75 and PRD55). In this study, drip lines were placed on the soil surface at a distance of 15 cm from the plant and plant rows were placed between drip lines. The irrigation interval was 4 days for all treatments. In the full irrigation and regulated deficit irrigation treatments, the plants were irrigated from two sides for every irrigation. In the PRD, one of two neighboring drip line was alternatively used for irrigation. The irrigation interval was 4 days for all treatments. Dry weight, leaf area index (LAI), number of shoots, plant height, water productivity, root fresh weight, root depth and root volume were measured. Since the highest essential oil of rosemary is at 50 percent of flowering time, the above-mentioned indices were measured at the middle of flowering (190 days after planting) by removing the side rows in each replicate and half a meter from the beginning and end of each row. As a marginal effect, 10 plants were randomly selected and sampled from two middle rows, each replicate of each treatment. The harvested bushes were dried at 25 °C for three weeks and then the dried weight of the vegetative organs was measured. Moreover, the number of 10 plants selected from each treatment was accurately counted to determine the number of shoots. Data were analyzed statistically using SAS Statistical software. Treatment means were compared using LSD test.
Results and Discussion: The results showed that highest herbage dry weight (145.3 g) and leaf area index in different stages of growth were under full irrigation treatment in which no significant difference between this treatment and 75 percent water replacement in partial root zone drying was observed. The highest number of shoots (128.7) and plant height (68.4 cm) were also obtained by full irrigation treatment and there was significant difference between this treatment and other treatments. However, the highest water productivity (2.06 kg/m3), root fresh weight (3.8 g), root depth (16.4 cm) and root volume (2.4 cm3) were found in 75 percent water replacement in partial root zone drying.
Conclusion: According to the results, 75 percent water replacement in partial root zone drying irrigation treatments, in addition to saving water consumption, provides better use of soil moisture and sunlight. Thus, this treatment can be considered as a suitable approach to cope with the water crisis and achieve a sustainable agriculture.
Keywords: Drip irrigation, Drought stress, Leaf area index, Medicinal plant, Rosmarinus officinalis, Water productivity
T. Raeisinejad; N. Yazdanpanah
Abstract
Introduction: Water has been known as an important limiting factor for plant growth and agricultural yields in arid and semi-arid regions. It is a significant input to agricultural production and also an essential requirement for domestic, industrial and municipal activities. Increasing population and ...
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Introduction: Water has been known as an important limiting factor for plant growth and agricultural yields in arid and semi-arid regions. It is a significant input to agricultural production and also an essential requirement for domestic, industrial and municipal activities. Increasing population and standards of living are contributing to a steep rise in demand for fresh water. By using proper irrigation management practices in farmlands, it is possible to utilize water, soil and fertilizer to produce high yield and quality products. Drip irrigation is considered as one of the most efficient irrigation methods. One of its major advantages is the ability to apply water to the soil as often as desired and in smaller quantity than the other irrigation methods. Two systems of drip irrigation including surface and subsurface drip irrigation methods have been widely used in arid and semiarid regions to reduce the water deficiency impact. Subsurface drip irrigation has been used for many years because of its effectiveness in reducing soil surface evaporation. It has been widely used in horticultural crops under both greenhouse and outdoor field conditions. However, the surface drip irrigation system can be used easier than the subsurface drip irrigation system. In addition, deficit irrigation is one of the strategies for efficient use of water and increasing water use efficiency in agricultural district. Deficit irrigation is a suitable solution to gain acceptable and economic performance by using minimum amount of water. The aim of this study was to evaluate the yield and yield components of sunflower affected by different levels of soil matric potential in combination with two contrasting drip irrigation method i.e. surface and subsurface. In addition, water use efficiency as an important criterion of yield was used to achieve the best and more suitable irrigation method under water scarcity conditions.
Materials and Methods: In order to investigate the irrigation management of sunflower, a field experiment was carried out during 2016 growing season at an experimental farm in Jiroft city. The treatments were laid out in split strip plots based on randomized complete block design with three replications. The treatments were comprised of three soil matric potentials of 40, 55, and 70 centibar for initiation of irrigation in the main plot and sub plots consisted of two drip irrigation systems (surface and subsurface). In the surface systems, drip lines were placed on the soil surface at a distance of 15 cm from the plant and in the subsurface systems, drip lines were placed at a depth of 30 cm. The irrigation time was determined based on the readings of metal tensiometers. These tensiometers were installed in three depths of 15, 30 and 50 cm of soil and at a distance of 20 cm from the plant. In this regard, in both irrigation systems, the mounted tensiometer at a depth of 15 cm of soil was used in the early growth and development, and mounted Tensiometers at depths of 30 and 50 cm soil were used in the middle and final stages of growth. In order to carry out irrigation at the potential point of view, the tensiometers were fully controlled and when the calibrated tensiometer screen showed the desired potential point, irrigation was carried out and the irrigation process continued until the soil moisture reached the crop capacity level. Yield, yield components such as number of seeds per head, along with water use efficiency were measured. Data were statistically analyzed using SAS Statistical software. Treatment means were compared using LSD test.
Results and Discussion: The results showed that the water usage parsimony of 153.6 mm (21.5 percent) between the 40 and 55 c-bar tensions caused that the yield, number of seeds per head and height of plant decreased by 12.5%, 12.8% and 11%, respectively, but water use efficiency increased 10.3%. Compared with 55 c-bar tention, 70 c-bar also decreased the yield, number of seeds per head and height of plant by 33.4%, 22.9% and 22.5%, respectively but increased water use efficiency by 4.7%. Moreover, the yield in subsurface drip irrigation increased by 499 kg/ha compared with surface irrigation. In addition, parsimony of water usage was 10% and water use efficiency increased by 21.5%. Number of seeds per head and the height of plant increased by 8.2% and 8.7%, respectively in subsurface drip irrigation.
Conclusion: According to the results of this study conducted on sunflower in Jirot area, it was concluded that the application of soil matric potential of 55 centibar in subsurface drip irrigation system is the best approach to increase water use efficiency during periods of drought.
Maryam Pourmorad; Mohammad Jafar Malakouti; Mohamad Tehrani
Abstract
Introduction: Optimum water consumption in agricultural production is of vital importance as one of the most important environmental factors affecting the growth and development of the plants, especially in arid and semi-arid regions such as Iran. On the other hand, drought stress, among other environmental ...
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Introduction: Optimum water consumption in agricultural production is of vital importance as one of the most important environmental factors affecting the growth and development of the plants, especially in arid and semi-arid regions such as Iran. On the other hand, drought stress, among other environmental stresses, is one of the most important factors that adversely affect the plant growth and yield. Due to the presence of hormonal compounds, organic acids (at low concentrations) can positively affect the production rate and the quality of agricultural products. Considering the water deficit and the necessity of saving water resources as well as the role of organic acids in reducing the negative effects of stress, in the present study attempts are made to investigate the effect of humic and fulvic acid on wheat yield (Triticum aestivum L.) under drought stress conditions.
Materials and Methods: The present study was carried out at the research farm of the national soil and water research institute located 15 km away from Karaj (with elevation of 1280 m) during the 1394-95 crop year. The experiment was a split-plot experiment based on randomized complete block design with three replications which included two main plots (full irrigation and stress) and 36 sub plots of Sivand cultivar. The treatments consisted of the main factor of irrigation regimes at full irrigation and stress levels (35% lower than water requirement) and a sub-factor including six control treatments (F0H0), no foliar application of fulvic acid, in-soil application of 20kg- ha of humic acid (F0H20), Foliar application of fulvic acid (F5H0), and no application of humic acid (F5H0), (F5H20), (F10H0) and treatment (F10H20). The wheat water requirement in the area was estimated by means of Netwat software and irrigation periods were determined based on weather forecast and soil moisture data. Irrigation was carried out using a system of drip irrigation with a specific pressure and discharge level. The stresses were applied from mid-April through consideration of different irrigation hours as compared to full irrigation time. After completion of the growth period, the plant water requirement was accurately estimated by Cropwat software and the percentage of applied stress was accurately calculated (approx. 35%). The Plant yield and some of its components were measured. Statistical analysis was performed through LSD method at 5% significance level using SAS software
Results: The mutual impact between irrigation and fulvic and humic acid applications on total and grain yield was not significant (P <0.05). The highest yield was related to the foliar application of fulvic acid (F10H0) with a total yield of 27331 kg/ha, which had no significant difference with treatment F5H20 (total yield of 25667 kg/ha). Under full irrigation conditions, treatments (F10H0, F5H20) led to 31.81% and 28.44% increase in grain yield (as compared to the treatment yield) respectively. Under low irrigation conditions, treatments (F10H0, F5H20) led to 46.66% and 34.33% increase in grain yield, respectively.
The Weight of 1000 Grains The application of humic acid and fulvic acid alone did not significantly increase the weight of 1000 grains. But the combined application of fulvic acid (F5H0) and humic acid (20 kg /ha) significantly increased the weight of 1000 grains (8.5%). Under low irrigation conditions, the combined application of humic acid and fulvic acid (F10H0) increased the weight of 1000 grains (as compared to the control group) by 14.75%.
Shoot Height The highest shoot height (126.86 cm) was obtained in foliar application of fulvic acid (F5H0) with the in-soil application of humic acid in full irrigation conditions, which increased the shoot height by 22.68% (as compared to the control group). The lowest average shoot height (99.66 cm) was obtained through no application of fulvic acid and humic acid in stress conditions.
Spike Length The application of fulvic acid (F5H0) had no significant effect on spike length. However, the combined application of humic acid (20 kg/ ha-) and fulvic acid (F5H0) increased the mean spike length. Regardless of irrigation conditions, the highest mean spike length was 9.188, 9.105 cm for treatments (F5H20, F10H0) and the lowest mean spike length was 8.258, 8.293 cm, for treatments (F5H0, F0H0).
A number of Grains per Spike The combined application of humic acid and fulvic acid (F5H0) and the application of fulvic acid (F10H0) led to 10% increase in the number of grains per spike as compared to the control group.
Water Use Efficiency The main effect of irrigation and the use of humic acid and fulvic acid on water efficiency was significant at 1% level. The mean comparison at 5% level showed that tension caused 68% increase in water use efficiency. The use of humic acid and fulvic acid increased water use efficiency significantly. The maximum water use efficiency (3.86 kg / m 3) was in spraying the fulvic acid at a concentration of 10 per thousand. Under full irrigation and low water use, the use of fulvic acid at a concentration of 10 per thousand increased water use efficiency as 43.34% and 62.25%
Conclusion: The results of this study showed that the combined application of fulvic acid (F5H0) and humic acid (F5H20) significantly increased all the traits under study. The application of humic acid in drought stress conditions led to 9.09 percent increase in grain yield as compared to the control groups in the full irrigation condition, and the application of humic acid and fulvic acid (F5H0), as well as foliar application of fulvic acid alone (F10H0) under stress conditions led to 23.86% and 24.9% improvement in grain yield respectively ( as compared to control treatments under full irrigation conditions) while foliar application of fulvic acid (F10H0) in drought stress conditions resulted in a 2.65% reduction in grain yield as compared to the same treatment under full irrigation conditions. The results showed that the application of fulvic and humic acid in low irrigation conditions can increase wheat yield and water use efficiency.
hamid reza mehrabadi; Ahmad Nezami; Mohammad Kafi; Malihe Ahmadifard
Abstract
Introduction: More plains of Iran are located in arid and semi-arid regions and so agricultural production systems depend heavily on water. Recently, the reduction of water resources has become a serious threat for crop production such as cotton planting. Therefore, application of low irrigation methods ...
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Introduction: More plains of Iran are located in arid and semi-arid regions and so agricultural production systems depend heavily on water. Recently, the reduction of water resources has become a serious threat for crop production such as cotton planting. Therefore, application of low irrigation methods can be an appropriate method to cope with mentioned condition. In addition, it is vital to identify the cotton cultivars reaction to water deficiency. Sensibility of some cotton cultivars is lower than others. Sensitive cultivars seed cotton yield decreases more than tolerant cotton cultivars. Moreover, some of growth stages in cotton plant are more sensitive to water deficiency stress. For example, flowering stage is more sensitive than vegetative growth stage, and boll number per plant is more effective parameter on yield than boll weight. Ulla and et al (2) showed that there are genetic variations for drought stress toleration in cotton plant. Afshar and Mehrabadi (3) indicated that low irrigation on the basis of 50% and 75% of cotton water requirement had no significant effect on vegetative growth of cotton plant. However, it caused the increase of flower and boll shedding per plant. Application of tolerant cultivars compared with sensitive cultivars can increase seed cotton yield under drought stress condition. Consequently, the aim of this study is to survey yield and related morphological traits reactions in sensitive and tolerant cotton cultivars to different water deficiency levels.
Materials and methods: Two tolerant cotton cultivars (Armagan and Varamin) and two sensitive cotton cultivars (Coker349 and Nazili84) as a subplot at three irrigation levels (as a main plot) using split plot design based on complete block design with three replications were carried out at Agricultural Research Station of Kashmar in 2011. Three levels of water consumption based on Penman-Montith method and using cotton KC coefficients were [33% (I33%), 66% (I66%) and 100% (I100% of water requirement)] that it were take placed using drip irrigation method. Yield and yield components traits such as height, the number of boll per plant, boll weight, flower and boll shedding percent, seed cotton yield, biological yield, earliness percent and harvest index were determined at the end of experiment. Data analysis was carried out using Excel and MSTAT-C software.
Results and Discussion: The results showed that although water deficiency stress decreased vegetative components, the amounts of decreasing were higher in tolerant cultivars than sensitive cultivars but, by contrast, the reproductive components of tolerant cultivars indicated lower decreasing than sensitive cultivars under water deficiency stress. For example, Varamin cotton cultivar had more number of bolls per plant than Coker349 as a sensitive cultivar. The results also showed that more retention of boll number per plant was the main factor of cultivars difference as for seed cotton yield. The highest number of boll and flower per plant retention belonged to sensitive cultivars such as Coker349 and Nazili (71.2 and 69 percent, respectively) at 66 percent of water consumption and the lowest number of boll and flower per plant retention were 92.3 percent belonging to Varamin as a tolerant cotton cultivar at full water irrigation treatment. The results indicated that all yield components except boll weight were significantly affected by low irrigation levels. In addition, the results revealed that low shedding of flower and boll and accordingly more retention of boll number per plant and also biomass preservation under drought stress were the main factor in yield of tolerant cultivars in comparison with sensitive cultivars. Biological yield reduction was higher than seed cotton yield under water stress condition. High and significant correlation was observed among yields with boll number per plant, biological yield and harvest index under drought stress. Moreover, there was a significant correlation between yield with plant height and biological yield only in full irrigated treatment. Furthermore, harvest index decreased significantly under drought stress. Harvest index value for Coker349 was significantly lower than other cultivars. Coefficient correlation between harvest index and yield and its components showed that harvest index was more dependent with seed cotton yield to biological yield. Therefore, tolerant cultivars had higher seed cotton yield and also biological yield in comparison with sensitive cultivars. While there was a significant correlation between yield with plant height and biological yield only in full irrigated treatment.
rahim motalebifard; Nosratollah Najafi; Shahin Oustan
Abstract
Introduction: In natural environments, plants are subjected to biotic (insects, bacteria, fungi, and viruses) and abiotic (light, temperature, water availability, nutrients, and soil structure) stresses that can have negative effect on growth, metabolism, and yield. Among these, drought is a major abiotic ...
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Introduction: In natural environments, plants are subjected to biotic (insects, bacteria, fungi, and viruses) and abiotic (light, temperature, water availability, nutrients, and soil structure) stresses that can have negative effect on growth, metabolism, and yield. Among these, drought is a major abiotic factor that limits agricultural crop production. Potato production has fourth rank in the world after rice, wheat, and maize with the production of 321 million tons from 19.6 million hectares. By about 3 percent of cultivation area, potato had 7.2 percent of total agricultural production (5.57 million tons) in our country (Iran). Limited studies have been conducted on the interactive effects of Zn and P on potato tubers quality under water deficit conditions.
Materials and Methods: This study was conducted for evaluating the effects of soil moisture, phosphorus (P) and zinc (Zn) levels on the chemical composition and nutrients content of potato (Solanum tuberosum L. cv. Agria) as a factorial experiment based on randomized complete blocks design with three factors under greenhouse conditions. The study was performed with factors of Zn at three levels (0, 10 and 20 mg Zn per kg dry soil as ZnSO4.7H2O), P at three levels (0, 30 and 60 mg P per kg dry soil as Ca(H2PO4)2.H2O (monocalcium phosphate)) and soil moisture at three levels (0.5FC-0.6FC, 0.7FC-0.8FC and 0.9FC-FC) using three replications and 81 pots. The soil moisture levels were imposed three weeks from the flowering (64th day) until harvest (85th day after planting). After imposing of soil moisture levels and at the harvest, the yield and yield components, reducing sugars concentration in fresh weight by di- nitro phenol method (Mostofi and Najafi, 2005) and starch by Antron method (Mostofi and Najafi, 2005), N, P, K, Mg, Na, Fe and Zn concentrations in dried potato tubers were measured. Data were subjected to analysis of variance as factorial 3×3×3 with n=3 by using MSTATC software. Duncan's multiple range tests at p≤0.05 probability level was applied to compare the mean values of measured attributes. The Excel software was used to draw Figures.
Results and Discussion: The results showed that water deficit significantly affected most of qualitative attributes and nutrients concentration of potato Tuber N, P and reducing sugar concentrations were significantly increased (p
borhan sohrabi
Abstract
Introduction: Iran is a vast country with limited water resources. Iran is located in arid areas and average precipitation is estimated to be 250 mm. In recent years, water shortage has created many problems for Iranian farmers. In these conditions, surface and ground water use is excessive. High consumption, ...
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Introduction: Iran is a vast country with limited water resources. Iran is located in arid areas and average precipitation is estimated to be 250 mm. In recent years, water shortage has created many problems for Iranian farmers. In these conditions, surface and ground water use is excessive. High consumption, low irrigation efficiency, bad time and geographical distribution of precipitation, population growth and increasing agricultural land are one of the main reasons for the irrigation water crisis. Therefore, the main problem of drought and water shortages still remains. The area of agricultural land in Golestan province is high, but most of them are rain-fed cultivation or left fallow. Due to the loss of irrigation water in traditional agriculture, development of pressurized irrigation as a solution to increase productivity and reduction of strain on water resources was raised. With government support, the use of pressurized irrigation systems is increasing.
Materials and Methods: To evaluate the effect of different amounts of water on new variety of cotton-Sepid, a two-year study was conducted using drip irrigation at Hashemabad Cotton Research Station, Gorgan, Iran.The Hashemabad Cotton Research Station is located in north of Iran at 36° 51' N latitude and 54° 16' E longitude at the south-east corner of Caspian Sea and its height from sea level is 13.3 meters. That station has a Mediterranean climate with relatively mild winters and relatively dry summers. The station's annual evaporation, precipitation and relative humidity are 1311mm, 525 mm and 71%, respectively. Soil texture of Hashem Abad station is silty clay loam. In this study, four levels of irrigation water: 0%, 40%, 70% and 100% evaporation of class A pan were studied in a randomized complete block design. Land was plowed in autumn last year and was ready for planting in April with the disc. During tillage, manure fertilizer on the soil surface was sprayed based on the soil test recommendations. At this stage, for combating weeds, herbicide trifluralin (2.5 liters per hectare) was used. Planting new varieties of cotton - Sepid was in the first decade of May. Each plot consists of 8 lines which was ten meters. After evaporation of 50 mm from Class A evaporation pan, irrigation is done. Irrigation tapes were placed just alternate between planting rows. Water consumption was measured using a volumetric water meter. To measure the product, cotton-seed of four rows of each plot were harvested. Yield components were measured in the same four rows. Product wastaken in October and early November during two harvesting.
Results and Discussion: Cotton as thermophilic plants, especially in humid areas, is strongly influenced by farm management. Among the controllable factors, irrigation management had very effective role in the balance between vegetative and reproductive growth. In other words, water stress control in cotton fields is essential for economic output. Through advanced techniques, drip irrigation despite high initial cost, will be the first choice. Because in addition to irrigation efficiency, with earliness management, mechanization harvesting is done better. According to the analysis of variance, the effect of different amounts of water on the total yield was significant at the level of one percent. The lack of statistical significant differences between treatments in terms of total yield of I100 and I70, the second treatment due to a 30% saving in water consumption and earliness as the best in the normal condition. One of the parameters that are usually affected by irrigation management is earliness. Average comparison shows in term of earliness, three treatments of I70، I40 and I0 in group A and treatment I100 are in the latter group. Thus, from this aspect I70 can be recommended. In terms of water use efficiency I40 and I70 with 1.44 and 1.17 kg per cubic meter had the highest WUE, respectively.
Conclusions: The results shown that irrigation water had significantly effects on first pic, second pic and total yield. But irrigation water treatments had no significant effect on earliness and boll weight. According to the combined analysis table (two years data), as much as % 70 of cumulative evaporation from class A pan, will be recommended for cotton farming in north of Iran in normal weather. In dry years, % 100 of cumulative evaporation from class Apan is suggested.
Afsaneh Tongo; A. Mahdavi; E. Saiad
Abstract
To study the effect of Aquazorb super absorbent polymer (SAP) on reducing Drought stress of Acacia victoriae seedling, a split plot experiment based on the completely randomized design was conducted. In this research, stressed treatment as the main plots and amount of superabsorbent were considered as ...
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To study the effect of Aquazorb super absorbent polymer (SAP) on reducing Drought stress of Acacia victoriae seedling, a split plot experiment based on the completely randomized design was conducted. In this research, stressed treatment as the main plots and amount of superabsorbent were considered as sub plot. Treatments were applied consisted of four levels of drought stress (15, 30, 60 and 100% of field capacity) and four levels of superabsorbent (0, 0.2, 0.4 and 0.6 wt%) Were studied. The results showed that survival of seedlings at the end of growth season between different treatments was the same, but the Acacia growth was responsed to the water stress and reduced growth traits were found. Using of the superabsorbent polymer had a significant effect on collar diameter, seedling height, fresh and dry root weight, relative water content of leaf and proline. According to the comparison of the means simple effects, in all of growth indices except the leaf area and root fresh weight the most means was obtained in 0.2% superabsorbent polymer treatment and also, in comparison the effect of diferent factors in most of the traits the highest means compared with 100% irrigation level without applying SAP related was to 60% irrigation level with 0.2 % SAP. That represents water savings is about 40%.
N. Ghasem Jokar; habib nadian; B. Khalili Moghaddam; m. heidari; M.H. Gharineh
Abstract
Introduction: Drought stress is one of the main problems in agricultural productions in arid and semiarid regions such as Iran. Lack of water influences on most of plant physiological processes such as photosynthes, cellular development and uptake and transmission of nutrients in plants. Some approaches ...
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Introduction: Drought stress is one of the main problems in agricultural productions in arid and semiarid regions such as Iran. Lack of water influences on most of plant physiological processes such as photosynthes, cellular development and uptake and transmission of nutrients in plants. Some approaches such as selection of resistance cultivars to drought stress, and selection of dripped irrigation have been applied in order to increase the irrigation efficiency. In recent years, biological approaches such as mycorrhizal symbiosis have been used to alleviate the detrimental effects of drought stress. Mycorrhizal symbioses increase the absorption of nutrients, especially phosphorus, and reduce the adverse effects of environmental stresses. It can also improve the host plant growth and yield. The percentage of mycorrhizal dependency of host plants depends on different environmental factors (such as light intensity, temperature, soil conditions), as well as morphological and physiological characteristics of plants. 1n 2010, a greenhouse pot experiment was conducted at University of Agriculture and Natural Resources Ramin. The effect of mycorrhizal inoculation on root morphology of three leek genotypes and uptake of phosphorous, calcium and potassium in shoot and root were studied.
Materials and Methods: The experiment was conducted in a completely randomized design consisting of a 3×3×2 factorial combination. Experimental factors included three levels of soil moisture (40, 60 and 80% of available water in the soil), two mycorrhizal status (with and without fungus Glomus intraradices) and three leek genotypes including: Shadegan (with low root branching, short and thin root length), Esfahan (with abundant root branching and long root length) and Porrum (with low root branching, short and thick root length). The treatments were replicated four times. The soil was autoclaved at 121°C and15 PSI for 15 minutes and gently packed into PVC pots, 200 mm long and 150 mm in diameter. Leek seeds were sterilized with sodium hypochlorite (NaOCl) solution (10%) for 20 min. Two hundred grams of inoculum (spore, hyphae, mycorrhizal clover of root fragments and soil) were placed in deep of plant root. Each pot received 10 cm-3 nutrients solution, free of P weekly. Plants equally watered for one mounth then, drought stresses were applied. Leeks were harvested 12 weeks after planting. Sub-samples of roots were taken for determination of root length were cleared in 10% (w/v) KOH solution and then were stained with trypan blue and root colonization was studied using modified Phillips & Hayman. The colonized root length was determined by binocular and gridline intersect method of Tennant. Phosphorus concentrations were measured by the method of colorimetery with a spectrophotometer. Potassium and calcium concentrations were determined by flame photometer and titration with vercin (Ethylene diamine tetra acetic acid: EDTA), respectively. The statistical analysis was performed using MSTAT-C statistical software and means were compared by Duncan’s multiple range test at the significance level of P
