Irrigation
Nadia Bahremand; Hossein Aroiee; Ahmad Aien
Abstract
Introduction: the watermelon (Citrullus lanatus) is a known product with high demand and nutritional value and the capability to export all over the world, and considering that the ultimate goal of all agricultural production systems is to achieve the maximum yield of the plant, and providing the water ...
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Introduction: the watermelon (Citrullus lanatus) is a known product with high demand and nutritional value and the capability to export all over the world, and considering that the ultimate goal of all agricultural production systems is to achieve the maximum yield of the plant, and providing the water required for the plant is most effective factor on yield, as a result, investigating of t water limitation effec seems to be an undeniable necessity. On the other hand, dificit irrigation has been introduced as a tool to increase water productivity, thus it is necessary to take into account the effects of this method of saving water consumption on plant production, which doubles the need for research and shows it more clearly, and in addition, Deficit irrigation is applied by providing a part of the plant's water needs, while regulated deficient irrigation is a type of deficient irrigation that can be implemented in several ways, including irrigation based on growth stages or, in other words, allocating of the water to stages that are more sensitive to drought. we should know that the response of plants to lack of the irrigation depends on several factors, including climatic conditions, type of plant, intensity and method of application of deficit irrigation, soil condition and management.
Materials and methods: In order to determine the effect of deficit irrigation and regulated deficit irrigation on yield and water productivity of the watermelon, an experiment in the form of randomized complete blocks with 8 treatments including three irrigation levels of 100, 70 and 50 % of the plant's water requirement (evapotranspiration estimated by the FAO-Penman-Monteith method) and 5 regulated deficit irrigation levels including 50% of the water requirement in the stages of seedling, vine, flowering, fruit expansion and fruit maturity was carried out with three repetitions under black plastic mulch, during 2020-2022, in the Research and Education Center of Agriculture and Natural Resources in the south of Kerman province. Irrigation as the main plot at three levels of 100, 70 and 50% of water requirement and mulching at three levels of crushed date palm leaf, black plastic and no mulch, as the sub-plot, were considered. Crimson B 34 watermelon seeds produced by Seminis company, were planted on January 2021, in plots with the size of 13.5 × 7 m, on furrows and ridges planting system (the width of furrows and ridges were 0.5 and 4 meters, respectively). After planting, bow-shaped wires were put on the planting rows and a transparent plastic was placed as a tunnel on them. In the first year, the total depth of the irrigation in aforesaid treatments was respectively 444, 321, 237, 413, 389, 435, 345 and 425, and in the second year 427, 303, 223, 395, 373, 416, 331 and 405 mm.
Results and Discussion: The results showed that the highest and lowest yield were observed in full irrigation and irrigation 50 % (60.1 and 16.3 t ha-1 respectively). Among the regulated deficit irrigation treatments, irrigation 50% at the seedling stage was the closest to full irrigation, and the irrigation 50 % at the fruit expansion stage had the lowest yield. the highest water productivity belonged to the irrigation 50 % in the seedling and vine stages (15.9 and 1.15 kg m-3 respectively). Irrigation 50% in fruit maturity stage despite irrigation 50% improved Qualitative characteristics such as soluble solids, vitamin C, dry matter, lycopene and fruit taste.
Conclusion: By applying of deficit irrigation with intensities used in this study, compared to full irrigation (control), a significant decrease in watermelon yield was observed. water productivity remained almost constant, there was no significant increase in the quality of the edible part, but treatments of regulated deficit irrigation including seedling stage in terms of yield without significant difference with full irrigation and irrigation 50 % of vine stage in terms of water productivity and irrigation 50% of fruit maturity stage were superior in terms of quality compared to the control. generally regulated deficit irrigation had better results than deficit irrigation due to less yield reduction, increased water productivity and fruit quality in the watermelon, which it can be noticeable in the conditions of water restriction. Finally, it is recommended that milder intensities of deficit irrigation that seem to have more favorable results in this plant should be investigated in the next studies.
Acknowledgement:
Irrigation
R. Saeidi
Abstract
IntroductionSalinity stress causes reduction of crop evapotranspiration (ETc) and yield. An unsuitable seed planting date can result in negative atmospheric effects, such as temperature stress, during the crop growth period. Consequently, salinity stress and unfavorable climatic conditions during this ...
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IntroductionSalinity stress causes reduction of crop evapotranspiration (ETc) and yield. An unsuitable seed planting date can result in negative atmospheric effects, such as temperature stress, during the crop growth period. Consequently, salinity stress and unfavorable climatic conditions during this period interact to reduce crop water uptake. The mentioned conditions effect, should be investigated on crop transpiration amount (actual water requirement) and soil surface evaporation losses. This research results will have a determinative effect on the optimal use of water resources. Materials and MethodsThe studied crop in this research was S.C 704 maize. The crop planting was conducted in mini-lysimeters with a diameter of 40 cm and a height of 70 cm. The experiment factors included soil salinity stress and seed planting date. Soil salinity treatments were selected at four levels of 1.7 (S1), 2.5 (S2), 3.8 (S3), 5.9 (S4) dS.m-1. Seed planting date included of 5 May (P1), 25 May (P2) 14 June (P3) and 4 July (P4). Crop growth period for all planting date treatments, was 140 days (FAO-56). Experiment was conducted as factorial based on completely randomized design with 16 treatments and three repetitions. Variance analysis and average comparison of data was done by SPSS software and with Duncan's multi-range test (at 5% probability level). Daily soil moisture amount was measured by a moisture meter. Irrigation time was determined for without water stress conditions. Readily available water limit was determined 0.4. Irrigation volume was calculated according to soil moisture deficit (up to FC limit), soil density, root depth, leaching fraction and soil surface area. To separate the evapotranspiration components, all treatments were performed in two series of mini-lysimeters. In the first series, soil moisture reduction was related to crop evapotranspiration amount. But in the second series, the plastic mulch was placed on soil surface. Soil moisture reduction in the second series, was only related to crop transpiration amount. Difference of data in the first and second series was equal to the evaporation amount. Linear function of Mass and Hoffman (1977) was used as the function of evapotranspiration-salinity, transpiration-salinity, and evaporation-salinity. Results and DiscussionAs salinity increased from S1 to S4 levels, evapotranspiration, transpiration, and evaporation amounts were measured on the planting dates P1, P2, P3, and P4. The measurements were as follows:Evapotranspiration (mm): 619-548 (P1), 621-549 (P2), 624-547 (P3), and 625-544 (P4)Transpiration (mm): 429-309 (P1), 421-295 (P2), 418-281 (P3), and 412-265 (P4)Evaporation (mm): 190-239 (P1), 200-254 (P2), 206-266 (P3), and 213-279 (P4)These ranges reflect the measured amounts for each variable under increasing salinity levels across the different planting dates. Under the influence of salinity stress, soil water potential decreases, leading to a reduction in water uptake by the crop and subsequently decreased crop transpiration. As a result of this reduction in crop water uptake, the remaining water in the soil is utilized for evaporation. In S4 level and on dates of: P1, P2, P3 and P4, crop transpiration portion decreased to 12.9%, 14.1%, 15.6% and 17.2%, respectively, and evaporation portion increased to the same amount. By adjusting the seed planting date to optimize the utilization of favorable atmospheric conditions during crop growth stages, the increase in the portion of evaporation is prevented. In initial stage of growth period, only 0 to 10% of soil surface is covered by crops (FAO-56) causing the evaporation component to have a dominant portion in the crop evapotranspiration parameter. As a result, placing of initial growth stage in warm days of year caused an increase in evaporation losses. It seems that S1P1 treatment was the optimal condition for transpiration increase and evaporation decrease. The estimated functions showed that (in salinity stress conditions) crop transpiration decreased more than ETc. Therefore, the transpiration rate should be considered as the crop's net water requirement instead of ETc (crop evapotranspiration). According to the Mass-Hoffman function, under stress conditions, the decreasing slope of transpiration and evapotranspiration and the increasing slope of evaporation become more pronounced. For instance, in planting dates of P1, P2, P3, and P4, for each unit (dS.m-1) of increase in soil salinity, the evapotranspiration rates decreased by 2.51%, 2.82%, 3.3%, and 3.65%, respectively. Similarly, the transpiration rates decreased by 6.1%, 7.34%, 8.42%, and 9.2%, respectively, while the evaporation rates increased by 5.5%, 6.7%, 7%, and 7.82%. ConclusionSalinity and atmospheric temperature stresses had interaction effects on evapotranspiration and components rates. Postponing the seed planting date and not utilizing optimal weather conditions, especially during spring, can lead to damage to transpiration, which is a favorable aspect; however it is unfavorable in evaporation,. Therefore, in irrigated crops, it is advisable not to plant seeds during the warm months of the year, especially in July and August. Consequently, by controlling soil salinity and selecting the appropriate planting date, water can be optimally utilized.
Irrigation
M. Goodarzi; F. Abbasi; A. Hedayatipour
Abstract
IntroductionThe lack of water resources and increase in water demand are among the effective factors in the imbalance of the water resources in each region, and it is necessary to manage the proper use of available water resources in all activities. Water in the agricultural sector is one of the main ...
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IntroductionThe lack of water resources and increase in water demand are among the effective factors in the imbalance of the water resources in each region, and it is necessary to manage the proper use of available water resources in all activities. Water in the agricultural sector is one of the main factors of production, which should be conveyed by irrigation systems to the field level and made available for the plant roots. The necessity of macro-planning in water management and consumption imposes a comprehensive study of the amount of water consumed in the agricultural sector. Hence, this study was conducted with the objective of directly measuring and field-assessing the applied water, water productivity, and water footprint associated with the primary crops cultivated in Markazi Province, all managed by local farmers.MethodologyFor this purpose, 141 farms were selected in the major production areas of the main agricultural and horticultural crops of Markazi province with the coordination of the Agricultural Jihad centers. Then, the volume of water applied was measured without interfering in the irrigation scheduling of the users. To do so, first, the flow rate of the water source (canal, well, aqueduct or spring) was measured with a suitable device (flume and meter) in each of the selected farms. Then, by carefully monitoring the irrigation schedule of the farm, including the time of each irrigation, the number of irrigation throughout the year, as well as measuring the area under crop cultivation, the amount of water used by the crop was measured for each of the selected farms during the season. Also, based on the measured data, the amounts of blue, green and gray water footprints were determined for each of the examined crops. For this purpose, the blue, green and gray water footprints of different crops were calculated using the framework provided by Hoekstra and Chapagain (2008), and Hoekstra et al., (2011).Results and DiscussionThe irrigation intervals in the studied fields varied between 3 and 15 days with an average of 8 days and the average irrigation depth varied between 26.2 and 99 mm with an average of 67.8 mm in different crops. The results showed that the average volume of applied water for the studied crops in Markazi province was 10782 cubic meters per hectare. Also, the minimum and maximum amount of applied water for the evaluated crops was as follows: barley 3783 and 7232, alfalfa 10382 and 19797, beans 8280 and 17840, watermelon 5333 and 7174, walnuts 4420 and 29600, almonds 3850 and 13932, peaches 6872 and 17727, cherries 7050 and 14645, pomegranates 7156 and 20790, and grapes 5937 and 18168 cubic meters per hectare. Furthermore, the average value of irrigation water efficiency index and water footprint was as follows: barley 0.46 and 1642, alfalfa 0.92 and 700, bean 2924 and 0.24, watermelon 9.37 and 117, walnut 0.1 and 6706, almonds 0.16 and 6857, peach 2.48 and 242, cherries 0.73 and 875, pomegranates 1.33 and 636, and grapes 11.2 and 322. Based on the obtained results, the average total water footprint index was equal to 2102 cubic meters per ton. On average, the almond with a water footprint of 6857 cubic meters per ton had the highest share in allocating the water footprint in the crop production of the province. Whereas, the lowest water footprint related to the watermelon with a water footprint of 117 cubic meters per ton. he average values of the irrigation application efficiency index, irrigation water productivity, and water footprint for the examined farms were 72.5%, 1.79 kg/m3, and 2,102 m3/ton, respectively. In summary, the results indicate that the combined volume of irrigation water and beneficial rainfall in the irrigated fields within Markazi Province surpasses the actual water demand of the crops. This underscores the substantial impact of irrigation management on water utilization in the region.ConclusionOn average, the total volume of irrigation water and effective rainfall in irrigated fields and gardens in Markazi Province is more than the actual water requirement of the plant. In general, the results showed that irrigation management has a great impact on the amount of water use in the region. Based on the obtained results, considering that most of the farms and gardens receive water in an intermittent manner, in principle, no special attention is paid to the need for water and even effective rainfall, and the amount of water availability has the greatest impact on water consumption. Therefore, in order to reduce water consumption and improve water efficiency, it is suggested to manage the delivery of water to farmers during the season and according to their crop water needs. Also, the results of the water footprint can be used to improve water resource policies at the province level, land use studies, cropping pattern modification, and environmental sector policies.
Irrigation
E. Asadi Oskouei; S. Kouzegaran; M.R. Yazdani; A. Rahmani
Abstract
Introduction: Correct assessment of evapotranspiration fluctuations in different meteorological scenarios plays an important role in the optimal management of water resources. Probability analyzes with different probabilities of occurrence can increase flexibility in decision making and increase the ...
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Introduction: Correct assessment of evapotranspiration fluctuations in different meteorological scenarios plays an important role in the optimal management of water resources. Probability analyzes with different probabilities of occurrence can increase flexibility in decision making and increase the reliability of decisions. Rice (Oryza sativa L.) is one of the most important agricultural products in the world. Although rice is cultivated in a wide range of climatic and geographical conditions, it is vulnerable to changes in environmental conditions. Planting management, design of irrigation systems, and suitable irrigation cycle for optimal production are important issues for sustainable production.
Materials and Methods: The study area includes the northern region of Iran, i.e. the provinces of Gilan, Mazandaran and Golestan, which is the main rice-growing area in Iran. Changes in rice evapotranspiration in three different cultivation dates with four different occurrence probabilities of 75, 50, 25 and 10%, was calculated using the FAO Penman-Monteith equation and meteorological data with a statistical period of 30 years (2020- 1990). Also, the average rice crop coefficient at different stages of growth in 10-day periods was estimated based on the Weibull model. These probabilities represent the probable limits of the expected values of evapotranspiration in different scenarios of low, normal, high, and very high evapotranspiration years.
Results and Discussion: The results showed a relatively constant difference of 1 to 2 mm between different rice cultivation histories in the major rice cultivation areas of Gilan and Mazandaran in normal to very high evapotranspiration years. In the years of low evapotranspiration, the water requirement was significantly different from the normal, high and very high evapotranspiration years, which decreased from east to west. This difference was approximately 30% higher in Golestan province as compared with other areas. In the early planting situation relative to the late planting situation in the major western and central coastal areas, there was a 10% decrease in water consumption. At the scale of the whole growing season in Gorgan, evapotranspiration in different conditions of planting date was on average 20% (1300 cubic meters) more than the main regions of Gilan and Mazandaran. In case of timely planting, the net irrigation requirement in very high evapotranspiration years was about 2000 cubic meters per hectare more than the normal years. In years with high evapotranspiration, late planting increased the net irrigation requirement by more than 210 mm compared to different planting dates in Gorgan. According to the obtained results, the largest difference between evapotranspiration values during normal and very high evapotranspiration years was in the late planting situation. Therefore, it seems that late planting causes a significant increase in water consumption in the high evapotranspiration years. Consequently, it is better to avoid rice cultivation when the rice growing season is anticipated to be warm.
Conclusion: Evapotranspiration, as one of the main components of the hydrological cycle, had a significant role in proper irrigation planning and water resources management. The results underline the importance of estimating the rice evapotranspiration to avoid appreciable yield loss under extreme conditions.
M.H. Rad; M.H. Asareh; M.R. Vazifeshenas; A.R. Kavand; M. Soltani Gerdeframarzi
Abstract
Introduction: Although jujube (Ziziphus jujuba Mill.) is known as a medicinal plant and is less important than other fruit trees, it has received more attention in recent years due to its significance in traditional Iranian medicine. There is no study on the actual water need for jujube trees and the ...
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Introduction: Although jujube (Ziziphus jujuba Mill.) is known as a medicinal plant and is less important than other fruit trees, it has received more attention in recent years due to its significance in traditional Iranian medicine. There is no study on the actual water need for jujube trees and the impact of irrigation on yield and water use efficiency in the country. However, some studies emphasized on the need of regular watering and irrigation to improve the quality and quantity of jujube fruit. Given the importance of jujube in China, extensive researches have been conducted on water requirements, plant strategies to save water, impact of drought stress on plant morpho-physiological behaviors, impact of appropriate water distribution on soil quantity and quality of plant development, root distribution patterns and its impact on the amount of water consumed. In all cases, it has been emphasized that the mechanisms of water consumption in jujube differ by climate, genotype, irrigation method and management. In order to improve the quantity and quality of jujube fruit, it is necessary to balance the soil moisture condition and keep the plant away from stress. However, dehydration in jujube is a serious issue that should be addressed with the aim of saving water and improving fruit quality. In this study, the actual water requirement of the plant, the effect of different levels of deficit irrigation on evapotranspiration (ET) and crop coefficient (Kc) rate, yield and water use efficiency (WUE) in jujube trees were investigated. The moisture stress was applied through all stages of plant growth by deficit irrigation. Materials and Methods: In this study, the lysimeter experiment site of Yazd (Shahid Sadoghi Desertification Research Station) with 20 weighing drainage lysimeters (170 cm in height and 121 cm in diameter) was used. To measure evaporation from the soil surface, one lysimeter without plant was used. Note that the moisture content in this lysimeter was always maintained at the field capacity. For the measurement of reference ET (ET0), one lysimeter was used and it compared with ET0 calculated by Penman-Monteith-FAO. After preparing the lysimeters and providing the conditions for planting seedlings, we planted one tree per lysimeter. Trees collected from the villages of Alqoor, Flarg and Gyuk (South Khorasan Province). The suckers were two-years-old with the same size and shape. Trees were irrigated with 50 liters water on a weekly basis for six months. At the beginning of autumn of 2018, treatments including complete irrigation (field capacity), 30% and 60% of deficit irrigation were conducted in a completely randomized design with six replications. Soil moisture measurement during the experiment was performed by TDR. Soil moisture was recorded at 4 depths (0-30, 30-60, 60-90 and 90-120 cm) and their mean was considered as an index of soil moisture status to compensate the irrigation fraction. During the experiment and at the end, indices such as different stages of plant growth, ET, ET0, Kc, yield and WUE were determined. The data were analyzed by analysis of variance (ANOVA) using the statistical package SPSS ver. 16.0, and the mean values were also compared using LSD multiple range test (α = 0.05). Results and Discussion: The results showed that the jujube trees began their vegetative growth from late March (leaves appear) until the end of November (leaves fall) over 2017-2018 agronomic year in Yazd. During this time, which lasted about 235 days, four major and important stages were evident. The steps cited were in FAO's recommendation for deciduous fruit trees (in Issue 122 of the Iranian Irrigation and Drainage National Committee). The results of these studies showed that the length of different growth periods of jujube trees (including early stage, plant development stage, mid stage and end stage) was different with another deciduous fruit trees. ET values in three irrigation regimes showed that the highest ET was observed in July and the lowest in March. Annual ET in control, 30% and 60% of deficit irrigation treatments were 828.06, 514.04 and 386.04 mm, respectively, with 0.45, 0.28 and 0.21, annual Kc, respectively. The results of ET and Kc computed at different growth stages showed that the reproductive growth development period (flowering, fruit set beginning of fruit growth) had the highest ET. In control treatment, the lowest ET (60.81 mm) and Kc (0.27) were observed in early growth period with less than 10% of crown cover. The highest ET (316.22 mm) and Kc (0.60) were found in growth development period with full crown cover. Analysis of variance showed that there was a significant difference (P <0.0001) between the different irrigation treatments in terms of dry matter yield. There was a significant difference for WUE (P <0.001) between different irrigation treatments. Each of different irrigation regimes had a significant difference in yield. The highest yield for each tree was found for the control treatment with 229.36 g and the lowest yield with 57.90 g was observed for 60% deficit irrigation regime. There was no significant difference between control and 30% deficit irrigation treatment in WUE. The value of WUE decreased with increasing the drought stress. In 60% deficit irrigation treatment, WUE was 0.366 g fruit dry weight per liter denoting the significant difference between this irrigation treatment and the others. Conclusion: The results of this study showed that jujube trees were susceptible to drought stress in all four stages of growth, especially the period of growth coinciding with flowering, fruit set and early fruit growth. Hence, jujube trees yield and WUE seem to decrease under drought.
Saeid ghavam seeidi noghabi; Abbas Khashei-siuki; Hossein Hammami
Abstract
Introduction: Water is one of the most important factors limiting agricultural developments in arid and semi-arid regions in the world. One of the important issues of water management is assessment and determination of water requirement of plants. One of the main water management strategies in agriculture ...
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Introduction: Water is one of the most important factors limiting agricultural developments in arid and semi-arid regions in the world. One of the important issues of water management is assessment and determination of water requirement of plants. One of the main water management strategies in agriculture is to assess and determine the plants water requirement. Due to dry and semi-arid weather conditions in Iran the optimal use of water resources is crucial. Plants water requirements are the important parts of the hydrological cycle, and its precise estimation is essential for water budget studies, facilities, management, design of new irrigation systems and water resources management. The determination of behavior and characteristics non-reference vegetation compared to reference vegetation (grass) is the first step in estimating the evapotranspiration of crops. It is important to determine the crop factor in order to measure the water requirement of the crop at different stages of growth. The crop coefficient expresses the effects of crop and soil moisture on a non-reference plant species relative to the reference plant. Among the medicinal herbs, Hibiscus sabdariffa L. is an annual tropical and sub-tropical herbaceous plant belongs to Malvaceae family. Red calyces of Roselle are a source of anthocyanins (about 1.5 g/100 g dry weight), vitamin C and other antioxidants, such as flavonoids (gossypetin, hibiscetine, and sadderetine). Roselle is a medicinal plant that cultivated in Iran especially in Sistan and Baluchestan province. Regarding the long history of cultivation, and high consumption in Iran and the world so far, there has not been a scientific report about Roselle water requirement at different stages of growth. Therefore, this research was carried out with the aim of obtaining Roselle water coefficients and studying the pattern of its changes during the growing season in dry and semi-arid climates of Birjand using the lysimetric method.
Materials and Methods: To determine the Roselle crop coefficient, as a valuable medicinal herb, a lysimetric experiment was conducted in faculty of agriculture, Birjand University during the growing season in 2017. The lysimeters used for this experiment have 20 cm diameter and 16 cm in height. Three lysimeters used for sowing Roselle and three lysimeters used for reference plant. There are six orifices as a water drain in the bottom of each lysimeter. Floor of lysimeter covered by 5 cm granule layer, then filled with soil and cow decayed fertilizer mixture. In each lysimeter, 25 seeds of Roselle were sown. To determine potential evapotranspiration, 12 centimeters height grass was used as the reference plant. Water requirement of Roselle was determined by water balance method. The Roselle growth period was divided into four stages included initial (10% plant growth after emergence), development (between 10% plant growth and before flowering), middle (between early flowering and end flowering), and end (between end flowering and seed ripening). Weed control was achieved by hand hoeing during the growth season. Drainage water was measured by weighting and soil moisture hold at field capacity during the growth season.
Results and Discussion: Results of this study showed that Roselle plant in the initial stage due to slow growth and low transpiration have low Kc compared to middle and development stage. The average coefficient of Roselle was 1.26, 1.55, 1.81, and 0.96 in the initial, development, middle, and end stages respectively. Duration of growth stages for Roselle in Birjand region is 35, 75, 100, and 30 days after emergence. This results revealed an increasing trend from initial to development and middle stages. However, in the end stage of Roselle, Kc decreased. The result of this study showed that evapotranspiration of Roselle was 3819.57 mm whereas the reference plant evapotranspiration was 2420.3 mm. Due to water shortage in the arid and semi-arid region, this plant is not proper for sowing in this area.
Conclusions: According to the results of this study, the annual average evapotranspiration rate of the Roselle was 3819.57 mm whereas the reference plant evapotranspiration was 2420.3 mm. Therefore, the water requirement of Roselle is very high during growth period. Finally, according to the high water requirement and water deficient in Birjand, Iran; it seems that Roselle is not a proper plant for sowing in this area.
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.
M. Ghorbanian Kerdabadi; Hamideh Noory; A.M. Liaghat
Abstract
Introduction: Crop coefficient varies in different environmental conditions, such as deficit irrigation, salinity and intercropping. The effect of soil fertility and texture of crop coefficient and evapotranspiration of maize was investigated in this study. Low soil fertility and food shortages as a ...
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Introduction: Crop coefficient varies in different environmental conditions, such as deficit irrigation, salinity and intercropping. The effect of soil fertility and texture of crop coefficient and evapotranspiration of maize was investigated in this study. Low soil fertility and food shortages as a stressful environment for plants that makes it different evapotranspiration rates of evapotranspiration calculation is based on the FAO publication 56. Razzaghi et al. (2012) investigate the effect of soil type and soil-drying during the seed-filling phase on N-uptake, yield and water use, a Danish-bred cultivar (CV. Titicaca) was grown in field lysimeters with sand, sandy loam and sandy clay loam soil. Zhang et al (2014) were investigated the Effect of adding different amounts of nitrogen during three years (from 2010 to 2012) on water use efficiency and crop evapotranspiration two varieties of winter wheat. The results of their study showed. The results indicated the following: (1) in this dry land farming system, increased N fertilization could raise wheat yield, and the drought-tolerant Changhan No. 58 showed a yield advantage in drought environments with high N fertilizer rates; (2) N application affected water consumption in different soil layers, and promoted wheat absorbing deeper soil water and so increased utilization of soil water; and (3) comprehensive consideration of yield and WUE of wheat indicated that the N rate of 270 kg/ha for Changhan No. 58 was better to avoid the risk of reduced production reduction due to lack of precipitation; however, under conditions of better soil moisture, the N rate of 180 kg/ha was more economic.
Materials and Methods: The study was a factorial experiment in a completely randomized design with three soil texture treatment, including silty clay loam, loam and sandy-loam soil and three fertility treatment, including without fertilizer, one and two percent fertilizer( It was conducted at the experimental farm in Jey and Qahab district of Isfahan. Reference evapotranspiration and actual evapotranspiration of maize were measured by evaporation pan method and volumetric soil water balance method using micro lysimeters, respectively. In order to accommodate the growing field conditions, a ditch with a depth of 25 cm, length of 240 cm and width of 300 cm were dug and micro-lysimeters were placed it in three rows (three replications) with a distance of 75 cm. After preparing the treatments, four seed Maize with variety of NS540 were planted at a depth of 3-5 cm on 5 August. To reduce the oasis effect on evapotranspiration, the same corn was planted in the vicinity of the project area with 500 square meters..
Results and Discussion: The results showed that using fertilizer caused increasing of crop evapotranspiration and crop coefficient of maize. Maximum of the ten-day average evapotranspiration of maize in the silty clay loam soil with two percent fertilizer was obtained 8.76 (mm/ day) on the fifth decade of growth and this value was found 45.5 percent higher than the lowest mean evapotranspiration value of the ten-day. Comparison evapotranspiration of maize in different soil fertility treatments showed that the greatest impact on increasing of maize evapotranspiration in SLF2, SCLF2, SLF2 treatments were obtained that was equal %19.1, %14.3 and %10.6, respectively (table 4). Most of the effects of fertility the crop coefficient of maize at the middle stage of growth was influenced more than other stages by the different treatments of soil fertility. Adding one and two percent of the fertilizer to treatment SCLF0 increased maize crop coefficient about 3.5 and 9.7 percent at development stage, respectively, That measured %6 and 11% for LF1 and LF2 treatments, respectively, and about 1.6 and 5.6% for SLF2 SLF1 treatment, respectively (Table 6). Comparison of maize middle crop coefficient in SLF2 and SLF1 for different soil fertility treatments showed that effect of increasing soil fertility on middle Kc of maize was more than other stages of plant growth (Table 6). The obtained results showed that the addition of one and two percent fertilizer to the silty clay loam soil increased, the middle crop coefficient 13.3% and 27%, respectively in.
Conclusion: Maximum and minimum effect of soil fertility on increasing crop coefficient of maize in the middle stage was equal to 37.8% in the loamy soil and 18.3% in the sandy loam soil with two percent fertilizer. The greatest effect of soil fertility on crop coefficient of maize was measured 8.37% in the middle stage of growth in LF2. The effect of soil fertility on crop coefficient of maize in loam and silty clay loam soils more than sandy loam soil, Because can be a further organic matter in these soils (loam and silty clay loam and also decreasing evaporation in sandy loam soil.
N. Reyhani; Abbas Khashei siuki
Abstract
Introduction: Water is one of the most important factors limiting agricultural developments in arid and semiarid regions in the world. To avoid and exit from water crisis, a proper agricultural and water resource management is required. One of the important parameters in this regard, is determination ...
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Introduction: Water is one of the most important factors limiting agricultural developments in arid and semiarid regions in the world. To avoid and exit from water crisis, a proper agricultural and water resource management is required. One of the important parameters in this regard, is determination of crops’ evapotranspiration. Evapotranspiration, water evaporation from the soil surface and transpiration of vegetation cover have a major trend and a key element in hydrological cycle for management of water resources, particularly in arid and semi-arid. Evapotranspiration is function of the soil, climate, land use, aerodynamic resistance levels and topography of the area. To provide a suitable irrigation schedule and apply an optimal water use management, determination of water requirement and crop coefficients in various growth stages seems necessary. Crop coefficient can be found through dividing the actual evapotranspiration by the potential evapotranspiration. Since the cuminum is commonly used in Birjand and has cultivated in farm and crop coefficients has not been determined , this study aimed to determine the crop coefficients of cuminum using lysimeter water balance in arid and semi-arid climatic conditions.
Materials and Methods: In this research, in order to determine cuminum crop coefficients, that is one of the important herbs, a lysimetric experiment was conducted during growth season in faculty of agriculture, Birjand university. This project, was done in lysimeter. For this purpose and due to the size and plant height in three lysimeter (as replications) with a diameter of 20 and a height of 16 cm was used order to the cultivation of Cuminum. In order to drainage at the bottom of each lysimeter was built orifice. For easily of lysimeters drainage, lysimeter floor was poured by small and large sand and lysimeter was filled by soil and animal Fertilizers for better plant growth. Three lysimeters were used; and water requirement of cuminum was calculated using water balance method. To calculate potential evapotranspiration, grass with 12 centimeters height was used as the reference plant. Crop coefficient can be achieved by dividing the actual evapotranspiration to reference evapotranspiration and is not fixed growth period. The cumin plant growth period was divided four stages (initial, development, middle and end). The initial phase of up to 10% on seed germination and plant growth, from 10 percent to flowering development stage, middle stage and final stage of the start of flowering to product reaches to harvest is the end of the middle stage. In each lysimeter average number of 20-15 of seed to increasing germination, were planted on the February 9, 2012. To control weeds, weed was done handing during the growing season. Drainage water is controlled over a period of time measured with weighting method and deep and volume of water was measured. Soil moisture at field capacity using pressure plates was measured. Measuring soil water content and determine irrigation time.
Results and Discussion According to the results obtained for the crop coefficient can be concluded that in the initial stages of plant growth that plant size is small, transpiration is low and therefore Kc have low value. In the middle and development stage increases canopy and increased transpiration rate and increases Kc. At the end stage to reducing activity of the leaves (old leaves) reduced transpiration. The average crop coefficient of cumin in the initial phase of growth during the study to 0.65, then with increasing plant growth, leaf area index were increased and crop coefficient increased to 0.92 in development stage. In the middle of this amount is 1.21 and in the end the 0.85 reached. Average crop coefficients for a four-stage is 0.9. Duration of growth stages for cuminum crops in Birjand region is 24 days for initial stage, 40 days for middle stage and 31 days for development and 19 days for end stage of growth stages.
Conclusions In this study according to important of drug and economic for cuminum plant and that there isn’t report for crop coefficient cuminum and Birjand region, we cultivate cuminum in arid area of Birjand in 2011 year. The results of lysimeters showed that Duration of plant growth stages and value of crop coefficients in the initial , development, middle and end stages, respectively (24, 40, 31 and 19 days) and (0.65, 0.921.21 and 0.85) respectiely.
kourosh majdsalimi; b. salavatian; e. amiri
Abstract
Introduction: Designing and management of sprinkler irrigation systems depend on the situation and location of its implementation and often rely on professional and long-term tests (9). Having a good irrigation system depends on knowledge of the relationship between soil, water, plants, irrigation scheduling, ...
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Introduction: Designing and management of sprinkler irrigation systems depend on the situation and location of its implementation and often rely on professional and long-term tests (9). Having a good irrigation system depends on knowledge of the relationship between soil, water, plants, irrigation scheduling, the required amount of irrigation water to the water-holding capacity of soil, climate and plant growth (6).The less use of sprinkler irrigation systems and less performed research projects in the Guilan province, lack of correct design parameters due to shortage of the required parameters for local and regional planning, has led to reliance on charts and tables. Therefore, planning water resources cannot be performed well and with accurate details. According to many researchers (8), the technical evaluation should be a regular and short-term process to review the problems and possible performance of irrigation systems. Merriam and Keller (10) defined the assessment of an irrigation system analysis, based on field measurements in real terms during the normal work of the system. Therefore, to develop these systems over the next few years, it is essential to evaluate the use of irrigation systems and review the performance of existing problems and utilizing the results to improve it. The aim of this study was to assess the current status of implemented irrigation systems in the tea plantations of Guilan and evaluate their performance.
Materials and Methods: In this study, six classic sprinkler irrigation systems in tea fields of Guilan province were evaluated during two years. Sprinkler irrigation systems of semi-portable, solid-set and solid-set (hand-move sprinkler) were selected randomly. To evaluate this irrigation systems, Christiansen’s uniformity coefficient (CU), distribution uniformity (DU), potential application efficiency of low-quarter (PELQ) and application efficiency of low-quarter (AELQ) in the form of trial blocks were estimated by measuring pressure fluctuations which were applied to the entire system. Using irrigated area and irrigation water depth, adequacy of irrigation curve, deep percolation losses and spray losses were determined on the basis of existing relationships.
Results and Discussion: Average values of CU, DU, PELQ and AELQ for 6 tea fields were 65, 52, 44 and 44 percent, respectively. Application efficiency in all irrigation systems, Christiansen’s uniformity coefficient and distribution uniformity were lower than recommended values in the references. Merriam and Keller (11) reported the allowable range for potential application efficiency of low-quarter between 65 to 85 percent. With respect to irrigation less than the actual water requirement of the plant in tea fields, AELQ was equal with PELQ. Untechnical design and implementation of irrigation systems, particularly poor operating pressure and economic problems were detected as the main reasons for the low PELQ. Simultaneous use of sprinklers with different specifications and models, old irrigation systems, water leakage from valves and other equipment, practically change the pressure and flow rate, which were the main reasons for the decrease in uniformity of water distribution and application efficiency of low-quarter. According to Cobban (4) uniformity coefficient of sprinkler irrigation systems were reported between 31 to 55 percent in Tanzania tea fields and in other reports were between 58 to 72 percent (7), which was due to poor design, long spacing of sprinklers and high speed wind. Christiansen’s uniformity coefficient and distribution uniformity of low-quarter in ED, WB & EP systems were lower than recommended values by Merriam and Keller (%81≥CU≥87% & %67≥DU≥80%)(10). In spite of the little losses in deep percolation, irrigation adequacy of these systems was relatively low and unacceptable. In such circumstances, only about 20 to 38% of irrigated area in WA and CK systems, respectively received the required water or more, according to lack of soil moisture (required irrigation depth). The main reason was low uniformity of water distribution in irrigation systems which was described previously. Evaluated spray losses in irrigation systems was variable between 4.8 to 13 percent. The losses obtained in irrigation systems in tea fields in comparison with the values 2.6 to 42.4 which were obtained in other regions of the country were less by (1, 3, 5 and 12) due to low wind speed and high relative humidity (2) as the main reasons.
Conclusion: Average values of CU, DU, PELQ and AELQ for 6 tea fields were 65, 52, 44 and 44 percent, respectively that were lower than recommended values in the references. The results showed that old irrigation systems in tea fields are not in good functional status due to untechnical design and implementation, operation, exploitation and inappropriate maintenance (due to economic problems and lack of farmer’s knowledge on irrigation). To improve the performance and efficiency of irrigation systems in the tea fields, detailed information are recommended, to design and implement with detailed information accomplished by regional companies. Moreover, the use of solid-set (hand-move sprinkler) sprinkler irrigation instead of semi-portable with manual handling (aluminum pipes), operation of irrigation groups and promoting farmers' knowledge about the principles of proper the scheduling and management, operation and maintenance of irrigation systems are very effective to improve the performance indices.
