Habib Abedi Babaheydari; Rohallah Fatahi Nafchi; Davood Namdar
Abstract
Introduction: The existence of 35 to 45 million hectares of desert areas in Iran and many restrictions such as lack of precipitation, have caused many challenges for the development of these areas. On the other hand, improper utilization of existing resources has resulted in desertification as a natural ...
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Introduction: The existence of 35 to 45 million hectares of desert areas in Iran and many restrictions such as lack of precipitation, have caused many challenges for the development of these areas. On the other hand, improper utilization of existing resources has resulted in desertification as a natural phenomenon, which is increasing annually. The activities that have been tracked down desertification decades ago have only managed to control a very small corner (about 9.1 million hectares) of these areas. Desertification is the consequence of two challenges of climate change and freshwater scarcity. In Iran, 43.7 million hectares are desert ecosystems in the wilderness of the country, of which about 20 million hectares of desert ecosystems are affected by wind erosion. Meanwhile, 4.6 million hectares in 183 districts in 82 counties and 18 provinces of the country are considered critical wind erosion centers. In general, natural and human factors are among the main origins of desertification. In arid and semi-arid areas due to lack of precipitation, water is the most important limiting factor for plant deployment. Due to the quantitative and qualitative limitations of water resources, the survival of plants in desert areas, mainly depends on the choosing appropriate irrigation method. The purpose of this study was to compare Water Box method, which is a particular form of irrigation, with surface and drip irrigations for planting hawthorn plant, which is often used for desertification projects in semi-arid areas such as Iran.
Materials and Methods: Experiments were carried out in the research field at Shahrekord University in the coordinate 32.3526° N, 50.8261° E and 2105 meters above sea level. The study area is 7 km far from the Shahrekord synoptic meteorological station. Shahrekord climate is categorized as Dcas climate by Copenhagen division method, which is characterized by moderate cold weather conditions with warm summers. In surface and drip irrigation methods, five irrigation regimes with zero, 25, 50, 75 and 90 percent of water requirements each with three replications were applied. In the Water box method, due to the self-regulation of the system and the no possibility of deficit irrigation, experiments with 15 similar replications were performed. Plant parameters such as stem diameter, height, seedling survival percentage and water content in each treatment were measured by one-month interval and compared to each other at the end of the study.
Results: The results of this study showed that the Water Box system, while significantly reducing the amount of consumed water (92% than drip irrigation) and high survival rate of seedlings (in this research 100%), is a useful method for establishing some hawthorn seedlings for combat and control of the desertification phenomenon. The highest growth was observed in irrigation treatments with 25 percent low irrigation with 60 cm height growth. Also, the lowest growth is due to irrigation with 90 percent low irrigation. In order to compare the mean annual growth rate of treatments, data were analyzed in SPSS software using the Duncan test at a significant level of 5 percent. The highest water use efficiency was related to water Box irrigation with 2.5 cc/l, which was obtained with a relatively large distance from other treatments, while, as mentioned in the previous sections, the water consumption of this treatment 92 percent low irrigation than full drip irrigation. The lowest water use efficiency was related to irrigation with 75% irrigation, which was 0.15 m3 l-1. In total drip irrigation treatment, water use efficiency was estimated to be 0.16 cm/liter, which shows that although the growth of this treatment was in good condition, it has poor results regarding water use efficiency.
Discussion: Due to the resistance of hawthorn to drought, only three of the cultivated seedlings were dried. The percentage of viability in the Water Box method was 100 percent. However, the difference in the percentage of vitality according to Duncan's method was not significant at 5 percent level. The results of seedling survival percentage were consistent with Naseri et al.(2005). They did not observe the significant difference between irrigation treatments in terms of viability. Due to the lack of research on irrigation with the Water box system, it is recommended that other researches be carried out on the use of this system for irrigation of other (productive) species. The location of the installation and tiling of wicks is one of the things that need to be addressed in the future research.
S.S. Nurbakhsh; M. Ghobadinia; A. Danesh-Shahraki; mohammad reza Nori Emamzadeie; R. Fatahi
Abstract
Introduction: Nowadays, due to lack of water resources and increasing demand for water, agricultural water planning issues need further consideration. With proper planning and determination of irrigation depth and time, the effects of stress and yield loss on the plants are reduced. Irrigation scheduling ...
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Introduction: Nowadays, due to lack of water resources and increasing demand for water, agricultural water planning issues need further consideration. With proper planning and determination of irrigation depth and time, the effects of stress and yield loss on the plants are reduced. Irrigation scheduling is one of the most important factors in crop’s quality and quantity. The main objective of irrigation scheduling is to control crop’s water conditions in order to achieve its optimum yield level. So irrigation timing is the vital factor on which crop water stress and eventually yield's level are dependent upon. Moreover, irrigation timing is used in irrigation scheduling. The aim of this study was to evaluate the effect of irrigation time on water consumption, water use efficiency and yield of beans.
Materials and Methods: In order to observe the effect of the amount and the time of the irrigation on water consumption, yields rate and water use efficiency, the current research was carried out at the University of Shahrekord during the summer of 2012. The experiment was done as a completely randomized design with 4 repetitions consisting of irrigation time and the amount of irrigation in 4 and 2 levels (at 6, 8, 14 and 18) and (deficit irrigation, full irrigation), respectively. Beans seeds were planted in 32 similar vases with a diameter of 45 cm and height of 60 cm, in each experiment. Treatments were begun after 37 days from planting. Treatments were irrigated when the average moisture in the root zone was equal to the lower border of readily available water of full irrigation. At the end of the experiments, plants were completely harvested. Then the plant’s height, number of branches, numbers of pods per plant, pod and seed weight were measured.
Results and Discussion: Results showed that irrigating at different times during the day influenced water use efficiency, water consumption, seeds yield and number of pods in the bush. The water consumption was affected by irrigation time. Among full irrigation treatments, irrigation at 2 p.m. and 6 a.m. had the highest and lowest water consumption, respectively. The total amount of water used in irrigation at 8 a.m., 2:00 p.m. and 6 p.m. compared to 6:00 a.m. was increased by1.6, 9.5 and 4.1 percent, respectively. The results showed that irrigation at 2:00 p.m., caused a significant reduction in yield. Moreover, water use efficiency in 6 a.m. treatments had increased 18.5 percent more than that of the 2:00 p.m. irrigation treatment. The time of irrigation did not have a meaningful effect on bush height, the number of minor branches, the pod's length. The effect of the amount of irrigation water was meaningful on bush height, number of minor branches, seeds yield, the number of pods in the bush, pods length and seed weight. Seed yield at 8:00 a.m., 2:00 p.m. and 6:00 p.m. treatments has shown 0.29, 17.1 and 7.6 percent decrease in comparison with 6:00 a.m. irrigation treatment, respectively. Moreover, 100-seed weights were significantly affected by the irrigation time. The maximum and minimum weights of 100-seed weights were obtained at 6:00 a.m. and 6:00 p.m. irrigation, respectively. Analysis of variance showed that the number of pods per plant was affected by irrigation time. The maximum number of pods per plant was 101 which belong to the 6:00 a.m. treatment. In this experiment in the case of irrigation at 2:00 p.m., the number of pods per plant was significantly decreased in full and deficit irrigation. The results showed that although the irrigation frequency was the same, irrigation at maximum evapo-transpiration caused the plant to be under stress and the yield was reduced. In other word, it can be said that time of irrigation had no meaningful effect on the appearance and shape of the plant while it was effective in terms of the yield. Overall assessments showed that maximum of the measured features were obtained in the case of 6:00 a.m. treatment.
Conclusion: The results showed that irrigation at different times of the day and the applied water stress, reduced water use efficiency. These caused traits such as plant height; number of branches; number of pods per plant; pod and seed weight to be affected by the irrigation depth. Based on the results of this experiment it can be stated that, when there is no limit of water supply, it is recommended to irrigate in the early morning, before the steep slope of the temperature rise. However, in the situations with water shortage problems, is better to manage the water and the product.
Keywords: Bean, Deficit irrigation, Irrigation time, Water use efficiency
