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.
Zeyneb Fathi Tilko; Parviz Fathi; Farzad Hosseinpanahi
Abstract
Introduction: water scarcity is one of the primary problems in arid and semi-arid regions such as Iran. In these regions, increasing water productivity in agriculture sector is inevitable. Water productivity can be increased using the drip irrigation method and application of irrigation strategies such ...
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Introduction: water scarcity is one of the primary problems in arid and semi-arid regions such as Iran. In these regions, increasing water productivity in agriculture sector is inevitable. Water productivity can be increased using the drip irrigation method and application of irrigation strategies such as deficit irrigation. Potato is the major crop in Dehgolan plain. Researches have shown that the potato crops very sensitive to water stress. Sprinkler and furrow irrigation systems are common methods for irrigation of potato crop in Dehgolan plain. In this plain, the main supply for irrigation water is groundwater resources. Due to the falling water table in this plain, high sensitivity of the potato crop to water stress and low efficiency of current irrigation systems in the plain, the use of modern methods such as drip-tape irrigation system is inevitable. Drip tape irrigation is one of the efficient methods to increase water productivity of agricultural crops. In this method, determining the optimal drip tape placement in the soil and irrigation water depth are the important factors for obtaining maximum yield and irrigation water productivity of potato crop. The purpose of this study was to investigate the effect of drip tape placement depth and irrigation level on water productivity of the potato crop (Agria cultivar) in Dehgolan plain of Kurdistan province.
Materials and Methods: A field experiment was conducted to evaluate the effect of drip tape placement depth and irrigation water level on water productivity of the potato crop (Agria cultivar) in Dehgolan plain of Kurdistan province in spring season of 2014. The results of water quality analysis showed that the irrigation water has not any limitation to plant growth. The soil texture of the field was silty clay. The experiment was arranged in split plot design based on randomized complete blocks Design with three replications. The main plots and subplots included the irrigation water levels (60, 80, 100 and 120 percent of the potato water requirement) and drip tape placement depth (0, 5, 10 and 15 centimeters), respectively. At the end of the growing season, tuber yield of potato was measured. Measured data were analyzed using statistical software, R.Also, mean comparisons were done using Duncan's test.
Results Discussion: The results showed that the effect of irrigation water and drip tape placement on yield and water productivity was significant (P= 0.01%). The maximum yield and water productivity of this crop were related to 120 and 60 percent of crop water requirement, respectively. The results also showed that drip tape placement depth equal 15 cm was the depth when using drip tape irrigation system in Dehgolan plain. Economic analysis of different treatments showed that irrigation water depth equal 120 percent of the potato water requirement has higher Benefit–cost ratio than other treatments, but the water produced related to it is minimized. Since the Dehgolan plain faced with an intense water deficit and groundwater level of this plain has lost, so maximizing the amount of water produced in Dehgolan plain is inevitable. The results showed that the applied irrigation water depth equal 60 percent of potato water requirement and installation of irrigation tape at a depth of 15 cm can be achieved highest irrigation water use efficiency of potato in Dehgolan plain.
The result of this research indicated that tuber yield and water productivity of the potato crop under subsurface drip irrigation systems is higher than surface drip irrigation. The ability of subsurface drip irrigation in the improving of tuber yield could be attributed to the less water lost from the soil surface through evaporation. Subsurface drip irrigation allows maintenance of optimum soil moisture content in the root zone, which improved the water productivity.
Conclusion: The results show that the maximum tuber yield of potato was related to 120 percent of the potato water requirement. But the maximum irrigation water use efficiency was related to treatment water equal 60 percent of water requirement and drips tape placement depth equal 15 cm. As a result, recommended to increase the irrigation water use efficiency in Dehgolan plain, deficit irrigation strategies applied. The results also showed that the yield and water productivity of the potato crop in subsurface drip irrigation method is more than surface drip irrigation method. In this way the growth of weed and water loss through evaporation was very low and therefore the plant uses the greater amount of irrigation water.
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.
