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.
tayebeh shojaee; Gholamabbas Fallah Ghalhari
Abstract
Introduction: In order to choose the best forms for each region and invest, the climatic conditions should be considered. Among the climatic elements, thermal indexes are effective factors in the production cycle, and the quality and quantity of grapes. Given the lack of water resources and the threat ...
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Introduction: In order to choose the best forms for each region and invest, the climatic conditions should be considered. Among the climatic elements, thermal indexes are effective factors in the production cycle, and the quality and quantity of grapes. Given the lack of water resources and the threat of climate change, there is a need for potentiometry and clustering of different regions.
Materials and Methods: According to the content and purpose of statistics and information, the hourly and daily climatic data of 200 climate stations were used. In order to compute the required chilling, the CH model was prepared and implemented. According to daily and monthly statistics, climate parameters were refined and investigated. We used a weighting method based on hierarchical approach for accurate decision making and identifying the relative importance of climatic criteria for grape cultivation. For the following climatic criteria, the information layer was arranged through a database of 200 meteorological stations of the Iranian Meteorological Organization. For the following geographic criteria, layers were used in the country. In order to determine the suitable areas for planting grapevine, using the Analytical Hierarchy Process (AHP) method in the Epert choice11 software environment, the criteria and sub criteria were weighted. Then, using the Geographical Information System, the layers were overlapped based on their weight and the final land suitability map for planting grapevine in Iran was obtained based on climatic conditions.
Results and Discussion: Pairwise comparison of criteria and sub-criteria based on hierarchical analysis showed that the criterion of climatic conditions with a weight of 0.63 was considered as the most important criterion in determining suitable areas for grapevine cultivation. Pairwise comparison of the climatic conditions criterion indicated that the sub-criteria of 451 were the highest among the sub-criteria in the grape trees. Temperature sub-criteria exhibited the greatest weight during the slump and growth period. Paired comparison and spatial distribution of the climate-chilling showed that a large part of the country does not supply winter creeps or cold storage for grapevine trees. The southern half of Iran is entirely unsuitable due to the existence of mild winters for commercial cultivation of creeping trees such as grapes. Paired comparison and spatial distribution under the climatic criterion of the slump period demonstrated that largest spatial distribution is allocated to the middle class in the margin of highlands and high latitudes regions. Paired comparison and spatial distributions under the scale of the growth period illustrated that the spatial pattern in this sub-criteria is highly dependent on the altitude and latitude. From the north to the south and from the west to the east, the suitability for growing grapevine decreases. Paired comparison and spatial distributions under the climatic criteria of absolute minimum temperature revealed that in terms of absolute minimum temperature, there is a limitation on grapevine for some regions of Iran. These areas are mainly mountainous belts of the Zagros mountain, the northwest cold region and northeastern Iran. Paired comparison and spatial distribution under the climate criteria of maximum air temperature showed that temperatures above the threshold of 40 degrees Celsius adversely influence the quality and yield of grapevine. In fact, in terms of absolute maximum temperatures, more than half of the country's surface area is unsuitable. Paired comparison and spatial distributions under the geographic scale elevation above sea level showed that suitable altitude areas are limited to the high and mountainous regions of the northwestern, northern, and northeastern Iran. Paired comparison and spatial distributions under the relative climate of relative humidity indicated that due to the relative humidity of the grape vine compared to many fruit trees, the relative humidity in Iran is high for the grapevine tree. Paired comparison and spatial distributions under the climatic criteria of sunshine hours illustrated that the distribution of sunshine hours affects the latitude factor causing an increase in sunshine hours from north to south. A wide range of growing fruit trees in terms of sunshine days can be found in Iran. Therefore, most regions in the country provide unlimited solar radiation for grapevine growth. Paired comparison and spatial distributions under the geographic scale elevation above sea level showed that altitude plays an important role for locating vineyards. Suitable high-altitude areas are limited to the high and mountainous regions of the northwestern, northern, and northeastern Iran. Paired comparison and spatial distribution below the gradient geographic scale showed that planting fruit trees, especially grapes, is more cost-effective in steep slopes. Considering the high adaptability and physiological conditions of the grapevine, almost all regions of Iran, except very high and mountainous regions, are suitable for planting grapes. Suitable vineyard cultivars are adapted to the slopes of mountainous and relatively high mountainous regions in the mid-west, northwest, northeast, and scattered areas of the center, east and south east of the country. The range of cultivating grapevine trees is 42% of the country's surface area.
Conclusion: The results revealed that the climate criterion has a pivotal role for determining land suitability for grapevine trees. The suitable vineyard cultivars are located in the mountainous and relatively hilly mountains in the northwest, northwest, northeast, and dispersed areas of the center, east and south east of Iran. These findings are important for land use planning and spatial planning with emphasis on climatic and geographic capabilities for efficient use of natural resources.
