masoud Naderi; M. Shayannejad; S. Heydari; B. Haghighati
Abstract
Introduction: Owing to drought, increasing demand for fresh water resources and low water use efficiency, the optimum use of water is essential in the agricultural sector. Therefore, this study was conducted to investigate the effect of different levels of irrigation water on quantitative and qualitative ...
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Introduction: Owing to drought, increasing demand for fresh water resources and low water use efficiency, the optimum use of water is essential in the agricultural sector. Therefore, this study was conducted to investigate the effect of different levels of irrigation water on quantitative and qualitative Characteristics of potato (Burren cultivar) and determination of its optimum consumptive use of water under Shahr-e kord environment.
Materials and Methods: This study was conducted at the Agricultural Research Center and Natural Resources in Shahr-e kord with longitude and latitude of 32˚18΄ and 50˚51΄ , respectively, in 2013. This experiment was performed in randomized complete block design with 7 treatments consisted of different levels of irrigation water and 3 replications. Different levels of irrigation water were: 40, 55, 70, 85, 100, 115 and 130 % of the soil moisture deficit. Potato seeds (burren cultivar) were planted with distance of 20 cm from each other and furrow width of 75 cm. Irrigation program were performed based on the measurement of soil moisture deficit. The irrigation intervals were considered as a fixed 7 day. Irrigation levels were applied to 105 days after planting and the total growth period was 130 days from planting to harvesting. The samples were taken from the two middle furrows. The evaluated parameters were included weight of tubers per plant, tuber diameter, weight of tuber in seed size, weight of tuber production in a plant in marketable size, tuber dry weight, the starch percent, percent of soluble sugars, nitrogen percent. The starch content was determined by Polarimetry method. The soluble sugars content was measured by Colorimetric method, the nitrogen content was measured by wet digestion method and using the Kjeldahl set. Then, the optimal depth of water consumption in conditions of limited water resources were determined by English method Statistical analysis of data and drawing graphs were done with SAS and EXCEL software, respectively.
Results Discussion: The effect of different levels of irrigation water on yield was significant at 1%. The yield increased with increase of irrigation water. The minimum and maximum yields were belonged to 40 and 130 % treatments with 13.2 and 45.2 tons per hectare, respectively. Whereas, the results revealed that treatments which recieved100, 115 and 130% of the soil moisture deficit had no significant effect on potato yield at 5% level. Thus, potato yield in 115 and 130% treatments were only 2.3 and 3.9% more than treatment receiving full irrigation, respectively. The potato production function was obtained using the depth of water which consumed during the growing season and yield in each treatment. The results showed that the effect of different levels of irrigation water was significant on yield, starch, soluble sugars, dry matter, irrigation water use efficiency and the weight of tuber production per plant in marketable size As the level of irrigation water increased, the yield, soluble sugars content and weight of tuber per plant in marketable size increased and the starch and dry matter content decreased. Moreover, effect of different levels of irrigation water on nitrogen percent and the weight of tuber in seed size were not significant. Maximum and minimum of irrigation water use efficiency were belonged to 85 and 40% with values of 6.96 and 4.84 Kg m-3, respectively. Maximum and minimum percentages of starch were belonged to 40 and 130% treatments with values of 76.6 and 61%, respectively. The soluble sugar content in potato can causes discoloration and darkness of the product, and accordingly it makes the non-marketability of the product. Maximum and minimum soluble sugar contents were belonged to 130 and 40% treatments with values of 2.12 and 3.07%, respectively. In addition, the increase of irrigation water caused to the increase of weight of tuber per plant in marketable size. Therefore, the highest marketable tuber yield was belonged to 130% treatment and it was 1.5 kg per plant and the lowest one was belonged to 40% treatment and it was 0.61 kg per plant. The applied water which maximized the income was 821 mm during the growth period.
Conclusion: The use of 82% full irrigation (533mm) can result in maximum net income and irrigated area can increase by 22% compare to full irrigation. If the purpose of planting is get to the maximum yield, the use of 130% irrigation treatment is recommended and if the purpose is the production of seed potatoes, the use of 85% irrigation, treatment is recommended.
bijan haghighati; saeed Broomand Nasab; AbdAli Naseri
Abstract
Introduction: Potato is one of the main products of agriculture in feeding the world's population and agricultural economy. The production of potato in the world occupies the forth place after wheat, rice and corn. In Iran, annual production of more than 5.5 million tons potato, has made this crop the ...
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Introduction: Potato is one of the main products of agriculture in feeding the world's population and agricultural economy. The production of potato in the world occupies the forth place after wheat, rice and corn. In Iran, annual production of more than 5.5 million tons potato, has made this crop the most important food after wheat. On the other hand, in arid and semi-arid regions, water is the most important limiting factor for production of agricultural crops such as potato. Considering the water use efficiency is one of the most effective ways to deal with the water crisis and increasing the quality and quantity of agricultural productions. Production increasing per unit of water consumed (increasing water productivity) by improving the selection of plant varieties, irrigation management and use of new irrigation methods may be feasible.
Material and Methods: The research was performed in the Chahartakhteh research station (32° 18' N. and 50° 55' E.) with 2090 m height above sea level and semi-humid climate with moderate summers and cold winters. Average annual rainfall is about 320 mm mostly during winter. The soil moisture and temperature regimes are Typic Xeric and Mesic, respectively. Soil texture is silty clay.
In order to determine the best method of deficit irrigation for optimizing water use efficiency and yield of two potato cultivars, an experiment was performed in Agricultural and Natural Resources Research Center of Chaharmahal va Bakhtiari farm in 2013. The experiment was based on randomized completely blocks with split - split plot design in three replications. The furrow and tape drip irrigation methods were as the main plots, two potato cultivars as sub plot units and four deficit irrigation managements as the secondary sub plot units including CI(100%), RDI80(80%), RDI65(65%) of available water depletion (AWD) and partial root-zone drying (PRD) during full growth period.
Almera and Burren cultivars are two new cultivars of high yield and quality of early growth period of approximately 90-80 days, high compatibility with Chaharmahal va Bakhtiari climate and more regions of Iran.
Results and Discussion: Analysis of variance (ANOVA) of studied factors showed that the deficit irrigation management on tuber yield (ton/ha), tuber yield per plant, the amount of starch, soluble sugar, proline, chlorophyll, water use efficiency, and water productivity were significant (P≤0.01). Effects of cultivar on tuber total yield, tuber yield per plant, soluble sugar, water use efficiency, and water productivity were significant (P≤0.01). The interaction between cultivar and deficit irrigation management was only significant (P≤0.05) on tuber yield (ton/ha), proline, water use efficiency and water productivity.
The results showed that Burren cultivar in comparison with Almera was better in tuber yield (19%), water productivity (20%), water use efficiency (19%), and resistance of draught in all deficit irrigation treatments. Maximum tuber yield (59.02 ton/ha) was obtained in Burren cultivar under complete irrigation. Minimum tuber yield (23.1 ton/ha) was obtained in Almera cultivar under deficit irrigation management RDI65 (65% of available water depletion). The maximum water use efficiency (16.79 Kg/m3) and water productivity (14.78 Kg/m3) were obtained under tape irrigation and partial root-zone drying (PRD) treatment. The minimum water use efficiency (7.46 Kg/m3) and water productivity (4.81 Kg/m3) were obtained under furrow irrigation and deficit irrigation management RDI65.
Effect of cultivar was not significant on amount of irrigation water during the growing season. The amount of irrigation water for two cultivars was the same and 4711 m3.ha-1. The amount of irrigation water in the different deficit irrigation managements showed that the highest water use was in CI (5615 m3 ha-1) and lowest water use was in deficit irrigation management RDI65 (4065 m3 ha-1) treatments.
Deficit irrigation management RDI80 ،PRD and RDI65 in comparison with CI led to reduction of irrigation water amount 16, 21 and 28% of irrigation water amount.
Conclusion: Due to the results of this study, the high consumption of water in agriculture, for optimal use of available water resources, the methods with high water use efficiency and productivity, such as tape irrigation, the PRD irrigation management and the use of drought resistant cultivars is recommended. According to the limitation of water resources, for optimizing water use, the best suggestion for reducing water use on potato, is using Burren cultivar with suitable quality and high yield potential, and deficit irrigation management (PRD).
