تعیین آب کاربردی و بهره‌وری مصرف آب در مزارع زعفران استان خراسان رضوی

در خصوص حجم اب کاربردی در بخش کشاورزی اعداد و ارقام ارائه شده در کشور بسیار متفاوت بوده و در خصوص صحت و سقم آن ها نیز تردیدهای جدی وجود دارد. لذا، انجام یک کار پژوهشی لازم و ضروری بوده و نتایج آن می تواند کمک شایانی به تصمیم گیری مسئولین مرتبط با آب و کشاورزی بنماید. بنابراین، هدف اصلی این طرح مطالعاتی، اندازه گیری مستقیم و مزرعه ای آب کاربردی زراعت زعفران تحت مدیریت کشاورزان است. بدین ترتیب، حجم آب مصرف شده برای تولید زعفران در شهرستان های عمده استان خراسان رضوی (تربیت حیدریه، و زاوه و گناباد) در سال زراعی ۹۸-۱۳۹۷ اندازه گیری شد. روش ابیاری در این زمارع یا بصورت آبیاری سطحی و یا بصورت آبیاری بارانی (رول لاین و پیفلکس) بود. نتایج نشان داد که نوبت های آبیاری بین چهار تا هفت نوبت و حجم آب کاربردی بین ۳۶۵۰ تا ۵۱۰۰ متر مکعبدر هکتار متغیر بود. منابع آبی شامل: چاه، رودخانه و قنات بود. تبخیر و تعرق پتانسیل بین ۴۸۲/۶ تا ۶۷۶ میلی متر و نیاز خالص آبیاری بین ۳۵۳ تا ۵۸۸ میلی متر متغیر بود. نتایج حاصل از اندازه گیری های میدانی نشان داد که حجم آب کاربردی زعفران در شهرستان های تربت حیدریه، زاوه و گناباد به ترتیب به میزان ۴۹۷۴،۴۸۱۶،۴۵۱۷ متر مکعب در هکتار بود. متوسط عملکرد زعفران در شهرستان های زاوه و تربت حیدریه به میزان ۷/۳ کیلوگرم در هکتار و در شهرستان گناباد به میزان ۵ کیلوگرم بر هکتار بود. بیشترین بهره وری مصرف آب در شهرستان زاوه به میزان ۰/۰۰۱۶۶۹ کیلوگرم بر متر مکعب و کمترین آن مربوط به شهرستان گناباد به میزان ۰/۰۰۱۰۷۶ کیلوگرم بر متر مکعب بدست آمد. همچنین نتایج نشان داد که در هر سه شهرستان، نیاز خالص اب آبیاری در سال انجام تحقیق از نیاز خالص محاسبه شده با داده های ده ساله اخیر بیشتر بود. راندمان کاربرد براساس آمار ده ساله در شهرستان های زاوه، تربیت حیدریه، و گناباد به ترتیب برابر با ۴۹.۵۱ و ۸۷ درصد بدست آمد

Introduction
Drought in Iran is a climatic fact and due to the growing need for water in different sectors, the problem of drought will become more acute in the coming years. In such cases, one of the practical solutions is the optimal use of water consumption. Water consumption management in agriculture can be very effective. Determining water consumption management indicators such as the amount of irrigation water, irrigation efficiency and water productivity in various crops and orchards in the country is one of the most important tools and key indicators in macro agricultural planning. Regarding the volume of irrigation water in the agricultural sector, the figures provided in the country are very different. Therefore, it is necessary to do a research work and its results would be a great help for decision makers. Therefore, the main purpose of this research project is direct measurement and irrigation water fields of saffron cultivation under the management of farmers.
Methodology
This project is a crop-based research that measured applied water by farmers to produce saffron during a growing season. The farms in Torbat e Heydarieh, Zaveh and Gonabad were identified and selected with the help of experts. In each selected plain, 6 farms were selected for data collection and monitoring. Three methods of surface irrigation, roll line and peifelex were evaluated in this project. The volume of irrigation water for saffron in each field was determined by measuring the flow rate of the water source and its operating time. For this purpose, first the output flow of the water source was measured with a suitable device (flume, couter) and then the irrigation time was measured. In each of the farms in questionnaire, the characteristics of the farms include; Crop area, total land area, field soil texture, soil electrical conductivity and irrigation water were measured. Some characteristics of farms such as location, irrigation method, irrigation water source, type of irrigation network (modern, traditional), characteristics of users, etc. were done by compiling information registration forms. In addition, the final yield of saffron was measured to calculate water use efficiency. The amount of saffron evapotranspiration in each region was calculated using meteorological data by Penman Mantis method.
Results and discussion
The results of field measurements showed that the average of applied water in Peifelex, roll line and surface irrigation systems were 3713, 3900 and 4691 m3 /ha respectively. The volume of saffron irrigation water in Torbat-e-Heydarieh, Zaveh and Gonabad cities was 4974, 4816 and 4517 m3 /ha, respectively. The average yield of saffron in Zaveh and Torbat-e Heydarieh counties was 7.3 kg / ha and in Gonabad county was 5 kg / ha. The highest crop water profuvtivity was 0.001669 kg / m3 in Zaveh city and the lowest was related to Gonabad city (0.001076 kg / m3). The results also showed that in all three studied regions, the net crop water requirement in the year of the research was higher than the last
decade. Application efficiency based on ten-year statistics in Zaveh, Torbat-e Heydarieh and Gonabad counties was 51, 49 and 87%, respectively.
Conclusions
This study showed that in saffron cultivation irrigation, among the three methods of surface irrigation, roll line and Piflex, farmers give the least volume of irrigation water to the plant by Piflex method and the highest volume of irrigation water to the plant by surface method. On the other hand, saffron yield in irrigation with Piflex pipes was 7.4 kg / ha and the lowest yield in surface irrigation was 6 kg. As a result, the highest water use efficiency of 0.00198 kg / m3 was obtained in irrigation with Piflex pipes and the lowest efficiency of surface irrigation method was 0.00129 kg / m3. Comparison of saffron irrigation water volume in the three studied regione of Zaveh, Gonabad and Torbat Heydarieh shows that the
highest volume of saffron irrigation water belongs to Torbat Heydarieh city and the lowest belongs to Gonabad. On the other hand, the highest yield of saffron was observed in Zaveh and Torbat-e Heydarieh counties and the lowest yield was observed in Gonabad. In total, the highest water use efficiency was 0.001714 kg / m3 in Zaveh city and the lowest productivity was 0.001103 kg / m3 in Gonabad. Water consumption efficiency in Torbat Heydarieh was equal to 0.001713 kg / m3. Application efficiency based on ten-year statistics in Zaveh, Torbat-e Heydarieh and Gonabad counties was 51, 49 and 87%, respectively. According to the volume of irrigation water and the area under cultivation, the average weight of irrigation water volume was 4296 cubic meters per hectare.