ارتقاء بهره‌وری آبیاری گندم در ایران (بخش اول: از دیدگاه سامانة آبیاری و مدیریت آب)

در بسیاری از کشورها مانند ایران، کشت آبی عامل اصلی تولید غذا بوده و آبیاری نقش کلیدی در افزایش تولید محصولات کشاورزی در 50 سال گذشته داشته است. یکی از مشکلات بزرگ تولید گندم، کمبود منابع آب است. بنابراین، ضرورت استفادة بهینه از منابع آب موجود و قابل استحصال و افزایش کارایی مصرف آب امری اجتناب‌ناپذیر است. آزمایش‌ها و تجارب نیم‌قرن اخیر در علم و فن آبیاری نشان داده است که تاثیر نهاده‌های مختلف از قبیل بذور اصلاح ‌شده، کودهای شیمیایی، عملیات مناسب کاشت، داشت و برداشت هنگامی تاثیر مثبت و مناسب در رشد گیاه دارد که مدیریت آبیاری که شامل مجموعه اقداماتی است که آب را به مقدار مشخص و در زمان مورد نیاز در اختیار گیاه قرار می‌دهد، به نحو مطلوبی انجام شده باشد. طبق اصل پارِتو، مناطقی که 80 درصد کشت و تولید گندم (آبی و دیم) در آن‌ها انجام می‌شود، مناطق اصلی تولید گندم هستند. بر همین اساس، 13 استان گلستان، کرمانشاه، آذربایجان غربی، آذربایجان شرقی، همدان، اردبیل، لرستان، مرکزی،‌ خوزستان، فارس، خراسان رضوی، کردستان و زنجان، به‌عنوان مناطق اصلی تولید گندم در ایران شناسایی شده و در این مطالعه نیز تمرکز اصلی بر روی این مناطق بود. تحلیل جامع بیان‌گر آن بود که وسعت پیشنهادی برای اجرای سامانة آبیاری موضعی نواری (تیپ) در سال زراعی 1400-1399، برابر 75000 هکتار بوده که 53523 هکتار (71.4 درصد) آن متعلق به 13 استان اصلی تولیدکننده یا همان مناطق عمدة تولید گندم است. هم‌چنین، نتایج نشان داد که کاهش مصرف آب در بخش کشاورزی با توسعة روش آبیاری موضعی نواری در مناطق اصلی تولید گندم منجر به کاهش 134.1 میلیون مترمکعب آب کشاورزی می‌شود. هزینة اجرایی این راه‌کار بر اساس متوسط اجرای هر هکتار آبیاری موضعی 400 میلیون ریال، 21409 میلیارد ریال در سال 1400 است. در نتیجه به‌کارگیری سامانة نوین آبیاری به‌عنوان یک ابزار مدیریتی می‌تواند منجر به ارتقاء بهره‌وری آب گندم در کشور شود.

improving wheat irrigation productivity in iran (part one: from the view point of irrigation system and water management)

introductionirrigation efficiency is one of the most important key indicators in the macro-planning of water supply, allocation, and basic water consumption in various sectors such as industry, drinking, environment, and other biological resources, especially agriculture. in many countries such as iran, irrigated agriculture is the main factor in food production and irrigation has played a key role in increasing the production of agricultural products in the last 50 years. one of the biggest problems for wheat production is the need for more water resources. therefore, the necessity of optimal use of available and extractable water resources and increasing water consumption efficiency is inevitable. experiments and experiences of the last half century in the science and technology of irrigation have shown that the effect of various inputs such as modified seeds, chemical fertilizers, appropriate planting operations, and harvesting has a positive and appropriate effect on plant growth. irrigation management, which includes a set of actions that provide water in a certain amount and at the required time to the plant, must be done in a good way. materials and methodsthe current study has targeted the main areas of wheat production in iran. due to its high nutritional value and strategic importance, wheat is cultivated in almost all areas of the country. according to the pareto principle, the areas where 80% of wheat cultivation and production (irrigated and rainfed) are carried out are the main wheat production areas. since in iran, the statistics of the agricultural situation are mainly presented based on political divisions, therefore, the major regions will be the set of provinces in which the above hypothesis is true. accordingly, 13 provinces of golestan, kermanshah, west azarbaijan, east azarbaijan, hamedan, ardabil, lorestan, central, khuzestan, fars, razavi khorasan, kurdistan, and zanjan have been identified as the main wheat production areas in iran and in this study also, the main focus was on these areas. since the vast country of iran has a diverse climate, to ensure that all the country’s climate groups are represented in the selected regions, an adaptation of these regions to the country’s climate groups was also done. results and discussionthe comprehensive analysis indicated that the area proposed for implementing the drip irrigation system (tape) in 2020-2021 was equal to 75,000 ha, of which 53,523 ha (71.4%) belong to the 13 main producing provinces or the main wheat production areas. also, the results showed that the reduction of agricultural water consumption with the development of a drip irrigation system in the main wheat production areas leads to a reduction of 134.1 million m3 of agricultural water. the implementation cost of this solution based on the average implementation of each ha of drip irrigation system is 400 million rials in the year 2021, equal to 21409 billion rials. among the limitations of wheat irrigation with the tape method, we can point out the spreading and distribution of tapes in the field, which is time-consuming, but with the introduction of sowing and distribution devices, this problem will be solved. at the beginning stage, care should be taken not to tear the tapes during the spraying and fertilizing stage. in the harvesting phase, before harvesting the crop, tapes should be collected from the field. in the whole system, strip drip irrigation (type) can be used for dense and row crops such as all kinds of vegetables, summer crops, corn, wheat, fodder, watermelon, melon, tomato, onion, potato, strawberry, sunflower, sugar beet, and cotton. conclusionone of the pressurized irrigation methods that have been developed for wheat cultivation in recent years is the drip (tape) irrigation system, most of the research and field investigations in iran have confirmed the high efficiency of this method in increasing wheat water productivity. as a result, using the modern irrigation system as a management tool can lead to the improvement of wheat water productivity in iran. the main problem in this system is the high cost and low knowledge of the farmer. we can also mention the weak points of increasing the cost of constructing the irrigation system, the problems of collecting strips for the next crop, and the accumulation of salt in areas with salty water. among the strengths, we can mention easier irrigation management, less labor, increased yield, reduced water consumption, increased productivity, and most importantly, increased cultivated area with the same amount of water. another advantage is the use of the water-fertilizer system, which will be very precise, the operation of fertilizing and irrigation will be done for cultivated crops.