اثر مدیریت آبیاری بر شاخص‌های بهره‌وری مصرف آب محصول یونجه

تحقیق حاضر با هدف پایش بهره وری مصرف آب محصول یونجه و بررسی اثر اصلاح برنامه آبیاری بر کاهش مصرف آب و ارتقای شاخص های بهره وری انجام شد. در مرحله اول تحقیق، تعداد 11 مزرعه یونجه واقع در استان زنجان انتخاب و مورد مطالعه قرار گرفت. عوامل مرتبط با بهره وری نظیر شدت جریان ورودی به مزارع، حجم آب مصرفی، برنامه آبیاری، مدیریت تغذیه، عملکرد محصول، هزینه های تولید و درآمد حاصل از فروش محصول تعیین و شاخص های فیزیکی و اقتصادی بهره وری مصرف آب محاسبه شد. در مرحله دوم، اصلاح مدیریت آبیاری به عنوان راهکار اجرایی به منظور بهبود بهره وری مصرف آب در شرایط واقعی مزرعه در قالب قطعات کنترل شده اجرا و با وضع موجود مقایسه شد. بر اساس نتایج حاصل از پایش های میدانی، میانگین حجم آب آبیاری در مزارع یونجه در حدود 14250 متر مکعب در هکتار و میانگین شاخص های بهره وری مصرف آب cpd، bpd و nbpd به ترتیب برابر 0/79 کیلوگرم بر متر مکعب، 13/1 و 8/9 هزار ریال بر متر مکعب برآورد شد. به طور میانگین اعمال برنامه صحیح آبیاری در قطعات کنترل شده منجر به کاهش 49/5 درصدی حجم آب آبیاری و به تبع آن افزایش 72 درصدی شاخص بهره وری فیزیکی شد. تثبیت الگوی اشتباه برنامه آبیاری و عدم کنترل و نظارت بر بهره برداری از منابع آب دلایل اصلی مصرف بی رویه آب در مزارع یونجه شناخته شد. نتایج مرحله دوم اجرای پژوهش نشان داد، تنها با اصلاح مدت زمان آبیاری می توان حجم آب آبیاری را بطور قابل ملاحظه ای کاهش و بهره وری مصرف آب را بهبود بخشید.

effect of irrigation management on water productivity indicators of alfalfa

introductionover the last years, long-term average rainfall has experienced a meaningful decrease (from 250 to 206 mm per year) leading to continuous drought in iran. in addition, population growth and increasing demand for food put more pressure on the limited available water resources. thus, the quantitative and qualitative improvement of agricultural products become a necessity. there is 640,000 hectares of alfalfa cultivated land, standing for 5.4% of the total cultivated area. one of the most basic obstacles in these farms is the unsuitable model of water consumption management. previous studies were conducted with the aim of evaluating the mutual effects of different treatments in controlled plots. nonetheless, there is a need for large-scale investigations to monitor and improve water productivity in agricultural systems. in this research, the focus was on irrigation management and optimizing irrigation timing as a potential solution to enhance water productivity, considering the fixed irrigation cycles and traditional use of available water resources. the study began by assessing the current water productivity in 11 alfalfa farms located across four regions in zanjan province, ensuring a suitable spatial distribution. subsequently, the impact of irrigation management, particularly the adjustment of irrigation timing, was evaluated to determine its effectiveness in improving water productivity in these farms.materials and methodseleven alfalfa farms, covering a total area of 28 hectares, were initially selected in the agricultural lands of zanjan province. the majority of these farms were equipped with sprinkler irrigation systems. from these 11 farms, two specific farms were chosen to implement the proposed methods aimed at improving water productivity. these selected farms served as experimental sites where the irrigation management techniques were applied and evaluated. improvement solutions were mainly focused on irrigation management. each farm was divided into two parts; one part with real conditions (farmers’ management) and the second one with controlled conditions. in the controlled treatments, irrigation management was implemented through optimization of irrigation time. a nutritional program was also prepared according to the soil quality of the fields and applied in the controlled treatments. in each farm, basic information such as area, physical and chemical properties of soil and water quality were determined. irrigation information (such as inflow discharge and irrigation schedule) was measured and determined at least three times during the cropping season. soil moisture were measured before and after irrigation in order to calculate the water application efficiency. the amount of harvested product and production costs were obtained at the end of the cropping season through measurements and interviews with farmers. in this research, the indicators including the volume of irrigation water, the water use efficiency, and the physical and economic efficiency of water have been calculated to analyze the water productivity.