تعیین خلا عملکرد سیب‌زمینی (solanum tuberosum l.) در استان گلستان

تحلیل خلا عملکرد یک روش کمّی برای افزایش احتمالی ظرفیت تولید گیاهان زراعی در یک ناحیه مشخص می‌باشد و یکی از مهم‌ترین بخش های طراحی راهبردهای تامین غذا در مقیاس منطقه ای، ملی و جهانی است. در این راستا، با استفاده از مدل شبیه‏سازی ssm-icrop2 مقدار عملکرد پتانسیل سیب‌زمینی (solanum tuberosum l.) برآورد شد و سپس با استفاده از نرم‌افزار gis و به‌کمک دو روش گیگا و درون‌یابی مقادیر عملکرد پتانسیل، عملکرد واقعی، خلا عملکرد برای استان گلستان محاسبه گردید. نتایج نشان داد که عملکرد واقعی استان گلستان (میانگین 10 ساله مورد بررسی) براساس گزارش جهاد کشاورزی معادل 22 تن در هکتار می باشد. همچنین عملکرد واقعی محاسبه شده براساس روش گیگا معادل 20 تن در هکتار و براساس روش درون‌یابی نیز 22 تن در هکتار به‌دست آمد. حداکثر عملکرد غده گزارش شده توسط کشاورزان 55 تن بوده است که بر این اساس مقدار عملکرد پتانسیل شبیه‌سازی شده ارزیابی گردید. در روش گیگا 52 تن در هکتار و در روش درون‌یابی 42 تن در هکتار به‌دست آمد. که این امر نشان ار دقت بالای روش گیگا در تخمین عملکرد پتانسیل دارد. مقدار خلا عملکرد و عملکرد نسبی مشاهده شده برابر با 33 تن در هکتار و 40 درصد، برای روش گیگا معادل 33 تن در هکتار و 38 درصد و در روش درون‌یابی برابر با20 تن در هکتار و 52 درصد به‌دست آمد. با مقایسه دو روش درون‌یابی و گیگا، می توان نتیجه گرفت هر دو روش، تخمین نسبتاً خوبی از مقدار عملکرد واقعی داشتند، ولی روش گیگا عملکرد پتانسیل را بهتر از روش درون‌یابی پیش‌بینی کرد. براساس داده های مورد نیاز اجرای مدل در سطح ملی، قابلیت مقایسه نتایج با تحقیقات صورت گرفته در اقلیم های مشابه در سراسر دنیا، تخمین عملکرد پتانسیل براساس مناطق عمده کاشت محصولات، روش گیگا به عنوان روش برتر می تواند برای تخمین خلا عملکرد در سطح کشور و برای سایر محصولات نیز مورد استفاده قرار گیرد.

Determination of Potato (Solanum tuberosum L.) Yield Gap in Golestan Province

Introduction Potato (Solanum tuberosum L.) accounts for the largest share in production of food products after wheat, rice and corn, which plays an important role in the nutrition and food basket of the world. Currently, the issue of food security and supplying is very important in different parts of the world and thus prediction of its demand that is increasing. Also, growing population will intensify this issue too. A key strategy to overcome the nutritional challenge of the growing population of the world is eliminating the gap between the current achievement in farms and the yield which can be achieved by using the best cultivars compatible with the environment and the best water, soil and plant management methods. Martials and Methods In this study, potential yield of potato was estimated using the SSM-iCrop2. then the production and yield gap of potato were investigated with two methods of Global Yield Gap Atlas (GYGA) and Arc GIS software by interpolation method for Golestan province. For this aim, the information of potato cultivation management in the province level and the daily data of 23 synoptic weather station as well as their soil data were used. Meanwhile, potential yield gap analysis protocol (GYGA protocol) was used to identify the main weather stations named reference weather stations (RWSs) and climates where potato is planted in Golestan province. Potential yield of potato was estimated within the area covered by each RWS, and then scaled up to the province level. In order to implement the interpolation method in ArcGIS software, initially, potential yield of 23 stations in the Golestan province was estimated. Afterwards, the potential and actual yield in the whole province was estimated using Kriging and IDW methods, respectively. Results and Discussions According to the Agricultural Jihad Report, the actual yield of Golestan province (a tenyear average) was reported as 22 t.ha1, while the actual yield calculated based on the interpolation method was estimated equal to 22 t.ha1. However, the actual yield calculated using the global yield gap atlas (GYGA) method was estimated as 20 t.ha1. Heigh yield of potato in the province was reported by farmers up to 55 tons, which was considered as potential in the province to be compared with GYGA and interpolation methods, so that in the GYGA method, 52 t.ha1 and in the interpolation method, finding was 42 t.ha1. yield gap and relative yield in the GYGA method (33 t.ha1 and 38 percent), and interpolation (20 t.ha1 and 52 percent) were obtained. Also, in GYGA method, the values ​​were estimated using only two stations, but in the interpolation method the province’s yield was estimated using 23 stations and daily meteorological data. The GYGA protocol is a bottomup approach used by Hochman et al. (2016) to assess the variation of national yield from climatic zoning to analyze similar agrocluster groups. So far, several studies have been done using this protocol. Gobbett et al. (2017) showed that wheat lands in Australia are located in six key climatic regions. They selected 22 reference stations in this area and calculated the limited water potential yield using the APSIM model (for the years of 1996 to 2010). Conclusion The results showed that both Global yield gap Atlas (GYGA) and interpolation method had accurate estimation of actual and potential production and yield, but those values obtained using statistics and 23 weather stations in the interpolation method, and using just 2 weather station (Hashemabad and Gorgan stations) in the Global Atlas method. As previously mentioned, the GYGA method is designed to estimate the yield gap at the national level, which can calculate the potential yield, production, and yield gap in a wide range even with the least amount of information. One of the advantages of GYGA protocol is that the results obtained at any point in the world are comparable to other areas and cultivations of that particular product. Based on the comparison made in this study, it was concluded that the Global yield gap Atlas method should be used to estimate the yield of the country.