Estimating the Potential Increase of Irrigated Barley Production over Iran via Closure of Yield Gap Based on GYGA Protocol

Document Type : Scientific - Research


1 Agronomy department, Gorgan University of Agricultural Sciences and Natural Resources, Iran

2 Agronomy Department, Gorgan University of Agricultural Sciences and Natural Resources, Iran.


Barley (Hordeum vulgare L.) is considered as the second most important grain crop after wheat, due to 1.75 million hectares harvested areas and 3.2 million tons’ production in Iran. The irrigated fields are contributed up to 45% of total barley harvested areas (equivalent to 1.7 million ha) and 70% of total barley production (equivalent to 2.2 million tons). Based on the statistics reported in recent years, about 2.5 million tons of barley imported from other countries. According to the impossibility of extending the barley cultivated areas and even the necessity of reducing fields in some parts of the country, increasing productivity per unit area of cultivated lands is recognized as the only practical way to boost the production of barley in Iran. In this regard, this study was conducted to estimate barley yield gap (Yg) and the potential of increasing barley production in irrigated condition as the first step to promote the yield and production of barley over the country.
Materials and Methods
Firstly, the main production zones of barley are determined; the zones which were contributed in more than 85% of barley production. The Designated climatic zones (DCZs) were identified using GYGA climatic zones (Global Yield Gap Atlas) and the distribution of barley harvested area raster layers. Subsequently, the Reference weather Stations (RWSs) within the DCZs were selected based on the values of the harvested area, and the types of soil in each of RWSs were determined by using of HC-27 soil map. SSM-iCrop2 as a crop simulation model has been employed to estimate the potential yield (Yp) in the RWSs of cultivated areas, which has previously been parameterized and evaluated, and the results have indicated the robustness of the model for simulating barley yield over the country. For estimating Yg, the data of actual yield (Ya) and the agronomic management data for estimating Yp during 15 growing seasons (2000-2014), were collected at RWSs scale. Using A bottom-up approach, the yield, and production gap values were calculated at RWSs and subsequently aggregated to DCZs and finally, extended from DCZ to country-level according to the spatial distribution of crop area and climate zones.
Results and Discussion
Based on GYGA protocol, 48 RWSs within 12 DCZs of irrigated barley harvested areas were demonstrated. Aggregation from the RWSs results to DCZs illustrated that the average of potential yield in DCZs of irrigated barley was estimated 7090 kg.ha-1 and the range varied from 5283 to 8286 kg.ha-1. Nevertheless, the Ya range in these climate zones was calculated between 1406 and 3723 with an average of 3009 kg.ha-1. According to the results, the DCZs which confronted to higher temperatures during the growing season have lower yields and also a significant reverse correlation between the potential yield and the growth length period (R2 = 0.88 and p ≤0.01) were shown. The correlation between total received daily solar radiation during the growing and Yp in the DCZs was significant, positively season (R2 = 0.98 and p ≤0.01). At present, the range of difference between actual and potential yield varies between 3237 to 4697 kg.ha-1 with an average of 4081 kg.ha-1 (equivalent to 58% yield gap). In other words, just around 24 to 50 percent (on an average of 42 percent) of estimated Yp in irrigated barley fields can be attainable. According to the irrigated barley harvested areas, the actual and potential production gap are calculated about 2.21 and 2.99 million tons in the country, respectively, and under the best management condition can lead the production to be about 4.17 million tons.
According to the results, it was demonstrated about 58% relative yield gap between the averages of actual yield (3008 kg.ha-1) and potential yield (7090 kg.ha-1), which can be reduced by improving the production management in irrigated barley cultivated areas. For this reason, the current production of barley in irrigated lands can be increased from 2.12 to 4.17 million tons. This increase in production (1.96 million tons) could provide a significant part of the country's need to the barley and bring the country closer to achieve full self-sufficiency.


Ahmadi, A., Hosseinpour, T., and Soltani, M., 2014. Effects of seed density on the yield and its components of three genotypes of rainfed barley. Agronomy Journal 102: 131-140. (In Persian with English Summary)
Alazmani, A., 2014. Effect of nitrogen fertilizer on feed and grain yield of barley cultivar. International Research Journal of Applied and Basic Sciences 8(11): 2013-2015.
Alasti, O., 2011. The accuracy of forecasting wheat yield in Mashhad conditions using CERES-Wheat model and simulated radiation. M.Sc. Thesis, Ferdowsi University of Mashhad, Iran.
Alasti, O., 2020. Modeling potential production and gap production of barley under current and future climates of Iran. PhD Desertation. Gorgan University of Agricultural Sciences and Natural, Gorgan, Iran.
Alasti O., Zeinali, E., Soltani, A., Torabi, B., 2020. Estimation of yield gap and the potential of rainfed barley production increase in Iran. Journsl of Crop Production 13(3): 41–60.
Anderson, W., Johansen, C., and Siddique, K.H.M., 2016. Addressing the yield gap in rainfed crops: A review. Agronomy for Sustainable Development 36(1): 1–13.
Ansari Maleki, Y., Jafarzadeh, J., Vaezi, B., Hosseinpour, T., and Ghasemi, M., 2009. Study on adaptability and grain yield stability of barley genotypes in warm rainfed areas. Seed and Plant Breeding 25(1): 297-313. (In Persian with English Summary)
Aramburu Merlos, F., Monzon, J.P., Mercau, J.L., Taboada, M., Andrade, F.H., Hall, A.J., Jobbagy, E., Cassman, K.G., and Grassini, P., 2015. Potential for crop production increase in Argentina through closure of existing yield gaps. Field Crops Research 184: 145–154.
ArcGIS [GIS software]., 2014. Version 10.3, Environmental Systems Research Institute, Inc. CA.
Bagheri, H., Jamshidi, S., and Andalibi, B., 2015. Comparison of agronomic characteristics of promising dryland barley genotypes with a conventional cultıvar in Miyaneh region. Journal of Crop Production and Processing 4(14): 63-76.
Boogaard, H., Wolf, J., Supit, I., Niemeyer, S., and van Ittersum, M., 2013. A regional implementation of WOFOST for calculating yield gaps of autumn-sown wheat across the European Union. Field Crops Research 143: 130–142.
Cuesta-Marcos, A., Kling, J.G., Belcher, A.R., Filichkin, T., Fisk, S.P., Graebner, R., Helgerson, L., Herb, D., Meints, B., Ross, A.S., Hayes, P.M., and Ulrich, S.E., 2015. Barley: Genetics and Breeding, In: Encyclopedia of Food Grains: Second Edition. Elsevier, pp. 287–295.
Deng, N., Grassini, P., Yang, H., Huang, J., Cassman, K.G., and Peng, S., 2019. Closing yield gaps for rice self-sufficiency in China. Nature Communications 10 (1725):1-9.
Etesami, M., Galeshi, S., Soltani, A., and Nooriani, A., 2008. Investigation of changes harvest index, yield and grain yield components in modern and old barley genotype. (Hordeum vulgare L.). Journal of Agricultural Sciences and Natural Resources 15(5): 19-25. (In Persian with English Summary)
Eyvazi, A.R., 2014. Effect of sowing date on resistance to chilling stress in winter and spring genotypes of barley. Journal of Crop Production and Processing 4(13): 281-294. (In Persian with English Summary)
Food and Agriculture Organization (FAO)., 2018. The FAOSTAT Database. Available at Web site (verified September 2019)
Ghaemi, A.A., and Zamani, B., 2015. Effect of different level of water stress and nitrogen fertilizer on yield and yield components of barley in Badjgah (Fars province). Journal of Water and Soil 29(4): 954-965. (In Persian with English Summary)
Ghanabari, A., Karbasi, A.R., Ahmadian, A., and Ghasemi, H., 2009. A Perspective Toward Water Crisis Management in Sistan, the Barriers and Solutions. 1th International Conference of Water Crisis.
Ghasemi, M., Vahabzadeh, M., Khalilzadeh, G., Gharib Eshghi, A., 2004. Study on grain yield, yield components and green fodder of triticale and barley cultivars. Seed and plant 20(3): 345-357. (In Persian with English Summary)
Gobbett, D.L., Hochman, Z., Horan, H., Navarro Carcia, J., Grassini, P., and Cassman, K.G., 2016. Yield gap analysis of rainfed wheat demonstrates local to global relevance. The Journal of Agricultural 115(2): 282-299.
Grassini, P., Cassman, K.G., and Van Ittersum, M., 2017. Exploring maize intensification with the Global Yield Gap Atlas. Better Crop. with Plant Food 101(2): 7–9.
Hajjarpoor, A., 2016. Evaluation of wheat yield gap in Golestan province. Ph.D. Dissertation, Faculty of Plant Production, Gorgan University of Agricultural Sciences and Natural Resources, Iran. (In Persian with English Summary)
Hamzei, J., and Seyedi, M., 2014. Responses of soil bulk density, some of agronomic characteristics and yield of rainfed barled to the various methods of tillages in Hamedan region. Water and Soil Science (Journal of Science and Technology of Agriculture and Natural Resources) 18(70): 147-156. (In Persian with English Summary)
Han, E., Ines, A., and Koo, J., 2015. Global High-Resolution Soil Profile Database for Crop Modeling Applications. Harvard Dataverse, V1.
HarvestChoice., 2014. Crop Production: SPAM. International Food Policy Research Institute, Washington, DC., and University of Minnesota, St. Paul, MN. Available online at
Hatfield, J.L., and Prueger, J. H., 2015. Temperature extremes: Effect on plant growth and development. Weather and Climate Extremes 10:4-10.
Hochman, Z., Gobbett, D., Holzworth, D., McClelland, T., van Rees, H., Marinoni, O., Garcia, J.N., and Horan, H., 2012. Quantifying yield gaps in rainfed cropping systems: A case study of wheat in Australia. Field Crops Research 136: 85–96.
Hosseinpour, T., 2012. Relationship among agronomic characteristics and grain yield in hull-less barley genotypes under rainfed conditions of Koohdasht. Iranian Journal of Crop Sciences 14(3): 263-279. (In Persian with English Summary) (Verified June 2019) (verified June 2017)
Hughes, M.A., and Dunn, M.A., 1990. The effect of temperature on plant growth and development. Biotechnology and Genetic Engineering Reviews 8:161-188.
Jamshidi, A., and Javanmard., H.R., 2017. Evaluation of barley (Hordeum vulgare L.) genotypes for salinity tolerance under field conditions using the stress indices. Ain Shams Engineering Journal 9(4): 2093-2099.
Jenab, M and Nazari, B., 2019. The study of water productivity and yield gap of wheat, barley and maize in Qazvin province. Iranian Journal of Soil and Water Research 49(6): 1405-1417.
Kamali, G.A., and Moradi, E., 2005. Solar radiation (Fundamentals and applications in agriculture and renewable energy). 20th Century Publisher, Tehran. p. 299.
Knol, R., 2016. Yield gap analysis of cereals in Romania: Causes and mitigation options. M.Sc. Thesis Plant Science. Plant Production Systems Department. Wageningen University. Netherland.
Komeili, R., and Sharafi, S., 2014. Evaluation of promising barley lines under normal and drought stress in farmer conditions. Crop Science Research in Arid Regions 2(2):119-132. (In Persian with English Summary)
Koo, J., and Dimes, J., 2010. HC27 Generic Soil Profile Database. Int. Food Policy Res.25 Inst. Washington, DC.
Koocheki, A., Nassiri, M.M., Mansoori, H., and Moradi, R., 2017. Effect of climate and management factors on potential and gap of wheat yield in Iran with using WOFOST model. Iranian Journal of Field Crops Research 15(2): 244-256. (In Persian with English Summary)
Liu, B., Chen, X., Meng, Q., Yang, H., and Van Wart, J., 2017. Estimating maize yield potential and yield gap with agro-climatic zones in China—Distinguish irrigated and rainfed conditions. Agricultural and Forest Meteorology 239: 108–117.
Lobell, D.B., Cassman, K.G., and Field, C.B., 2009. Crop yield gaps: their importance, magnitudes, and causes. Annual Review of Environment and Resources 34(1): 179.
Lu, C., and Fan, L., 2013. Winter wheat yield potentials and yield gaps in the North China Plain. Field Crops Research 143:98-105.
Moosavi, S.S., Zahedi-No, M., Chaichi, M., and Abdollahi, M.R., 2014. Assessment of diversity and identifying of effective traits on grain yield of barley (Hordeum vulgare L.) under non-stress and terminal moisture stress conditions. Cereal Researches 4(2): 155-173. (In Persian with English Summary)
Mousavi, S.G.R., and Seghatoleslami, M.J., 2011. Effect of different chemical and bio-fertilizers on morphological traits, yield and yield components of barley. Advances in Environmental Biology 5(10): 3312-3317.
Naghaii, V., and Asgharipour, M.R., 2011. Difference in drought stress responses of 20 barley genotypes with contrasting drought tolerance during grain filling. Advances in Environmental Biology 5(9): 3042-3049.
Nehbandani, A.R., 2018. Evaluation of soybean yield gap in Iran. Ph.D. Dissertation, Faculty of Plant Production, Gorgan University of Agricultural Sciences and Natural Resources, Iran. (In Persian with English Summary)
Oraki, A., Siahpoosh, MR., Rahnama, A., and Lakzadeh, I., 2016. The effects of terminal heat stress on yield, yield components and some morpho-phenological traits of barley genotypes (Hordeum vulgare L.) in Ahvaz weather conditions. Iranian Electronic Journal of Crop Production 47(1): 29-40. (In Persian with English Summary)
Paulescu, M., Stefu, N., Calinoiu, D., Paulescu, E., Pop, N., Boata, R., and Mares, O., 2016. Ångström–Prescott equation: Physical basis, empirical models and sensitivity analysis. Renewable and Sustainable Energy Reviews 62: 495–506.
Pourmotabbed, MR., Farnia, A., and Fard Alishir, N., 2014. Effect of planting date on ecophysiological and morphological characteristics of lines and varieties of barley in different regions of Kermanshah. Journal of Biodiversity and Environmental Sciences 5(2): 572-577.
Ramezani Etedali, H., Nazari, B., Tavakoli, A., and Parsinejad, M., 2009. Evaluation of CROPWAT model in deficit irrigation management of wheat and barley in Karaj. Journal of Water and Soil (Agricultural Sciences and Technology) 23(1):119-129. (In Persian with English Summary)
Ravari, S.Z., 2003. Effects of sowing date on yield of some barley advanced lines and cultivars. Seed and Plant. 19(3): 401-411. (In Persian with English Summary)
Roozitalab, M.H., Siadat, H., and Farshad, H., 2018. The Soils of Iran. Springer International Publishing. p. 255.
Roshanfekr, H.A., Meskarbashi, M., Kashani, A. 2008. Evaluation of the agronomic traits and yield of hulless barley genotypes in Ahvaz. The Scientific Journal of Agriculture. 4(1): 9-23. (In Persian with English Summary)
Saberi, M.H., Nikkhah, H.R., Tajali, H., and Arazmjo, E., 2014. Effects of terminal season drought stress on yield and choosing best tolerance indices in promising lines of Barley. Agronomy Journal (Pajouhesh and Sazandegi) 107: 124-132. (In Persian with English Summary)
Sadeghi, H., and Kazemeini, A.R., 2011. Effect of crop residue management and nitrogen fertilizer on grain yield and yield components of two barley cultivars under dryland conditions. Iranian Journal of Crop Science 13(3): 436-451. (In Persian with English Summary)
Saeedi, M., and Azhand, M., 2014. Effect of photosynthesis resources constraint and water-deficit stress after flowering on the grain yield and gas exchanges in various genotypes of barley. Journal of Crop Improvement 16(4): 840-856. (In Persian with English Summary)
Saeidi, M., Abdoli, M., Azhand, M., and Khas-Amiri, M., 2013. Evaluation of drought resistance of barley (Hordeum vulgare L.) cultivars using agronomic characteristics and drought tolerance indices. Albanian Journal of Agricultural Sciences 12(4): 545-554.
Shafagh-Kolvanagh, J., Zehtab-Salmasi, S., Nasrollahzadeh, S., Hashemi-Amidi, N., and Dastborhan, S., 2015. Evaluation of yield and protein content of barley grain in response to nitrogen and weeds interference. Journal of Agricultural Science 25(4): 120-134.
Shirinzadeh, A., Soleimanzadeh, A., and Shirinzadeh, Z., 2013. Effect of seed priming with plant growth promoting rhizobacteria (PGPR) on agronomic traits and yield of barley cultivars. World Applied Sciences Journal 21(5): 727-731.
Soltani, A., Alimagham, S.M., Nehbandani, A., Torabi, B., Zeinali, E., Dadrasi, A., Zand, E., Ghassemi, S., Pourshirazi, S., Alasti, O., Hosseini, R.S., Zahed, M., Arabameri, R., Mohammadzadeh, Z., Rahban, S., Kamari, H., Fayazi, H., Mohammadi, S., Keramat, S., Vadez, V., Van Ittersum, M.K., and Sinclair, T.R., 2020. SSM-iCrop2: A simple model for diverse crop species over large areas. Agricultural Systems 182: 102855.
Soltani, A., and Sinclair, T.R., 2012. Modeling physiology of crop development, growth and yield. CAB International, Wallingford, UK.
Soltani, A., Maddah, V., and Sinclair, T.R., 2013. SSM-Wheat, a simulation model for wheat
development, growth and yield. International Journal of Plant Production 7(4): 711- 740.
Tabarzad, A., Ghaemi, A.A., and Zand-Parsa, S., 2016. Barley grain yield and protein content response to deficit irrigation and sowing dates in semi-arid region. Modern Applied Science 10(10): 193-207.
Vaezi, B., and Ahmadikhah, A., 2010. Evaluation of drought tolerance of twelve improved barley genotypes in dry and warm condition. Journal of Plant Production 17(1): 23-44.
Van Bussel, L.G.J., Grassini, P., Van Wart, J., Wolf, J., Claessens, L., Yang, H., Boogaard, H., de Groot, H., Saito, K., Cassman, K.G., and Van Ittersum, M.K., 2015. From field to atlas: Upscaling of location-specific yield gap estimates. Field Crops Research 177: 98–108.
Van Ittersum, M.K., Howden, S.M., and Asseng, S., 2003. Sensitivity of productivity and deep drainage of wheat cropping systems in a Mediterranean environment to changes in CO2, temperature and precipitation. Agriculture, Ecosystems and Environment 97(1): 255–273.
Van Ittersum, M.K., Cassman, K.G., Grassini, P., Wolf, J., Tittonell, P., and Hochman, Z., 2013. Field crops research yield gap analysis with local to global relevance — A review. Field Crops Research 143: 4–17.
Van Wart, J., van Bussel, L.G. J., Wolf, J., Licker, R., Grassini, P., Nelson, A., Boogaard, H., Gerber, J., Mueller, N. D., Claessens, L., van Ittersum, M. K., and Cassman, K.G., 2013. Use of agro-climatic zones to upscale simulated crop yield potential. Field Crops Research 143: 44–55.
Yousefi Rad, M., Asghari, M., Mohammadi, M., and Masoumi Zavarian, A., 2016. Effect of drought stress on yield, yield components and some physiological characteristics of seven barley varieties. Journal of Crop Improvement. 7(4): 297-308. (In Persian with English Summary)
Zahed, M., 2018. Modeling the production and yield gap of wheat in Iran. Ph.D. Dissertation, Faculty of Plant Production, Gorgan University of Agricultural Sciences and Natural Resources, Iran. (In Persian with English Summary)