Modeling of irrigated wheat yield potential and gap in Iran

Document Type : Research Paper

Authors

1 University Agricultural Sciences and Natural Resources,Gorgon, Iran

2 University of Agricultural Sciences and Natural Resources, Gorgan , Iran

3 University Agricultural Sciences and Natural Resources, gorgan, Iran

4 University Agricultural Sciences and Natural Resources, Gorgan, Iran

5 Department of Weed Research, Plant Protection Research Institue, Tehran, Iran

6 Department Of Agronomy, Gorgon University Agricultural Sciences and Natural Resources, Iran

Abstract

Modeling of irrigated wheat yield potential and gap in Iran
Abstract

Background and objectives: Wheat has an important role in feeding the people of world and Iran as well. It provides around 40 percent of edible energy and protein for people in Iran. Closing yield gap can increase wheat production, significantly. The first step of closing yield gap is to quantify the yield gap at a given region or country. The amount of wheat yield gap hasn’t been measured for whole Iran by a global standard protocol so far. The aim of this study is to estimate irrigated wheat yield gap for Iran based on the global yield gap analysis (GYGA) protocol.

Materials and methods: GYGA protocol suggested a method to calculate yield gap on a large scale like a country. Based on this protocol, at first the area covered by each weather stations were specified. Second, the main weather stations where cover irrigated wheat lands were selected named reference weather stations (RWS). Third, irrigated wheat potential yield was estimated by SSM-iCrop2-wheat simulation crop model within the RWSs. The actual irrigated wheat yield was calculated for each RWS based on GYGA protocol as well. Forth, amount of the actual and potential yield was calculated for whole country by using the values calculated for the RWS according to GYGA protocol. Finally, the yield gap was calculated by difference between potential and actual yield for the country.

Results: The results of this study showed that average irrigated wheat in Iran was 3.4 ton/ha, average potential yield was 8.8 ton/ha and average yield gap was 5.4 ton/ha (62%). At the moment, irrigated wheat producers just use 38 present of the existing wheat cultivars and environment potential. There was no significant relationship between climate in the irrigated wheat production RWS and irrigated wheat yield gap (based on percent) in Iran and the yield gap was around 62 percent in all the RWSs. If farmers could reach 80% of potential yield of their locations, by improving agronomy practices, average irrigated wheat would reach 7 tons/ha and there is around 2.2 million ha irrigated wheat area in Iran. Thus, average wheat production in irrigated condition would increase from 7.5 million tons to 19.8 million tons.

Conclusion: Owing to existing wheat cultivars and climates in the main irrigated wheat production RWS in Iran, there is a big yield gap of wheat in Iran. The low actual irrigated wheat yield in Iran (3.4 tone/ha) can be attributed to the poor management condition because the existing cultivars and climates have no limitation to reach the yield around 8.8 tone/ha. There are many factors to reduce the yield such as poor seedbed preparation, late planting date, weeds, pests and diseases, nutrition’s deficits, fertilizer amount and timing, irrigation amount and timing etc. If we want to close the yield gap, we have to identify the reasons of yield gap in a given region.

Keywords


Ahmadi, H. 2017. Modeling wheat production and yield gap in Golestan province. Ph.D thesis, Gorgan University of Agricultural Sciences and Natutal Resources, Gorgan, Iran. (In Persian)
2. Amiraslani, F., and Dragovich, D. 2011. Combating desertification in Iran over the last 50 years: An overview of changing approaches. J. Environ. Manage. 92: 1-13.
3., andarzian, B., Bakhshandeh, A.M., Bannayan, M., and Emam, Y. 2008. Evaluation of the CERES-wheat model in Ahvaz condition. J. Field Crops Res. 6: 1. 11-22. (In Persian)
4.Azizizahan, A.A., Shahabifar, M., Ebrahimipak, N.A., Razavi, R., Ghalebi, S., Soraee tabrizi, M., Toloee, R., and Piri, R. 2014. An evaluation on wheat water efficiency in Iran and world. 1st National Conference Management of Soil and water in wheat production. P. 2-15.
5.Edreira, J.I., Guilpart, N., Sadras, V., Cassman, K., van Ittersum, M., Schils, R.L.M., and Grassini, P. 2018. Water productivity of rainfed maize and wheat: A local to global perspective. Agric. Meteorol. 259: 364-373.
6.Esfandiyavpor, A. 2015. Increasing the main products (wheat) self sufficiency coefficient. Ministry of Agriculture Jihad. A project to increase the self sufficiency coefficient of 8 main products of the country.  
7.Espe, M.B., Cassman, K.G., Yang, H., Guilpart, N., Grassini, P., VanWart, J., Anders, M., Beighley, D., Harrell, D., Linscombe, S., and McKenzie, K. 2016. Yield gapanalysis of US rice production systems shows opportunities for improvement. Field Crops Res. 196: 276-283.
8.FAOSTAT. 2015. http://faostat3.fao.org/ download/E/EF/EFAO (accessed at: 19-10-2015).
9.Fisher, R.A. 2014. Definitions and determination of crop yield, yield gaps, and of rates of change. Field Crops Res., 6359: 1-10.
10.Foley, J.A., Ramankutty, N., Brauman, K.A., Cassidy, E.S., and Gerber, J.S., et al. 2011. Solutions for a cultivated planet. J. Nature. 478: 337–342.
11.Gobbett, D.L., Hochman, Z., Horan, H., Navarro Garcia, J., Grassini, P., and Cassman, K.G. 2016. Yield gap analysis of rainfed wheat demonstrates local to global relevance. J. Agri. Sci. P. 1-18.
 12.Grassini, P., van Bussel, L.G., Van Wart, J., Wolf, J., Claessens, L., Yang, H., Boogaard, H., De Groot, H., vanIttersum, M.K., and Cassman, K.G. 2015. How good is good enough? Data requirements for reliable crop yield simulations and yield-gap analysis. Field Crops Res. 177: 49-63.
13.Hajjarpoor,  A.,  Soltani, A., and Torabi, B. 2015. Using boundary line analysis in yield gap studies: Case study of wheat in Gorgan. J. Crop Prod. 8: 183-201. (In Persian).
14.Hajjarpoor, A. 2016. Analysis of the yield limitations in Golestan province. Ph.D thesis, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran. (In Persian)
15.Hochman, Z., Gobbett, D., Horan, H., and Navarro Garcia, J. 2016. Data rich yield gap analysis of wheat in Australia. Field Crops Res. 197: 97-1066.
16.Kamaladdin, H., and Dehghanzadeh, B. 2013. Investigation irrigation water saving in wheat agronomy in Ahvaz. J. Water Eng. 75-85. (In Persian)
17.Koo, J., and Dimes, J.P. 2010. Generic Soil Profiles for Crop Modeling Applications (HC27)." International Food Policy Research Institute, Washington, D.C., and University of Minnesota, St. Paul, MN. Available online at http://harvest choice.org/node/662.
18.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. Agric. For. Meteorol. 239: 108-117.
19.Meghdadi, N., Soltani, A., Kamkar, B., and Hajarpoor, A. 2014.  Agroecological zoning of Zanjan province for estimating yield potential and yield gap in dryland-base chickpea production systems. J. Plant Prod., Res. 21: 3. 27-49. (In Persian)
20.Merlos, F.A., 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 Res. 184: 145-154.
21.Ministry of Agriculture Jihad. 2001-2015. Planning and Economical Division. Bureau for Statistics and Information Technology. (In Persian)
22.Motagh, M., Walter, T.R., Sharifi, M.A., Fielding, E., Schenk, A., Anderssohn, J., and Zschau, J. 2008. Land subsidence in Iran caused by widespread water reservoir overexploitation. Geophysical Research Letters 35, L16403.
23.Mousavi, S.M., Shamsai, A., Hesham El Naggar, M., and Khamehchian, M. 2001. A GPS-based monitoring program of land subsidence due to groundwater withdrawal in Iran. Can J. Civil Eng. 28: 3. 452-464.
24.Mueller, N.D., Gerber, J.S., Johnston, M., Ray, D.K., and Ramankutty, N. et al. 2012. Closing yield gaps: nutrient and water management to boost crop production. J. Nature. 490: 254-257.
25.Nakhjavanimoghadam, M.M., Ghahraman, B., and Zarei, Gh. 2017. Wheat Water Productivity Analysis under Different Irrigation Management Practices in Some Regions of Iran. J. Water Res. in Agri. 31: 1. 43-57. (In Persian)
26.Nehbandani, A. 2018. Yield gap analysis of soybean in Iran. Ph.D thesis, Gorgan University of Agricultural Sciences and Natutal Resources, Gorgan, Iran. (In Persian)
27.Nekahi, M.Z., Soltani, A., Siahmarguee, A., and Bagherani, N. 2014. Yield gap associated with crop management in wheat (Case study: Golestan province-Bandar-gaz). J. Crop Prod. 7: 135-156. (In Persian)
28.Patrignani, P., Lollato, R.P., Ochsner, T.E., Godsey, C.B., and Edwards, J.T. 2014. Yield gap and production gap of rainfed winter wheat in the Southern Grain Plains. J. Agro. 106: 1329-1339.
29.Razavi, R. 2008. The effect of elimination of irrigation at Stages of wheat growth on water use efficiency and its quantitative and qualities yield. J. Water Soil Sci. 22: 1. 37-145. (In Persian)
30.Sadras, V.O., and Roget, D.K. 2004. Production and environmental aspects of cropping intensification in a semiarid environment of southeastern Australia. J. Agro. 96: 236-246.
31.Sepahvand, M. 2009. Comparing the water requirement (WR), water productivity (WP) and economical water productivity (EWP) of wheat and rapeseed in wet years in western Iran in wet years. J. Water Res. 3: 4. 63-68. (In Persian)
32.Shahbazi, K., and Besharati, H. 2013. Overview of Agricultural Soil Fertility Status of Iran. J. Land Mang. 1: 1. 1-15. (In Persian)
33.Soltani, A., and Sinclair, T.R. 2011. A simple model for chickpea development, growth and yield. Field Crops Res. 124: 252-260.
34.Soltani, A., Sinclair, T.R. 2012. Modeling physiology of crop development, growth and yield. CABi. 322 (In Persian)
35.Soltani, A., Maddah, V., and Sinclair, T.R. 2013. SSM-Wheat: a simulation model forwheat development, growth andyield.  J. Plant Prod. 7: 711-740.
36.Torabi, B.  2011. Analysis of the yield limitations in Gorgan using simulation model and hierarchical process (AHP). Ph.D thesis, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran. (In Persian)
37.Torabi, B., Soltani, A. Galeshi, S., and Zeinali, E. 2012. Analyzing Wheat Yield Constraints in Gorgan. J. Crop Prod. 4: 1-17. (In Persian)
38.van Bussel, L.G., Grassini, P., VanWart, J., Wolf, J., Claessens, L., Yang, H., Boogaard, H., de Groot, H., Saito, K., Cassman, K.G., and vanIttersum, M.K. 2015. From field toatlas: upscaling of location-specific yield gap estimates.  Field Crops Res. 177: 98-108.
39.Van Ittersum, M. K., Cassman, K. G., Grassini, P., Wolf, J., Tittonell, P., and Hochman, Z. 2013. Yield gap analysis with local to global relevance—A review. Field Crops Res. 143: 4-17.