Estimating Silage Maize Crop Coefficient and Water Stress Coefficient under Different Irrigation Levels using Soil Water Balance Method (Case Study: Varamin Region)

Document Type : Research Paper


1 4. Graduated Student, Water Management and Engineering Department, Collage of Agriculture, Tarbiat Modares University, Tehran

2 Water Management and Engineering Department, Collage of Agriculture, Tarbiat Modares University, Tehran, Iran

3 Associate Researcher, Agricultural Engineering Research Institute, Agricultural Research, Education and Extension Organization, Karaj, Alborz, Iran

4 4. PhD Student, Water Management and Engineering Department, Collage of Agriculture, Tarbiat Modares University, Tehran, Iran


The Crop coefficient (Kc) is one of the most important parameters in irrigation scheduling. The purpose of this study is to determine silage maize Kc under different irrigation levels using the soil water balance method and presenting the equations for estimating silage maize crop coefficients in terms of the days after sowing during the summer growing season in the Varamin region. The Kc was calculated from the division of actual evapotranspiration (ETa) to reference evapotranspiration (ETo). Soil water balance equation was used to determine silage maize ETa during the growing season. An experiment in the form of split-strip plots based on a randomized complete block design with three replications was conducted in 2019. The main factor included three levels of irrigation, supplying 100, 80, and 60% of maize water requirement (I1, I2, and I3, respectively) and the sub-main factor included two types of irrigation management: pulsed (P) and continuous (C). The value of ETa calculated from the soil water balance method for different treatments ranged from 319.6 to 242.5 mm. Also, the value of irrigation depth during the growing season for full and deficit irrigation treatments ranged from 325 to 195 mm. The mean values of silage maize crop coefficient for initial, middle and final growing stages of full irrigation treatments were 0.27, 1.04, and 0.89, respectively. The water stress coefficients were calculated for deficit irrigation treatments during the growing season. Statistical analysis between ETc calculated from Kc values obtained from the proposed equation in this study and Ks values and Eta obtained from the water balance method indicated that the proposed Kc equation and Ks values in this study have good accuracy in the research area. Therefore, the extracted Ks and proposed Kc equations can be used to estimate silage maize evapotranspiration in the studied region with good accuracy.


Alijan, B., Karimi, A., Farhadi, B., and Broumandnasab, S. (2011). Determining Maize Water Requirement and Crop Coefficient using Water Balance Method.  4th Iran Water Resources Management Conference, Tehran, AmirKabir University. (In Farsi)
Allen R.G., Pereira L.S., Raes D and Smith M. 1998. Crop evapotranspiration. Guidelines for Computing Crop Water Requirements. FAO Irrigation Drainage Paper No. 56, FAO. Rome, Italy. pp 1-326.
Azari, A., Broumandnasab, S., Behzad, M., and Moeiri, M. (2007). Assessing Mazie Yield under T-Tape Drip Irrigation System.  The Scientific Journal of Agriculture, 30(2), 82-87.
Azizi-Zohan, A., A. A. Kamgar-Haghighi, and A. R. Sepaskhah. "Crop and pan coefficients for saffron in a semi-arid region of Iran." Journal of Arid Environments 72, no. 3 (2008): 270-278.
Bafkar, A., Farhadi, B., and Karimi, A. R. (2013). Estimation of crop coefficients (KC) of grain corn SC 704 using the physiological properties (Case study: Kermanshah-Mahidsht). (In Farsi)
Bandyopadhyay, P. K., and Mallick, S. (2003). Actual evapotranspiration and crop coefficients of wheat (Triticum aestivum) under varying moisture levels of humid tropical canal command area. Agricultural water management59(1), 33-47.
Benli, B., Kodal, S., Ilbeyi, A., and Ustun, H. (2006). Determination of evapotranspiration and basal crop coefficient of alfalfa with a weighing lysimeter. Agricultural water management, 81(3), 358-370.
Doorenbos, J. (1977). Guidelines for predicting crop water requirements. FAO irrigation and drainage paper, 24, 1-179.
Edalatnasab M. 2002. Fertilizer prices reduces the profits of wheat. Iranian Journal. 19th years. 5496: 24-25. (In Farsi)
Eric, S., David, S., and Robert, H. (2004). To pulse or not to pulse drip irrigation that is the question UF/IFAS. Horticultural Sciences Department, Florida.
Gao, Y., Duan, A., Sun, J., Li, F., Liu, Z., Liu, H., and Liu, Z. (2009). Crop coefficient and water-use efficiency of winter wheat/spring maize strip intercropping. Field Crops Research111(1-2), 65-73.
Ghamarnia H., Jafari Zadeh M., Miri E., and Eghbal Ghobadi E. 2002. Coriandrum sativum L. crop coefficient determination in a semi-arid climate. Journal of Water and Irrigation Management. 1(2): 73-83. (in Persian with English abstract). (In Farsi)
Gong, X., Qiu, R., Sun, J., Ge, J., Li, Y., and Wang, S. (2020). Evapotranspiration and crop coefficient of tomato grown in a solar greenhouse under full and deficit irrigation. Agricultural Water Management235, 106154.
Gupta, A., Rao, K. V. R., Singh, S., Soni, K., and Sawant, C. (2019). Water productivity and yield of baby corn (Zea mays L.) as influenced by irrigation levels under subsurface drip irrigation. Int. J. Chem. Stud, 7, 128-135.
Igbadun, H. E., and Salim, B. A. (2011). Field-based crop coefficients (Ke) for a maize crop under deficit irrigation scheduling. Nigerian Journal of Technological Development8(2), 74-91.
Kar, G., Kumar, A., & Martha, M. (2007). Water use efficiency and crop coefficients of dry season oilseed crops. Agricultural water management, 87(1), 73-82.
Kerdabadi, M. G., Noory, H., and Liaghat, A. M. (2016). Investigating the effect of soil texture and fertility on evapotranspiration and crop coefficient of maize forage. Journal of Water and Soil, 30(2), 459-471. (In Farsi)
Li, Y. L., Cui, J. Y., Zhang, T. H., and Zhao, H. L. (2003). Measurement of evapotranspiration of irrigated spring wheat and maize in a semi-arid region of north China. Agricultural Water Management61(1), 1-12.
Miranda, F. D., Gondim, R. S., and Costa, C. A. G. (2006). Evapotranspiration and crop coefficients for tabasco pepper (Capsicum frutescens L.). Agricultural Water Management, 82(1-2), 237-246.
Mohammadi, S., Mirlatifi, S. M., Homaee, M., Dehghanisanij, H., and Hajirad, I. (2021). Determination of Silage Maize Crop Coefficient under Pulsed Drip Irrigation using Water Balance Method in Varamin. Iranian Journal of Soil and Water Research, 52(5), 1223-1237. (In Farsi)
Mohammadi, S., Mirlatifi, S. M., Homaee, M., Dehghanisanij, H., and Hajirad, I. (2019). The Conversion of Permittivity Measured by a PR2/6 into Volumetric Soil Moisture Content in a Loamy Soil under Field Calibration. The 1st International and 4th National Congress on Iranian Irrigation and Drainage, 13-14 Nov, 2019, Urmia University, Iran, pp, 1-9. (In Farsi)
Payero, J. O., Tarkalson, D. D., Irmak, S., Davison, D., and Petersen, J. L. (2008). Effect of irrigation amounts applied with subsurface drip irrigation on corn evapotranspiration, yield, water use efficiency, and dry matter production in a semiarid climate. Agricultural water management, 95(8), 895-908.
Piccinni, G., Ko, J., Marek, T., and Howell, T. (2009). Determination of growth-stage-specific crop coefficients (KC) of maize and sorghum. Agricultural water management96(12), 1698-1704.
Rasool, G., Guo, X., Wang, Z., Ullah, I., and Chen, S. (2020). Effect of two types of irrigation on growth, yield and water productivity of maize under different irrigation treatments in an arid environment. Irrigation and Drainage, 69(4), 732-742.
Sepaskhah, A. R., Tavakoli, A. R., and Mousavi, S. F. (2006). Principles and application of deficit irrigation. National Committee on Irrigation and Drainage of Iran, 288p. (In Farsi)
Williams, L. E., and Ayars, J. E. (2005). Grapevine water use and the crop coefficient are linear functions of the shaded area measured beneath the canopy. Agricultural and Forest Meteorology, 132(3-4), 201-211.