~ 281 ~ The Pharma Innovation Journal 2020; 9(9): 281-286 ISSN (E): 2277- 7695 ISSN (P): 2349-8242 NAAS Rating: 5.03 TPI 2020; 9(9): 281-286 © 2020 TPI www.thepharmajournal.com Received: 28-06-2020 Accepted: 12-08-2020 Sanjay H Parmar Ph. D Scholar Irrigation and Drainage Engineering, College of Agricultural Engineering and Technology, Anand Agricultural University, Godhra, Gujarat, India Dr. Mukesh K Tiwari Assistant Professor and Head of Department of Irrigation and Drainage Engineering, College of Agricultural Engineering and Technology, Anand Agricultural University, Godhra, Gujarat, India Corresponding Author: Sanjay H Parmar Ph. D Scholar Irrigation and Drainage Engineering, College of Agricultural Engineering and Technology, Anand Agricultural University, Godhra, Gujarat, India Crop water requirement (ETc) of Maize crop of Panchmahal Region of Gujarat Sanjay H Parmar and Dr. Mukesh K Tiwari DOI: https://doi.org/10.22271/tpi.2020.v9.i9d.5124 Abstract Accurate estimation of crop water requirements (ETc) of any crop is essentially for irrigation scheduling and water management. The present study was undertaken to estimate the crop water requirement (ETc) of maize crops grown in winter seasons in middle Gujarat region of Panam command area Gujarat. The daily reference evapotranspiration (ETo) was estimated by FAO Penman-Monteith method using 11 years (2006 to 2016) mean meteorological data of Panam command. The most common and practical approach widely used for estimating crop water requirement, and the operational monitoring of soil-plant water balance is the FAO-56 method. In the FAO-56 approach, crop evapotranspiration is estimated by the combination of a reference evapotranspiration (ETo) and crop coefficients. The Kc values for maize as given in FAO-56 was used in which Kcmid and Kcend were corrected for climatic conditions of stations. The corrected Kc values were used to calculate the daily crop water requirement (ETc) for maize crops grown at Panchmahal region. The results revealed that during winter season (15 October to 15 January) the mean daily (ETo) varies from 5.5 to 7.32 mm day -1 . The mean water requirement of maize during initial stage is 1.085 mm day -1 , during developmental stage it varies between 1.085 to 4.35 mm day-1, and during the mid-season stage ETc varies between 4.35 to 5.76 mm day -1 and during late season stage it decreases upto 3.20 mm day -1 . The seasonal water requirement of winter maize varies between 312.49 mm to 487.08 mm. This study established precise estimation of evapotranspiration which was the only beneficial water loss from the field. The information generated can be used in scheduling irrigation for winter season maize crops of Panchmhal region. Keywords: Evapotranspiration, FAO-56 penman monteith, crop coefficient, maize crop water requirement Introduction Evapotranspiration plays an important role in areas of ecology, hydrology and atmospheric sciences. ET is the second most important element of the hydrological cycle after precipitation because it facilitates the continuation of precipitation by replacing the vapour lost through condensation (Brutsaert, et al., 2009) [3] . ET is also crucial for the transportation of minerals and nutrients required for plant growth; creates a beneficial cooling process to plant canopies in many climates; and influences the Earth’s energy and water balance because of the direct association with latent heat flux (LE). ET consumes large amounts of energy during the conversion of liquid water to vapor, hence playing an important role in hydrology, agriculture, climatology and meteorology. Accurate estimates of ET contribute to improved quantification of the catchment water balance and in the facilitation of decision making for sustainable water resource management (Su, et al., 2002; Allen, et al., 2007 Mu, et al., 2007) [12, 2] . Increasingly higher demands are being placed on water resources each year. With the increasing stress, water resource managers must continually expand methods to assist them in the quantification and allocation of water consumptive use. The quantification of water consumption requires knowledge of the evaporation of water from the earth and plant surfaces as well as how water is consumed by plants by way of transpiration. The combination of these two phenomena, namely surface evaporation and transpiration, are collectively referred to as evapotranspiration. Evapotranspiration (ET) is the largest consumer of irrigated water and quantifying the amount of ET occurring in an area provides water managers a valuable tool for quantifying water consumption. ET is among the most difficult parts of the hydrological cycle to quantify due to the complex interaction between the land surface, vegetation and atmosphere (Xu & Singh 2005; Fang et al. 2012) [14, 6] . ET is also difficult and expensive to measure on an operational basis.