Effects of Temperature and Growing Seasons on Crop Water Requirement:
Implications on Water Savings
* 1ABDULLAH, ABBAS; SHAKHAWAT, CHOWDHURY*
Department of Civil and Environmental Engineering, Water Resources Group, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia; Tel: 966-13-860-2560; Fax: 966-13-860-2879; Email: SChowdhury@kfupm.edu.sa
J. Appl. Sci. Environ. Manage. June. 2016 Vol. 20 (2) 424 – 433 :
ABSTRACT:
Water savings can be improved through reducing agricultural water consumption. The crop water requirement (CWR) depends on several factors including temperature and growing seasons. This study investigated the effects of temperature and growing seasons on CWR in Saudi Arabia. Increase in temperature by 1°C increased the CWR by 1.9 - 2.9%, 1.9 – 3.0% and 2.2 – 3.8% for dates, alfalfa and wheat respectively. Total CWR was estimated to be 8713 million cubic meters in 2011, which showed an increase of 1.8 – 2.9% for 1°C increase in temperature. CWR for wheat was more sensitive to growing seasons than dates and alfalfa. Empirical relationship was developed to predict the effects of growing seasons on CWR for wheat while changes in CWR for dates and alfalfa were not significant. Through shifting growing seasons and minimizing the effects of temperature for the major crops, significant amount of groundwater may be saved, which can reduce the production of costly desalinated water. © JASEM
Keywords: Water resources; conservation; crop water requirement; temperature; growing seasons; policy;
Introduction
Increase in demands for food and energy crops have resulted in an increase in the demand for water around the globe (Rosegrant and Ringler, 2000; Liu et al., 2008). Crop production consumes over 80% of global freshwater supplies (Shiklomanov, 2000). The global water footprint (WFP) for crop production was 7404 billion cubic meters (BCM) per year during 1996– 2005, in which wheat, rice and maize consumed 1087, 992 and 770 Gm3 /yr of water respectively (Mekonnen and Hoekstra, 2010). The WFP for wheat, rice and maize were in the ranges 1805-1868, 1519-2102 and 1101-1229 m3 /ton respectively (Mekonnen and Hoekstra, 2010). The agricultural water demand is affected by the types and amounts of crops, efficiency of cultivation, length and timing of growing seasons and climatic conditions (Hoekstra and Chapagain, 2007). Higher temperature can have higher evaporative demand, leading to additional water requirement for crop production (Allen et al., 1998; Chowdhury and Al-Zahrani, 2013a).
Saudi Arabia produces several crops, including wheat, alfalfa, dates, maize, vegetables, grapes and citrus (SSYB, 2012; MOA, 2012). Recent studies have indicated that the usual practices of cultivation might have detrimental effects on groundwater reserves (AlSheikh, 1998; FAO, 2009). The country has adopted a policy to reduce water withdrawals from the nonrenewable sources by reducing agricultural activities and introducing modern irrigation practices (SSYB, 2012). Past studies have projected the increase of temperature in the ranges of 1.8° - 4.1°C and 2.5° - 5.1°C by 2050 and 2070–2100 respectively, which can increase reference evapotranspiration (ETo) by 10.3 - 27.4% (Al-Zawad, 2008; Chowdhury and Al-Zahrani, 2013a). In addition, crop growing seasons and type of crop can affect water demands (Allen et al., 1998; AlSheikh, 1998). For example, water demands for wheat, vegetables and fodder crops in Saudi Arabia were 13173, 18000 and 39000 m3 per hectare respectively (Al-Sheikh. 1998). Al-Omran and Shalaby, (1992) estimated CWR for wheat, maize, tomato, citrus and dates in the Eastern and Central regions of Saudi Arabia as 883, 751, 1703, 2259 and 4021 mm/yr respectively. In the Wadi Sirhan, Al-Jouf (Saudi Arabia), Saifuddin et al., (2004) reported CWR for alfalfa, potato and wheat as 34864, 6522 and 6473 m3 /ha/season respectively. CWR for millet, wheat, maize and alfalfa in Makkah were 728, 519, 453 and 1923 mm/yr respectively (Hashim et al., 2012).
Understanding of the effects of temperature and growing seasons on CWR is important to manage water resources. This paper aims to analyze the effects of temperature and growing seasons on CWR for crops in different regions of Saudi Arabia. The growing seasons of the main crops were differed and CWR were predicted. Effects of such shifts were estimated. Empirical relationship was developed for water savings in producing wheat.
Full Text
ليست هناك تعليقات:
إرسال تعليق