3
is becoming critical in the arid and semiarid areas of the world (Forouzani and
Karami 2011). A general perception has been existed worldwide that agricultural
water as the major user, is often wasteful and has less value, compared to other uses
(Jury and Vaux 2006). Furthermore, irrigation consumes a significant amount of
energy, compared to other operations (Topak et al. 2010). In addition, rapid urbanization has caused conflict between the need for freshwater in agriculture and other
sectors. Consequently, fresh water resources available to agriculture will need to be
re-rationalized to satisfy the developmental needs of other sectors (Chai et al. 2016).
Increasing the effective use of water resources in many parts of the world is required
to enhance food security, where availability of water for food production becomes
more acute (FAO 2012). Globally, 40% of annual food production comes from irrigated land, which consumes 70% of all fresh water withdrawals (FAO 2007).
Applying irrigation to cultivated crops is crucial to attain stable agricultural production, where the supply of water to crops done by artificial means. Irrigation also
aids crop intensification and diversification in dry land areas thereby permitting
multiple cropping per year (two to four crops) (Vlek et al. 2008). Furthermore, other
intensification inputs, namely fertilizers and agricultural chemical are provided by
irrigation (Kögler and Söffker 2017). Surface irrigation is still the most widely used
technique despite its relatively poor application efficiency, which may cause water
logging. Water logging is the saturation of the root zone with water that leads to
reduced aeration, nutrient uptake, crop growth, and yield, carbon dioxide accumulates to a toxic level results in crop failure (Vlek et al. 2008). Furthermore, current
rates of agricultural water use are unsustainable in many parts of the world, generating an urgent need to improve its management strategies (Lopez et al. 2017). Thus,
irrigation water management in the current era of water scarcity need to be conducted most efficiently, aiming at saving water and maximizing its productivity
(Johnson et al. 2001).
The sustainable water management concept refers to all practices that improve
crop yield, and minimize non-beneficial water losses (Johnson et al. 2001).
Additionally, improving irrigation water use efficiency, namely the ratio of consumed water to crop yield (Stanhill 1986), and water productivity, namely the ratio
of applied water to crop yield (Kumar et al. 2010) are significant to attain the sustainability of water resources. This goal could be achieved through improved management practices on farm level using appropriate methods of irrigation scheduling.
Irrigation scheduling is a process used to determine the amount of water applied to
the crop and the timing for application; as it determines seasonal irrigation volume
and crop yield (Fernandez and Cuevas 2010). Tanner and Sinclair (1983) stated that
the primary aim of irrigation scheduling is to minimize wasteful losses of water
(percolation beyond what is necessary for salt leaching, surface runoff and evaporation) and maximize transpiration, which is the beneficial loss of water due to its
direct link with dry matter production. Thus, efficient irrigation scheduling aims to
supply the crop with enough water to ensure optimum production while minimizing
water loss and nutrient leaching (Fernandez and Cuevas 2010).
1 Water Scarcity Leads to Food Insecurity
is becoming critical in the arid and semiarid areas of the world (Forouzani and
Karami 2011). A general perception has been existed worldwide that agricultural
water as the major user, is often wasteful and has less value, compared to other uses
(Jury and Vaux 2006). Furthermore, irrigation consumes a significant amount of
energy, compared to other operations (Topak et al. 2010). In addition, rapid urbanization has caused conflict between the need for freshwater in agriculture and other
sectors. Consequently, fresh water resources available to agriculture will need to be
re-rationalized to satisfy the developmental needs of other sectors (Chai et al. 2016).
Increasing the effective use of water resources in many parts of the world is required
to enhance food security, where availability of water for food production becomes
more acute (FAO 2012). Globally, 40% of annual food production comes from irrigated land, which consumes 70% of all fresh water withdrawals (FAO 2007).
Applying irrigation to cultivated crops is crucial to attain stable agricultural production, where the supply of water to crops done by artificial means. Irrigation also
aids crop intensification and diversification in dry land areas thereby permitting
multiple cropping per year (two to four crops) (Vlek et al. 2008). Furthermore, other
intensification inputs, namely fertilizers and agricultural chemical are provided by
irrigation (Kögler and Söffker 2017). Surface irrigation is still the most widely used
technique despite its relatively poor application efficiency, which may cause water
logging. Water logging is the saturation of the root zone with water that leads to
reduced aeration, nutrient uptake, crop growth, and yield, carbon dioxide accumulates to a toxic level results in crop failure (Vlek et al. 2008). Furthermore, current
rates of agricultural water use are unsustainable in many parts of the world, generating an urgent need to improve its management strategies (Lopez et al. 2017). Thus,
irrigation water management in the current era of water scarcity need to be conducted most efficiently, aiming at saving water and maximizing its productivity
(Johnson et al. 2001).
The sustainable water management concept refers to all practices that improve
crop yield, and minimize non-beneficial water losses (Johnson et al. 2001).
Additionally, improving irrigation water use efficiency, namely the ratio of consumed water to crop yield (Stanhill 1986), and water productivity, namely the ratio
of applied water to crop yield (Kumar et al. 2010) are significant to attain the sustainability of water resources. This goal could be achieved through improved management practices on farm level using appropriate methods of irrigation scheduling.
Irrigation scheduling is a process used to determine the amount of water applied to
the crop and the timing for application; as it determines seasonal irrigation volume
and crop yield (Fernandez and Cuevas 2010). Tanner and Sinclair (1983) stated that
the primary aim of irrigation scheduling is to minimize wasteful losses of water
(percolation beyond what is necessary for salt leaching, surface runoff and evaporation) and maximize transpiration, which is the beneficial loss of water due to its
direct link with dry matter production. Thus, efficient irrigation scheduling aims to
supply the crop with enough water to ensure optimum production while minimizing
water loss and nutrient leaching (Fernandez and Cuevas 2010).
1 Water Scarcity Leads to Food Insecurity