Water-Saving Agricultural Technologies: Comparison
Please note this is a comparison between Version 2 by Vivi Li and Version 1 by Mohammad Abdul Mojid.

Increasing food demand has exerted tremendous stress on agricultural water usages worldwide, often with a threat to sustainability in agricultural production and, hence, food security. Various resource-conservation technologies like conservation agriculture (CA) and water-saving measures are being increasingly adopted to overcome these problems. While these technologies provide some short- and long-term benefits of reduced labor costs, stabilized or increased crop yield, increased water productivity, and improved soil health at farm scale, their overall impacts on hydrology outcomes remain unclear at larger temporal and spatial scales. Although directly linked to the regional hydrological cycle, irrigation remains a less understood component. The ecological conditions arising from the hydrology outcomes of resource-conservation technologies are associated with sustainability in agricultural production.

  • irrigation management
  • rice
  • percolation
  • scale effects
  • hydrologic cycle

1. Introduction

The global demand for food, energy and water by the ever-growing population has been forecasted to increase by 50%, 50% and 30%, respectively, in 2030 compared to 2012 [1]; in the same base period, food demand will increase by 70% to 100% by 2050 [2]. The Indo-Gangetic Plains (IGP) comprising more than 250 Mha of area across Bangladesh, India, Pakistan and southern Nepal have over 100 Mha of agricultural land and host over 750 million people [3]. The Lower Gangetic Plain, called the Eastern Gangetic Plain (EGP), comprises the adjoining states of Bihar and northern West Bengal in North-eastern India, the North-West of Bangladesh and the Terai plains of Nepal (

Figure 1). The EGP is characterized by the world’s highest density of rural poor, persistent yield gaps, low agricultural productivity, limited crop diversification, ample water resources [4,5], and highly fertile lands [6,7] of agricultural importance [8]. The region is therefore a global priority for sustainably increasing food production [9].

). The EGP is characterized by the world’s highest density of rural poor, persistent yield gaps, low agricultural productivity, limited crop diversification, ample water resources [4][5], and highly fertile lands [6][7] of agricultural importance [8]. The region is therefore a global priority for sustainably increasing food production [9].

Figure 1.

 Location and area map of the Eastern Gangetic Plain (EGP) region.

Agricultural productivity is critically dependent on the availability of water. Adequate water supply significantly increases crop productivity [10,11] by introducing high yielding crop varieties, a better cropping pattern, and increasing cropping intensity [12]. Compared to rain-fed agriculture, irrigated agriculture produces two to four times more crop yields [13]. This contribution of irrigation increased global irrigated land by 76% between 1970 and 2012 [14]; the reliance of agricultural production on irrigation is expected to further increase in the future [15]. Farmers’ capacity to access and use water is a major driving factor in obtaining the best yield and hence is an important variable for the food security index [16]. However, the growing competition for water by various sectors will affect farmers’ ability to produce food [17,18]. So, making food production sustainable, while conserving diminishing water supplies, will be a great challenge in the future [19].

Agricultural productivity is critically dependent on the availability of water. Adequate water supply significantly increases crop productivity [10][11] by introducing high yielding crop varieties, a better cropping pattern, and increasing cropping intensity [12]. Compared to rain-fed agriculture, irrigated agriculture produces two to four times more crop yields [13]. This contribution of irrigation increased global irrigated land by 76% between 1970 and 2012 [14]; the reliance of agricultural production on irrigation is expected to further increase in the future [15]. Farmers’ capacity to access and use water is a major driving factor in obtaining the best yield and hence is an important variable for the food security index [16]. However, the growing competition for water by various sectors will affect farmers’ ability to produce food [17][18]. So, making food production sustainable, while conserving diminishing water supplies, will be a great challenge in the future [19].

The Ganges basin has a tropical climate, with a distinct wet monsoon (June–September) and a dry winter (November–February); the summer is characteristically hot and humid. Except for the East and North-East hilly regions of the basin where annual rainfall often exceeds 4000 mm, the average annual rainfall in most other parts is 1500 mm. The rainfall is mostly concentrated in the monsoon season and the winter is almost rainless [20] but the main cropping season. In many parts of the IGP, agricultural drought and other climatic shocks severely affect crop production, thus, necessitating an adequate water supply to stabilize agricultural production [21,22]. Surface water is inadequate in the dry season, but groundwater plays a vital role in sustaining agricultural productivity. In India, 60% of the agricultural water requirement is satisfied from groundwater, covering over 50% of the irrigated area [23]; in Bangladesh, the corresponding quantities are 79% and 85% [24]. Of the many factors now threatening sustainability in agricultural productivity, water is the most crucial [25,26,27,28,29,30,31,32,33] since, without further improvement in water productivity, the amount of water needed for crop agriculture is predicted to increase by 70–90% by 2050 [34].

The Ganges basin has a tropical climate, with a distinct wet monsoon (June–September) and a dry winter (November–February); the summer is characteristically hot and humid. Except for the East and North-East hilly regions of the basin where annual rainfall often exceeds 4000 mm, the average annual rainfall in most other parts is 1500 mm. The rainfall is mostly concentrated in the monsoon season and the winter is almost rainless [20] but the main cropping season. In many parts of the IGP, agricultural drought and other climatic shocks severely affect crop production, thus, necessitating an adequate water supply to stabilize agricultural production [21][22]. Surface water is inadequate in the dry season, but groundwater plays a vital role in sustaining agricultural productivity. In India, 60% of the agricultural water requirement is satisfied from groundwater, covering over 50% of the irrigated area [23]; in Bangladesh, the corresponding quantities are 79% and 85% [24]. Of the many factors now threatening sustainability in agricultural productivity, water is the most crucial [25][26][27][28][29][30][31][32][33] since, without further improvement in water productivity, the amount of water needed for crop agriculture is predicted to increase by 70–90% by 2050 [34].

Several resource-conservation technologies like minimum tillage, no/zero-tillage, direct-seeding, bed-planting, laser land-leveling and residue retention [35,36,37], and water-saving technologies like alternate wetting and drying (AWD) and deficit irrigation methods have been developed over the past three decades and are being practiced in many parts of the world, including the EGP. In addition to the benefits from the conserved resources, these technologies can also change crop-water use and the regional water cycle [38] with negative impact on groundwater dynamics [39]. They save water by reducing water application in the fields, with resulting lower percolation and groundwater recharge. Large-scale adoption of these technologies can therefore lead to significant decline in groundwater levels [40,41,42], with possible degradation of soil quality and damage of vegetation [43]. In many parts of the EGP, groundwater level has declined significantly, and is now threatening sustainable water supply for irrigation and drinking [44,45,46,47,48,49] with resulting negative impacts on the economy, society and environment [50,51,52,53]. Although less than one-third of the IGP has experienced declining groundwater levels [54] the situations in high-population centers (e.g., Dhaka city) and other stressed areas (e.g., the Barind area) are potentially alarming [49].

Several resource-conservation technologies like minimum tillage, no/zero-tillage, direct-seeding, bed-planting, laser land-leveling and residue retention [35][36][37], and water-saving technologies like alternate wetting and drying (AWD) and deficit irrigation methods have been developed over the past three decades and are being practiced in many parts of the world, including the EGP. In addition to the benefits from the conserved resources, these technologies can also change crop-water use and the regional water cycle [38] with negative impact on groundwater dynamics [39]. They save water by reducing water application in the fields, with resulting lower percolation and groundwater recharge. Large-scale adoption of these technologies can therefore lead to significant decline in groundwater levels [40][41][42], with possible degradation of soil quality and damage of vegetation [43]. In many parts of the EGP, groundwater level has declined significantly, and is now threatening sustainable water supply for irrigation and drinking [44][45][46][47][48][49] with resulting negative impacts on the economy, society and environment [50][51][52][53]. Although less than one-third of the IGP has experienced declining groundwater levels [54] the situations in high-population centers (e.g., Dhaka city) and other stressed areas (e.g., the Barind area) are potentially alarming [49].

Agriculture in the IGP is mostly dominated by irrigated rice–wheat systems, which cover 13.5 Mha and play a crucial role in the food security and livelihoods of millions of people [37,55,56]. In Bangladesh and West Bengal, rice is produced on 6.05 Mha and 5.5 Mha, respectively [57]. Both mechanized and tillage-based traditional agriculture and transplanted rice cultivation with flood irrigation requiring a huge quantity of water [58,59,60] are a major challenge in agriculture, in order to maintain or increase rice production. Shifting current agriculture to water-efficient ones [61,62,63,64,65] would conserve water from being wasted through unintended purposes and make considerable water savings [66,67,68,69] to face the challenge. Conversion of conventional agriculture to resource-conservation ones [70,71,72] using resource-conservation technologies and water-saving measures has been demonstrated as of particular interest in this regard [29,73,74,75,76].

Agriculture in the IGP is mostly dominated by irrigated rice–wheat systems, which cover 13.5 Mha and play a crucial role in the food security and livelihoods of millions of people [37][55][56]. In Bangladesh and West Bengal, rice is produced on 6.05 Mha and 5.5 Mha, respectively [57]. Both mechanized and tillage-based traditional agriculture and transplanted rice cultivation with flood irrigation requiring a huge quantity of water [58][59][60] are a major challenge in agriculture, in order to maintain or increase rice production. Shifting current agriculture to water-efficient ones [61][62][63][64][65] would conserve water from being wasted through unintended purposes and make considerable water savings [66][67][68][69] to face the challenge. Conversion of conventional agriculture to resource-conservation ones [70][71][72] using resource-conservation technologies and water-saving measures has been demonstrated as of particular interest in this regard [29][73][74][75][76].

When water is applied in a crop field, not all of it is consumed as illustrated in 

Figure 2. The local surface and sub-surface hydrological systems retain a considerable portion of the applied water, which might be reusable later by other users. Consequently, irrigation has a direct link to the regional hydrological cycle, especially in areas with shallow groundwater [54]. A large part of the applied irrigation water infiltrates below the root zone and is stored in the underlying aquifer [7,43] or in downstream surface water bodies. 

. The local surface and sub-surface hydrological systems retain a considerable portion of the applied water, which might be reusable later by other users. Consequently, irrigation has a direct link to the regional hydrological cycle, especially in areas with shallow groundwater [54]. A large part of the applied irrigation water infiltrates below the root zone and is stored in the underlying aquifer [7][43] or in downstream surface water bodies. 

 conceptualizes the flow paths of the components of water from a rice field under conventional flood irrigation with pumped groundwater. The percolated water is perceived as lost by the farmers and irrigation practitioners [77] but is a gain to the local surface and sub-surface hydrological systems. The efficiency of water usage at any separate component (e.g., crop fields, ponds) within the hydrological system may be low, but the overall efficiency of the entire system can be much higher than in the individual components. So, the general concept of water use efficiency undervalues the real efficiency of the whole hydrological system. Water recycling must be integrated into the concept of water-use efficiency to develop new realistic concepts [78]. The water flux exchanging between the aquifer and vadoze zone greatly controls the dynamics of the groundwater table [39] thus raising a valid question of how the currently advocated water-saving measures impact on the hydrological cycle of a groundwater basin. Do these water-saving measures assure proper utilization of groundwater reserves? In situations where downstream aquifers and surface water bodies are fed from upstream aquifers, what will be the effects of the water-saving measures on these downstream water resources (

)? These important issues have not yet been investigated critically on the system level; only some field-scale studies have investigated the possibilities, which are also contrasting in nature. A summary of the major previous studies assessing the impacts of various agricultural water-saving technologies on local and regional hydrology is presented in 

. In light of this short-coming, this paper comprehensively reviewed the available literature to evaluate the present state of knowledge and emerging knowledge-gaps on this subject so as to guide future research on this topic. Note that since rice-based cropping systems dominate the agricultural landscape of the EGP [56], this study focuses on the exchange of water flux between irrigated rice fields and the underlying aquifers. The paper is structured into five major sections in addition to an introduction and a concluding section. The benefits and impacts of conservation agriculture have been reviewed in the second section. The third section highlights the complementary and contemporary meanings of water saving while the fourth section addresses the impacts of agricultural water-saving methods on regional hydrology outcomes (i.e., links between various components of the regional hydrological cycle). The next section identifies current knowledge gaps in the key water-saving issues, including scale-effects and policy, before an overall summary and concluding section on water-saving measures and regional hydrology outcomes.

Figure 2.

 Utilization and fate of applied water to crop fields and hydrological links to groundwater resources.

Figure 3.

 The pathways of the components of water from a rice field under conventional irrigation with groundwater.

2. Agricultural Water–Saving

2.1. Water-Saving Measures

Water-saving irrigation, groundwater regulation, shifts to rain-fed agriculture, artificial recharge to groundwater, rainwater preservation, virtual water imports and indirect approaches like energy pricing and regulation are the currently available measures to reduce regional water use [134,180]. However, appropriate water-accounting is essential to identify the scope of these water-saving practices [181]. Based on the approach of reducing evaporation, runoff losses, and the extent of free water on the soil surface [182] irrigation strategies like shallow water depth associated with wetting and drying [183,184], alternate wetting and drying, AWD [108,124,185,186], semi-drying [187], aerobic rice cultivation [188,189], partial root-zone drying [190], and non-flooded mulching [191] are being practiced in different rice-growing regions. The AWD technique allows the soil to dry for a certain pre-determined number of days after depletion of the standing water in the field before the next irrigation [192]. The multiple-shallow irrigation method (1–3 cm irrigation applied frequently) can efficiently utilize rainfall and reduce percolation and surface runoff [94]. In the aerobic cultivation method, rice is grown in well-drained dry soils with supplementary irrigation, as with upland crops [188]. Furrow irrigation with raised beds, mulching, conservation tillage, deficit irrigation [193,194,195] and improved weed control can also achieve substantial water-saving.

Water-saving irrigation, groundwater regulation, shifts to rain-fed agriculture, artificial recharge to groundwater, rainwater preservation, virtual water imports and indirect approaches like energy pricing and regulation are the currently available measures to reduce regional water use [79][80]. However, appropriate water-accounting is essential to identify the scope of these water-saving practices [81]. Based on the approach of reducing evaporation, runoff losses, and the extent of free water on the soil surface [82] irrigation strategies like shallow water depth associated with wetting and drying [83][84], alternate wetting and drying, AWD [85][86][87][88], semi-drying [89], aerobic rice cultivation [90][91], partial root-zone drying [92], and non-flooded mulching [93] are being practiced in different rice-growing regions. The AWD technique allows the soil to dry for a certain pre-determined number of days after depletion of the standing water in the field before the next irrigation [94]. The multiple-shallow irrigation method (1–3 cm irrigation applied frequently) can efficiently utilize rainfall and reduce percolation and surface runoff [95]. In the aerobic cultivation method, rice is grown in well-drained dry soils with supplementary irrigation, as with upland crops [90]. Furrow irrigation with raised beds, mulching, conservation tillage, deficit irrigation [96][97][98] and improved weed control can also achieve substantial water-saving.

2.2. Apparent and Actual Water-Saving

The impact of efficiency of water consumption and water productivity on water-saving has been investigated at field scale on several occasions e.g., [196,197,198,199,200]. Any effort toward improving irrigation efficiency is valuable [201], but the commonly used concepts of water-use efficiency underestimate the system-level’s actual efficiency [78]. The actual fraction of the applied water that is used efficiently at a regional scale has not yet been quantified; current measurement methods are inadequate for such quantification.

The impact of efficiency of water consumption and water productivity on water-saving has been investigated at field scale on several occasions e.g., [99][100][101][102][103]. Any effort toward improving irrigation efficiency is valuable [104], but the commonly used concepts of water-use efficiency underestimate the system-level’s actual efficiency [78]. The actual fraction of the applied water that is used efficiently at a regional scale has not yet been quantified; current measurement methods are inadequate for such quantification.

All the water applied in the crop/rice fields ends up at any of, or a combination of, consumptive use, non-consumptive use, non-recoverable flow (

Figure 2), and change in storage [95]. These water use-terms allow a clearer definition of various issues and options for water usage in irrigated agriculture. Water-saving through a resource-conservation technology refers to a narrow local perspective of water application by reducing percolation rates, as conceptualized in 

), and change in storage [105]. These water use-terms allow a clearer definition of various issues and options for water usage in irrigated agriculture. Water-saving through a resource-conservation technology refers to a narrow local perspective of water application by reducing percolation rates, as conceptualized in 

. This water-saving does not account for return flows from the irrigated field that may be either non-recoverable outflow (e.g., to saline or otherwise polluted groundwater or surface water as schematized in 

Figure 5) or recoverable outflow, where it ends up in rivers or as useable groundwater source [94,95]. The return flow may be a significant contributor to groundwater recharge [131,202,203,204].

) or recoverable outflow, where it ends up in rivers or as useable groundwater source [95][105]. The return flow may be a significant contributor to groundwater recharge [106][107][108][109].

Figure 4.

 Conceptualizing of impacts of water-saving measures on regional surface and groundwater sources when irrigation uses groundwater.

Figure 5.

Water loss and water saving issues under conventional and water-saving irrigation from surface water sources when underground aquifer contains polluted water (e.g., saline water).

Due to various natural calamities (e.g., seasonal storms, hailstorms, cyclonic storms, heavy rainfall and floods), dry season is the main and safe cropping season in the EGP, which has an annually renewable groundwater system. Here irrigation is predominantly done with groundwater; 79% of total irrigation in Bangladesh and more than 90% of irrigation in North-West India uses groundwater. An individual farmer considers the combined outflow of water by evapotranspiration, seepage and percolation as water usage by his/her rice field and hence actual water loss in the field. However, when considering a large spatial scale, achieving water-saving by one user may be a loss to another since the seepage and percolation from one’s field enter the underlying aquifer or nearby surface water sources, from where others can reuse the water [75,103] causing no net loss to the system [205,206]. The real water-saving occurs only when the non-recoverable non-usable water losses (

Due to various natural calamities (e.g., seasonal storms, hailstorms, cyclonic storms, heavy rainfall and floods), dry season is the main and safe cropping season in the EGP, which has an annually renewable groundwater system. Here irrigation is predominantly done with groundwater; 79% of total irrigation in Bangladesh and more than 90% of irrigation in North-West India uses groundwater. An individual farmer considers the combined outflow of water by evapotranspiration, seepage and percolation as water usage by his/her rice field and hence actual water loss in the field. However, when considering a large spatial scale, achieving water-saving by one user may be a loss to another since the seepage and percolation from one’s field enter the underlying aquifer or nearby surface water sources, from where others can reuse the water [75][110] causing no net loss to the system [111][112]. The real water-saving occurs only when the non-recoverable non-usable water losses (

Figure 2) are eliminated or reduced. Avoidance of peak evaporative demand, use of short-duration varieties, cultivating less water-demanding crops, and changing from ponded to non-ponded rice culture are the potential technologies for reducing evapotranspiration [205,206,207]. The practicability and effects of technologies on crop yields must, however, be investigated before their large-scale field adoption.

) are eliminated or reduced. Avoidance of peak evaporative demand, use of short-duration varieties, cultivating less water-demanding crops, and changing from ponded to non-ponded rice culture are the potential technologies for reducing evapotranspiration [111][112][113]. The practicability and effects of technologies on crop yields must, however, be investigated before their large-scale field adoption.

Modifications of the water balance components by resource-conservation technologies, the fate of water saved through reduced application, and hydrologic interactions across spatial scales determine whether any reduction in water application leads to actual water-saving and reduces water usage [75]. Farmers always intend to achieve maximum output from the water resource, leading them to utilize as much water as they can have access to. Society, on the other hand, prefers utilizing scarce water to maximize profits by shifting water from agriculture to high-value economic sectors. The goals of the two entities in utilizing the scarce water are clearly opposing, and therefore appropriate terminology to describe real water-saving remains a central issue of debate [95].

Modifications of the water balance components by resource-conservation technologies, the fate of water saved through reduced application, and hydrologic interactions across spatial scales determine whether any reduction in water application leads to actual water-saving and reduces water usage [75]. Farmers always intend to achieve maximum output from the water resource, leading them to utilize as much water as they can have access to. Society, on the other hand, prefers utilizing scarce water to maximize profits by shifting water from agriculture to high-value economic sectors. The goals of the two entities in utilizing the scarce water are clearly opposing, and therefore appropriate terminology to describe real water-saving remains a central issue of debate [105].

Interactions between non-agricultural and agricultural water usages are scale-dependent and play a major role in water-saving [208]. At basin scale, the main interest is to reduce water usage in irrigated agriculture and transfer water to other higher-valued usages. This again implies that actual water-saving can be achieved only by reducing evaporation and water-flows to non-recoverable sinks [107]. The basin approach, instead of paying attention to individual water usage, assesses return flows, estimates water-use efficiencies at field- and basin-scales and differentiates consumptive water-saving from non-consumptive saving (

Interactions between non-agricultural and agricultural water usages are scale-dependent and play a major role in water-saving [114]. At basin scale, the main interest is to reduce water usage in irrigated agriculture and transfer water to other higher-valued usages. This again implies that actual water-saving can be achieved only by reducing evaporation and water-flows to non-recoverable sinks [115]. The basin approach, instead of paying attention to individual water usage, assesses return flows, estimates water-use efficiencies at field- and basin-scales and differentiates consumptive water-saving from non-consumptive saving (

Figure 2) while accounting for water and analyzing water-use efficiencies [209,210,211,212,213]. Despite many complexities in perceptions of water-saving, its ultimate objectives are clear and undisputable: to stop unsustainable exploitation of the available water resources and to increase the quantity of water for other essential and more beneficial usages. It is therefore essential to understand the scale-effects of water usage clearly to improve water-savings and water productivity [124,210,214,215,216].

) while accounting for water and analyzing water-use efficiencies [116][117][118][119][120]. Despite many complexities in perceptions of water-saving, its ultimate objectives are clear and undisputable: to stop unsustainable exploitation of the available water resources and to increase the quantity of water for other essential and more beneficial usages. It is therefore essential to understand the scale-effects of water usage clearly to improve water-savings and water productivity [86][117][121][122][123].

2.3. Impacts on Water Use

AWD effect: Irrigation management through alternate wetting and drying is widely practiced in many countries/regions like the Philippines, Vietnam, China and EGP [217,218,219,220]. Under AWD, the percolation rate decreases leading to water-saving; the reduction in evapotranspiration plays only a minimal role [221]. Compared to the continuous standing water rice system, the levels of water-saving by the AWD method are listed in 

AWD effect: Irrigation management through alternate wetting and drying is widely practiced in many countries/regions like the Philippines, Vietnam, China and EGP [124][125][126][127]. Under AWD, the percolation rate decreases leading to water-saving; the reduction in evapotranspiration plays only a minimal role [128]. Compared to the continuous standing water rice system, the levels of water-saving by the AWD method are listed in 

Table 3. Percolation from the crop fields controls the transport of nitrate [94], heavy metals [222], salts [223], nutrients [224], and pesticides [225] to groundwater. So, with reduced percolation the quality of groundwater remains under safeguard. The AWD method also reduces greenhouse gas emission [226,227], uptake of arsenic in rice grain [228,229], the cost of pumping water [230,231], and concentration of methyl mercury in field soil [232].

. Percolation from the crop fields controls the transport of nitrate [95], heavy metals [129], salts [130], nutrients [131], and pesticides [132] to groundwater. So, with reduced percolation the quality of groundwater remains under safeguard. The AWD method also reduces greenhouse gas emission [133][134], uptake of arsenic in rice grain [135][136], the cost of pumping water [137][138], and concentration of methyl mercury in field soil [139].

Table 3.

 Levels of water-saving by alternate wetting and drying (AWD) method compared to the continuous standing water rice system.

Type of Effect Quantity References
Water saving 23% [108][85]
Water saving 15–40% [109,[140] 110,111,221,233][141][142][128][143]
Water saving 30–60% [112][144]
Percolation reduction 50–80% [112][144]
Percolation reduction 19–28% [60]
Bund effect: An unsaturated zone beneath standing water and a higher hydraulic conductivity zone beneath the bunds in rice fields are developed. This causes the applied irrigation water to move through the bunds and recharges the underlying aquifer [234]. The destinations of the applied irrigation water in the rice fields were measured on several occasions e.g., [205,235,236,237,238] and a significant portion was reported to percolate through the field boundaries. This type of lateral seepage flow field is horizontal first and then vertical below the bunds [239]. Often rice fields of irregular shape are transformed into regular rice fields in order to improve irrigation efficiency, keeping part of the previously generated plow pan beneath the bunds of the reformed rice field [234]. Consequently, the dominant movement of water is in the horizontal direction through the bund. The seepage flux is, however, much less than the deep percolation rate [239,240,241] except when rice is cultivated on terraced fields, where the seepage water moves to the downstream plots through the bunds [239]. In flat rice fields, the infiltration rate below the bunds remains close to the average infiltration rate for the crop field with plow pan beneath the bunds, but may double or more without plow pan beneath the bunds [205,239]. [234] demonstrated 50% of water lost through the bunds, 25% through evapotranspiration, and 25% equally through infiltration providing an estimated annual water loss of 41 km

Bund effect: An unsaturated zone beneath standing water and a higher hydraulic conductivity zone beneath the bunds in rice fields are developed. This causes the applied irrigation water to move through the bunds and recharges the underlying aquifer [145]. The destinations of the applied irrigation water in the rice fields were measured on several occasions e.g., [111][146][147][148][149] and a significant portion was reported to percolate through the field boundaries. This type of lateral seepage flow field is horizontal first and then vertical below the bunds [150]. Often rice fields of irregular shape are transformed into regular rice fields in order to improve irrigation efficiency, keeping part of the previously generated plow pan beneath the bunds of the reformed rice field [145]. Consequently, the dominant movement of water is in the horizontal direction through the bund. The seepage flux is, however, much less than the deep percolation rate [150][151][152] except when rice is cultivated on terraced fields, where the seepage water moves to the downstream plots through the bunds [150]. In flat rice fields, the infiltration rate below the bunds remains close to the average infiltration rate for the crop field with plow pan beneath the bunds, but may double or more without plow pan beneath the bunds [111][150]. [145] demonstrated 50% of water lost through the bunds, 25% through evapotranspiration, and 25% equally through infiltration providing an estimated annual water loss of 41 km

3

through percolation underneath the bunds of rice fields in Bangladesh. Based on this field scale estimate, sealing of bunds (e.g., by puddling) can reduce seasonal water use by 52 ± 17%. Much greater savings (~90%) can be achieved in the fields with larger perimeter-to-area ratio.

Puddling effect: Puddling eliminates large pores and alters the field soils to stratified layers: a top puddled layer, muddy layer and plow pan overlying a lower layer [242,243]. A low-permeable layer, formed above the puddled layer, comprises a finer fraction of the soils in suspension [244,245]. Puddling creates a 5 to 10-cm layer of plow pan, of low hydraulic conductivity, 20–25 cm below the ground surface. The hydraulic properties of plow pan regulate the water regime in the irrigated field [236,237,238,239,240,241,242,243,244,245,246,247]. Water flow occurs under unsaturated conditions below the plow pan [243]. The percolation rate varies widely with soil texture, 3–17 mm/day for clay and 13–30 mm/day for sandy loam [245,248]. The intensity [249] and depth of puddling [250], soil-type and post-puddling time period [251], and ponding water depth [252] regulate reduction of the percolation rate in the puddled soils. The percolation rate is high during the early growth period but decreases by 35–45% with the advance of the growth stage [253,254,255].

Puddling effect: Puddling eliminates large pores and alters the field soils to stratified layers: a top puddled layer, muddy layer and plow pan overlying a lower layer [153][154]. A low-permeable layer, formed above the puddled layer, comprises a finer fraction of the soils in suspension [155][156]. Puddling creates a 5 to 10-cm layer of plow pan, of low hydraulic conductivity, 20–25 cm below the ground surface. The hydraulic properties of plow pan regulate the water regime in the irrigated field [147][148][149][150][151][152][153][154][155][156][157][158]. Water flow occurs under unsaturated conditions below the plow pan [154]. The percolation rate varies widely with soil texture, 3–17 mm/day for clay and 13–30 mm/day for sandy loam [156][159]. The intensity [160] and depth of puddling [161], soil-type and post-puddling time period [162], and ponding water depth [163] regulate reduction of the percolation rate in the puddled soils. The percolation rate is high during the early growth period but decreases by 35–45% with the advance of the growth stage [164][165][166].

Re-bound effect: The re-bound effect, a less-known proposition, suggests that when efficiency of using a resource increases, its consumption rate also increases simultaneously [113]. Jevon’s contradiction/paradox in economics advocates that any technologies aimed at saving energy actually end up by achieving the contrary of what they were supposed to do. Although the re-bound effect is quite well-known in energy usage [256], it is less known in the irrigation literature. Any intervention to modernize irrigation systems will improve efficiency, reliability and flexibility of the system, with a consequent increase in demand and consumption of water, especially by progressive farmers. The re-bound effect is therefore a potential problem in water resource management as recognized by [117].

Re-bound effect: The re-bound effect, a less-known proposition, suggests that when efficiency of using a resource increases, its consumption rate also increases simultaneously [167]. Jevon’s contradiction/paradox in economics advocates that any technologies aimed at saving energy actually end up by achieving the contrary of what they were supposed to do. Although the re-bound effect is quite well-known in energy usage [168], it is less known in the irrigation literature. Any intervention to modernize irrigation systems will improve efficiency, reliability and flexibility of the system, with a consequent increase in demand and consumption of water, especially by progressive farmers. The re-bound effect is therefore a potential problem in water resource management as recognized by [169].

Water-saving technologies are promoted based on the supposition that a reduction in water inputs per unit of output makes a comparable water-saving. However, this assumption may not be factual for two reasons. First, whether the quantity of water spared by reducing input transforms into real water-saving depends on the destination of the saved water. A significant part of the applied irrigation water percolates to the underlying aquifer, which can be pumped by the same or other farmers for reuse (

Figure 1) and hence is not lost or wasted [212]. So, there is a risk of focusing on local efficiency alone and ignoring the return flows [126]. Secondly, based on economic theory [257], water-saving technologies, by adding more value to water, may encourage farmers to use more water as observed by [114] in Pakistan and Yemen where the overall water usage increased significantly [127,258]. Contrasting evidence is also found in the central United States where new technologies reduced water usage [74].

) and hence is not lost or wasted [119]. So, there is a risk of focusing on local efficiency alone and ignoring the return flows [170]. Secondly, based on economic theory [171], water-saving technologies, by adding more value to water, may encourage farmers to use more water as observed by [172] in Pakistan and Yemen where the overall water usage increased significantly [173][174]. Contrasting evidence is also found in the central United States where new technologies reduced water usage [74].

It is crucial to quantify water extracted and water consumed separately in order to effectively investigate the re-bound effect in irrigation. The usage of extracted water can comprise a consumed part and a non-consumed part. The consumed part may comprise both beneficial and non-beneficial evapotranspiration and runoff or percolation loss that are not recoverable. The non-consumed part comprises parts of the runoff and percolation that are recoverable for further use [213,259]. So, efficiency improvements do not always reduce overall water use; these actually reduce the effective cost of net irrigation encouraging the farmers to achieve more benefit by increasing net irrigation [115,260,261,262].

It is crucial to quantify water extracted and water consumed separately in order to effectively investigate the re-bound effect in irrigation. The usage of extracted water can comprise a consumed part and a non-consumed part. The consumed part may comprise both beneficial and non-beneficial evapotranspiration and runoff or percolation loss that are not recoverable. The non-consumed part comprises parts of the runoff and percolation that are recoverable for further use [120][175]. So, efficiency improvements do not always reduce overall water use; these actually reduce the effective cost of net irrigation encouraging the farmers to achieve more benefit by increasing net irrigation [176][177][178][179].

3. Summary and Conclusions

Manifold attempts have been made in different regions of the world to increase food production for the rapidly growing population since the early 1960s. There has been great success in increasing food production globally but with a tremendous resulting pressure on the production-linked resources, specifically water and soil. The accelerating stress on these vital resources in the EGP raises sustainability concerns regarding agricultural production systems. Researchers and practitioners have been facing these challenges, both locally and regionally, over the last few decades. They have developed resource-conservation technologies as a response to concerns about agricultural sustainability, with basic principles of rebuilding the soil, optimizing inputs for crop production, increasing food production, and optimizing profits [84,86,87]. This review study has summarized the benefits of these technologies, and the scale-dependency and uncertainty of some of the benefits. Also identified are the gaps in current knowledge regarding the conceptual aspects of these technologies to make agriculture sustainable over a large regional scale so as to guide the future research in proper directions.

Manifold attempts have been made in different regions of the world to increase food production for the rapidly growing population since the early 1960s. There has been great success in increasing food production globally but with a tremendous resulting pressure on the production-linked resources, specifically water and soil. The accelerating stress on these vital resources in the EGP raises sustainability concerns regarding agricultural production systems. Researchers and practitioners have been facing these challenges, both locally and regionally, over the last few decades. They have developed resource-conservation technologies as a response to concerns about agricultural sustainability, with basic principles of rebuilding the soil, optimizing inputs for crop production, increasing food production, and optimizing profits [180][181][182]. This review study has summarized the benefits of these technologies, and the scale-dependency and uncertainty of some of the benefits. Also identified are the gaps in current knowledge regarding the conceptual aspects of these technologies to make agriculture sustainable over a large regional scale so as to guide the future research in proper directions.

Of these resource-conservation technologies, conservation agriculture and water-saving measures are being practiced in many regions of the world, including the EGP [85,87]. Some benefits of these technologies, such as reduced energy and nutrients usage and reduced agrochemical leaching, are scale-invariant and intuitively clear [37,83]. However, the issue of water-saving remains uncertain at the system level since it is both a temporal and spatial scale-dependent element and linked to the regional hydrologic cycle [94,95]. Water saved at the farm level could otherwise join the groundwater or surface water systems to be used later by the same or other users [75,103]. Consequently, whether water-saving achieved at the farm level makes any real saving when considering the entire groundwater or river basin has not yet been adequately investigated. Furthermore, there is evidence of increasing demand for water after adding more value by technological interventions, such as increasing irrigation efficiency by adopting water-saving measures [114]; however, contrasting evidence has also been observed [74]. Whether or not the reduced extraction of groundwater, as well as reduced recharge, under resource-conservation technologies raise groundwater storage/groundwater level or reduce it remains unresolved [306]. Apparently, the reduced extraction of groundwater is expected to increase groundwater storage, but this likelihood is also uncertain since most aquifers in the Gangetic basin discharge to the rivers as base flow in the dry season. Thus, the current level of understanding of the complexity of the hydrological link to field-applied water is inadequate due to lack of measured data on the components of regional water balance. Lack of shared knowledge on the impacts of resource-conservation technologies on regional water balance among the pertinent disciplines, such as agricultural production practitioners (e.g., agronomists, economists, irrigation engineers) and hydrologists (e.g., groundwater hydrologists, surface water hydrologists), is another drawback in planning and implementing holistic approach to investigate regional hydrology outcomes. This inadequate knowledge of inter-linked water systems may lead to the implementation of wrong policy [121,122,123] merely based on local perspectives with eventual worsening of the water-scarcity situation. Therefore, all pertinent disciplines should adopt integrated research approaches to measure the components of local and regional water balance and quantify regional hydrology outcomes over a large temporal scale. Only then proper water management policy can be planned and implemented for sustainable agricultural production.

Of these resource-conservation technologies, conservation agriculture and water-saving measures are being practiced in many regions of the world, including the EGP [183][182]. Some benefits of these technologies, such as reduced energy and nutrients usage and reduced agrochemical leaching, are scale-invariant and intuitively clear [37][184]. However, the issue of water-saving remains uncertain at the system level since it is both a temporal and spatial scale-dependent element and linked to the regional hydrologic cycle [95][105]. Water saved at the farm level could otherwise join the groundwater or surface water systems to be used later by the same or other users [75][110]. Consequently, whether water-saving achieved at the farm level makes any real saving when considering the entire groundwater or river basin has not yet been adequately investigated. Furthermore, there is evidence of increasing demand for water after adding more value by technological interventions, such as increasing irrigation efficiency by adopting water-saving measures [172]; however, contrasting evidence has also been observed [74]. Whether or not the reduced extraction of groundwater, as well as reduced recharge, under resource-conservation technologies raise groundwater storage/groundwater level or reduce it remains unresolved [185]. Apparently, the reduced extraction of groundwater is expected to increase groundwater storage, but this likelihood is also uncertain since most aquifers in the Gangetic basin discharge to the rivers as base flow in the dry season. Thus, the current level of understanding of the complexity of the hydrological link to field-applied water is inadequate due to lack of measured data on the components of regional water balance. Lack of shared knowledge on the impacts of resource-conservation technologies on regional water balance among the pertinent disciplines, such as agricultural production practitioners (e.g., agronomists, economists, irrigation engineers) and hydrologists (e.g., groundwater hydrologists, surface water hydrologists), is another drawback in planning and implementing holistic approach to investigate regional hydrology outcomes. This inadequate knowledge of inter-linked water systems may lead to the implementation of wrong policy [186][187][188] merely based on local perspectives with eventual worsening of the water-scarcity situation. Therefore, all pertinent disciplines should adopt integrated research approaches to measure the components of local and regional water balance and quantify regional hydrology outcomes over a large temporal scale. Only then proper water management policy can be planned and implemented for sustainable agricultural production.

References

  1. Parry, M. Food and energy security: Exploring the challenges of attaining secure and sustainable supplies of food and energy. Food Energy Secur. 2012, 1, 1–2.
  2. World Bank. World Development Report: Agriculture for Development; World Bank: Washington, DC, USA, 2008.
  3. Fendorf, S.; Benner, S.G. Hydrology: Indo-Gangetic groundwater threat. Nat. Geosci. 2016, 9, 732–733.
  4. Bharati, L.; Sharma, B.R.; Smakthin, V. (Eds.) The Ganges River Basin: Status and Challenges in Water, Environment and Livelihoods, 1st ed.; Routledge: London, UK/New York, NY, USA, 2016.
  5. Jain, M.; Singh, B.; Srivastava, A.A.K.; Malik, R.K.; McDonald, A.J.; Lobell, D.B. Using satellite data to identify the causes of and potential solutions for yield gaps in India’s Wheat Belt. Env. Res. Lett. 2017, 12, 094011.
  6. Soneja, S.I.; Tielsch, J.M.; Khatry, S.K.; Curriero, F.C.; Breysse, P.N. Highlighting uncertainty and recommendations for improvement of black carbon biomass fuel-based emission inventories in the Indo-Gangetic Plain region. Curr. Environ. Health Rep. 2016, 3, 73–80.
  7. Bhanja, S.N.; Mukherjee, A.; Rangarajan, R.; Scanlon, B.R.; Malakar, P.; Verma, S. Long-term groundwater recharge rates across India by in situ measurements. Hydrol. Earth Syst. Sci. 2019, 23, 711–722.
  8. Timsina, J.; Connor, D.J. Productivity and management of R–W cropping systems: Issues and challenges. Field Crops Res. 2001, 69, 93–132.
  9. Urfels, A.; McDonald, A.J.; Krupnik, T.J.; van Oel, P.R. Drivers of groundwater utilization in water-limited rice production systems in Nepal. Water Int. 2020, 45, 39–59.
  10. Narayanamoorthy, A.; Deshpande, R.S. Where Water Seeps: Towards a New Phase in India’s Irrigation Reforms; Academic Foundation: New Delhi, India, 2005.
  11. Narayanamoorthy, A.; Hanjra, M.A. Rural infrastructure and agricultural output linkages: A study of 256 Indian districts. Indian J. Agric. Econ. 2006, 61, 444–459.
  12. Vaidyanathan, A.; Krishanakumar, A.; Rajagopal, A.; Varatharajan, D. Impact of irrigation on productivity of land. J. Indian School Polit. Econ. 1994, 6, 60–145.
  13. Renner, J. Global Irrigated Area at Record Levels, But Expansion Slowing; Worldwatch Institute: Washington, DC, USA, 2012; Available online: (accessed on 4 September 2019).
  14. BADC (Bangladesh Agricultural Corporation). Data on Irrigation and Groundwater Tables; Bangladesh Agricultural Development Corporation: Dhaka, Bangladesh, 2016.
  15. Zilberman, D.; Taylor, R.; Shim, M.E.; Gordon, B. How politics and economics affect irrigation and conservation. Choices 2017, 32, 1–6.
  16. Santeramo, F.G. On the composite indicators for food security: Decisions matter. Food Rev. Int. 2015, 31, 63–73.
  17. Loeve, R.; Dong, B.; Hong, L.; Chen, C.D.; Zhang, S.; Barker, R. Transferring water from irrigation to higher valued uses: A case study of the Zhanghe irrigation system in China. Paddy Water Environ. 2007, 5, 263–269.
  18. Godfray, H.C.J.; Beddington, J.R.; Crute, I.R.; Haddad, L.; Lawrence, D.; Muir, J.F.; Pretty, J.; Robinson, S.; Thomas, S.M.; Toulmin, C. Food security: The challenge of feeding 9 billion people. Science 2010, 327, 812–818.
  19. Leemans, R.; de Groot, R.S. Millennium Ecosystem Assessment: Ecosystems and Human Well-Being; Island Press: Washington, DC, USA, 2005; Volume 5.
  20. Hoque, M.A.; Burgess, W.G. 14C-dating of deep groundwater in the Bengal Aquifer System, Bangladesh: Implications for aquifer anisotropy recharge sources and sustainability. J. Hydrol. 2012, 444, 209–220.
  21. Federico, G. Feeding the World: An Economic History of Agriculture, 1800–2000, 1st ed.; Princeton University Press: New York, NY, USA, 2008.
  22. Hansen, J.; Hellin, J.; Rosenstock, T.; Fisher, E.; Cairns, J.; Stirling, C.; Lamanna, C.; van Etten, J.; Rose, A.; Campbell, B. Climate risk management and rural poverty reduction. Agric. Syst. 2019, 172, 28–46.
  23. Shah, T.; Roy, A.D.; Qureshi, A.S.; Wang, J. Sustaining Asia’s Groundwater Boom: An Overview of Issues and Evidence. In Natural Resources Forum; Blackwell Publishing Ltd.: Oxford, UK, 2003; Volume 27, pp. 130–141.
  24. FAO (Food and Agriculture Organization of the United Nations). AQUASTAT: FAO Database. Available online: (accessed on 12 September 2020).
  25. Cassman, K.G. Ecological intensification of cereal production systems: Yield potential, soil quality and precision agriculture. Proc. Natl. Acad. Sci. USA 1999, 96, 5952–5959.
  26. Alam, K. Farmers’ adaptation to water scarcity in drought-prone environments: A case study of Rajshahi District, Bangladesh. Agric. Water Manag. 2015, 148, 196–206.
  27. Ladha, J.K.; Pathak, H.; Gupta, R.K. Sustainability of the rice–wheat crop-ping system: Issues, constraints, and remedial options. J. Crop Improv. 2007, 19, 125–136.
  28. Hira, G.S. Water management in northern states and the food security of India. J. Crop Improv. 2009, 23, 136–157.
  29. Humphreys, E.; Kukal, S.S.; Christen, E.W.; Hira, G.S.; Sharma, R.K. Halting the Groundwater Decline in North-West India—Which Crop Technologies Will Be Winners? Adv. Agron. 2010, 109, 155–217.
  30. Stevenson, J.R.; Villoria, N.; Byerlee, D.; Kelley, T.; Maredia, M. Green Revolution research saved an estimated 18 to 27 million hectares from being brought into agricultural production. Proc. Natl. Acad. Sci. USA 2013, 110, 8363–8368.
  31. Montpellier Panel. Sustainable Intensification: A New Paradigm for African Agriculture, London. 2013. Available online: (accessed on 26 February 2021).
  32. Kabir, M.S.; Salam, M.U.; Chowdhury, A.; Rahman, N.M.F.; Iftekharuddaula, K.M.; Rahman, M.S.; Rashid, M.H.; Dipti, S.S.; Islam, A.; Latif, M.A.; et al. Rice vision for Bangladesh: 2050 and beyond. Bangladesh Rice J. 2015, 19, 1–18.
  33. Bhanja, S.N.; Mukherjee, A.; Rodell, M.; Wada, Y.; Chattopadhyay, S.; Velicogna, I.; Pangaluru, K.; Famiglietti, J.S. Groundwater rejuvenation in parts of India influenced by water-policy change implementation. Sci. Rep. 2017, 7, 7453.
  34. Gleick, P.H.; Heberger, M. Water and Conflict. In The World’s Water; Island Press: Washington, DC, USA, 2014; pp. 159–171.
  35. PARC-RWC. Pakistan Agricultural Research Council–Rice–Wheat Consortium (PARC-RWC) for the Indo-Gangetic Plains. In Proceedings of the National Workshop on Rice–Wheat Systems, Islamabad, Pakistan, 11–12 December 2002; Pakistan Agricultural Research Council and Rice–Wheat Consortium for the Indo-Gangetic Plains: Islamabad, Pakistan/New Delhi, India, 2003; p. 118.
  36. Mujeeb-ur-Rehman, H.; Ali, S.; Akram, M.M. Resource conservation strategy for enhancing wheat productivity in Pakistan. Mycopath 2011, 9, 79–85.
  37. Tesfaye, K.; Khatri-Chhetri, A.; Aggarwal, P.K.; Mequanint, F.; Shirsath, P.B.; Stirling, C.M.; Jat, M.L.; Rahut, D.B.; Erenstein, O. Assessing climate adaptation options for cereal-based systems in the eastern Indo-Gangetic Plains, South Asia. J. Agric. Sci. 2019, 157, 189–210.
  38. Liu, Z.; Chen, H.; Huo, Z.; Wang, F.; Shock, C.C.; Clothier, B.E. Analysis of the contribution of groundwater to evapotranspiration in an arid irrigation district with shallow water table. Agric. Water Manag. 2016, 171, 131–141.
  39. Zhang, Z.; Hu, H.; Tian, F.; Yao, X.; Sivapalan, M. Groundwater dynamics under water-saving irrigation and implications for sustainable water management in an oasis: Tarim River basin of western China. Hydrol. Earth Syst. Sci. 2014, 18, 3951–3967.
  40. Tabbal, D.F.; Bouman, B.A.M.; Bhuiyan, S.I.; Sibayan, E.B.; Sattar, M.A. On-farm strategies for reducing water input in irrigated rice; case studies in the Philippines. Agric. Water Manag. 2002, 56, 93–112.
  41. Mays, L.W. Groundwater resources sustainability: Past, present, and future. Water Resour. Manag. 2013, 27, 4409–4424.
  42. Grogan, D.S.; Wisser, D.; Prusevich, A.; Lammers, R.B.; Frolking, S. The use and re-use of unsustainable groundwater for irrigation: A global budget. Environ. Res. Lett. 2017, 12, 034017.
  43. Chen, H.; Liu, Z.; Huo, Z.; Qu, Z.; Xia, Y.; Fernald, A. Impacts of agricultural water saving practice on regional groundwater and water consumption in an arid region with shallow groundwater. Environ. Earth Sci. 2016, 75, 1204.
  44. Shahid, S. Spatial and temporal characteristics of droughts in the western part of Bangladesh. Hydrol. Process. 2008, 22, 2235–2247.
  45. Shahid, S.; Behrawan, H. Drought risk assessment in the western part of Bangladesh. Nat. Hazards 2008, 46, 391–413.
  46. Jahan, C.; Mazumder, Q.H.; Islam, A.T.M.M.; Adham, M. Impact of irrigation in Barind area, North-west Bangladesh-an evaluation based on the meteorological parameters and fluctuation trend in groundwater table. J. Geol. Soc. India 2010, 76, 134–142.
  47. Jahan, C.; Mazumder, Q.H.; Akter, N.; Adham, M.I.; Zaman, M. Hydrogeological environment and groundwater occurrences in the plio-pleistocene aquifer in Barind area, North-west Bangladesh. Bangladesh Geosci. J. 2012, 16, 23–37.
  48. Shamsudduha, M.; Taylor, R.; Longuevergne, L. Monitoring groundwater storage changes in the highly seasonal humid tropics: Validation of GRACE measurements in the Bengal Basin. Water Resour. Res. 2012, 48, W02508.
  49. Mojid, M.A.; Parvez, M.F.; Mainuddin, M.; Hodgson, G. Water table trend—A sustainability status of groundwater development in North-West Bangladesh. Water 2019, 11, 1182.
  50. Takara, K.; Ikebuchi, S. Japan’s 1994 drought in terms of drought duration curve. In Proceedings of the 5th Symposium of Water Resources, Japan, 12–14 November 1997; pp. 467–477.
  51. Sajjan, A.; Muhammed, B.; Dey, N.C. Impact of 1994–95 Drought in the North-West of Bangladesh through Questionnaire Survey. In Proceedings of the 2nd Annual Paper Meet of Agriculture Engineering Division; Institution of Engineers: Bangladesh, 2002; Volume 35, pp. 31–35.
  52. Dey, N.C.; Alam, M.S.; Sajjan, A.K.; Bhuiyan, M.; Ghose, L.; Ibaraki, Y.; Karim, F. Assessing environmental and health impact of drought in the North-west Bangladesh. J. Environ. Sci. Nat. Resour. 2011, 4, 89–97.
  53. Dey, N.C.; Saha, R.; Parvez, M.; Bala, S.K.; Islam, A.S.; Paul, J.K.; Hossain, M. Sustainability of groundwater use for irrigation of dry-season crops in northwest Bangladesh. Groundwater Sustain. Dev. 2017, 4, 66–77.
  54. MacDonald, A.M.; Bonsor, H.C.; Ahmed, K.M.; Burgess, W.G.; Basharat, M.; Calow, R.C.; Dixit, A.; Foster, S.S.D.; Gopal, K.; Lapworth, D.J.; et al. Groundwater Quality and Depletion in the Indo-Gangetic Basin Mapped From in Situ Observations. Nat. Geosci. 2016, 9, 762–766.
  55. Akhilesh, S. Zero tillage – A profitable resource conservation technology in agriculture. Adv. Plants Agric. Res. 2017, 6, 24–25.
  56. Gatto, M.; Petsakos, A.; Hareau, G. Sustainable Intensification of Rice-Based Systems with Potato in Eastern Indo-Gangetic Plains. Am. J. Potato Res. 2020, 97, 162–174.
  57. ICAR (Indian Council of Agricultural Research). State-Specific Interventions for Higher Agricultural Growth. 2018. Available online: (accessed on 11 September 2020).
  58. Wolff, P.; Stein, T.M. Water efficiency and conservation in agriculture–opportunities and limitations. Agric. Rural Dev. 1998, 2, 2–20.
  59. Liu, Y.; Yu, X.; He, Y. The Research Progress of Water-Saving Irrigation in China Since 2000. In Advanced Materials Research; Trans Tech Publications Ltd.: Bach, Switzerland, 2014; Volume 955, pp. 3206–3210.
  60. Tan, X.; Shao, D.; Gu, W.; Liu, H. Field analysis of water and nitrogen fate in lowland paddy fields under different water managements using HYDRUS-1D. Agric. Water Manag. 2015, 150, 67–80.
  61. Lamaddalena, N.; Shatanawi, M.; Todorovic, M.; Bogliotti, C.; Albrizio, R. Water use efficiency and water productivity. WASAMED Projects (EU Contract ICA3-CT-2002-10013). In Proceedings of the 4th WASAMED Workshop, Aman-Jordan. Options Mediterraneennes SERIES B: Studies and Research, Bari, Italy, 26–30 September 2005; Number 57, CIHCIHEAM/IAMB—EU DG IAMB. 2007; pp. 5–6.
  62. Perry, C.; Steduto, P.; Allen, R.G.; Burt, C.M. Increasing productivity in irrigated agriculture: Agronomic constraints and hydrological realities. Agric. Water Manag. 2009, 96, 1517–1524.
  63. Heydari, N. Water productivity in agriculture: Challenges in concepts, terms and values. Irrig. Drain. 2014, 63, 22–28.
  64. Fishman, R.; Devineni, N.; Raman, S. Can improved agricultural water use efficiency save India’s groundwater? Environ. Res. Lett. 2015, 10, 084022.
  65. Wang, M.H.; Shao, G.C.; Meng, J.J.; Chen, C.R.; Huang, D.D. Variable fuzzy assessment of water use efficiency and benefits in irrigation district. Water Sci. Eng. 2015, 8, 205–210.
  66. Gonçalves, J.M.; Pereira, L.S.; Fang, S.X.; Dong, B. Modelling and multi criteria analysis of water saving scenarios for an irrigation district in the upper Yellow River Basin. Agric. Water Manag. 2007, 94, 93–108.
  67. Khan, S. Pathways for Realizing Water Conservancy in Irrigation Systems. In Proceedings of the International Forum on Water Resources Management and Irrigation Modernization in Shanxi Province, China; FAO Rap Publication: Roma, Italy, 2007.
  68. Pereira, L.S.; Gonçalves, J.M.; Dong, B.; Mao, Z.; Fang, S.X. Assessing basin irrigation and scheduling strategies for saving irrigation water and controlling salinity in the upper Yellow River Basin, China. Agric. Water Manag. 2007, 93, 109–122.
  69. Han, D.; Song, X.; Currell, M.J.; Cao, G.; Zhang, Y.; Kang, Y. A survey of groundwater levels and hydro-geochemistry in irrigated fields in the Karamay agricultural development area, Northwest China: Implications for soil and groundwater salinity resulting from surface water transfer for irrigation. J. Hydrol. 2011, 405, 217–234.
  70. Hobbs, P.R.; Sayre, K.; Gupta, R. The role of conservation agriculture in sustainable agriculture. Philos. Trans. R. Soc. B Biol. Sci. 2008, 363, 543–555.
  71. Giller, K.E.; Witter, E.; Corbeels, M.; Tittonell, P. Conservation agriculture and smallholder farming in Africa: The heretics’ view. Soil Tillage Res. 2009, 114, 23–34.
  72. Jat, R.A.; Wani, P.S.; Saharwat, K.L. Conservation agriculture in the semi-arid tropics: Prospects and problems. Advan. Agron. 2012, 117, 192–273.
  73. Peterson, J.M.; Ding, Y. Economic adjustments to groundwater depletion in the high plains: Do water-saving irrigation systems save water? Am. J. Agric. Econ. 2005, 87, 147–159.
  74. Zhang, J.P.; Tian, H.Y.; Guo, B.T. Determination method of water saving threshold in arid area. Procedia Eng. 2012, 28, 873–876.
  75. Masih, I.; Giordano, M. Constraints and opportunities for water savings and increasing productivity through Resource Conservation Technologies in Pakistan. Agric. Ecosyst. Environ. 2014, 187, 106–115.
  76. Rizwan, M.; Bakhsh, A.; Li, X.; Anjum, L.; Jamal, K.; Hamid, S. Evaluation of the impact of water management technologies on water savings in the lower chenab canal command area, Indus River Basin. Water 2018, 10, 681.
  77. Foster, S.; Tuinhof, A.; Kemper, K.; Garduno, H.; Nanni, M. Groundwater Management Strategies: Facets of the Integrated Approach; (No30091, p. 1); The World Bank: Washington, DC, USA, 2003.
  78. Seckler, D.; Molden, D.; Sakthivadivel, R. The concept of efficiency in water resources management and policy. Water Product. Agric. Limits Oppor. Improv. 2003, 1, 37–51. Available online: (accessed on 4 September 2019).
  79. Aeschbach-Hertig, W.; Gleeson, T. Regional strategies for the accelerating global problem of groundwater depletion. Nat. Geosci. 2012, 5, 853–861.
  80. FAO (Food and Agriculture Organization of the United Nations). Global Diagnostic of Groundwater Governance—Thematic Papers. 2016. Available online: (accessed on 12 September 2020).
  81. Gleick, P.H.; Christian−Smith, J.; Cooley, H. Water−use efficiency and productivity: Rethinking the basin approach. Water Int. 2011, 36, 784–798.
  82. Johnson, N.; Revenga, C.; Echeverria, J. Managing Water for People and Nature. Science 2001, 292, 1071–1072.
  83. Mao, Z. Water Efficient Irrigation and Environmentally Sustainable Irrigated Rice Production in China. International Commission on Irrigation and Drainage. 2001. Available online: (accessed on 12 September 2020).
  84. Liang, Y.; Li, F.; Nong, M.; Luo, H.; Zhang, J. Microbial activity in paddy soil and water use efficiency of rice as affected by irrigation method and nitrogen level. Comm. Soil Sci. Plant Anal. 2015, 47, 19–31.
  85. Bouman, B.A.M.; Tuong, T.P. Field water management to save water and increase its productivity in irrigated lowland rice. Agric. Water Manag. 2001, 49, 11–30.
  86. Loeve, R.; Dong, B.; Molden, D. Field-Level Water Savings in the Zhanghe Irrigation System and the Impact at the System Level. In Proceedings of the International Workshop on Water-wise Rice Production, Los Baños, Philippines, 8–11 April 2002; p. 356.
  87. Tan, X.; Shao, D.; Liu, H.; Yang, F.; Xiao, C.; Yang, H. Effects of alternate wetting and drying irrigation on percolation and nitrogen leaching in paddy fields. Paddy Water Environ. 2013, 11, 381–395.
  88. Ye, Y.; Liang, X.; Chen, Y.; Liu, J.; Gu, J.; Guo, R.; Li, L. Alternate wetting and drying irrigation and controlled-release nitrogen fertilizer in late-season rice. Effects on dry matter accumulation, yield, water and nitrogen use. Field Crops Res. 2013, 144, 212–224.
  89. Prathapar, S.A.; Qureshi, A.S. Modelling the effects of deficit irrigation on soil salinity, depth to water table and transpiration in semi-arid zones with monsoonal rains. Water Resour. Dev. 1999, 15, 141–159.
  90. Bouman, B.A.M.; Feng, L.; Tuong, T.P.; Lu, G.; Wang, H.; Feng, Y. Exploring options to grow rice using less water in northern China using a modelling approach II. Quantifying yield, water balance components and water productivity. Agric. Water Manag. 2007a, 88, 23–33.
  91. Kato, Y.; Okami, M. Root morphology, hydraulic conductivity and plant water relations of high−yielding rice grown under aerobic conditions. Ann. Bot. 2011, 108, 575–583.
  92. El-Sadek, A. Water use optimisation based on the concept of partial rootzone drying. Ain Shams Eng. J. 2014, 5, 55–62.
  93. Zhang, Z.; Zhang, S.; Yang, J.; Zhang, J. Yield, grain quality and water use efficiency of rice under non-flooded mulching cultivation. Field Crops Res. 2008, 108, 71–81.
  94. Feng, L.P.; Bouman, B.A.M.; Tuong, T.P.; Cabangon, R.J.; Li, Y.L.; Lu, G.A.; Feng, Y.H. Exploring options to grow rice using less water in northern China using a modeling approach – 1. Field experiments and model evaluation. Agric. Water Manag. 2007, 88, 1–13.
  95. Li, Y.; Šimůnek, J.; Wang, J.; Yuan, J.; Zhang, W. Modeling of soil water regime and water balance in a transplanted rice field experiment with reduced irrigation. Water 2017, 9, 248.
  96. Zaman, A.; Gangarani, T. Aerobic Rice Cultivation on Adoption of Water Saving Technologies and Improving Agronomic Practices during Summer Season under Conservation Agriculture. In Proceedings of the Conference on Conservation Agriculture for Smallholders in Asia and Africa, Mymensingh, Bangladesh, 7–11 December 2014; Vance, W., Bell, R.W., Haque, M.E., Eds.; 2014. Published as an E-book.
  97. Kader, M.A.; Senge, M.; Mojid, M.A.; Onishi, T.; Ito, K. Effects of plastic-hole mulching on effective rainfall and readily available soil moisture under soybean (Glycine max) cultivation. Paddy Water Environ. 2017, 15, 659–668.
  98. Kader, M.A.; Nakamura, K.; Senge, M.; Mojid, M.A.; Kawashima, S. Numerical simulation of water-and heat-flow regimes of mulched soil in rain-fed soybean field in central Japan. Soil Tillage Res. 2019, 191, 142–155.
  99. Igbadun, H.E.; Salim, B.A.; Tarimo, A.K.P.R.; Mahoo, H.F. Effects of deficit irrigation scheduling on yields and soil water balance of irrigated maize. Irrig. Sci. 2008, 27, 11–23.
  100. Karam, F.; Lahoud, R.; Masaad, R.; Kabalan, R.; Breidi, J.; Chalita, C.; Rouphael, Y. Evapotranspiration, seed yield and water use efficiency of drip irrigated sunflower under full and deficit irrigation conditions. Agric. Water Manag. 2007, 90, 213–223.
  101. Gowing, J.W.; Rose, D.A.; Ghamarnia, H. The effect of salinity on water productivity of wheat under deficit irrigation above shallow groundwater. Agric. Water Manag. 2009, 96, 517–524.
  102. Zhou, Y. A critical review of groundwater budget myth, safe yield and sustainability. J. Hydrol. 2009, 370, 207–213.
  103. Rao, S.S.; Tanwar, S.P.S.; Regar, P.L. Effect of deficit irrigation, phosphorous inoculation and cycocel spray on root growth, seed cotton yield and water productivity of drip irrigated cotton in arid environment. Agric. Water Manag. 2016, 169, 14–25.
  104. Babajimopoulos, C.; Panoras, A.; Georgoussis, H.; Arampatzisb, G.; Hatzigiannakisb, E.; Papamichail, D. Contribution to irrigation from shallow groundwater table under field conditions. Agric. Water Manag. 2007, 92, 205–210.
  105. Perry, C.; Steduto, P.; Karajeh, F. Does Improved Irrigation Technology Save Water? A Review of the Evidence; Food and Agriculture Organization of the United Nations: Cairo, Egypt, 2017; p. 42.
  106. Giordano, M. Global groundwater? Issues and solutions. Annu. Rev. Environ. Resour. 2009, 34, 153–178.
  107. Keller, A.; Keller, J.; Seckler, D. Integrated Water Resource Systems: Theory and Policy Implications; Research Report 3; International Water Management Institute: Colombo, Sri Lanka, 1996.
  108. Ahmad, M.U.D.; Bastiaanssen, W.G.; Feddes, R.A. Sustainable use of groundwater for irrigation: A numerical analysis of the subsoil water fluxes. Irrigation and Drainage. J. Int. Comm. Irrig. Drain. 2002, 51, 227–241.
  109. Tuong, T.P.; Bouman, B.A.M.; Mortimer, M. More rice, less water-integrated approaches for increasing water productivity in irrigated rice based systems in Asia. Plant Product. Sci. 2005, 8, 231–241.
  110. Molden, D.; Fraiture, C.D.E. Comprehensive assessment of water management in agriculture. Agric. Water Manag. 2010, 97, 493–578.
  111. Huang, H.-C.; Liu, C.-W.; Chen, S.-K.; Chen, J.-S. Analysis of percolation and seepage through paddy bunds. J. Hydrol. 2003, 284, 13–25.
  112. Ahmad, M.D.; Kirby, M.; Islam, M.S.; Hossain, M.J.; Islam, M.M. Groundwater use for irrigation and its productivity: Status and opportunities for crop intensification for food security in Bangladesh. Water Resour. Manag. 2014, 28, 1415–1429.
  113. Acharjee, T.K.; van Halsema, G.; Ludwig, F.; Hellegers, P.; Supit, I. Shifting planting date of Boro rice as a climate change adaptation strategy to reduce water use. Agric. Syst. 2019, 168, 131–143.
  114. Khan, S.; Best, L.; Wang, B. Surface-Ground Water Interaction Model of the Murrumbidgee Irrigation Area; CSIRO Land and Water Technical Report 36/02; CSIRO Land and Water: Griffith, Australia, 2002.
  115. LaHue, G.T.; Linquist, B.A. The contribution of percolation to water balances in water-seeded rice systems. Agric. Water Manag. 2021, 243, 106445.
  116. Seckler, D. The Sardar Sarovar Project in India: A Commentary on the Report of the Independent Review. Water Resources and Irrigation Division (Discussion Paper 8); Winrock International: Arlington, VA, USA, 1992.
  117. Seckler, D. The New Era of Water Resources Management: From ‘Dry’ to ‘Wet’ Savings; Research Report No. 1; International Irrigation Management Institute (IIMI): Colombo, Sri Lanka, 1996.
  118. Frederiksen, H.D.; Perry, C. Needs and Priorities in Water-Related Research; Draft Paper; International Irrigation Management Institute (IIMI): Colombo, Sri Lanka, 1995.
  119. Keller, A.; Keller, J.; Seckler, D. Integrated Water Resource Systems: Theory and Policy Implications; International Irrigation Management Institute (IIMI): Colombo, Sri Lanka, 1995.
  120. Simons, G.W.H.; Bastiaanssen, W.G.M.; Cheema, M.J.M.; Ahmad, B.; Immerzeel, W.W. A novel method to quantify consumed fractions and non-consumptive use of irrigation water: Application to the Indus Basin Irrigation System of Pakistan. Agric. Water Manag. 2020, 236, 106174.
  121. Molden, D. Accounting for Water Use and Productivity; SWIM Paper 1; International Water Management Institute (IWMI): Colombo, Sri Lanka, 1997.
  122. Garrick, D.; Bark, R.; Connor, J.; Banerjee, O. Environmental water governance in federal rivers: Opportunities and limits for subsidiarity in Australia’s Murray–Darling River. Water Policy 2012, 14, 915–936.
  123. Jiang, G.; Wang, Z. Scale effects of ecological safety of water-saving irrigation: A case study in the arid inland river basin of Northwest China. Water 2019, 11, 1886.
  124. Sandhu, B.S.; Khera, K.L.; Prihar, S.S.; Singh, B. Irrigation needs and yield of rice on a sandy-loam soil as affected by continuous and intermittent submergence. Indian J. Agric. Sci. 1980, 50, 492–496.
  125. Li, Y.; Barker, R. Increasing water productivity for paddy irrigation in China. Paddy Water Environ. 2004, 2, 187–193.
  126. Bouman, B.A.M.; Lampayan, R.M.; Tuong, T.P. Water Management in Irrigated Rice: Coping with Water Scarcity; International Rice Research Institute, IRRI: Los Banos, Philippines, 2007.
  127. Sattar, M.A.; Maniruzzaman, M.I.; Kashem, M.A. National Workshop Proceedings on AWD Technology for Rice Production in Bangladesh; Bangladesh Rice Research Institute: Gazipur, Bangladesh, 2009; p. 54.
  128. Li, T.; Humphreys, E.; Gill, G.; Kukal, S.S. Evaluation and application of ORYZA2000 for irrigation scheduling of puddled transplanted rice in North-West India. Field Crops Res. 2011, 122, 104–117.
  129. Xu, J.; Wei, Q.; Yu, Y.; Peng, S.; Yang, S. Influence of water management on the mobility and fate of copper in rice field soil. J. Soils Sediments 2013, 13, 1180–1188.
  130. Chen, Y.; Zhang, G.; Xu, Y.J.; Huang, Z. Influence of irrigation water discharge frequency on soil salt removal and rice yield in a semi-arid and saline-sodic area. Water 2013, 5, 578–592.
  131. Chivenge, P.; Angeles, O.; Hadi, B.; Acuin, C.; Connor, M.; Stuart, A.; Puskur, R.; Johnson-Beebout, S. Ecosystem Services in Paddy Rice Systems. In The Role of Ecosystem Services in Sustainable Food Systems; Academic Press: Cambridge, MA, USA, 2020; pp. 181–201.
  132. Sudo, M.; Goto, Y.; Iwama, K.; Hida, Y. Herbicide discharge from rice paddy fields by surface runoff and percolation flow: A case study in paddy fields in the Lake Biwa basin, Japan. J. Pestic. Sci. 2018, 43, 24–32.
  133. Li, C.; Salas, W.; De Angelo, B.; Rose, S. Assessing alternatives for mitigating net greenhouse gas emissions and increasing yields from rice production in China over the next twenty years. J. Environ. Qual. 2006, 35, 1554–1565.
  134. Wassmann, R.; Nelson, G.C.; Peng, S.B.; Sumfleth, K.; Jagadish, S.V.K.; Hosen, Y.; Rosegrant, M.W. Rice and Global Climate Change. In Rice in the Global Economy: Strategic Research and Policy Issues for Food Security; Pandley, S., Byerlee, D., Dawe, D., Dobermann, A., Mohanty, S., Rozelle, S., Eds.; International Rice Research Institute: Los Baños, Philippines, 2010; pp. 411–432.
  135. Das, S.; Chou, M.-L.; Jean, J.-S.; Liu, C.-C.; Yang, H.-J. Water management impacts on arsenic behavior and rhizosphere bacterial communities and activities in a rice agro-ecosystem. Sci. Total Environ. 2016, 542, 642–652.
  136. Linquist, B.; Anders, M.M.; Adviento-Borbe, M.A.A.; Chaney, R.L.; Nalley, L.L.; DaRoda, E.F.F.; Van Kessel, C. Reducing greenhouse gas emissions, water use, and grain arsenic levels in rice systems. Glob. Chang. Biol. 2014, 21, 407–417.
  137. Kürschner, E.; Henschel, C.; Hildebrandt, T.; Jülich, E.; Leineweber, M.; Paul, C. Water Saving in Rice Production-Dissemination, Adoption and Short Term Impacts of Alternate Wetting and Drying (AWD) in Bangladesh; SLE Publication Series S 241; Zerbe Druck & Werbung: Berlin, Germany, 2010.
  138. Nalley, L.L.; Linquist, B.; Kovacs, K.F.; Anders, M.M. The economic viability of alternate wetting and drying irrigation in Arkansas rice production. Agron. J. 2015, 107, 579–587.
  139. Rothenberg, S.E.; Anders, M.; Ajami, N.J.; Petrosino, J.F.; Balogh, E. Water management impacts rice methylmercury and the soil microbiome. Sci. Total Environ. 2016, 572, 608–617.
  140. Hira, G.S.; Rachhpal, S.; Kukal, S.S. Soil matric suction: A criterion for scheduling irrigation to rice (Oryza sativa). Indian J. Agric. Sci. 2002, 72, 236–237.
  141. Humphreys, E.; Kukal, S.S.; Amanpreet, K.; Sudhir, T.; Sudhir, Y.; Yadvinder, S.; Balwinder, S.; Timsina, J.; Dhillon, S.S.; Prashar, A.; et al. Permanent Beds for Rice–Wheat Systems in Punjab, India 2: Water Balance and Soil Water Dynamics. In ACIAR Proceedings Series; ACIAR: Canberra, Australia, 2008; pp. 37–61.
  142. Zhang, H.; Xue, Y.; Wang, Z.; Yang, J.; Zhang, J. Alternate wetting and moderate soil drying improves root and shoot growth in rice. Crop Sci. 2009, 49, 2246–2260.
  143. Jalota, S.K.; Singh, K.B.; Chahal, G.B.S.; Gupta, R.K.; Chakraborty, S.; Sood, A.; Ray, S.S.; Panigrahy, S. Integrated effect of transplanting date, cultivar and irrigation on yield, water saving and water productivity of rice (Oryza sativa L.) in Indian Punjab: Field and simulation study. Agric. Water Manag. 2009, 96, 1096–1104.
  144. Feng, Z.Z.; Wang, X.K.; Feng, Z.W. Soil N and salinity leaching after the autumn irrigation and its impact on groundwater in Hetao Irrigation District, China. Agric. Water Manag. 2005, 71, 131–143.
  145. Neumann, R.B.; Polizzotto, M.L.; Badruzzaman, A.B.M.; Ali, M.A.; Zhang, Z.; Harvey, C.F. Hydrology of a groundwater-irrigated rice field in Bangladesh: Seasonal and daily mechanisms of infiltration. Water Resour. Res. 2009, 45.
  146. Walker, S.H.; Rushton, K.R. Verification of lateral percolation losses from irrigated rice fields by a numerical-model. J. Hydrol. 1984, 71, 335–351.
  147. Tuong, T.P.; Wopereis, M.C.S.; Marquez, J.A.; Kropff, M.J. Mechanisms and control of percolation losses in irrigated puddled rice fields. Soil Sci. Soc. Am. J. 1994, 58, 1794–1803.
  148. Patil, M.D.; Das, B.S.; Bhadoria, P.B.S. A simple bund plugging technique for improving water productivity in wetland rice. Soil Tillage Res. 2011, 112, 66–75.
  149. Patil, M.D.; Das, B.S. Assessing the effect of puddling on preferential flow processes through under bund area of lowland rice field. Soil Tillage Res. 2013, 134, 61–71.
  150. Liu, C.W.; Huang, H.C.; Chen, S.K.; Kuo, Y.M. Subsurface return flow and ground water recharge of terrace fields in northern Taiwan 1. JAWRA J. J. Am. Water Resour. Assoc. 2004, 40, 603–614.
  151. Chen, Z.; Govindaraju, R.S.; Kavvas, M.L. Spatial averaging of unsaturated flow equations under infiltration conditions over areally heterogeneous fields-1. Development of models. Water Resour. Res. 1994, 30, 523–534.
  152. Zhu, Y.; Shi, L.; Lin, L.; Yang, J.; Ye, M. A fully coupled numerical modeling for regional unsaturated-saturated water flow. J. Hydrol. 2012, 475, 188–203.
  153. Liu, C.W.; Chen, S.K.; Jou, S.W.; Kuo, S.F. Estimation of the infiltration rate of a paddy field in Yun-Lin Taiwan. Agric. Syst. 2001, 68, 41–54.
  154. Tournebize, J.; Watanabe, H.; Takagi, K.; Nishimura, T. The development of a coupled model (PCPF-SWMS) to simulate water flow and pollutant transport in Japanese paddy fields. Paddy Water Environ. 2006, 4, 39–51.
  155. Humphreys, E.; Muirhead, W.A.; Fawcett, B.J. The Effect of Puddling and Compaction on Deep Percolation and Rice Yield in Temperate Australia. In Soil and Water Engineering for Paddy Field Management, Proceedings of the International Workshop held at the Asian Institute of Technology, 28−30 January, 1992, Bangkok, Thailand; Murty, V.V.N., Koga, K., Eds.; CSIRO: Canberra, Australia, 1992; pp. 212–219.
  156. Kukal, S.S.; Aggarwal, G.C. Percolation losses of water in relation to puddling intensity and depth in a sandy loam rice (Oryza sativa) field. Agric. Water Manag. 2002, 57, 49–59.
  157. Chen, S.K.; Liu, C.W. Analysis of water movement in paddy rice fields (I) experimental studies. J. Hydrol. 2002, 260, 206–215.
  158. Wencai, D.; Fangfei, C.; Qiang, F.; Chengpeng, C.; Xue, M.; Xianye, Y. Effect of soybean roots and a plough pan on the movement of soil water along a profile during rain. Appl. Water Sci. 2019, 9, 138.
  159. Humphreys, E.; Muirhead, W.A.; Fawcett, B.J.; Townsend, J.T.; Murray, E.A. Puddling in Mechanized Rice Culture: Impacts on Water Use and the Productivity of Rice and Post-Rice Crops. In Management of Clay Soils for Rainfed Lowland Rice-based Cropping Systems; ACIAR Proceedings No. 70; Kirchhof, G., So, H.B., Eds.; Australian Centre for International Agricultural Research: Canberra, Australia, 1996; pp. 213–218.
  160. Aggarwal, G.C.; Sidhu, A.S.; Sekhon, N.K.; Sandhu, K.S.; Sur, H.S. Puddling and N management effects on crop response in a rice–wheat cropping system. Soil Tillage Res. 1995, 36, 129–139.
  161. Sharma, P.K.; Bhagat, R.M. Puddling and compaction effects on water permeability of texturally different soils. J. Indian Soc. Soil Sci. 1993, 41, 1–6.
  162. Singh, V.P.; Wichkam, T.H. Water Movement through Wet Soils. In Proceedings of the Symposium on Soils and Rice; IRRI: Los Banos, Phillipines, 1977; Volume 2.
  163. Tabbal, D.F.; Lampayan, R.M.; Bhuiyan, S.I. Water Efficient Irrigation Technique for Rice. In Proceedings of the International Workshop on Soil and Water Engineering for Paddy Field Management, Asian Institute of Technology, Bangkok, Thailand, 28–30 January 1992; pp. 146–159.
  164. Bouman, B.A.M.; Wopereis, M.C.S.; Kroff, M.J.; Ten Berge, H.F.M.; Tuong, T.P. Water use efficiency of flooded rice fields. (II) Percolation and seepage losses. Agric. Water Manag. 1994, 26, 291–304.
  165. Guerra, L.C.; Bhuiyan, S.I.; Tuong, T.P.; Barker, R. Producing More Paddy with Less Water from Irrigated Systems; SWIM Paper 5 International Water Management Institute (IWMI): Colombo, Sri Lanka, 1998.
  166. Sanchez, P. Soil Management in Rice Cultivation. In Properties and Management of Soils in the Tropics; Cambridge University Press: Cambridge, UK, 2019.
  167. Berbel, J.; Gutiérrez-Martín, C.; Rodríguez-Díaz, J.A.; Camacho, E.; Montesinos, P. Literature review on re-bound effect of water saving measures and analysis of a Spanish case study. Water Resour. Manag. 2015, 29, 663–678.
  168. Greening, A.L.; Greene, L.D.; Difiglio, C. Energy efficiency and consumption—The re-bound effect—A survey. Energy Policy 2000, 28, 389–401.
  169. European Commission (EC). A Blueprint to Safeguard Europe’s Water Resources, Brussels. Available online: (accessed on 12 September 2020).
  170. Qureshi, M.E.; Grafton, R.Q.; Kirby, M.; Hanjra, M.A. Understanding irrigation water use efficiency at different scales for better policy reform: A case study of the Murray-Darling Basin, Australia. Water Policy 2011, 13, 1–17.
  171. Caswell, M.; Zilberman, D. The effects of well depth and land quality on the choice of irrigation technology. Am. J. Agric. Econ. 1986, 68, 798–811.
  172. Loch, A.; Adamson, D. Drought and the Re-bound Effect: A Murray–Darling Basin Example. Nat. Hazards 2015, 79, 1429–1449.
  173. Ahmad, M.U.D.; Turral, H.; Masih, I.; Giordano, M.; Masood, Z. Water Saving Technologies: Myths and Realities Revealed in Pakistan’s Rice-Wheat Systems; International Water Management Institute (IWMI): Anand, India, 2007.
  174. Kemper, K.E. Ground water—From development to management. Hydrogeol. J. 2004, 12, 3–5.
  175. Burt, C.M.; Clemmens, A.J.; Strelkoff, T.S.; Solomon, K.H.; Bliesner, R.D.; Hardy, L.A.; Howell, T.A.; Eisenhauer, D.E. Irrigation performance measures: Efficiency and uniformity. J. Irrig. Drain. Eng. 1997, 123, 423–442.
  176. Koech, R.; Langat, P. Improving irrigation water use efficiency: A review of advances, challenges and opportunities in the Australian context. Water 2018, 10, 1771.
  177. Huffaker, R.; Whittlesey, N. Agricultural Water Conservation Legislation: Will It Save Water? Choices 1995, 4, 24–28.
  178. Whittlesey, N.K. Improving Irrigation Efficiency through Technology Adoption: When Will It Conserve Water? In Water Resources Perspectives: Evaluation, Management and Policy; Alsharhan, A.S., Wood, W.W., Eds.; Elsevier Science: Amsterdam, The Netherlands, 2003; pp. 53–62.
  179. Pfeiffer, L.; Lin, C.-Y.C. Does efficient irrigation technology lead to reduced groundwater extraction? Empirical evidence. J. Environ. Econ. Manag. 2013, 67, 189–208.
  180. Dumanski, J.; Peiretti, R.; Benetis, J.; McGarry, D.; Pieri, C. The paradigm of conservation tillage. Proc. World Assoc. Soil Water Conserv. 2006, 1, 58–64.
  181. FAO (Food and Agriculture Organization of the United Nations). Conservation Agriculture; Food and Agriculture Organization: Rome, Italy, 2018; Available online: (accessed on 27 May 2018).
  182. Islam, S.; Gathala, M.K.; Tiwari, T.P.; Timsina, J.; Laing, A.M.; Maharjan, S.; Chowdhury, A.K.; Bhattacharya, P.M.; Dhar, T.; Mitra, B.; et al. Conservation agriculture based sustainable intensification: Increasing yields and water productivity for smallholders of the Eastern Gangetic Plains. Field Crops Res. 2019, 238, 1–17.
  183. Jat, R.K.; Sapkota, T.B.; Singh, R.G.; Jat, M.L.; Kumar, M.; Gupta, R.K. Seven years of conservation agriculture in a rice-wheat rotation of Eastern Gangetic Plains of South Asia: Yield trends and economic profitability. Field Crops Res. 2014, 164, 199–210.
  184. Pokharel, D.; Jha, R.K.; Tiwari, T.P.; Gathala, M.K.; Shrestha, H.K.; Panday, D. Is conservation agriculture a potential option for cereal-based sustainable farming system in the Eastern Indo-Gangetic Plains of Nepal? Cogent Food Agric. 2018, 4, 1557582.
  185. MOA; FAO. Master Plan for Agricultural Development in the Southern Region of Bangladesh; Ministry of Agriculture (MoA, Government of Bangladesh of Bangladesh) and United Nations Food and Agriculture Organization: Dhaka, Bangladesh, 2013; p. 104.
  186. Winter, T.C.; Harvey, J.W.; Franke, O.L.; Alley, W.M. Ground Water and Surface Water: A Single Resource. USGS Circular 1139; US Geological Survey: Denver, CO, USA, 1998.
  187. Fullagar, I.; Brodie, R.; Sundaram, B.; Hostetler, S.; Baker, P. Managing Connected Surface Water and Groundwater Resources. In Science for Decision Makers; Australian Government, Bureau of Rural Sciences: Canberra, Australia, 2006.
  188. Brkić, Ž.; Kuhta, M.; Larva, O.; Gottstein, S. Groundwater and connected ecosystems: An overview of groundwater body status assessment in Croatia. Environ. Sci. Eur. 2019, 31, 75.
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