water

Article Evolution of Crop Water Productivity in the over Three Decades (1985–2015)

Samia M. El-Marsafawy 1, Atef Swelam 2,3,* ID and Ashraf Ghanem 4

1 Soils, Water & Environment Research Institute, Agricultural Research Centre, 12112, ; [email protected] 2 Agricultural Engineering Department, Faculty of Agriculture, University of , Zagazig 44511, Egypt 3 International Centre for Agricultural Research in the Dry Areas (ICARDA), 2416, Egypt 4 Irrigation and Hydraulics Department, Faculty of Engineering, Cairo University, Giza 12613, Egypt; [email protected] * Corresponding: [email protected]; Tel.: +20-233-367-514

 Received: 23 May 2018; Accepted: 21 August 2018; Published: 31 August 2018 

Abstract: Estimating crop water productivity (CWP) for spatially variable climatic conditions in Egypt is important for the redistribution of crop planting to optimize production per unit of water consumed. The current paper aims to estimate maximum CWP trends under conditions of the Northern Nile Delta over three decades to choose crops that exhibit a higher productivity per unit of water and positive trends in the CWP. The Governorate was selected to represent the Northern Nile Delta Region, and mean monthly weather data for the period of 1985 to 2015 were collected to calculate standardized reference evapotranspiration and crop water use for a wide array of crops grown in the region using the CROPWAT8.0 model. The CWP was then calculated by dividing crop yield by seasonal water consumption. The CWP data range from 0.69 to 13.79 kg·m−3 for winter field crops, 3.40 to 10.69 kg·m−3 for winter vegetables, 0.29 to 6.04 kg·m−3 for summer field crops, 2.38 to 7.65 kg·m−3 for summer vegetables, 1.00 to 5.38 kg·m−3 for nili season crops (short-season post summer), and 0.66 to 3.35 kg·m−3 for orchards. The crops with the highest CWP values (kg·m−3) over three decades in descending order are: sugar beet (13.79), potato (w2) (10.69), tomato (w) (10.58), eggplant (w) (10.05), potato (w1) (9.98), cucumber (w) (9.81), and cabbage (w) (9.59). There was an increase in CWP of 41% from the first to the second and 22% from the second to the third decade. The CWP increase is attributed to a small decrease in water consumption and to a considerable increase in crop yield. The yield increases are attributed mainly to the planting of higher yielding varieties and/or the application of better agronomic practices.

Keywords: CROPWAT8.0; crop yield; evapotranspiration; crop pattern planning; irrigation; climate

1. Introduction In the face of growing water scarcity, declining water quality, and the uncertainties of climate change, improving the efficiency and productivity of crop water use, while simultaneously reducing negative environmental impacts is of utmost importance in responding to the increasing food demand of the growing world population. To this end, irrigated and rain-fed agriculture must adopt more science-based, intensive management solutions (Pasquale et al., 2012) [1]. In arid and semi-arid lands, irrigated agriculture is by far the largest consumer of developed water supply. With a growing population, competing demands between industry and municipal water use and use in agriculture are increasing. Since less water is available for agricultural production, future food security is endangered. Consequently, it is imperative to produce more food with less water by increasing CWP. Several strategies for enhancement of CWP by integrating improved crop varieties and better resource

Water 2018, 10, 1168; doi:10.3390/w10091168 www.mdpi.com/journal/water Water 2018, 10, 1168 2 of 12 management at different levels are suggested by the author of Woolley et al., 2009 [2]. Possible strategies include: (1) increasing the harvest index; (2) improving drought and salinity tolerance; (3) applying deficit irrigation; and (4) adjusting the planting and tillage dates to reduce evaporation and increase infiltration; reusing water, and using spatial analysis to identify areas of maximum production and minimum evapotranspiration (ET). A higher CWP results from either decreasing water usage, increasing production, or some combination of both that narrows the gap between supply and demand. In this study, CWP (kg·m−3) is defined as the ratio of marketable crop yield to evapotranspiration (Zwart and Bastiaanssen, 2004) [3]. Numerous studies have documented CWP for various crops throughout the world. Examples include a CWP evaluation of drip irrigated corn grown in the Bekaa Valley of Lebanon (Karam et al., 2003) [4]. A study to compare regional yield, actual water consumption, and water productivity of cotton lint grown in Arizona and California was presented by Grismer (2002) [5]. In Egypt, as a result of the limited water resources, expansion of agricultural lands, and high population growth, evaluating CWP for different climatic zones is important for the development of agricultural policies and strategies. The Nile Delta presents about 50% of all agricultural lands of Egypt and is home to about half the Egyptian population. This study investigates the changes in maximum CWP over three decades to identify trends in CWP. The paper ranks the crops by CWP with the aim to provide decision support for deciding which crops perform best in a particular region. The paper presents a methodology as a guide for other regions of Egypt to recommend redistribution of the cropping pattern and crop choices for better production and income. However, the choice of crops also depends on markets and social and economic considerations, which are important and need consideration when using the guidelines in this paper.

2. Materials and Methods

2.1. Study Area Kafr El-Sheikh Governorate was selected to represent the conditions in the northern part of the Nile Delta Region. Kafr El Sheikh is located in the Northern Nile Delta, extending between the Branch of the Nile in the west and in the east. It is bordered in the north by the Mediterranean Sea and in the south by Gharbia Governorate. This region is often seen as a model basin, due to its innovative approaches to manage and allocate water resources sustainably across economic sectors. The selected site represents agriculture and aquaculture ecosystems. Kafr El Sheikh Governorate covers an area of about 3748 km2. El Burullus Lake, which is one of Egypt’s major northern lakes and a natural protectorate, occupies about 48,000 ha of the governorate area. With 251,000 ha of agricultural lands, Kafr El Sheikh is one of the leading agricultural governorates in Egypt. Most of the lands in the middle and southern parts of the governorate are covered by Holocene clay deposits, overlying Pleistocene marine deposits, while the northern part is covered predominantly by sandy Pleistocene marine deposits and sand dunes. The governorate ranks first in Egyptian fish production (about 34% of the total). Kafr El Sheikh has a moderate Mediterranean climate. Mean temperatures range between 13.2 ◦C in winter and 26.6 ◦C in summer. The annual rainfall varies between about 50 mm in the south to 200 mm in the north, with an annual mean of about 97 mm (EEAA, 2015) [6]. In the Nile Delta, water adequacy is not a major issue at the system level, because water is recycled and reused several times throughout the area with a subsurface drainage system. Thus, reusable drainage water is accessible to farms that experience local temporary water shortage. However, sometimes farmers located at the tail end of canals face water shortage due to operational issues, which are recoverable by using the drainage water. Moreover, farming systems in the Nile Delta are intensifying and diversifying, which puts more pressure on the water delivery supply system. This has increased multiple cropping and double cropping considerably in the Nile Delta. Therefore, improving application efficiency is a major challenge because farmers often use more water than needed, which Water 2018, 10, 1168 3 of 12 causes about 30% to 50% on-farm water loss. However, this is not an absolute water loss at the system level, owing to solutions offered by the water reuse drainage system. The source of water for the study area is from the Nile; there is no shortage year-round and no reduction in water allocation during the growing seasons (summer, nili and winter).

2.2. Tested Crops Egypt has several perennial crops that grow all year where field crops are planted mainly in two or three seasons: winter (October through April), summer (May through September), and sometimes in the nili season (July through October). Ten winter crops (barley, faba bean (green), faba bean (dry), flax, garlic, lentil, lupine, onion, sugar beet, and wheat), eight winter vegetables (cabbage, cucumber, eggplant, pepper, potato (w1), potato (w2), squash, and tomato), six summer crops (cotton, maize, rice, soybean, sugarcane, and sunflower), nine summer vegetables (cabbage, cucumber, eggplant, okra, pepper, potato, squash, tomato, and water melon), two nili crops (maize and tomato), and seven orchard crops (apple, banana, date palm, grapes, mango, orange, and peach) were examined. Note that potato (w1) is sown in September and potato (w2) is sown in November.

2.3. Estimation of Crop Water Productivity According to Kassam and Smith [7], CWP is defined as crop yield divided by water consumptively used for ET. The data on crop yield for winter, summer, nili, and perennial crops were obtained from MALR [8]. The unavailability of yield data for some crops reduces the number of representative years for analysis, but there is sufficient data for this study. There are a few records of crop evapotranspiration (ETc) measurements within the area during the three-decade study period. Consequently, ETc calculations from climate data are used to identify the seasonal crop water use. According to the author of Allen et al., 1998 [9], well-watered crop evapotranspiration (ETc) is calculated by multiplying the reference crop evapotranspiration (ETo) by a crop coefficient (Kc):

ETc = Kc × ETo (1)

−1 where ETc is in mm d ,Kc is the crop coefficient (dimensionless), and ETo is the standardized reference evapotranspiration in mm d−1. −1 The ETo (mm d ) was calculated by the Food and Agriculture Organization of the United Nations (FAO) Penman-Monteith method using the decision support software CROPWAT 8.0 developed by FAO. The standardized ETo equation is:

900 0.408∆(Rn − G) + γ T + 273 u2(es − ea) ETo = (2) ∆ + γ(1 + 0.34u2)

−2 −1 −2 −1 where Rn (MJ m d ) is the net radiation, G is the soil heat flux density (MJ m d ), T is the mean ◦ −1 daily air temperature at 1.5 to 2 m height ( C), u2 is the mean daily wind speed at 2 m height (m s ), es is the saturation vapour pressure (kPa), ea is the actual vapour pressure (kPa), es − ea is the saturation vapour pressure deficit (kPa), ∆ is the slope of the vapour pressure curve (kPa ◦C−1) at the mean daily temperature (◦C), and γ is the psychrometric constant (kPa ◦C−1). The agricultural lands in the study area are fully irrigated with flood irrigation having a typical distribution uniformity DU = 0.60. The crops are grown on heavy clay soil and there is ample year-round irrigation water application; thus, it is assumed that there is no water stress and measured actual (ETact) and well-watered (ETc) are equal for recent measurements in the study area. The area is served by an agricultural drainage system, which consists of subsurface field drains discharging into a dendritic open drain system. The open drains are used by farmers for supplemental irrigation in case of temporary water shortage in the irrigation canals. Comparisons were made between observed water consumption and ETc estimated for wheat grown in Egypt using the same Kc values; however, ETo using the modified Penman, Penman-Monteith, and Doorenbos-Pruitt equations is Water 2018, 10, 1168 4 of 12 reported by the authors of El-Marsafawy et al., 1998 [10]. They found that the ratio between the actual water consumption and ETc estimated by the three formulas were 1.05, 1.02, and 0.95, respectively. Similar results were obtained by the authors of Mohamed et al., 2004; El-Samanody et al., 2004; El-Marsafawy et al., 1998; Rayan et al., 2000 [11–14] for other crops. The results indicate that the Penman Monteith method provides the closest match between ETact and ETc. Therefore, the calculated values of ETc are used in this research to determine crop water consumption and CWP. Archived daily meteorological data from the weather station located in the Agricultural Research Center station in Sakha, Kafr El Sheikh Governorate (Elevation: 20 m; Latitude: 31.07◦ N, Longitude: 30.57◦ E), which is representative of the Northern Nile Delta Region, are used to compute monthly ETo data for each year of the three decades. The monthly ETc data are computed with Equations (1) and (2) using monthly ETo estimated from the weather data and appropriate crop coefficients from CROPWAT 8.0. For each growing season, the CWP was computed from the observed yield and the cumulative seasonal ETc, assuming well-watered conditions. The CWP is computed as:

YLD CWP = (3) CETC

−2 3 −2 where the crop yield (YLD, kg·m ) and the seasonal cumulative ETc (CETc, m m ) are inputs. Therefore, since no water stress is assumed in these data, the CWP values represent the maximum crop water productivity values by season, and the analysis in this paper shows how these peak values change over the study period due to CETc differences. For future studies on how water stress affects CWP, results from this study will be useful to identify maximum yields from seasonal ETc. To simplify the presentation of the CWP results, the values are determined by crop and season for all crops and years, and the mean CWPs by decade are calculated to investigate trends in CWPs over time. The objective is to present data that help the decision-making process that identifies what crops to grow within the study region and whether or not the maximum CWPs increase or decrease with time.

3. Results and Discussion

3.1. Winter Field and Vegetable Crops Mean CWP by decade for the winter field crops barley, faba bean (green), faba bean (dry), flax, garlic, lentil, lupine, onion, sugar beet and wheat are plotted in Figure1. The trend of increasing CWP for several crops with time is clear, with a few exceptions. The CWP trends are near unit for faba bean (dry), lentil and lupine and slightly increased for wheat and barley. Moderate to high increases were observed for faba bean (green), flax, garlic, and pepper. The onion, sugarbeet, cabbage, cucumber (w), eggplant (w), potato (w1), potato (w2), squash, and tomato showed high CWP values, which indicate good water productivity in the region. Sugarbeet, cabbage (w), cucumber (w), eggplant (w), potato (w1), potato (w2) and tomato showed the biggest trends toward high CWP, especially in the last two decades. Cucumber showed a large increase in CWP from the first to second, with a drop in the third decade. However, the CWP in the third decade was still considerably higher than the first. Water productivity trends show that some crops increase productivity much faster than others. The fluctuation in results may be due to differences in weather conditions, genotypes, agricultural practices, and disease, among others. Average CWP for winter vegetables over the study period reached 9.59, 9.81, 10.05, 3.40, 9.98, 10.69, 6.51 and 10.58 kg·m−3 for cabbage, cucumber, eggplant, pepper, potato (w1), potato (w2), squash and tomato, respectively. Data presented in the graphs clearly show an increase in CWP of cabbage, eggplant, pepper, squash and tomato in the third decade. Percentage increase for the respective crops was 35%, 40%, 97%, 19%, and 210% compared to the first decade and 17%, 59%, 62%, 21%, and 72% compared to the second decade. Water 2018, 10, 1168 5 of 12

With regard to potato (w1, sown in September) and potato (w2, sown in November), as stated above, potato (w1) was not grown in the first decade and potato (w2) was not grown in the third decade. The results indicate that CWP of the third decade surpassed that of the second decade for potato (w1)Water 2018 and, 10 the, x FOR second PEER REVIEW decade surpassed the 1st decade for potato (w2). As for cucumber,5 of 12 the percent change in CWP of the third decade was +81% compared with the first decade and −40% comparedpercent with change the second in CWP decade. of the third decade was +81% compared with the first decade and −40% compared with the second decade.

20.00

15.00 )

-3 10.00

5.00

CWP (kg.m 0.00 Flax Lentil Garlic Barley Lupine Wheat Onion (w) Sugarbeet Pepper (w) Squach (w) Squach Tomato (w) Potato (w2) Potato potato (w1) potato Cabbage (w) Eggplant (w) Cucumber (w) Faba bean (dry) bean Faba Faba bean (green) bean Faba

1st decade (1985-1994) 2nd decade (1995-2004) 3rd decade (2005-2015)

Figure 1. Crop water productivity (CWP) for winter field and vegetable crops over three decades under Figure 1. Crop water productivity (CWP) for winter field and vegetable crops over three decades under Northern Nile Delta conditions. Northern Nile Delta conditions. The water utilization efficiency (kg·m−3) reported by the author of Doorenbos and Kassam, 1986 The[15] water were utilizationfor cabbage efficiency(12–20), dry (kg bean·m− (0.3–0.6),3) reported onion by (8–10), the author pepper of(1.5–3.0), Doorenbos potato and(4–7), Kassam, sugarbeet (6–9), tomato (10–12), and wheat (0.8–1.0). In comparison, the third decade values from 1986 [15] were for cabbage (12–20), dry bean (0.3–0.6), onion (8–10), pepper (1.5–3.0), potato (4–7), this study were lower for lentil and cucumber; higher for barley, faba bean (green), faba bean (dry), sugarbeetflax, (6–9), garlic, tomato onion, (10–12),wheat, cabbage, and wheat pepper, (0.8–1.0). potato Inand comparison, squash; and the much third higher decade for sugarbeet, values from this study wereeggplant lower and for tomato. lentil Therefore, and cucumber; the North higher Nile forDelta barley, Region faba is probably bean (green), a better faba place bean to grow (dry), flax, garlic, onion,potato, wheat, sugarbeet, cabbage, and tomato pepper, than potato the typical and region squash; represented and much in FAO higher 33. forThe sugarbeet,author of Rayan eggplant et and tomato.al., Therefore, 1999 [16] theindicated North that Nile the Delta CWP Regionobserved is fo probablyr wheat crop a better in the place Shandaweel to grow region potato, (Upper sugarbeet, −3 −3 and tomatoEgypt) than ranged the between typical 0.43 region to 1.44 represented kg·m and between in FAO 0.83 33. to The 1.70 author kg·m in of the Rayan Giza Region et al., 1999of [16] Middle Egypt (El-Marsafawy, 2000) [17]. This is lower than the CWP (close to 2.0 kg·m−3) observed in indicatedthe that third the decade CWP of this observed study. This for implies wheat that crop it inis probably the Shandaweel better to grow region wheat (Upper in the Northern Egypt) ranged −3 −3 betweenNile 0.43 Delta to 1.44Region kg than·m theand regions between further 0.83 south. to 1.70 kg·m in the Giza Region of Middle Egypt (El-Marsafawy, 2000) [17]. This is lower than the CWP (close to 2.0 kg·m−3) observed in the third decade of3.2. this Summer study. Field This and Vegetable implies Crops that it is probably better to grow wheat in the Northern Nile Delta Region thanValues the regions of CWP further for summer south. field crops varied in the past three decades. CWP values were quite low and showed little or no increasing trend for cotton, soybean, and sunflower (Figure 2). The CWP 3.2. Summerwas a Field bit higher and Vegetable for maize, Crops rice and peppers with an increasing trend. Sugarcane, cabbage (s), cucumber (s), eggplant (s), okra, and squash showed higher CWP and bigger trends. The highest ValuesCWP ofand CWP biggest for trends summer were fieldexhibited crops by potato varied (s), in tomato the past (s) and three watermelon. decades. Based CWP on valuesthese were quite lowobservations, and showed potato little (s), tomato or no increasing(s), and waterm trendelon for have cotton, the highest soybean, CWP as and well sunflower as the biggest (Figure 2). The CWPtrend was towards a bit higher higherfor CWP. maize, In comparison rice and pepperswith the results with an in increasingFigure 1, tomatoes trend. have Sugarcane, higher CWP cabbage (s), cucumberin the (s), winter eggplant than the (s), summer. okra, and The potatoes squash also showed have higher higher CWP CWP in the and winter bigger (Figure trends. 1) than The the highest CWP andsummer biggest (Figure trends 2). It were seems exhibited likely that bythe potatoreduced (s), CWP tomato in summer (s) and is due watermelon. to higher ET rates Based and on these possible effects of some heat stress on production. observations, potato (s), tomato (s), and watermelon have the highest CWP as well as the biggest trend towards higher CWP. In comparison with the results in Figure1, tomatoes have higher CWP in the winter than the summer. The potatoes also have higher CWP in the winter (Figure1) than the summer (Figure2). It seems likely that the reduced CWP in summer is due to higher ET rates and possible effects of some heat stress on production. Water 2018, 10, 1168 6 of 12

Water 2018, 10, x FOR PEER REVIEW 6 of 12

Water 2018, 10, x FOR PEER REVIEW 6 of 12 10.00

8.00 10.00 )

-3 6.00 8.00

) 4.00 -3 6.00

CWP (kg.m 2.00 4.00 0.00 CWP (kg.m 2.00

0.00

1st decade (1985-1994) 2nd decade (1995-2004) 3rd decade (2005-2015)

Figure 2. Crop1st decade water productivity(1985-1994) (CWP)2nd for decade summer (1995-2004) field and vegetable3rd decade crops (2005-2015) over three decades Figure 2. Crop water productivity (CWP) for summer field and vegetable crops over three decades under Northern Nile Delta conditions. under Northern Nile Delta conditions. Figure 2. Crop water productivity (CWP) for summer field and vegetable crops over three decades 3.3. Nili Crops under Northern Nile Delta conditions. 3.3. Nili Crops Mean CWP over the study period amounted to 1.00 and 5.38 kg·m−3 for maize and tomato, Mean3.3.respectively. Nili CWP Crops CWPover thewas studysomewhat period lower amounted for maize to grown 1.00 andduring 5.38 the kg nili·m −period3 for maize(Figure and3) than tomato, −3 respectively.duringMean summer CWP CWP was (Figureover somewhat the 2), study and lowerthe period CWP for amounted maizetrend for grown tomaize 1.00 during wasand near5.38 the 1.0 nilikg·m kg·m period−3 for permaize (Figure decade. and3) thanTomatotomato, during CWP values were similar in the nili and summer periods, but both were lower than the winter summerrespectively. (Figure2 ),CWP and thewas CWPsomewhat trend lower for maize for maize was near grown 1.0 kgduring·m− 3theper nili decade. period Tomato(Figure CWP3) than values period (Figure 1). All three periods showed increasing CWP trends over−3 the three decades, wereduring similar summer in the nili(Figure and 2), summer and the periods, CWP trend but for both maize were was lower near than1.0 kg·m the winter per decade. period Tomato (Figure 1). indicating improvements in production and/or reductions in water consumption. All threeCWP periods values showedwere similar increasing in the nili CWP and trends summer over pe theriods, three but decades, both were indicating lower than improvements the winter in period (Figure 1). All three periods showed increasing CWP trends over the three decades, production and/or reductions in water consumption. indicating improvements in production and/or reductions in water consumption. 8.00

8.006.00 ) -3 6.004.00 ) -3 2.00 CWP (kg.m 4.00

2.000.00 CWP (kg.m Maize (n) Tomato (n) 0.00 1st decade (1985-1994)Maize2nd (n) decade (1995-2004) Tomato3rd decade (n) (2005-2015)

Figure 3. Crop1st waterdecade productivity (1985-1994) (CWP)2nd for decade nili crops (1995-2004) over three decades3rd decade under (2005-2015) Northern Nile Delta conditions. Figure 3. Crop water productivity (CWP) for nili crops over three decades under Northern Nile Delta Figure3.4. Orchard 3. Trees conditions.Crop water productivity (CWP) for nili crops over three decades under Northern Nile DeltaMean conditions. CWP for orchard trees over three decades reached 2.16, 3.35, 3.32, 3.07, 0.66, 2.62, 1.98 3.4.kg·m Orchard−3 for apple, Trees banana, date palm, grapes, mango, orange, and peach, respectively. The CWP 3.4. Orchard Trees valuesMean (Figure CWP 4) forwere orchard generally trees lower over thanthree that decades of the reached high CWP 2.16, field 3.35, and 3.32, vegetable 3.07, 0.66, crops 2.62, sugar 1.98 beet, −cabbage,3 cucumber, eggplant, potato, and tomato (Figures 1–3), which implies that they are not the Meankg·m CWPfor apple, for banana, orchard date trees palm, over grapes, three mango, decades orange, reached and 2.16,peach, 3.35, respectively. 3.32, 3.07, The 0.66,CWP 2.62,

1.98 kgvalues·m− 3(Figurefor apple, 4) were banana, generally date lower palm, than grapes, that of the mango, high CWP orange, field and and peach,vegetable respectively. crops sugar The beet, cabbage, cucumber, eggplant, potato, and tomato (Figures 1–3), which implies that they are not the CWP values (Figure4) were generally lower than that of the high CWP field and vegetable crops

Water 2018, 10, 1168 7 of 12 sugar beet, cabbage, cucumber, eggplant, potato, and tomato (Figures1–3), which implies that they are notWater the 2018 best, 10, cropsx FOR PEER to grow REVIEW in terms of water productivity. However, in economic terms,7 of they 12 are oftenWater highly 2018,productive. 10, x FOR PEER REVIEW This aspect will receive more attention in future research. Of the7 of orchard 12 cropsbest shown crops into Figuregrow in4 ,terms mango of water is clearly productivity. less water However, productive in economic than terms, the other they are trees. often In highly addition, productive. This aspect will receive more attention in future research. Of the orchard crops shown in therebest are obviouscrops to grow CWP in improvements terms of water forproductivity. all the crops, However, with in bananas, economic dates, terms, and they grapes are often exhibiting highly the Figure 4, mango is clearly less water productive than the other trees. In addition, there are obvious CWP biggestproductive. trends. This aspect will receive more attention in future research. Of the orchard crops shown in improvementsFigure 4, mango for is all clearly the crops, less water with bananas,productive da thantes, and the grapesother trees. exhibiting In addition, the biggest there trends.are obvious CWP improvements for all the crops, with bananas, dates, and grapes exhibiting the biggest trends.

5.00 4.005.00 ) -3 3.004.00 ) -3 2.003.00 1.002.00 CWP (kg.m 0.001.00 CWP (kg.m Apple Banana Date palm Grapes Mango Orange Peach 0.00 Apple Banana Date palm Grapes Mango Orange Peach 1st decade (1985-1994) 2nd decade (1995-2004) 3rd decade (2005-2015)

1st decade (1985-1994) 2nd decade (1995-2004) 3rd decade (2005-2015) Figure 4. Crop water productivity (CWP) for orchards over three decades under North Nile Delta Figure 4. Crop water productivity (CWP) for orchards over three decades under North Nile conditions. DeltaFigure conditions. 4. Crop water productivity (CWP) for orchards over three decades under North Nile Delta conditions. As described, Egyptian agriculture has demonstrated increasing CWP during the recent Asdecades. described,As described,For most Egyptian crops, Egyptian the agriculture improvementsagriculture has demonstratedhas are demon mainlystrated due increasing to increasingthe application CWP CWP during of during good the agricultural recentthe recent decades. For mostpracticesdecades. crops, Forthat the mosthelp improvements crops,to maximize the improvements arethe mainlyproductivity dueare main toper the unitly applicationdue of waterto the consumed.application of good agricultural Theseof good efforts agricultural practices help to that help tomaintainpractices maximize availablethat thehelp productivity resourcesto maximize and perthe achieve unitproductivity ofsustainability. water per consumed. unit A ofplot water Theseof the consumed. mean efforts CWP help These for to all maintainefforts crops help under available to study is shown in Figure 5. The crops with the highest CWP values (kg·m−3) under North Nile Delta resourcesmaintain and available achieve resources sustainability. and achieve A plot sustainability. of the mean A CWP plot of for the all mean crops CWP under for all study crops is under shown in conditions include: sugar beet (13.79), potato (w2) (10.69), tomato (w) (10.58), eggplant (w) (10.05), Figurestudy5. The is shown crops within Figure the highest5. The crops CWP with values the highest (kg ·m −CWP3) under values North (kg·m Nile−3) under Delta North conditions Nile Delta include: potatoconditions (w1) include: (9.98), cucumber sugar beet (w) (13.79), (9.91), potato and cabbage (w2) (10.69), (w) (9.59). tomato On (w) the (10.58), other hand,eggplant crops (w) with (10.05), the sugar beet (13.79), potato (w2)−3 (10.69), tomato (w) (10.58), eggplant (w) (10.05), potato (w1) (9.98), lowestpotato (w1)mean (9.98), CWP cucumber(kg·m ) are: (w) cotton(9.91), (0.29),and cabbage soybean (w) (0.45), (9.59). sunflower On the other (0.54), hand, lupine crops (0.69), with and the cucumber (w) (9.91), and cabbage (w) (9.59). On the other hand, crops with the lowest mean CWP mangolowest (0.72).mean CWP (kg·m−3) are: cotton (0.29), soybean (0.45), sunflower (0.54), lupine (0.69), and · −3 (kg mmango) are: (0.72). cotton (0.29), soybean (0.45), sunflower (0.54), lupine (0.69), and mango (0.72).

14.00 12.0014.00 10.0012.00 10.00

) 8.00 -3

) 6.008.00 -3 4.006.00

CWP (kg.m 2.004.00

CWP (kg.m 0.002.00 Flax

0.00 Rice Okra Lentil Garlic Apple Peach Barley Maize Lupine Wheat Cotton Mango Grapes Orange Banana Flax Rice Soybean Okra Maize (n) Maize Potato (s) Potato Lentil Onion (w) Garlic Apple Sugarbeet Pepper (s) Squach (s) Squach Date palm Date Faba bean… Faba Sugarcane Peach Barley Tomato (s) Maize Pepper (w) Squach (w) Squach Lupine Wheat Tomato (n) Cotton Mango Grapes Tomato (w) Cabbage (s) Eggplant (s) Orange Potato (w2) Potato potato (w1) potato Banana Cabbage (w) Eggplant (w) Soybean Sunflower (s) Sunflower Water melon Cucumber (s) Maize (n) Maize Potato (s) Potato Cucumber (w) Onion (w) Sugarbeet Pepper (s) Squach (s) Squach Date palm Date Faba bean… Faba Sugarcane Tomato (s) Pepper (w) Squach (w) Squach Tomato (n) Faba bean (dry) bean Faba Tomato (w) Cabbage (s) Eggplant (s) Potato (w2) Potato potato (w1) potato Cabbage (w) Eggplant (w) Water melon Sunflower (s) Sunflower Cucumber (s) Cucumber (w) Figure 5. Average (dry) bean Faba crop water productivity (CWP) for Egyptian crops grown in the Northern Nile DeltaFigure Region 5. Average over three crop decadeswater productivity (av. 1985–2015). (CWP) Note: for Egyptianw = winter crops season; grown s =in summer the Northern season; Nile n Figure 5. Average crop water productivity (CWP) for Egyptian crops grown in the Northern Nile Delta =Delta nili Regionseason. over three decades (av. 1985–2015). Note: w = winter season; s = summer season; n Region= nili over season. threedecades (av. 1985–2015). Note: w = winter season; s = summer season; n = nili season.

Water 2018, 10, 1168 8 of 12

Water 2018, 10, x FOR PEER REVIEW 8 of 12 TheWater CWP2018, 10 percentage, x FOR PEER REVIEW change trends from decade 1 to 3 are shown in Figure6 and from8 decade of 12 2 The CWP percentage change trends from decade 1 to 3 are shown in Figure 6 and from decade 2 to 3 in Figure7. to 3 inThe Figure CWP 7. percentage change trends from decade 1 to 3 are shown in Figure 6 and from decade 2 to 3 in Figure 7.

220 220200 200180 180160 160140 140120 120100 10080

Change % 8060

Change % 6040 4020 200 -200 -20 Flax Rice Okra Lentil Garlic Apple Peach Barley Maize Lupine Wheat Cotton Mango Grapes Orange Banana Flax Rice Okra Soybean Lentil Maize (n) Maize Garlic Apple Potato (s) Potato Peach Onion (w) Barley Pepper (s) Sugarbeet Squach (s) Squach Date palm Date Maize Sugarcane Lupine Wheat Cotton Mango Tomato (s) Grapes Pepper (w) Squach (w) Squach Orange Tomato (n) Banana Tomato (w) Cabbage (s) Eggplant (s) Potato (w2) Potato potato (w1) potato Soybean Cabbage (w) Eggplant (w) Maize (n) Maize Sunflower (s) Sunflower Water melon Cucumber (s) Potato (s) Potato Onion (w) Pepper (s) Sugarbeet Squach (s) Squach Date palm Date Cucumber (w) Sugarcane Tomato (s) Pepper (w) Squach (w) Squach Tomato (n) Tomato (w) Cabbage (s) Eggplant (s) Potato (w2) Potato potato (w1) potato Faba bean (dry) bean Faba Cabbage (w) Eggplant (w) Sunflower (s) Sunflower Water melon Cucumber (s) Cucumber (w) Faba bean (green) bean Faba

Faba bean (dry) bean Faba

Figure 6. Percent (green) bean Faba change in CWP for crops grown in the Northern Nile Delta Region in the third Figure 6. Percent change in CWP for crops grown in the Northern Nile Delta Region in the third decade Figuredecade 6.(2005–2015), Percent change compared in CWP to the for first crops decade grown (1985–1994). in the Northern Nile Delta Region in the third (2005–2015), compared to the first decade (1985–1994). decade (2005–2015), compared to the first decade (1985–1994).

80 80 60 60 40 40 20 20 0 Change % 0

Change % -20 -20 -40 -40 -60 -60 Flax Rice Okra Lentil Garlic Apple Peach Barley Maize Wheat Lupine Cotton Mango Grapes Orange Banana Flax Rice Okra Soybean Lentil Maize (n) Maize Garlic Apple Potato (s) Potato Peach Onion (w) Barley Pepper (s) Sugarbeet Squach (s) Squach Date palm Date Maize Sugarcane Wheat Lupine Cotton Mango Tomato (s) Grapes Pepper (w) Squach (w) Squach Orange Tomato (n) Banana Tomato (w) Cabbage (s) Eggplant (s) Potato (w2) Potato potato (w1) potato Soybean Cabbage (w) Eggplant (w) Maize (n) Maize Water melon Sunflower (s) Sunflower Cucumber (s) Potato (s) Potato Onion (w) Pepper (s) Sugarbeet Squach (s) Squach Date palm Date Sugarcane Cucumber (w) Tomato (s) Pepper (w) Squach (w) Squach Tomato (n) Tomato (w) Cabbage (s) Eggplant (s) Potato (w2) Potato potato (w1) potato Faba bean (dry) bean Faba Cabbage (w) Eggplant (w) Water melon Sunflower (s) Sunflower Cucumber (s) Cucumber (w) Faba bean (green) bean Faba

Faba bean (dry) bean Faba

Figure 7. Percent (green) bean Faba change in CWP for crops grown in the Northern Nile Delta Region in the third Figuredecade 7.(2005–2015), Percent change compared in CWP to the for second crops decadegrown (1995–2004).in the Northern Note: Nile The Delta absence Region of some in the crops third in Figure 7. Percent change in CWP for crops grown in the Northern Nile Delta Region in the third decade decadethe graph (2005–2015), indicates the compared absence to of the crop second cultivation decade during (1995–2004). that decade. Note: The absence of some crops in (2005–2015),the graph compared indicates tothe the absence second of crop decade cultivation (1995–2004). during Note: that decade. The absence of some crops in the graph indicates the absence of crop cultivation during that decade.

WaterWater 20182018,, 1010,, 1168x FOR PEER REVIEW 99 ofof 1212

4. Analysis of Results 4. Analysis of Results An increase in CWP was observed for most crops during the study period. Mean CWP increase for allAn crops increase amounted in CWP to was 41% observed from the for first most to th cropse second during decade the study and period.22% from Mean the CWPsecond increase to the forthird. all To crops examine amounted the reasons to 41% behind from the the first increase to the in second CWP, decadea closer and look 22% at the from trends the second of crop to yield the third.and water To examine consumption the reasons over behindthe study the period increase is inneed CWP,ed. aFigure closer 8 look presents at the values trends of of crop crop yield (ton and −1 waterha−1) for consumption crops under over consideration the study period in the study, is needed. and Figurean increasing8 presents yield values trend of is crop apparent. yield (ton The hamean) forincrease crops for under all crops consideration was 41% infrom the the study, first andto the an second increasing decade yield and trend 22% is from apparent. the second The meanto the increasethird. The for trends all crops are was likely 41% related from theto the first utilization to the second of higher decade yield and cultivars 22% from and/or the second an improvement to the third. The trends are likely related to the utilization of higher yield cultivars and/or an improvement of of agronomic practices. Figure 9 shows that the crop water consumption, represented by ETc, is agronomic practices. Figure9 shows that the crop water consumption, represented by ET , is declining declining with time. It is noted that the ETo decreased by 3% from the first to second decadec and by with time. It is noted that the ET decreased by 3% from the first to second decade and by 6% from 6% from the second to the third. oThe ETo changed due to climatic factors and not due to agronomic the second to the third. The ET changed due to climatic factors and not due to agronomic practices. practices. The same Kc values wereo used in CROPWAT 8.0 for all of the years; thus, our estimates of The same K values were used in CROPWAT 8.0 for all of the years; thus, our estimates of ET also ETc also decreasedc by 3% and 6% over time. In the third decade, new agronomic practicesc that decreasedreduce ET by were 3% andwidely 6% overadopted time. in In theEgypt. third Thes decade,e practices new agronomic are discussed practices below that reduce(Swelam, ET 2016; were widelyAlwang adopted et al., 2018; in Egypt. Molden These et al., practices 2010; Ghazouani are discussed et al., below2015; Lal (Swelam, and Stewart, 2016; Alwang2012; Swelam et al., et 2018; al., Molden2015) [18–23]. et al., 2010;While Ghazouani they are widely et al., adopted 2015; Lal and and can Stewart, explain 2012; some Swelam addition etal al., increases 2015) [18 in–23 CWP]. While due theyto decreases are widely in adoptedET, the main and can reason explain for somethe incr additionaleases in increases CWP are in clearly CWP duedue to to decreases better production in ET, the main reason for the increases in CWP are clearly due to better production from using higher yielding from using higher yielding crops and better crop and water management. Since the Kc values were cropskept constant and better over crop the and three water decades management. (except for Since rice, the whose Kc values variety were has keptchanged constant from over long the to threeshort decadesduration) (except the reduction for rice, in whose water variety consumption has changed must be from related long to to changes short duration) in climatic the conditions reduction inin waterthe study consumption area. The mustreasons be relatedbehind to this changes trend inare climatic under conditionsinvestigation in theand study shall area.be the The subject reasons of behindanother this publication. trend are under investigation and shall be the subject of another publication.

100.00

90.00

80.00

70.00

60.00

50.00

40.00

30.00 Decade average average cropDecade yield(ton/ha) 20.00

10.00

0.00 Flax Rice Okra Lentil Garlic Apple Peach Barley Maize Maize Wheat Lupine Cotton Mango Grapes Orange Banana Soybean Maize (n) Maize Potato (s) Potato Onion (w) Pepper (s) Pepper Sugarbeet Squach (s) Squach Date palm Sugarcane Tomato (s) Pepper (w) Pepper Squach (w) Squach Tomato (n) Tomato (w) Cabbage (s) Cabbage Eggplant (s) Eggplant Potato (w2) Potato potato (w1) potato Cabbage (w) Cabbage (w) Eggplant Sunflower (s) Sunflower Water melon Cucumber (s) Cucumber (w) Faba bean (dry) bean Faba Faba bean (green) bean Faba

1985-1994 1995-2004 2005-2015

Figure 8. Evolution of crop yield over three decades. Figure 8. Evolution of crop yield over three decades.

Water 2018, 10, 1168 10 of 12 Water 2018, 10, x FOR PEER REVIEW 10 of 12

18000

16000

14000

12000

10000 /ha) 3 (m

act 8000 ET

6000

4000

2000

0 Flax Rice Okra Lentil Garlic Apple Peach Barley Maize Maize Lupine Wheat Cotton Mango Grapes Orange Banana Soybean Maize (n) Maize Potato (s) Potato Onion (w) Pepper (s) Pepper Sugarbeet Squach (s) Squach Date palm Sugarcane Tomato (s) Pepper (w) Pepper Squach (w) Squach Tomato (n) Tomato (w) Cabbage (s) Eggplant (s) potato (w1) potato (w2) Potato Cabbage (w) Eggplant (w) Sunflower (s) Sunflower Water melon Cucumber (s) Cucumber (w) Cucumber Faba bean (dry) Faba bean Faba bean (green) Faba bean

1985-1994 1995-2204 2005-2015

Figure 9. Variation of ETact over three decades. Figure 9. Variation of ETact over three decades. The observed CWP increases are related to a decrease in crop water consumption to some extentThe and observed to an increase CWP increases of crop areyield related to a larger to a decrease extent. The in crop increase water in consumption CWP is also to partly some due extent to andbetter to anagronomic increase ofpractices. crop yield Many to a studies larger extent. and investigations The increase incarried CWP isout also on partly different due tocrops better in agronomicdifferent climatic practices. zones Many in Egypt studies have and shown investigations that using carried good agricultural out on different and irrigation crops in differentpractices climaticincreases zones crop inproductivity Egypt have and shown saves that irrigation using good water. agricultural For example, and irrigation recent studies practices showed increases that cropusing productivity raised beds andrather saves than irrigation basin irrigation water. For increased example, the recent yield studiesof wheat showed by 25% that and using it reduced raised bedsapplied rather water than by basin 25%, irrigation mainly due increased to reduction the yield in ofsoil wheat evaporation by 25% and(Swelam, it reduced 2016) applied [18]. The water raised by 25%,bed system mainly saves due tolabor, reduction time, water in soil and evaporation energy cost (Swelam,s. The raised 2016) bed [18 ].system The raised increases bed farm system yield saves by labor,30% while time, reducing water and production energy costs. costs The by raised 25%, bedcompared system to increases traditional farm farming yield by practices. 30% while According reducing productionto the authors costs of byAlwang 25%, comparedet al., 2018; to Molden traditional et al., farming 2010; Ghazouani practices. et According al., 2015; toLal the and authors Stewart, of Alwang2012; Swelam et al., 2018;et al., Molden2015 [19–23], et al., in 2010; Egypt, Ghazouani the usage et of al., raised 2015; beds Lal and has Stewart,improved 2012; surface Swelam irrigation et al., 2015efficiency [19–23 and], in crop Egypt, productivity. the usage Using of raised raised beds beds has at improved a width of surface 130 cm irrigation with 180 efficiencykg N ha−1 led and to crop the −1 productivity.highest wheat Using grain raisedyield. Thus, beds atin adry width areas, of 130where cm water with 180resources kg N haare oftenled tolimited the highest and nutrient wheat grainuptake yield. and efficiencies Thus, in dry are areas, low, the where use waterof a raised resources bed system are often with limited optimal and nitrogen nutrient fertilizer uptake level and efficienciesprovides a distinct are low, advantage. the use of a raised bed system with optimal nitrogen fertilizer level provides a distinctIn Egypt, advantage. land levelling is practiced on a large scale by the government and/or private sector. A goodIn example Egypt, landinvolves levelling sugarcane is practiced fields, on where a large the scale government by the government is subsidizing and/or laser private levelling sector. by Aabout good 50% example of its cost involves to improve sugarcane water fields, productivity where theand government reduce applied is subsidizing water. Another laser example levelling is by in aboutrice cultivation, 50% of its costwhere to levelling improve wateris done productivity in flooded fields and reduce using applieda wooden water. beam Another and animal example traction. is in riceThis cultivation, minimizes wherepercolation levelling through is done the in soil flooded profile. fields According using a woodento the author beam of and Allam animal et al., traction. 2005 This[24], minimizesthe main objectives percolation of through land levelling the soil are profile. to achieve According better to thewater author distribution of Allam uniformity et al., 2005 [and24], theincreased main objectives crop production of land levellingas well as are minimize to achieve water better losses water through distribution reducing uniformity run-off. and Thus, increased about crop31% of production the applied as water well as is minimizesaved by waterusing laser losses land through leveling reducing in Egypt. run-off. Thus, about 31% of the applied water is saved by using laser land leveling in Egypt. 5. Conclusions In view of the growing water scarcity, declining water quality, and the uncertainties of climate change, improving irrigation efficiency and water productivity, while simultaneously reducing

Water 2018, 10, 1168 11 of 12

5. Conclusions In view of the growing water scarcity, declining water quality, and the uncertainties of climate change, improving irrigation efficiency and water productivity, while simultaneously reducing negative environmental impacts is of utmost importance in responding to the increasing food demand of the growing world population. To this end, irrigated agriculture must adopt more knowledge-intensive management solutions. In the current study, crop water productivity (CWP) trends were calculated over three decades, with a focus on the productivity trend of the third decade relative to the first and second decades. The study also identifies crops with high and low CWP under Northern Nile Delta climate conditions. The CWP increased for most crops under investigation in the region. Crops that achieved the highest increase in mean decadal CWP from the first to the third decade include winter tomato (210%), mango (154%), summer tomato (145%), winter onion (132%), nili tomato (128%), grapes (122%) and flax (114%). The analysis showed that most of the increase in CWP is related to increase in crop yield, which increased by 41% for all crops from the first to the second decade and by 22% from the second to the third decade. The increase is mainly attributed to the application of better agronomic practices and/or to the utilization of higher yielding varieties. A small decline in overall crop water consumption was observed, i.e., a mean decrease of 3% from the first to the second and 6% from the second to the third decade. The reduction in water consumption is likely related to changes in climatic conditions within the study area. In descending order, the crops with the highest CWP values (kg/m3) over three decades were sugar beet, potato (w2), tomato (w), eggplant (w), potato (w1), cucumber (w), and cabbage (w). This study emphasizes biophysical water productivity rather than policy and economics. Biophysical water productivity is insufficient as a standalone indicator for crop selection. Thus, economic and social comparison is needed for policy support. The objective of this work is to determine what crops have the highest water productivity per unit of water consumed in the Northern Nile Delta Region of Egypt. The results of the study are useful for comparison with other agricultural regions having different climatic conditions to determine which region has the highest water productivity for a particular crop.

Author Contributions: Conceptualization, A.S. and S.M.E.-M.; Methodology, A.S. and S.M.E.-M.; Software and validation, S.M.E.-M., A.S. and A.G.; Formal Analysis, A.S. and S.M.E.-M.; Investigation, A.G.; Resources, A.S.; Data Curation, S.M.E.-M.; Writing-Original Draft Preparation, S.M.E.-M. and A.S.; Writing-Review & Editing, A.G.; Visualization, A.S. and A.G.; Supervision, A.S.; Project Administration, A.S.; Funding Acquisition, A.S. Funding: This research was funded by the Arab fund for Economic and Social Development (AFESD) through the Research Collaboration Agreement between The Agricultural Research Center of the Egyptian Ministry of Agriculture and Land Reclamation (ARC) and the International Centre for Agricultural Research in the Dry Areas (ICARDA) under the title, “Sustainability and Operation of the Regional Research Centers in a Number of Arab Countries”. Acknowledgments: The Authors would like to thank Richard Snyder, Biometeorologist at University of California, Davis and Usman Awan, Groundwater specialist at ICARDA for their technical support and review this paper during the writing and preparation processes. Conflicts of Interest: Declare conflicts of interest or state.

References

1. Pasquale, S.; Theodore, C.; Hsiao, E.F.; Dirk, R. FAO Irrigation and Drainage Paper 66, Crop Yield Response to Water; Food and Agriculture Organization of the United Nations: Rome, Italy, 2012. 2. Woolley, J.; Cook, S.E.; Molden, D.; Harrington, L. Water, food and development: The cgiar challenge program on water and food. Water Int. 2009, 34, 4–12. [CrossRef] 3. Zwart, S.; Bastiaanssen, W. Review of measured crop water productivity values for irrigated wheat, rice, cotton and maize. Agric. Water Manag. 2004, 69, 115–133. [CrossRef] 4. Karam, F.; Breidy, J.; Stephan, C.; Rouphael, J. Evapotranspiration, yield and water use efficiency of drip irrigated corn in the Bekaa Valley of Lebanon. Agric. Water Manag. 2003, 63, 125–137. [CrossRef] Water 2018, 10, 1168 12 of 12

5. Grismer, M.E. Regional cotton lint yield, ETc and water value in Arizona and California. Agric. Water Manag. 2002, 54, 227–242. [CrossRef] 6. Egyptian Environmental Affairs Agency (EEAA). The Environmental Profile of Kafr El Sheikh; EEAA: Cairo, Egypt, 2015. (In Arabic) 7. Kassam, A.; Smith, M. FAO methodologies on crop water use and crop water productivity. In Proceedings of the Expert Meeting on Crop Water Productivity, Rome, Italy, 3–5 December 2001. 8. Ministry of Agriculture and Land Reclamation (MALR). Economic Affairs Sector—Bulletin of Important Indicators of the Agricultural Statistics; Volumes No. 1986; MALR: Cairo, Egypt, 2016. 9. Allen, R.G.; Pereira, L.S.; Raes, D.; Smith, M. Crop Evapotranspiration-Guidelines for computing crop water requirements-FAO Irrigation and drainage paper 56. Fao Rome 1998, 300, D05109. 10. El-Marsafawy, S.M.; Ali, M.A.; Salib, A.Y.; Eid, H.M. Effect of different sowing dates on some wheat varieties yield and their water relations. In Proceedings of the Third Conference of Meteorology & Sustainable Development, Cairo, Egypt, 15–17 February 1998. 11. Mohamed, K.A.; El Lithy, R.E.; Samia, M.E. Effect of withholding irrigation at different growth stages on productivity of some soybean varieties. Ann. Agric. Sci. Moshtohor 2004, 42, 1441–1456. 12. El-Samanody, M.K.M.; Awad, M.A.; El-Marsafawy, S.M. Scheduling irrigation of canola under nitrogen sources in Middle Egypt. Misr J. Agric. Eng. 2004, 21, 165–188. 13. El-Marsafawy, S.M.; Salib, A.Y.; Ali, M.A.; Eid, H.M. Row width and nitrogen levels impacts on water relations, growth and yield of maize crop. In Proceedings of the Third Conference of Meteorology & Sustainable Development, Cairo, Egypt, 15–17 February 1998. 14. Rayan, A.A.; Mohamed, K.A.; Khalil, F.A.; El-Marsafawy, S.M. Scheduling irrigation of cotton crop under different nitrogen fertilizer levels in Upper Egypt. In Proceedings of the 5th Conference Meteorology & Sustainable Development, Cairo, Egypt, 22–24 February 2000. 15. Doorenbos, J.; Kassam, A. Yield Response to Water. FAO Irrigation; Drainage Paper No. 33; Pergamon Press: Oxford, UK, 1986. 16. Rayan, A.A.; El-Marsafawy, S.M.; Mohamed, K.A. Response of some wheat varieties to different sowing dates and irrigation regimes in Upper Egypt. In Proceedings of the 3rd Conference of On-Farm Irrigation and Agroclimatology, Cairo, Egypt, 25–27 January 1999. 17. El-Marsafawy, S.M. Scheduling irrigation of wheat crop under different phosphorus fertilizer application times in Middle Egypt. In Proceedings of the 5th Conference of Meteorology & Sustainable Development, Cairo, Egypt, 22–24 February 2000. 18. Swelam, A. Science Impact: Raised-Bed Planting in Egypt: An Affordable Technology to Rationalize Water Use and Enhance Water Productivity. Available online: http://www.icarda.org/sites/default/files/u158/ Science%20Impact%20Raised-Bed_final.pdf (accessed on 6 February 2016). 19. Alwang, J.; Sabry, S.; Shideed, K.; Swelam, A.; Halila, H. Economic and food security benefits associated with raised-bed wheat production in Egypt. Food Secur. 2018, 10, 589–600. [CrossRef] 20. Molden, D.; Oweis, T.; Steduto, P.; Bindraban, P.; Hanjra, M.A.; Kijne, J. Improving agricultural water productivity: Between optimism and caution. Agric. Water Manag. 2010, 97, 528–535. [CrossRef] 21. Ghazouani, W.; Molle, F.; Swelam, A.; Rap, E.; Abdo, A. Understanding Farmers’ Adaptation to Water Scarcity: A Case Study from the Western Nile Delta, Egypt; IWMI: Colombo, Sri Lanka, 2015. 22. Lal, R.; Stewart, B.A. Soil Water and Agronomic Productivity; CRC Press: New York, NY, USA, 2012. 23. Swelam, A.A.; Hassan, M.A.; Osman, E.A.M. Effect of raised bed width and nitrogen fertilizer level on productivity and nutritional status of bread wheat. Egypt J. Appl. Sci. 2015, 30, 223–234. 24. Allam, M.N.; El Gamal, F.; Hesham, M. Irrigation systems performance in Egypt. Irrig. Syst. Perform. Options Méditerr. Sér. B Etudes Rech. 2005, 52, 85–98.

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).