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Adaptation to climate change in desertified lands of the marginal regions in Egypt through sustainable crop and livestock diversification systems

2015-12-19HassanElShaer

Sciences in Cold and Arid Regions 2015年1期

Hassan M.El Shaer

Desert Research Center,Mataria,Cairo,Egypt

1 Egypt's topography and climate

Egypt is located in northeastern corner of Africa,bordering the Mediterranean Sea between Libya and the Gaza Strip,with a coastal strip extending for about 3,500 km(facing the Mediterranean Sea in the north,and the Red Sea in the east).It covers an area of slightly more than 1 million km2.Almost all(99%)of the 85 million population lives in about 4% of the total land in a small band alongside the Nile River,in the Nile Valley,in the Nile Delta,and in coastal areas.Egypt's densely packed population makes the country extremely vulnerable to climate change.The coastal zone of the Nile Delta in Egypt is perceived as vulnerable to the impacts of climate change,not only because of expected sea level rise but also because of the effects on water resources,agricultural resources,tourism,and human settlements.The indirect impacts of climate changes are perceived to include demographic dislocations and socioeconomic disruptions.

Egypt's climate is semi-desert characterized by hot,dry summers,moderate winters,very little rainfall(5–200 mm/a),and high evaporation rates(1,500–2,400 mm/a).The country is characterized by particularly good wind regimes,with excellent sites along the Red Sea and Mediterranean coasts.

Despite its aridity,the year-round climate of Egypt is ideal for a wide variety of crops.This makes it possible to adopt an intensive cropping system which permits the production of more than one crop per year in most of the cultivated areas(EEAA,1997;El-Nahrawy,2008).

2 Impact of climate changes on agriculture

Agriculture is a key sector in the Egyptian economy.It contributes about 40% to the gross domestic product(GDP)and 22% to commodity exports,and accounts for 50% of overall employment.Approximately 54% of Egypt's population lives in rural areas(SADS,2009).The agricultural production is mostly for home consumption,but Egypt is far from being self-sufficient in certain food materials.Climate change would make the situation even worse as a result of its expected adverse impact on the national production of many crops.

Environmental degradation resulting from current climate changes,including prolonged drought,land degradation,desertification,and loss of biodiversity,is presenting enormous challenges to achieve food security and eradication of poverty in the marginal regions,which represent about 90% of the total area of Egypt(EEAA,1997).Such regions are subjected to improper land and water management,and there is a lack of knowledge,technologies,and experience to address the current severe climatic changes.

3 Impact of climate changes on water resources

Egypt has only one main source of water supply,the Nile River,which supplies more than 95% of the water needs of the country.The country has no effective rainfall except in a narrow band along the northern coast.There is some winter rain in the delta and along the Mediterranean coast,west of the delta.Non-renewable underground aquifer water supplies are accessible outside the river valley,especially in the oases.Consequently,agricultural development is closely linked to the Nile River and its management.Although the impact of climate change has not yet been predicted in the Nile Basin,there are indications that the effects will be significant(EEAA,1997;El-Nahrawy,2008).Any decrease in the total supply of water,coupled with the expected increase in consumption due to the high population growth rates,will have drastic impacts.Therefore,water management is one of the most important adaptation actions.Adaptive strategies include measures to improve rain harvesting techniques,increase extraction of groundwater,recycle water,desalinate water,improve water transportation,and rationalize water use.

Meanwhile,adaptation of demand requires minimizing the need for water and optimizing the economic return on its unit volumes.For example,mega projects to divert some of the Nile River water to northern Sinai and to the Toshka Depression in southern Egypt are underway to address the rapidly growing water needs of the country.The total available water resources are estimated at 73.8 billion m3annually,and the total annual water use is about 62.6 billion m3.Agriculture's share of the water budget is about 81%,and increased to 85% in 2006(El-Beltagy and Abo-Hadeed,2008).According to the Sustainable Agricultural Development Strategy Towards 2030(SADS,2009),per capita fresh water use is expected to decline from 711.0 m3in 2008 to 550 m3in 2030.An increase in water availability could result from proper management of water through more effective on farm water management practices,shifts in cropping patterns toward less-water-consuming crops,the introduction of improved irrigation systems,and reuse of drainage water and treated sewage water(Abouzeid,1992;FAO,2003;SADS,2009).

4 Impact of climate changes on livestock and rangeland resources

Livestock constitutes an important component of the agricultural sector,representing about 24.5% of the agricultural GDP with a value of about US$6.1 billion(SADS,2009).Livestock production occurs mainly in the private sector,with the majority of animal breeders being smallholding farmers;the share of the government sector is less than 2% of the total animal numbers.The ruminant sector is well-integrated with croplands,since Egypt has limited natural pastures.Animal production is highly dependent on cattle and buffalo as milk-producing animals,and male animals and non-reproductive females are fattened for meat.

According to the Statistical Bulletin for Year 2012 for Livestock(MALR,2012),the total numbers of animals were estimated as 4.9 million cattle,4.2 million buffalo,5.2 million sheep,4.3 million goats,and 141,537 camels,in addition to 1.4 million other domestic animals like horses,donkeys,etc..The availability of balanced feeds is crucially important in animal production in Egypt.In 2012 the amounts of feed produced were decreased due,in part,to the impact of climate changes on cultivation of feed ingredients(MALR,2012).

Egypt has poor rangelands(FAO,2010).Hegaziet al.(2005)indicated that the main rangeland areas are distributed over the northwestern coast(NWC)region,the Sinai Peninsula,and the Halaib-Shalateen region in the southeastern corner of Egypt.The natural vegetation of these regions is the principal feed resource there(El Shaer,2006).The vegetation cover is seasonally and drastically variable depending on rainfall.It is generally of low forage yield and quality due to several environmental and management factors(El Shaer,1981,2004).As animal feeds,the yields of this vegetation do not cover the annual nutritional requirements for livestock(El-Lakany,1987;El Shaer,2010).The range vegetation in most of these regions is characterized by stands of shrubs and semi-shrubs with a cover of short-lived annual forbs and grasses.The degradation of natural resources in the NWC and Sinai regions is part of an endemic cycle of poverty,lack of viable production alternatives,and uncoordinated regional development(FAO,2010).

Fodder crops are forages irrigated with Nile River water,mainly in Nile Delta region,and constitute about 18% of the value of field crops(El-Lakany,1987;Etmanet al.,1994;El-Nahrawyet al.,1996).These include berseem(Trifolium alexandrinumL.),alfalfa(Medicago sativaL.),hybrid forage sorghum(Sorghum sudanense X Sorghum bicolor),Sudan grass(Sorghum sudanense(Piper)Stapf.),pearl millet(Pennisetum glaucumL.);fodder maize(Darawa)(Zea maysL.),and minor forages such as cowpeas(Vigna sinensisL.),teosinte(Euchlanea mexicanaSchrad.),Italian ryegrass(Lolium multiflorum),guar(Cyamposis tetragonoloba),fodder beets(Beta vulgarisL.),chickling peas or rough peas(Lathyrus sativus),elephant grass(Pennisetum purpureumSchumach),amshot(Echinochloa stagninum),sesbania(Sesbania sesbanL.),and triticale.

5 Livestock and rangelands production limitations

During the last few decades these rangelands have been degraded by transformation into agricultural land(increased water and wind erosion),and by overgrazing that has led to further erosion and reduced botanical diversity.Increasing animal numbers have disturbed the balance between available forage and carrying capacity,as reported by El Shaer(2010).However,there are several constraints that limit rangeland utilization and livestock production,such as:

1)Inadequate feeding causes high mortality of young animals,low daily gain,and reproduction performance well below the genetic potential.Inadequate feeding results from low pasture quality and productivity,especially in the rainfed areas,and inadequate diet formulations due to farmers' lack of knowledge of nutritional values and feed requirements.This is the major limiting factor for livestock production;

2)Inadequate stock water in most range areas.Animals may have to travel long distances to water points,and some water is of poor quality;

3)Inadequate herd management practices leading to uncontrolled reproduction;

4)Herd health management is still insufficient;

5)Resource degradation,including soil loss to water and wind erosion,loss of soil fertility,soil salinization,decrease of aquifers,and degradation of range due to overgrazing and cultivation of marginal lands;

6)Climate change constraints,particularly high-frequency and long-term drought.

Because most of the rangelands are degraded by recurrent drought and overgrazing,they provide only 5% of livestock feed(FAO,2010).It is therefore crucial to find sustainable sources of feed resources,especially forage crops.There must be greater emphasis on the establishment of viable management systems to alleviate the degradation of the rangelands,and developing and distributing fodder shrubs to control desertification and cope with impacts of climate changes.Utilization of salt-affected soils and saline/brackish water resources for crop/forage production could be a potential approach for alleviating the impact of climate changes,particularly in marginal areas in Egypt(Anon,2009,2013).

Cultivating irrigated forages in salt-affected soils using poor-quality water is considered one of the best ways of overcoming shortages in feed,especially in the Egyptian desert areas(Anon,2009).Several studies(Fahmy,2001;El Shaer,2006,2010)recommended the following potential fodders for this purpose:alfalfa(Medicago sativaL.),ryegrass(Lolium perenneL.),pearl millet(Pennisetum glaucumL.),cowpeas(Vigna sinensisL.),Egyptian clover(Trifolium alexandrinumL.),Rhodes grass(Chloris gayana),fodder beets(Beta vulgarisL.),Acacia cyanophila,Sesbania sesban,Leucaena leucocephala,Prosopis cheilanse,andProsopis jioflora.

6 Livestock/salt-tolerant fodder crop integrated system

In the marginal areas of Egypt,agriculture development approaches should exploit and utilize the most-common natural resources(saline soils and saline irrigated water)in a more efficient manner to improve the livelihoods and social lives of local people.There is a great need for establishing sustainable integrated ecosystem rehabilitation and management programs to overcome agro-environmental challenges,particularly in the Sinai Peninsula.

A series of research and development projects have been conducted since 2006 to improve the livelihoods of smallholders through enhancing the efficient management and utilization of local resources that can cope with the drastic changes of climate in the Sinai Peninsula.An integrated livestock/salt-tolerant fodder crop system was introduced in 2010 to many smallholders in Wadi Sudr area in South Sinai governorate by our project team work(DRC).The main objectives of this program were:

1)Proper utilization of the most-commonly available natural resources(saline soils and water,and natural vegetation)to produce fodder crops;

2)To provide appropriate feed all over the year for all livestock species at adequate economic and nutritional levels;

3)Reduce the cost of livestock products;

4)Increase the net profit for farmers,consequently improving their livelihoods and their income.

6.1 General characteristics of Wadi Sudr area

The Wadi(Valley)Sudr area in the South Sinai region was chosen to implement the project.It is located about 45 km south of Suez City at the eastern side of the Suez Gulf.It is characterized by extremely arid conditions,where the annual rainfall is about 16 mm/a.The relative humidity is generally low,about 45% to 55%,and does not vary widely throughout the year.The air temperature is mild with a mean annual maximum of 28 °C and a mean annual minimum of 18 °C;the mean annual temperature is 22 °C.

The most important program achievements were:

1)Testing,cultivation,and adaptation of some native and exotic fodder plant species under different saline conditions;

2)Evaluation of the growth and yield parameters of such forage species grown in saline conditions;

3)Evaluation of the palatability,consumption,and nutritive values of the recommended fodder crops for sheep and goats;

4)Utilization of such fodder crops in livestock production;

5)Economic evaluation of livestock production under saline conditions.

6.2 Soil and irrigation water characteristics

Eight sites were selected for the project activities at Wadi Sudr(Sudr Valley),South Sinai.Several conventional salt-tolerant forage species(salinity levels up to 15 dS/m)and non-conventional salt-tolerant species(salinity levels up to 25 dS/m)and accessions suitable for the farming system in the region were identified.In addition,several conventional succession(winter followed by summer)forage species and accessions were planted for evaluation and utilization.

Soil chemical properties and the chemical contents of irrigation water were also tested.The plant species were irrigated with two levels of saline groundwater:medium salinity(>4,000 mg/kg total salts)and high salinity(>7,000 mg/kg total salts).Two types of irrigation systems were evaluated:a drip irrigation system(DIS)and a gated pipe irrigation system(GPIS)were used(Anon,2009).

Research was conducted to evaluate and assess the effect of salinity in irrigation water,soil,and irrigation systems on plant growth,production,nutritive values,and utilization by sheep and goats.Several growth characteristics were determined for each of the three evaluated grass species:plant height(cm),number of leaves per plant,fresh weight(g),dry weight(g),leaf area(cm2),and fodder yield(kg/hm2).The crop forage production,as fresh or in terms of dry matter(DM),total digestible nutrients(TDN),or digestible crude protein(DCP)yield and nutritive value were also evaluated(Anon,2009).

Based on the field and laboratory investigations,soil profiles of the demonstration farms are summarized in Table 1.The surface topography and the slope were almost flat and the top soils were relatively deep(150 cm).The texture ranged from sandy to clay loam and the structure was single grains or masses,sometimes stratified;the soil consistency was friable and firm.The rock fragment content varied widely from common to abundant(6.7%-80.6%)with no specific trend.Generally,the soils were moderately alkaline(pH 7.7–8.2).

The main water resource for the agriculture sector in the Ras Sudr area is groundwater from a Quaternary aquifer.The depth to water was <100 m and the salinity varied from 4,000 to 9,000 mg/kg.Chemical analysis of the groundwater irrigation indicated that the salinity concentration in the high-salinity irrigation water was almost double that of the medium-salinity irrigation water(13.90 vs.7.53 dS/m);most of the mineral concentrations in the high-salinity water,such as Na,K,and Cl,were higher than those of the medium-salinity water,which would be expected to affect the plant growth parameters and nutritive values(El Shaeret al.,1987;Youssefet al.,2009).

Table 1 Soil characteristics of the demonstration farms

6.3 The main results and achievements

The main results and achievements of this study and program were as follows.

6.3.1 Forage genotypes and production traits

Analysis of 10 exoticSorghum bicolorL.genotypes,tested for genetic diversity by using the ISSR(Inter Simple Sequence Repeats)marker tool,pointed out that certain genotypes(Omani landrace,and Pioneer 858)were grouped closer to each other and their similarity ranged from 92% to 91%.

Three genotypes of barley were grown in salt-affected soils and irrigated with different saline water levels.Their yield attributes(number of tillers/m2),biological yields(kg/hm2),and grain yields(kg/hm2)were significantly affected by water irrigation salinity levels,irrigation system type,and project locations.Apparently the increasing salinity level significantly decreased the yield and yield attributes of barley under the two irrigation methods.The highest values of biological and grain yield were recorded using a drip irrigation system under 4,000 mg/kg salinity,whereas the lowest values of biological yield were obtained using a furrow irrigation system under high-salinity conditions.There were no significant differences among the two irrigation methods in barley grain yield under high-salinity(7,000 mg/kg)conditions.

The productivity of three fodder beet genotypes can be summarized as follows:

1)Regardless of the genotype factor,all production traits of the three fodder beet genotypes were greatly affected by project locations,irrigation salinity levels,and irrigation systems(DIS vs.GPIS);

2)Apparently the fodder beet genotype R1 was generally superior to the other genotypes with regard to all production parameters.

The productivity of 38 introduced pearl millet genotypes grown under saline conditions(approximately 4,500 mg/kg total salinity in the irrigation water)indicated that most of these introduced millet lines were adapted to the salinity conditions of the South Sinai region.

When three summer grasses were compared,pearl millet had a greater ability to tolerate salinity than did Sudan grass and sorghum in all locations at the medium-salinity level(>4,000 mg/kg)and high-salinity level(>7,000 mg/kg)for all measured growth characters.The sorghum yield had a moderate ability to tolerate salinity.Its yield was poor under high-salinity(>7,500 mg/kg)irrigation water in different locations.The millet yield was the most affected by increasing the salinity level of the irrigation water over >4,000 mg/kg.

The drip irrigation system was the most efficient for the three grass crops;the yields of millet,sorghum,and Sudan grass under the drip irrigation system were higher than those under the gated pipe irrigation system in all locations.Based on these measured parameters,the drip irrigation system was more suitable than the gated pipe irrigation system under high-salinity conditions,and pearl millet was superior in all growth characteristics and fodder yield.

Tissue culture studies revealed thatAtriplex halimus,Nitraria retusa,Periploca angustifolia,andMoricandia nitensshowed promising results inin vitropropagation during the tested stages for each plant.They need further studies to obtain established plantlets able to survive the existing saline conditions.

6.3.2 Utilization of salt-tolerant fodders in livestock feeding

All fodder species grown during the project were directly used for feeding sheep,goats,cattle,and camels in fresh form or ensiled with other feed ingredients,either offered as a single fodder or mixed with others.Intensive studies were conducted to evaluate the effects of feeding halophytic and salt-tolerant feedstuffs on livestock nutrition,physiology,production,and reproduction in the South Sinai region(Fahmy,2001;Anon,2009;Youssefet al.,2009;El Shaer,2010;Fahmyet al.,2010;Anon,2013).Some data on salt-tolerant grasses will be briefly discussed herein.

The grasses irrigated with medium-salinity(>4,000 mg/kg)and high-salinity(>7,000 mg/kg)water appeared to be nutritious for small ruminants,as it contained enough CP contents(average 13%)to meet their protein requirements.On an overall average basis,they attained high organic matter contents with low concentrations of ADF and ADL,as shown in Table 2.The concentrations of the tested major and trace elements were in the normal range of common grasses,regardless of the high salinity in the irrigation water.

Table 2 Chemical composition and fiber constituents of three grasses(%,on dry matter basis)irrigated with medium-and high-salinity water

Table 3 shows that the crop production,as fresh(green)weight or in terms of DM,TDN,or DCP yield per hectare,for the three grasses irrigated with medium-salinity water was greater than those irrigated with high-salinity water.Regardless of the water salinity levels,sorghum grass irrigated using medium-salinity water recorded the highest fresh biomass production(23,521 kg/hm2),DM yield(8,349 kg/hm2),CP yield(986 kg/hm2),TDN yield(5,018 kg/hm2),and DCP yield(697 kg/hm2).The production of these nutrients per hectare of such grasses could meet the maintenance and lactation requirements of 55 and 24 sheep,respectively,for 90 days when these animals are fed sorghum grass irrigated with medium-salinity water.These results indicate that the tested salt-tolerant grass species showed great potential as good-quality animal feed under saline conditions of the region,particularly during the summer and autumn seasons when traditional feed materials are not available and natural rangelands are in very poor condition(Moawd,1998;El Shaer,2006,2010;Anon,2009).

Table 3 Average crop yields of three cultivated salt-tolerant grasses(kg/hm2)

These results suggest that feeding sorghum,pearl millet,and Sudan grass grown in saline soils and irrigated with high-saline water would be economically feasible because the low-and medium-saline water could be saved and used for producing conventional cash crops.At the individual farmer level,feeding salt-tolerant fodders to livestock resulted in an increase of about 60% in milk production and 80% in meat production,and reduced feed costs by about 40%.Accordingly,a 70% increase in family income was achieved.

Therefore,the benefits of an integrated livestock/crop production system are:

1)Ensure socio-economic and technical support for small holders;

2)Enhance the sustainability of natural resources efficient utilization;

3)Increase animal protein products(e.g.,meat,milk,eggs);

4)Increase the income of farmers;

5)Reduce feed imports and increase the marketing of forages and animal products.

7 Conclusion

In conclusion,better utilization of fragile ecosystem resources and planting salt-tolerant fodder crops and oil plants may contribute to the development of the marginal areas in Egypt and enhance the living standards of the local people.

The author greatly acknowledges the International Centre for Biosaline Agriculture(ICBA),the Islamic Development Bank(IDB),the OPEC Fund for International Development(OFID),and the International Fund for Agricultural Development(IFAD)for their financial support to enable the project team work of the Desert Research Center(DRC)to conduct this project.

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