Eng6

1. Jfuas No.2 December 2013 Review ofWater Harvesting Techniques for the Improvement of Crop Production in North Darfur State Salih Ahmedai Abdalla, Faculty of Environmental Sciences and Natural Resources University of Al-Fashir, Sudan

2. ! # $% 77 JW

3. !1 2 345 6 # * +, -. ,

6. '() K

7. ! #$ ! ? ! ? @ K6 :. ;()* $=* 7 80 9( -8A( B C DE( F E

8. EG H 'IJ K LK(D 3: M ND O( KP' N, LQ )' H'#5 6 U'$ @ T : P ' S) N, H '#5 -8A( BL R

9. :. -

10. # :Z 6

11. ( Y D: - 4 X B

12. ')8 J T + J 6 D'IW( V) ')8J -8A( KL

13. M^ Q ]$? T J 8: 8[

14. KH[8 :Z a b DJ 8 G

15. :QL (W1 2000 , _:Z `', 6U'$ -2) I'L 8 T ' '] :5 T 6D

16. ( @ T: R

17. bD (W1 300 _ )J '[()* !K K- 4 X B / c 6 D'IW( - 2) -8A( 5 !9 d)eL H '#( PK 1 f N(5 K 8'D#( ':. X EL )# ! J

18. 4 b8 #5 C g H '#( PK 1 C D[ 8 : h:. ID i N(0 $DW j b ? ! k LQD 6L

19. (l ! Z 8: 5 H '#( PK 1 K '[

20. ( * +' l '(m n +' ID '[()* ! Z '

21. P' K95 LQ L

22. Nm 'D# H L? p # #( B YD: 8:5 R

23. 'D fD4

24. 5 oU 4B Kq'

25. 185 #$ T 8?

26. 2013 ,-./( – *+ () - #$% ! – 78 Abstract The climatic zones of Darfur region are characterized by low rainfall in the northern parts desert and semi-desert and moderate to high rainfall in the southern parts. North Darfur State lies in the Sahel zone. This zone is about 800 km wide and has a dry period of up to 9 months. It is characterized by a recurrent periodic drought, traditional rain-fed agricultural production and low yield per unit area. Runoff is the main source of surface and ground water. Water resources assessment showed that there are vast amounts of ground water with good to excellent quality which can be used for crop production. Under erratic rainfall conditions in the semi-arid zone of sub-Sahara Africa, a major contribution to improve crop production can be anticipated from improved and up- scale soil water conservation and rainwater harvesting practices. Rainwater harvesting is essential for supporting sustainable crop production in sub-Sahara Africa facing climatic change impacts. Supplementary irrigation is practiced in Sag El Naam project. Flood diversion is practiced in Kidinir area using a canal for diverting flows to 8 km and annually 2000 ha were being irrigated. Spread irrigation systems like hafirs surrounded by embankment for collection of floodwater, with siphon inlet provided with sluice gate and off-spreading were practiced along the wadis. In Malam El Wadayin project the water stored in the dam was diverted by two canals to irrigate 300 ha. These practices improve hydrological indicators such as infiltration and groundwater recharge. Nutrients and biomass increase with subsequent higher yields. Higher

27. Jfuas No.2 December 2013 biomass supports a higher number of plants and animals, although native species might be replaced by crops as the landscape might change as a whole. This might trigger conflicts between nomadic and sedentary population. Use of micro catchments, water spreading techniques and introduced new technologies offer opportunities for runoff farming .Early maturing varieties adapted to the environment with their higher yields were preferred for providing the farmers with subsistence food and fodder for their livestock. 1-Introduction North Darfur State lies between latitudes 12º N and 20º N and longitudes 21º 52 E and 27º 54 E. Its population is 1.3 million according to 1993 census. The State is located on the southern edge of the Sahara desert and falls within the arid climatic Sahel zone, which extends from the Atlantic coast of West Africa to the Sudan. The boundaries of the Sahel are demarcated by the 100mm and 600mm isohyets average annual rainfall. In the Sahel zone three precipitation regimes are recognized, the sub-desert 200mm, the typical Sahel 200-400mm with a rainy season of 2 to 2.5 months and the Sahel of Sudanese border (400-600mm). The rainy season extends from May to October with a peak in August. The rainfall fluctuates in north and middle parts of the state. There are many Wadis (seasonal stream), which drain large amounts of surface runoff and its use is very limited in runoff farming and agricultural production. There are three types of soils classified as sandy, loam and clay. Sandy soils have a high infiltration rate, but low retention capacity. It consists of 60% coarse 79

28. 2013 ,-./( – *+ () - #$% ! – to fine sand and less than 10% clay. Loamy and clay soils cover limited areas. The most suitable soils for water harvesting are generally medium- textured, deep loam soils (2m) with the capacity to store the harvested runoff water. Sodic and saline soil zones which have excess soluble salts should be avoided. People practice rain-fed shifting cultivation on sandy and clay soils. They cultivate sorghum, millet, sesame and groundnuts during the rainy season and they keep livestock. Traditionally, farmers practice a type of rotating fallow agriculture, which leaves portion of the land with some form of ground cover. The term water harvesting is used to describe the technique of collecting and storing water for later beneficial use from an area modified to increase precipitation runoff. The collected water can be used for domestic and animal uses and for crops growing. All water harvesting systems have a catchment area for collecting and concentrating the precipitation and storage facility for holding the collected water. A typical storage technique can be an earth reservoir, lined pits and various steel, plastic, concrete or wooden tanks. The first water harvesting technique was nothing more than depressions in a rock surface that trapped rainwater. These water depression storage facilities are still found in many parts of the world and serve as drinking water supplies for many forms of wild life. It is highly probable that the first constructed facility was simply an excavated pit or other water storage container at the outfall of rocks. Water harvesting is defined as: the complete facility for collecting and storing the runoff water” (FAO, 1994). UNEP (1983) defined 80

29. Jfuas No.2 December 2013 rainwater harvesting as: the deliberate collection of rainwater from surface catchments and its storage to provide a supply of water”. A similar definition was given by International Water and Sanitation Center (IRC, 1992) in which rainwater harvesting is defined as: the collection, concentration and storage of water that runs off a natural or man-made catchments surface. These are generalized definitions which depend on generation, collection and utilization of surface runoff for agriculture or domestic use. The objectives of the study to assess the relationship between precipitation and crop production and collecting data and information about the state. Also includes identify, quantify and analyze the impact of water harvesting techniques on ecosystem services ranging from hydrology functions, nutrient cycling, biomass production and maintenance of semi-arid ecosystem, and biodiversity conservation to food security, water availability and income generation. 2-Classification of water harvesting techniques Runoff may be harvested from-roofs, ground surface and intermittent or ephemeral water courses. Water harvesting techniques which harvest runoff from roofs and ground surfaces fall under the term rainwater harvesting while all systems which collect discharges from water courses are grouped under the term floodwater harvesting. Floodwater harvesting or floodwater farming often referred to as water spreading and sometime spate irrigation (FAO, 1991).Classification of water harvesting techniques is varied as its terminology (Pacey and Cullies 1986). Matlock and Dutt (1986) 81

30. 2013 ,-./( – *+ () - #$% ! – 82 classified water harvesting according to the form of runoff into water spreading, diversion and micro catchment. A general and practical classification has been established by the World Bank (1984) in sub- Sahara study (Table1).

33. $%

35. Jfuas No.2 December 2013 83

39. ( )

40. * (.

43. %!$,

45. 2013 ,-./( – *+ () - #$% ! – 84

50. #/ 4

52. %$ ,$

54. 2 #/

55. Jfuas No.2 December 2013 85 3

57. / -

58. 78 5 ( - 6 6

59. - #

60. 78 7

61. MTSS = Micro catchments technique short slope. ECLS = External catchments long slope. FWHT= Floodwater harvesting technique. Source:-World Bank (1984).

62. 2013 ,-./( – *+ () - #$% ! – 3-Types of water harvesting techniques 3-1 Surface harvesting system This system catches rapid runoff from natural or man-made surfaces and stored and often used for agriculture or domestic use. They can be built whenever the landscape has characteristics which produce large quantities of runoff from rainstorm on a regular basis e.g. rock catchments, excavated reservoirs and earthen dams. The main aim of such works is to conduct the sheet runoff onto restricted area by limiting the area which receives the runoff and the amount of water given per surface unit is increased. a- Runoff farming systems Runoff farming is a water harvesting system especially designed to furnish water for growing crops. Runoff farming systems are not used for drinking water and their main aim is to control runoff water in an agriculturally productive manner, raising infiltration and improving soil moisture conditions for crop growth. At the same time, this prevents soil erosion by reducing runoff volume and velocity. Runoff farming stabilizes soils, increases soil moisture and therefore increases crop production. There are ranges of different runoff farming system, some collect and concentrate water within the confines of a single field and others collect water from external catchments and divert water from streams or drains onto adjacent field. b- Direct water system (Micro catchment) A micro catchment consists of small prepared runoff collector area directly upslope of the growing area. The runoff flows a short 86

63. Jfuas No.2 December 2013 distance to the infiltration crop growing area. The runoff water is stored in the soil profile of the crop growing area during the precipitation event. Runoff to run on area ratios vary from 1:1 to 20:1 depending upon the quantity of water which can be collected and infiltrate into the soil profile. Micro catchment systems are relatively effective in collecting water during precipitation events because of their relatively small size and they are used in growing trees and shrubs. c- Supplementary water system The runoff or the collected water is stored off site in some reservoirs or storage container and applied later to the crop area with some form of irrigation system. These systems have the advantage of being able to supply the water received on the crop growing area during the rainfall. They have extra costs associated with providing the water storage and irrigation facilities. If the catchments or storage facility are located above or upslope of the cropping area, a simple gravity furrow irrigation can be used as an effective means of applying the stored water. Drip and trickle irrigation systems have been used and they have a high water application efficiency but are expensive to install. d- Combination system The runoff water flows to the crop area where some water will infiltrate into the soil profile and the excess water flows into a storage facility for later application to the crop through some form of irrigation system. A typical system may have the land shaped into 87

64. 2013 ,-./( – *+ () - #$% ! – large ridges 5 to 10% side slope, and furrows on a 0.5 to 1% gradient down the furrow. The plants are grown in the bottom of the furrow. These systems known as eroded catchments and have been used with trickle irrigation for crops and trees (FAO, 1994). 3-2 Underground harvesting system These systems exploit water already infiltrated and concentrated through natural hydrological processes into the soil. They comprise sub-surface and raised sand dams. These systems provide a large concentrated source for communal use and the stored water quality is generally high due to in filtering and purifying effect on sand through which it flows towards the dam or well. 3-3Water spreading It is known as the use of run-on areas. The soil type influences the method in different ways and deep soil can absorb large amounts of water. Clay soils have low infiltration rates and high moisture capacity, so they are suitable for deep flooding with subsequent cropping. Sandy soils have quick infiltration and low storage and it is suitable for the diversion. The Mediterranean climate which has low evaporation and winter rainfall of about 100 mm is suitable for runoff farming. In tropical summer rainfall and high evaporation water harvesting is useful in areas with more than 250 mm. When the rain and the growing period do not coincide, it’s necessary to store water for later use. If the rainfall and the growing period are the same, several application of water is needed during crop growth. Water spreading can be divided into: 88

65. Jfuas No.2 December 2013 89 a- Natural Runoff There are many examples of traditional use of naturally occurring runoff in areas where rain is not sufficient for growing crops. Natural runoff describes use of natural or unimproved runoff. Several tribes use floodwater farming in the south-west of North America (FAO, 1983).In Arizona they use runoff from sandstone outcrops to water alluvial soil (Billy, 1981). They collect the runoff by leaving the upper part of the field unplanted or increasing the storage by simple impounding dams. Crops like maize and melons are cultivated and this system does not use large investment of labor and it takes advantage of any favorable feature such as roads which act as a collector drain. Kovda (1961) reported that the use of natural occurring runoff in arid areas of the USSR and ''Kair'' farming is the cropping on flood terraces where the soil moisture is partly the result of surface flooding and Khaki farming in Turkmenistan where runoff from mountains inundates gentle slopes in the plains. In Ethiopia similar practice the flooded plains recede are cleared and planted with maize and sorghum (Carr, 1979). In Kenya pastoral community with annual rainfall of less than 200 mm cultivate small patches of sorghum by local traditional conditions practicing runoff farming (Hillman, 1980). Where the rainfall is sufficient for cropping (500 mm) it may be possible to make use of run-on areas by increasing cropping intensity. Conservation bench terraces, separate rotations are used for natural runoff in Morocco.

66. 2013 ,-./( – *+ () - #$% ! – b -Collected and diverted runoff Collected runoff system describes schemes where there is some element of manipulation or management of land or the runoff. In terraced wadis and other management schemes in valley bottoms, man sets to manage the land and the water. Some of the ancient Negev valley floor cultivation systems used only spate runoff down the valley depended on the collection of the runoff from surrounding hills. Some methods for inducing runoff, collecting it in channels and distributing it to various terraced fields. Stone-line conduits were used to take the water down to the farms with minimum loss by infiltration and evaporation (Evenari, et al. 1982). In North Africa and the Middle East the starting point of this type of water harvesting lies on the alluvium in filling wadi floors and the traditional cross- wadi walls in Jordan, built of stones, are a typical example. The walls have height of about 0.5- 1 m. The walls are permeable and have no separate overflow structures. Farming valley bottoms is an ancient practice in Tunisia in an area with 100-150 mm of rainfall. Rows of olive trees are planted across the width of valley bottom near a minor barrage which slows down the floods and result in deposition of silt with terracing effect (Damagnez, 1979). In Mexico silt traps are used as a form of inbeds flood water harvesting (UNEP, 1983). They are built with stones in series in narrow valleys, gorges or gullies and they trap water as well as sediment. They are built incrementally with the accumulation of sediments. The structures are always kept some 25- 50 m apart in order to minimize water loss by overtopping. Sizes of 90

67. Jfuas No.2 December 2013 the silt traps vary 0.15 - 0. 7 m in height and 1.5 - 9 m in length. The size of the fields varies enormously from less than 2 m square to about 4 hectares. In many places terraced wadi systems exist with impermeable earth dams. The earth dams are cheaper to construct. This type of terraced wadi system called jessour in Tunisia and Jessour are the area to be cultivated and mainly practiced across wadis and also constructed on slopes in 100 - 200 mm rainfall zones. Another form of water spreading in USSR known as Liman irrigation consists of contour ramparts a cross the slope and they are large structures 2 m high and 4 m wide and drain holes are used to pass and control water movement (Kovda, 1961) . In Pakistan runoff diverted from springs, streams and melt water from snow and glaciers onto terraced alluvial fans called Oasis.In Yemen the floodwater is diverted onto terraces in area of 400-600 mm annual rainfall (Damangnez, 1979). Level bench terraces are constructed on steep slopes with rocks 2- 3 m high and the terraced field 2-10 m wide. Runoff from mountains carried the terraces and stone-lined canals carry the water down and sometimes with the canals running underneath the terraces. A similar system called Sayl irrigation is the diversion of floodwater out of wadis onto leveled terraces.In Australia two approaches are used to make more efficient of the runoff. First approach to encourage grass growth by retaining runoff on the ridges using short contour furrow. The other approach to catch the runoff in drains and lead it to be spread on land for fodder crops and pastures (Cunningham, 1967). 91

68. 2013 ,-./( – *+ () - #$% ! – 92 c- Inundation methods Inundation methods describe systems where floodwaters are impounded and retained long enough to saturate the soil so that a crop can be grown on moisture stored in the soil. In Sudan simple systems are used known as Teras collect and hold runoff on gently sloping land embankments. After the water has soaked into the soil millet is planted. In the semi-arid region of Brazil the government research organization has studied a similar method and produced designs for the optimum shape and size of the bunds and cropping of the stored moisture with variations in cropping pattern depending upon the amount of rainfall and runoff stored. In Rajasthan in areas of low rainfall the method has been more successful. Low contour bunds 0.3 m high divide the land into strips are inundated with flooding to depth of 0.2 m and when the rains ceases, the stored water infiltrates and a winter crop is grown.In semi-arid areas of Bihar and Uttar Paradesh large scale inundation schemes have been used for water control and land management. There are thousand of ahars covering about 800000 ha. Low earth bunds are built to retain runoff and most ahars flood less than 500 ha but others more than 4000 ha (Kolarkar, 1983). The soil must have enough depth and moisture holding capacity and the crops are grown in winter. The volume of water stored is less important than the area of the land which submerged. The retaining is usually 3 m high and may extend several kilometers on the contour. There is a waste-weir to serve as emergency spillway. The spillway is required because of the danger of

69. Jfuas No.2 December 2013 heavy storm occurring when is full and ahars are usually built in a series down the slope and the failure of any one would imperil those lower down the slope. The crop is winter wheat planted as soon as the flooded land has dried out. Sometimes subsidiary crop known as floating rice is grown during the summer monsoon. This technique of cultivation floating rice followed by a second crop after the water has receded is also practiced in Thailand. A second advantage of this system soils in semi-arid areas often have salinity and this is controlled by leaching. The infiltration amount of water may have the effect of raising the water table near the ahars with improvement of the water supply in shallow wells. Inundation farming is used in Rajastan (Kolarker, 1983). Earth bunds are built across the valley plain to catch and store runoff and silt and these are called submergence tanks or Khadins. The tanks are designed in areas where the annual rainfall is 165 mm and the catchment ratio of at least 15:1. The construction features are the same as ahars with emergency spillway and sluices to release the water. Winter wheat crop is grown or legume.Secondary benefits of most inundation systems are the leaching of salinity by the stored water and the improvement to the yield of wells down stream. d- Flood diversion Flood diversion systems concern with diversion and spreading of floods and spate flows. Diversion of flood water from its channel usually involves some forms of structure, a barrage or weir to divert the water. Simple diversion constructed annually using stones, wire 93

70. 2013 ,-./( – *+ () - #$% ! – netting, poles, brush wood and boulders and probably will be destroyed by flash floods. The floods are also likely to damage the conveyance channel unless it’s provided with safety devices to spill water. The canal is excavated in the river bank so that the level of the canal bed is higher than the bed level of the river. This system is widely used in Sind province in Pakistan to collect water from the river. Generally heavy deposition of sediments at the beginning of the canal occurred and clearing is essential. Regulators are used for flood water diversion out of its channel by raising the water level through some form of weir or barrage and may be temporary or permanent structures. Floodwater diversion techniques are those techniques which force the water to leave its natural course. The water diverted conveyed to allocations suitable for crop production and applied through a system of channels, dams and bunds. A famous example of flow diversion from ancient times in the great dam near Marib in North Yemen (NAS, 1974). At present flood irrigation is practiced in Marib by means of simple sandy diversion dams along the wadi. Another ancient system is reported by UNEP (1983) from Northern Mexico. Around 1000 AD an intricate system functioned in area with rainfall 125-175 mm, incorporating diversion dams, canals, head gates and bordered gardens and it was receiving water from many catchments covering 4250 ha. 3-4 Developing ground waters The sources of water storage are the spate flows in streams, rivers and runoff stored in tanks and dams. The conditions required for 94

71. Jfuas No.2 December 2013 recharge includes adequate surface for infiltration, good water storage capacity which defined as specific yield or the volume of water which drains from the rock under gravity and hydraulic conductivity. Two problems may occur of salinity and silting due to flash runoff which usually carries a heavy sediment load which is likely to block the soil surface and reduce infiltration and siltation tanks are commonly used to reduce this problem. Recharge methods can either be carrying runoff to an infiltration zone or seepage through the bottom of canal. The exploitation of groundwater may offer a solution in arid regions and shallow wells is a common way of using groundwater. In India a common design is stone-lined circular wells and this traditional method has been successfully operated for centuries and the water is lifted by hand or ox-power for domestic use and irrigation. Boreholes equipped with hand pumps, hand-dug wells and horizontal wells are used in many countries. A modern development of the age-old system of driving a horizontal shaft into the side of a hill until it reaches the water table and the water flow out through tunnel under gravity. This method is widespread in North Africa `foggaras` and in Iran `ganats` and in Afghanistan and Pakistan they are called `Karezes`. The danger of ecological damage resulting from the over exploiting of groundwater particularly fossil water which can not be replaced. 3-5 Floodwater development In dry land countries with ephemeral water courses (wadis), significant improvement to runoff farming can be achieved through 95

72. 2013 ,-./( – *+ () - #$% ! – spreading and retention of floodwaters for a finite duration to permit infiltration. In order to implement this concept a system of structures will be required to increase infiltration and retention time, thereby slowing down and reducing the runoff velocity. The following functional applications of detention, dispersion and diversion structures are used.Detention structures are built of locally available material (soil, gravel, stone, boulder, and rock). The height of these structures is usually less than 10 meter across wadis or valleys for slowing down and retaining floodwater and healing gullies. They are suitable where relatively deep wadi course with gently sloping valleys are becoming gullied. A detention dam would be designed to specific height to retain temporarily a large portion of the maximum flow, thus allowing recharge of the alluvium upstream. Due to constant crest elevation distribution of flow by dispersion uniformly through area will be achieved for increasing the soil moisture both upstream and downstream of the dam. During long- term operation, the wadi main channel and flood plain behind the dam would be filled with sediment. Water diversion is the traditional way of using flash floods and it is used to irrigate areas close to or within the water course. Three types of water harvesting techniques may be practiced. Lateral diversion technique consists of diverting apart of the floodwater from an ephemeral water courses or a gully to a conveyance channel which may provide water for cultivation downstream. This system has been generally used in streams with deep steep bed slopes 5 to 10%. The off- take is excavated in the stream bank and several off- takes can be 96

73. Jfuas No.2 December 2013 used to irrigate the same land.Earth dike diversion is an improved version of the lateral diversion. The primary objectives is to provide head for the off- take to irrigate greater areas. It’s used on streams with relatively low bed slopes. Small retention dams practice is usually encountered in the Saharan zone where floods are less frequent and have limited runoff volumes. It consists of small earth or loose rock dikes constructed across the river and designed to store water for crop cultivation and to recharge groundwater.All these techniques are subject to the natural damage and occasionally washouts particularly for the diversion dams. It need cleaning of the sediment deposited upstream the dikes. Their reconstruction and maintenance require a tremendous effort in terms of labor and may be a way of promoting solidarity within the community. 4-Results Semi-arid areas in Africa face climatic variability at different temporal scales. Higher natural inter-annual climatic variability is expressed as drought and floods; a high seasonal variability leads to dry spells. Farmers in semi-arid zones have therefore developed strategies including rainwater harvesting techniques e.g. supplementary irrigation to cope with this uncertain and erratic rainfall patterns. Rainwater harvesting practices refer to practices whereby rainwater is collected artificially to make it available for cropping or domestic purposes. 97

74. 2013 ,-./( – *+ () - #$% ! – 4-1Water harvesting in relation to crop production The main factors determining the magnitude of runoff in the catchments area are the rainfall characteristics, soil and topography. In larger catchments runoff has to cover longer distances, implying a longer retention time. Micro catchments response rapidly to rain by generating small amounts of runoff and do not create erosion problems (Boers et al. 1986). Macro catchments produce runoff less frequently than micro catchments and at larger volumes with addition of erosion hazard. Crops considered for growth under runoff conditions should be screened for high and resilient food, fodder and firewood production and for shrubs and trees. They should tolerate periods of prolonged droughts, salinity and water logging. Leguminous species are of particular interest as they improve the nitrogen status of the soil. Water requirement of annual crops is generally less than crops like shrubs and trees. The different runoff systems impose various growing conditions like the amount of runoff, event, the depth of infiltration and the catchments size. Crop selection and associated water use are strongly linked to the type of runoff system applied. Water harvesting helps crops by providing extra moisture at different stages of growth. Periods of extra moisture of significant differences are around sowing time when germination and establishment can be improved, during a mid season dry spell when a crop can be supported until the next rains and while the crop is at the vital stages of flowering and grain fill. The most common cereal crops 98

75. Jfuas No.2 December 2013 grown under water harvesting are sorghum, pearl millet and maize. Sorghum is most common grain crop under water harvesting systems. It is a crop of dry areas, drought resistant, tolerate water logging and used in parts of East and Southern Africa as a food grain. For high production rainfall of 450-650 mm is needed but satisfactory crop can be obtained with about 300-380 mm (ILO, 1999).The selection and testing of alternative crop varieties and the selection and breeding cultivars for semi-arid regions are promising. Some varieties adjust their growth habit according to the available moisture by tillers when moisture is available or going dormant when the moisture is short or only carrying through to ripening a proportion of the seed heads available. 4-2Water harvesting techniques adapted in North Darfur State Several water harvesting techniques were practiced (Reij et al. 1986; Mohammed, 2000). Farmers adopted bench terracing system for many thousand years ago, the signs of which are still found in hilly areas such as Jebel Marra (HTS, 1958). Spore (1997) noted that Water harvesting techniques was developed by the ancient Nabateans over 3000 years ago in Jordan and it is probably not a coincidence that very similar technique have been developed and have survived in the Red Sea Hills of North East Sudan and in the Central Darfur region). Teras technique is a more common practice all over the state. Teras is a piece of arable land bounded on three sides to capture runoff from adjacent catchments. It is a small scale privately managed and is built in earth structures and used for subsistence crop 99

76. 2013 ,-./( – *+ () - #$% ! – production. It aims at water harvesting and moisture conservation beside nutrient harvesting and erosion control (Mohammed, 1994). Dams up to 4 m high provided with concrete lined or masonry spillways and sometimes with bottom outlets retain floodwater from the wadi for a few months (ILO, 1999). Small earth dams are the most common type and they require some care in design, construction and regular maintenance. Supplementary irrigation is practiced in Sag El Naam project (Mohammed, 1994).Flood diversion is practiced in Kidinir area using a canal for diverting wadai flows to 8 km and annually 2000 ha are being irrigated. Spread irrigation systems like hafirs for collection of floodwater surrounded by embankment, with siphon inlet provided with sluice gate and off-spreading were practiced along the wadis. In Malam El Wadayin project the storage water in the dam was diverted by two canals to irrigate 300 ha(Abdalla,2008). Flood irrigation systems consist of small earth dams generally 'U' shaped with upward opening for the retention of rainwater. Small embankments about 2 m high for the delimitation of impounding reservoirs and the water diverted from the wadi during floods. The main limiting factors of crop production in North Darfur State are water shortage, lack of inputs, techniques and marketing. The use of water harvesting techniques can shift millet and sorghum cultivation from the impoverished sands to the clay soils along wadis beds. Areas having characteristics of the flat valley along wadis near Al Fashir are approximately 100000 ha. These areas have adequate exploitable discharge of wadi runoff, slight and uniform slopes, soils 100

77. Jfuas No.2 December 2013 with good permeability, and absence of chemical anomalies and coarse texture. Different water harvesting techniques of micro catchments, water spreading and floodwater farming exist. Use of water harvesting techniques will increase food, fuel wood and forage production and rehabilitate the sandy soils and control land degradation and combat desertification. 5- Discussion African dry lands are affected by climate change. It was confirmed temperature increases for most of Africa, while expected rainfall tends vary and the climatic variability will increase, leading to an increase in droughts and floods and growing uncertainty about the on set of the rainy season. In the context of agricultural production in African dry lands soil and water conservation practices such as rainwater harvesting provide an opportunity to stabilize agricultural landscapes in semi-arid regions and make them more productive. Water harvesting is the most common soil and water conservation techniques is massively promoted by farmers, extension services and government agencies (Stroosnijder, 2003). Rain water harvesting techniques are generally considered to be only beneficial in this respect but the main problems are low rates of adoption (Tabor, 1995; Bodnar and de Graaff, 2003) or failed adoption processes due to lack of participation by farmer .Rainwater harvesting practices have an overall positive effect on landscape functions and hydrological improvement concerns the recharge of aquifers and increase in soil water. Rain water harvesting systems aim to minimize seasonal 101

78. 2013 ,-./( – *+ () - #$% ! – variation in water availability such as droughts and dry spells (Rockestrom et al., 2002). 6- Conclusion Rainwater harvesting are mostly simple and there are more space for technical improvement. Crop yields are higher when water spreading techniques were applied and reduce crop failure during dry spells, droughts and thus help to enhance food security .The adoption of techniques proved to have positive effect to increase farmer’s income. The major challenges lie in improving nutrient management through mulching, animal traction and the traditional practices may be combined. For more in-depth research is required at local scales. The socio-economic conditions are qualitatively known (Oweis, et al. 1999) but not applied quantitatively to understand and support the individual decisions of farmers. Crop and risk assessment models and approaches must be developed so far rainwater harvesting techniques (Young et al., 2002) rely mainly on ecological and technical information. Economic, social and cultural factors are not combined for access to markets and labor. REFERENCES 1. Abdalla, S.A. (2008). Use of controlled spate irrigation for the improvement of sorghum growth and productivity in North Darfur State. Ph.D. Thesis, University of Khartoum. 2. Billy, B. (1981). Water harvesting for dry land and floodwater farming on the Navajo Indian Reservation 3–7. In: Rainfall Collection for Agriculture in Arid and Semi – arid 102

79. Jfuas No.2 December 2013 Regions.Dutt, G.R.; Hutchinson, C.F. and Garduno, A. (Eds). Workshop at Tucson Arizona, USA. Pub. By Commonwealth Agri-Bureau, Farnham Royal,Bucks. UK. 3. Boers, T.M., Graaf, M. dc. Febbs, R.A. and Ben Asher, J. (1986). A linear regression model combined with a soil water balance model to design micro–catchments for water harvesting in arid regions. Agricultural Water Management 12: 21–39 4. Bodnar, F.,de Graaff,J., 2003. Factors influencing adoption of soil and water conservation in Southern Mali. Land Degraded. Deevelop,14,515-525. 5. Carr, M.K.V. (1979). Land use and irrigated agriculture in the Woito and Lower Omo river valleys. UNDP/FAO Project E T H /78 /013 Development of Irrigated / Agriculture. 6. Cunningham, G.M. (1967). Furrow aids revegetation at Cobar despite the worst drought on record. J. Soil Water Conservation of N. S.W. 23 (3): 192-202. 7. Damagnez, J. (1979).Mediterranean climate, the economic use of water, and crop production. In: Soils in Mediterranean Type Climates and their Yield Potential, PP 43- 55- Proc. 14h coll Int. Potash Inst. Berne, Switzerland. 8. Evenari, M. L., Shanan, L. and Tadmor, N. (1982). The Negev: The challenge of the desert, Harvard University Press, Cambridge. 9. FAO (1983). Field measurement of soil erosion and runoff. FAO Soils Bulletin No. 69. FAO, Rome. 103

80. 2013 ,-./( – *+ () - #$% ! – 10.FAO (1994). Water for improved agricultural production. Proceedings of the FAO Expert Consultation, Cairo, Egypt, 21– 25 November 1993. Water Report No. 3. FAO, Rome. 11.FAO (1991). Network on erosion. Induced loss in Soil 104 Productivity. FAO, Rome. 12.Hillman, F. (1980). Water harvesting in Turkana district, Kenya. Pastoral Network Paper 10 d. ODI, London. 13.HTS. (1958). Jebel Marra investigations. Report in Phase I Studies. 14. ILO (1999). The effects of the projects components on the environment.El Fashir and El Obied Districts, Darfur and Northern Kordufan. 15.Kolarkar, A. S.,Murthy, K. N. K., and Singh, N. (1983). “ Khadin - A method of harvesting water for agriculture in the Thar Desert, Journal of Arid Environments, 6,pp 59. 66, London. 16.Kovda, V. A. (1961). Land use development in the arid regions of the Russian plain, the Caucause, and Central Asia. In: A history of land use in arid regions. Arid Zone Research Vol XVII. UNESCO, Paris. 17.Matlock, W. G. and Dutt, G. R. (1986). A primer on water harvesting and runoff farming. College of Agriculture, University of Arizona. Irrigation and Water Management Institute.

81. Jfuas No.2 December 2013 18.Mohamed, Y. A. (1994). Traditional water harvesting Techniques and their contribution to food security: case study of Wadda Village, North Darfur, Sudan. In: M. M. M. Ahmed (Ed), Indigenous knowledge for sustainable development in the Sudan. Khartoum University Press, Khartoum, Sudan, 178– 214. 19.Mohamed, A. A. (2000). Water harvesting for crop production. Ph. D, Thesis, University of Khartoum. 20.NAS (1974). More water for Arid Lands. Promising Technology and Research Opportunities.Washington, D.C 21.Oweis, T.,Hachum,A., Kijne, J.( 1999). Water Harvesting and Supplemental Irrigation for Improved Water Use Efficiency in Dry Areas. International Water Management Institute, Colombo, Sri Lanka, pp .1-51. 22.Pacey.A.with Cullis, A. (1986). Rainwater Harvesting. The Collection of Rainfall and Runoff in Rural Areas. Intermediate Technology Publications, London, UK. 23.Reij,C.; Turner, S.D. and Kuhman, T. (1986). Soil and water conservation in Sub-Saharan Africa: Issues and options, IFAD, Rome/CDCS, Amsterdam. 24.Rockstrom, J.,Barron, J.,Fox, P.( 2002). Rainwater management for increased productivity among small-holder farmers in drought prone environments. Phys.Chem. Earth 27, 949-959 25.Spore. (1997). More crops with less water. Spore No. 70, P. 5. 105

82. 2013 ,-./( – *+ () - #$% ! – 26.Stroonijder, L.(2003). Technologies for improvising rainwater use efficiency in semi-arid Africa. In: Proceeding of the symposium and Workshop on water conservation Technologies for Sustainable Dry land Agriculture in Sub-Saharan Africa, Bloemfontein, South Africa, and April 8 – 11 2003. Pretoria, South Africa .ARC- Institute for Soil, Climate and Water, pp.60-74. 27.Tabor,J.A.(1995). Improving crop yields in the Sahel by means of water harvesting. J. Arid Environ. 30, 83-106. 28.UNFP (1983). Rain and storm water harvesting in rural areas: Ed. UNEP Tycooly International, Dublin, Ireland. 29.World Bank (1984). Towards sustainable development in Sub- Saharan Africa. Washington DC: The World Bank2. 30.Young. M.D.B., Growing, J.W., Wyseure, G.C.L., Hatibu, N.(2002). Parched- thirst:Development and validation of a process- based model of rainwater harvesting .Agricultural Water Management 55,121-140. 106

Eng6

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Viewers also liked

Viewers also liked (11)

Similar to Eng6

Similar to Eng6 (20)

More from Sulieman Bahar

More from Sulieman Bahar (20)

Recently uploaded

Recently uploaded (20)

Eng6