a.a. 2012/2013pienocampo.it/solinas/design of drip irrigation...tigray gereb-beati dam ethiopia...
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ISTITUTO AGRONOMICO
PER L'OLTREMARE
UNIVERSITÀ DEGLI STUDI DI FIRENZE
FIRST LEVEL MASTER DEGREE IN
IRRIGATION PROBLEMS
IN DEVELOPING COUNTRIES
THESIS ON
DESIGN OF DRIP IRRIGATION SYSTEM FOR PRODUCTION OF
COMMONLY GROWN VEGETABLE CROPS IN SEMI-ARID REGION OF
TIGRAY GEREB-BEATI DAM ETHIOPIA
Supervisor I Student Name
DR. AGR. IVAN SOLINAS ABEBATSEGAZA
A.A. 2012/2013
i
DEDICATION
I would like to dedicate my Thesis to My Beloved Parents
ii
ACKNOWLEDGEMENT
Many thanks to God for providing me with the opportunity to step in the excellent
World of science and giving me the strength and ability to complete this work.
It would not have been possible to complete this Thesis without the help and
support of the many kind people around me, to only some of whom it is possible to
give particular mention here.
Special thanks go to the IAO for offering me a scholarship to pursue the Masters,
and the entire IAO staff particularly, Dr. Giovanni Totino Director General, IAO;
Dr. Tiberio Chiari, Technical Director IAO and tutors; - Drs. Paolo Enrico Sertoli,
Andrea Merli, and Elisa Masi for having assisted and accompanied me throughout
the course duration.
I am particularly grateful to my supervisor, Dr. Solinas Ivan for the guidance you
gave me from start to the completion of the Thesis – I owe you a great deal
THANKS!
A lot of thanks go to Prof. Ing. Elena Bresci, the Masters Course Coordinator for
the good guidance you always us as students.
Finally, to all other people who, directly or indirectly, helped me during the study.
iii
APPROVAL
Dr. Agr. Ivan Solinas
Supervisor’s signature: ……………………......…………………..…….………….
Date: ………............................................................................................................
Student: Abeba Tsegazab
Student’s signature: ……………………………………………..…………..…...…
Date: …………………………………..…………………………………..…...….
iv
Table of Content pages
DEDICATION ..................................................................................................................... i
ACKNOWLEDGEMENT .................................................................................................. ii
APPROVAL .......................................................................................................................iii
LIST OF TABLES ............................................................................................................. vi
LIST OF FIGURES .......................................................................................................... vii
1. Introduction ..................................................................................................................... 1
1.2 .Problem Statement ......................................................................................................... 3
1.3 .Objective ........................................................................................................................ 4
A. General objective ............................................................................................................. 4
2. LITERATURE REVIEW .............................................................................................. 6
2.1 Water Requirement of Crop ............................................................................................ 8
2.2 .Irrigation Scheduling ..................................................................................................... 9
2.3 Irrigation Scheduling Under Drip irrigation ................................................................... 9
2.4: Advantages of a Drip Irrigation System ...................................................................... 11
2.5 . disadvantages of a Drip Irrigation System .................................................................. 11
2.6 Crop Production ............................................................................................................ 12
2.6.1 Tomato ...................................................................................................................... 13
2.6.1.Onion ......................................................................................................................... 15
3.1 Location and physiographic .......................................................................................... 20
3 .2 Methodology ................................................................................................................ 21
3.2. 1 Collection of agro-climatic data ................................................................................ 21
3.2.2 Geology and Soil ....................................................................................................... 21
3.2.3 Water source .............................................................................................................. 23
3.2.4. Climate ...................................................................................................................... 23
v
3.3. Determination of tomato, onion, pepper) grown crops water requirement .................. 24
3.3.1 The crop coefficient Kc ............................................................................................. 24
3.4. Design Software ........................................................................................................... 27
3.4.1. Choice of Plot ........................................................................................................... 29
4. Result and Discussion ................................................................................................... 31
4.1 Crop Water Requirements of Each Crop ...................................................................... 31
4.2 Cropping pattern ........................................................................................................... 34
4.3. Schemes supply ............................................................................................................ 35
4.3 Network of the design ................................................................................................... 39
4.5 System in operation ...................................................................................................... 40
4.2 Characteristics of system components .......................................................................... 42
6. Conclusion and recommendation ................................................................................ 43
5. Reference ....................................................................................................................... 45
Appendix ............................................................................................................................ 48
vi
LIST OF TABLES Table 1: soil mapping unit ................................................................................................. 22
Table 2: Tomato Growth Stages and Crop Coefficient Kc ................................................ 24
Table 3: onion Growth Stages and Crop Coefficient Kc ................................................... 25
Table 4 : Potato Growth Stages and Crop Coefficient Kc ................................................. 25
Table 5: Climate data ......................................................................................................... 26
Table 6: monthly Rainfall .................................................................................................. 26
Table 7: Felid measurements ............................................................................................. 30
Table 8: Tomato crop water requirement ........................................................................... 31
Table 9: Potato crop water requirements ........................................................................... 32
Table 10: crop water requirements of onion ..................................................................... 33
Table 11: scheme supply .................................................................................................... 35
Table 12: system components ............................................................................................ 42
vii
LIST OF FIGURES Figure 1: location of Gereb Beati ....................................................................................... 20
Figure 2: Vegetation period of Gereb beati ....................................................................... 23
Figure 3 :plot division ........................................................................................................ 30
Figure 4:area cropping pattern ........................................................................................... 34
Figure 5 :drip line for potato .............................................................................................. 36
Figure 6: checking drip ...................................................................................................... 36
Figure 7: pressure compensating ....................................................................................... 37
Figure 8 :onion drip line .................................................................................................... 38
Figure 9: Tomato ............................................................................................................... 39
Figure 10: Network of the design ...................................................................................... 39
Figure 11: system watering of field one ............................................................................ 40
Figure 12 : system watering of field two ........................................................................... 40
Figure 13: system watering of field 3 part lot 1 ................................................................. 40
Figure 14: system watering of field 3 part lot .................................................................... 41
viii
ABBREVIATIONS
Asl above sea level
BoAN Bureau of agriculture and natural resources
BoANR Bureau of Agriculture and Natural Resource
COSAERT Commission for Sustainable Agriculture and Environmental
Rehabilitation in Tigray
DA’s Development Agent
ERHA the Ethiopian Rainwater Harvesting Association
FAO Food and Agricultural Organization
IWMI International water management institute
MoAR Ministry of Agriculture and Rural Development
MOWR Ministry of Water Resource
REST Relief Society of Tigray
RIS Relative irrigation supply
RWS Relative water supply
SARET sustainable agriculture and environmental rehabilitation Tigray
UNDP United Nation Development Program
WDC Water delivery capacity
ix
Abstract
This research was conducted with the aim of designing a drip irrigation system for
production of commonly grown vegetable crops in the semi-arid area of Gereb-
Beati, Tigray region, Ethiopia. These crops include maize, tomato and onion. Crop
water requirement and irrigation scheduling for each of the crops was determined
by using 30-year climatic data in CROPWAT. In this study, various software like
Google earth, CLIMWAT 2.0, SPAW, the CROPWAT, Ve.pro.LG.s, and
EPANET 2.0 were used to evaluate field and coordinates, get climatic data,
determine soil characteristics, the crop water requirements, determine efficiency of
the irrigation system are used respectively in the selected agricultural district.
Cropping pattern of the vegetable crops is 44% tomato, 33% onion and 23% potato
coverage. Having identified and ranked the drip lines available with the software
Ve.Pro.LG, the drip line best drip line from select 11 drip lines is stream line
,having uniformity of 93.6 ,spacing 0.4 inlet pressure 8 and discharge of 2.04 l/h m
and irrigation intensity of 4.1mm/h.
1
1. Introduction
Globally rainfed agriculture is practiced in almost all hydro climatic zones, it is
practiced on 83 percent of cultivated land, and supplies more than 60 percent of
the world's food. In water-scarce tropical regions such as the Sahelian countries,
rainfed agriculture is practiced on more than 95 percent of cropland. In temperate
regions with relatively reliable rainfall and productive soils, and in the sub humid
and humid zones of tropical regions, rainfed agriculture can have some of the
highest yields (FAO ,2002). In Sub-Saharan Africa (SSA) over 95% of the farm
land is under rain fed. Sub-Saharan Africa has vast untapped water resources.
Expansion of the irrigated area has the potential to make a substantial contribution
to agricultural development and address the problem of food insecurity (Suhas et
al., 2009).
Ethiopia is a land-locked country in the Horn of Africa, bordered by Eritrea in the
north, Sudan and South Sudan to the west, Djibouti and Somalia to the east
and Kenya in the south (Vagnat, 2013). Agriculture in Ethiopia is the foundation
of the country's economy, accounting for half of gross domestic product (GDP),
83.9% of exports, and 80% of total employment. Ethiopia's agriculture is plagued
by periodic drought, soil degradation caused by overgrazing, deforestation, high
population density, high levels of taxation and poor infrastructure (making it
difficult and expensive to get goods to market). Yet agriculture is the country's
most promising resource. A potential exists for self-sufficiency in grains and for
export development in livestock, grains, vegetables, and fruits. As many as 4.6
million people need food assistance annually. In Ethiopia, about 94% of the total
74.3 million hectare of arable land is rainfed (MARD, 2009).
In countries like Ethiopia where widespread poverty, poor health, low farm
productivity and degraded natural resources are major problems the need to
involve irrigated agricultural system in the agricultural practice of the country is
2
very vital. Ethiopian agriculture is largely small-scale, subsistence-oriented, and
crucially dependent on rainfall (Girmay et al., 2010).
Mintesinot et al., (2004) reported that in tigray generally traditional surface
irrigation methods (basin, border and furrow) are used to irrigate crops. Farmers
have been producing different crops under traditional irrigation since a long time.
The diversion of perennial streams using temporary diversion structures during the
dry season has been the major means of irrigation. In addition flood spreading
using runoff water form higher altitudes and upper catchment-areas is also
practiced.
Erratic rainfall in the region over the past years has resulted wide spread crop
failure and has brought a growing awareness of the importance of irrigation.
Therefore, small-scale irrigation development for food production became of
primary interest in Tigray in view of the recurrent drought and famine condition.
Condition experienced during the 1970’s and1980’s. The previous military
government after 1984/85-famine period started the development of these small-
scale irrigation schemes. The aim was to boost food production and achieve food
self-sufficiency. From that time onwards, modern irrigation practices have been
developed in Tigray. Therefore it is dire need to adopt modern efficient irrigation
methods like drip. Drip irrigation method offers several advantages over surface
irrigation methods, including higher water use efficiency, better fertilizer
application and high yield (Mintesinot et al., 2004) .
Estimating actual crop water requirement and irrigation schedule are essential for
designing of the irrigation systems, storage construction and water conveyance
structures. In arid and semi-arid regions, water availability is a serious limitation
for crop production due to poor and irregular rainfall, high evaporative demand
and inadequate management. Planning and management of water resources have
become a very important issue in arid and semi-arid regions.
3
Understanding crop water needs is essential for irrigation scheduling and water
saving measures in an arid region because of its limited water supply. One of the
drought prone areas in Ethiopia is the Tigray region. Determination of crop water
requirement is one of the key parameters for precise irrigation scheduling,
especially in regions with limited water resources, such as Tigray. In semi-arid
regions water resources are limited. Despite the number of challenges like less
fertile soil, highly variable rainfall, and highly degraded land, designing and the
subsequent use of drip irrigation will help to save water through efficient use. As a
result, a larger area will be irrigated and this will ensure food security. However,
many of the soil and water conservation structures constructed in Tigray are non-
engineered (constructed by local communities without some technical support by
experts and fully owned by the communities) and no thorough study of the
irrigation water requirements and irrigation scheduling in the region has been
undertaken.
This research therefore seeks to recommend introduction of an affordable micro -
irrigation technology which will help local farmers increase their production levels
through irrigation. Increased productivity provides potential to accelerate poverty
alleviation within rural communities of developing countries from agricultural
sales.
1.2 .Problem Statement
In Ethiopia Small-scale irrigation recently gained importance because of its
potential to combat hunger, reducing poverty, and generating economic growth, as
well as climate adaptation of our people. Rainfall in the semi-arid Ethiopian
highlands is characterized by erratic nature and dry spells during crop growing
season is a critical problem in the rainfed production systems. One of the drought
prone areas in Ethiopia is Tigray region. Rainfed farming therefore needs to be
supported by appropriate determination of crop water requirement and irrigation
scheduling. Determination of crop water requirement is one of the key parameters
for precise irrigation scheduling, especially in regions with limited water
4
resources, such as, Tigray region. On crop water requirements is very vital in the
planning and operation of soil and water management strategies. knowledge of
crop water use is required when planning erosion control measures such are
terracing and contour building, planning and design of micro- and macro-
catchment rain/runoff water harvesting systems, surface and subsurface drainage
systems, and other soil moisture conservation techniques.
Most of the systems mentioned above are usually required to manage soil and
water in rainy season. Information on crop water requirements in literature are
largely those used for the purpose of irrigation, and were most probably developed
during the dry season. However, a thorough study of the irrigation water
requirements and irrigation scheduling in the region has not been undertaken.
Irrigation scheduling and use of drip irrigation are principal tools for striking this
balance through improving water application and water utilization efficiencies.
Despite such high investment and the lofty expectations that irrigation can shift
upward the production frontier in the region, there has been no empirical study to
investigate the efficiency of irrigated agriculture in the study area.
1.3 .Objective
A. General objective
To design a drip irrigation system for production of commonly grown vegetable
crops in semi-arid region of Tigray gereb-beati dam Ethiopia.
B. Specific objective
1. To estimate Crop Water Requirement (CWR) for commonly grown crops in the
area (tomato, onion, maize).
2. To develop irrigation regimes (when and how much to irrigate) for most market
oriented crops in the area.
3. To satisfy and fulfillments requirements of the farmer to suggest guidelines for
farming community.
5
4. Design drip irrigation method conserve water, increase crop production, and
improve crop quality.
6
2. LITERATURE REVIEW
Rain-fed agriculture dominates in Ethiopia. However, rainfall distribution and
intensity vary spatially and temporally resulting in incidents of drought every 4-5
years. These rainfall patterns affect crop and livestock production and contribute to
volatility in food price. Rainfall in Ethiopia is varying highly and erratic in time
and space (Yazew, 2005).
(CSA, 2007) states that Ethiopia has approximately 12 river basins with an
annual runoff of 122 billion m3 and with 2.6 billion m3 of groundwater .With all
this potential, however, it fails to produce enough food to feed its population. The
country’s perennial dependence on food aid has been attributed largely to an over-
reliance on rain-fed smallholder agriculture. For example, only 5-6% of the 4.25
million hectares of irrigable land is currently developed through traditional, small-,
medium-, and large-scale irrigation schemes (Awulachew et al., 2007).
In countries like Ethiopia where widespread poverty, poor health, low farm
productivity and degraded natural resources are major problems the need to
involve irrigated agricultural system in the agricultural practice of the country is
very vital. The importance of intervening irrigated agriculture in the economy of
developing countries results from the fact that rain fed agricultural system is not
capable of supplying the desired amount of production to feed the increasing
population. The issue of food security is a serious concern especially in arid and
semi-arid regions like Tigray, which is vulnerable to climatic instability and
frequent droughts. To see the positive effect of irrigation on livelihood, the
management aspect of irrigation must be taken in to account. Nevertheless, the
management aspect of irrigation is often neglected while priorities are given to the
construction of irrigation (Habtamu Worku, 2011).
The potential irrigable land in Ethiopia is between 3.7 and 4.3 million hectares but
the actual irrigated area is estimated at just 7-10% of this. Of this area
approximately 55% is traditional irrigation schemes, 20% is modern small-scale,
and 25% is medium- and large-scale irrigated commercial farms (private and state-
7
owned). Field assessments in small-scale irrigation projects indicate that some
irrigation schemes are not functional due to shortage of water, damaged structures
and poor water management.
Water harvesting technologies to mitigate the moisture stress during critical crop
growth stage of the main season, to increase opportunities for irrigated
horticultural production in dry land. With this aim, a wider scale of water
harvesting technology dissemination program was carried out in these areas of
Ethiopia since 2002/03. In Tigray region, on-farm level household ponds, larger
communal ponds, and a series of ponds were the three types of water harvesting
technologies promoted by the program since it initiation to store and utilize rain
water/runoff. Different soil/water conservation, water recharging, and water
harvesting structures have been constructed in Tigray. More than 80% of the
region is now covered. The whole activity is moving from soil/water conservation
to water harvesting (Habtamu Worku, 2011).
Kifle Woldearegay (2012), states that Tigray is considered as the most degraded
region in Ethiopia. Despite this, a number of positive changes have been recorded.
There is a great opportunity that the efforts made in Tigray could be scaled-up to
other regions of Ethiopia and beyond for a number of reasons: Less degraded land
better experience in the country. Other regions of Ethiopia have started massive
watershed management.
Tagar et al (2012) reported that drip irrigation generally achieves better crop yield
and balanced soil moisture in the active root zone with minimum water loses. On
the average, drip irrigation saves about 70 to 80% water as compared to
conventional flood irrigation methods, tolerance to windy atmospheric conditions,
reduced labor cost, improved diseased and pest control, feasible for undulating
sloppy lands, suitability on problem soils and improved tolerance to salinity. Many
factors influence appropriate drip irrigation management, including system design,
soil characteristics, crop and growth stage, environmental conditions, etc. The
8
influences of these factors can be integrated into a practical, efficient scheduling
system which determines quantity and timing of drip irrigation (Hartz, 1999).
2.1 Water Requirement of Crop
Water requirement of crop is the quantity of water regardless of source, needed for
normal crop growth and yield in a period of time at a place and may be supplied
by precipitation or by irrigation or by both.
Water is needed mainly to meet the demands of evaporation (E), transpiration (T)
and metabolic needs of the plants, all together is known as consumptive use (CU).
Since water used in the metabolic activities of plant is negligible, being only less
than one percent of quantity of water passing through the plant, evaporation (E)
and transpiration (T), i.e. ET is directly considered as equal to consumptive use
(CU). In addition to ET, water requirement (WR) includes losses during the
application of irrigation water to field (percolation, seepage, and run off) and water
required for special operation such as land preparation, transplanting, leaching etc.
WR = CU + application losses + water needed for special operations.
Water requirement (WR) is therefore, demand and the supply would consist of
contribution from irrigation, effective rainfall and soil profile contribution
including that from shallow water tables (S)
WR = IR + ER + S
Under field conditions, it is difficult to determine evaporation and transpiration
separately. They are estimated together as evapotranspiration (ET) (Langbein,
2013). IR is the irrigation requirement. Determination of crop water requirement is
one of the key parameters for precise irrigation scheduling, especially in regions
with limited water resources, such as Tigray region.
9
2.2 .Irrigation Scheduling
Irrigation Scheduling is the process of determining when to irrigate and how much
water to apply. It depends upon design, maintenance, and operation of the
irrigation system and the availability of water. The objective of irrigation
scheduling is to apply only the water that the crop needs, taking into account
evaporation, seepage, and runoff losses, and leaching requirements. Scheduling is
especially important to pump irrigators if power costs are high. The purpose of
irrigation scheduling is to determine the exact amount of water to apply to the field
and the exact timing for application. The amount of water applied is determined by
using a criterion to determine irrigation need and a strategy to prescribe how much
water to apply in any situation. Irrigation scheduling is a planning and decision-
making process, the primary decision being: how much water to apply and when to
apply it. Providing the right amount of water at the right time results in optimal
yields and quality, saves on energy, labor, and fertilizer costs and protects ground
water quality (Broner, 2005).
Water management is a critical aspect of successful production in Tigray. This
region commonly experience drought conditions some time even during the
rainseason so supplemental water application through irrigation is necessary. In
addition, water can be a scarce resource in many areas and its efficient use must be
a high priority. Irrigation scheduling is an importat aspect of good water
management (Broner, 2005).
2.3 Irrigation Scheduling Under Drip irrigation
Drip irrigation is sometimes called trickle irrigation and involves dripping water
onto the soil at very low rates (2-20 liters/hour) from a system of small diameter
plastic pipes fitted with outlets called emitters or drippers. Water is applied close
to plants so that only part of the soil in which the roots grow is wetted unlike
surface and sprinkler irrigation, which involves wetting the whole soil profile.
With drip irrigation water, applications are more frequent (usually every 1-3 days)
10
than with other methods and this provides a very favorable high moisture level in
the soil in which plants can flourish (FAO, 2009).
Drip irrigation is the most efficient method of irrigating. While sprinkler systems
are around 75-85% efficient, drip systems typically are 90% or higher. What that
means is much less wasted water, for this reason drip is the preferred method of
irrigation in the desert regions of the United States. But drip irrigation has other
benefits which make it useful almost anywhere. It is easy to install, easy to design,
can be very inexpensive, and can reduce disease problems associated with high
levels of moisture on some plants. If you want to grow a rain forest however, drip
irrigation will work but might not be the best choice (Jess Stryker, 1997-2011).
Typical ingredentis of drip/micro system includes, pump, filters chemical
injectors, main and submainlines, laterals and emitters (Jess Stryker, 1997-2011).
Unlike conventional irrigation methods, drip/micro irrigation delivers frequent,
localized small doses of water. Therefore, drip/micro irrigation scheduling is
usually based on frequent replacement of the water consumed by the crop to
maintain essentially steady level of moisture content in the root zone. The
frequent water application makes the possibility of excessive soil moisture
depletion between irrigations very slim, and could improve plant nutrient-
uptake. However, due to the limited water storage in the root zone under
drip/micro irrigation and the system small application rate, it is essential to
monitor soil moisture depletion in the root zone regularly to ensure that consumed
water is timely replenished by irrigation. Irrigation scheduling and use of drip
irrigation are principal tools for striking this balance through improving water
application and water utilization efficiencies (Simonne et al., 2012).
11
2.4: Advantages of a Drip Irrigation System
A drip irrigation system results in healthy, fast-growing plants, and is very
efficient in its use of water. Little is lost to evaporation, and walkways and areas
between plants remain dry. Drip irrigation applies water only where it is needed,
with less runoff and evaporation. Studies on drip irrigation systems are show
results of up to 60% more efficiency over sprinkler systems (Jess Stryker, 1997-
2011) .
This also reduces weed growth, and makes cultivation possible during and
immediately after an irrigation cycle. Drip irrigation allows a large area to be
watered from a small water source, since it uses water more slowly than other
methods. The biggest savings for the home gardener is time: you can now garden
on a larger scale, and with an automatic timer, you can travel or deal
Drip irrigation method is not affected by high wind velocity as it applies water
directly to the root zone of plants. Its major advantages as compared to other
methods include, higher crop yields, saving in water, increased fertilizer use
efficiency, and reduced energy consumption (Jess Stryker, 1997-2011).
2.5. Disadvantages of a Drip Irrigation System
Not everything can be considered an advantage. The possible problems that can be
associated with drip irrigation are: First clogging of emitters is the most serious
problem associated with drip irrigation. To prevent blockage, care should be taken
to filter the water properly before use, depending on the particular particle size
and type of suspended material contained in the irrigation water. Second cost
conventional drip irrigation systems typically cost USD 5000–10,000 per hectare,
or more, when installed in East Africa. Third Water management when practising
drip irrigation, farmers do not see the water. This often results in over irrigation
and the loss of the benefits of high irrigation efficiency.
12
Over-irrigation will also make the soil excessively wet and therefore promote
disease, weed growth and nutrient leaching.fourth restricted root zone Plant root
activity is limited to the soil bulbs wetted by the drip emitters; a much smaller soil
volume than that wetted by full-coverage sprinkler or surface irrigation systems.
2.6 Crop Production
Rain fed crop production is the common land use practice in the study area. Agricultural
productivity is low and, the sustainability of traditional agricultural systems is threatened
by degradation of cropland. Crops like, maize, wheat, Teff are commonly grown by rain
fed, were as crops like potato, onion, tomato, pepper are grown under irrigation in the
area.
In response to change in climate, which resulted in increased moisture stress and
reduced soil fertility, the crop varieties grown in the past could not produce sufficient
yield to meet the subsistence requirement of the farming community
http://www.utviklingsfondet.noaccessed in 19 June 2013.
Some of the adaptations measures made by the farming communities, with the
support from Relief Society of Tigray (REST) within the project watersheds,
were the following: Development of irrigation structures such as check dam
ponds, underground water tankers, river diversion, hand-dug well, mini-dam,
Waterpump,treadlepump,motorizedpumps,watersavingtechnologiessuchasdripirrig
ationandwaterharvesting http://www.utviklingsfondet.noaccessed in 19 June 2013.
Early maturing and moisture stress tolerant varieties of crops have been
introduced. Because the period of rainfall is shorter a change towards a more
intensified production system was necessary. Early maturing cereals, short cycle
crops for rain fed agriculture, and new vegetables, root crops and fruits that can be
grown using irrigation has been adopted. Compost (from livestock dung), is used
to fertilize the soil) http://www.utviklingsfondet.no accessed in 19 June 2013
.Vegetable as well as livestock producers in tigray region have been strongly
linked with the Bureau of Agriculture and Rural Development (BoARD).
13
Vegetable is an edible plant or its part, intended for cooking or eating raw. In
biological terms, vegetable designates members of the kingdom. In grebe beati
districts, drip irrigation is not widely used for vegetable production, although it has
the potential to improve irrigation performance. Instated the use alternative furrow
irrigation guided by local community to produce crops most of them for
themselves and local market. Irrigation in the grebe beati districts vegetable
production has traditionally been dominated by the use of surface irrigation.
However as the area is semiarid, drip irrigation has the potential to use scarce
water resources most efficiently to produce vegetables (Locascio, 2005).
2.6.1 Tomato
Tomato (Lycopersicon esculentum) is the second most important vegetable crop
next to potato. Present world production is about 100 million tons fresh fruit from
3.7 million ha).
Tomato is a rapidly growing crop with a growing period of 90 to 150 days. It is a
day length neutral plant. Optimum mean daily temperature for growth is 18 to 25ºC
with night temperatures between 10 and 20ºC. Larger differences between day and
night temperatures, however, adversely affect yield. The crop is very sensitive to
frost. Temperatures above 25ºC, when accompanied by high humidity and strong
wind, result in reduced yield. Night temperatures above 2OºC accompanied by high
humidity and low sunshine lead to excessive vegetative growth and poor fruit
production. High humidity leads to a greater incidence of pests and diseases and
fruit rotting. Dry climates are therefore preferred for tomato production.
Tomato can be grown on a wide range of soils but a well-drained, light loam soil
with pH of 5 to 7 is preferred. Water logging increases the incidence of diseases
such as bacterial wilt. The fertilizer requirements amount, for high producing
varieties, to 100 to 150 kg/ha N, 65 to 110 kg/ha P and 160 to 240 kg/ha K.
The seed is generally sown in nursery plots and emergence is within 10 days.
Seedlings are transplanted in the field after 25 to 35 days. In the nursery the row
14
distance is about 10 cm. In the field spacing ranges from 0.3/0.6 x 0.6/1 m with a
population of about 40,000 plants per ha. The crop should be grown in a rotation
with crops such as maize, cabbage, cowpea, to reduce pests and disease
infestations.
The crop is moderately sensitive to soil salinity. Yield decrease at various ECe
values is: 0% at ECe 2.5 mmhos/cm, 10% at 3.5, 25% at 5.0, 50% at 7.6 and 100'/.
at ECe 12.5 mmhos/cm. The most sensitive period to salinity is during germination
and early plant development, and necessary leaching of salts is therefore frequently
practised during pre-irrigation or by over-watering during the initial irrigation
application.
The crop has a fairly deep root system and in deep soils roots penetrate up to some 1. 5
m. The maximum rooting depth is reached about 60 days after transplanting. Over 80
percent of the total water uptake occurs in the first 0.5 to 0.7 m and 100 per-cent of the
water uptake of a full grown crop occurs from the first 0.7 to 1.5 m (D = 0.7 - 1.5 m).
Under conditions when maximum evapotranspiration (ETm) is 5 to 6 mm/ day water
uptake to meet full crop water requirements is affected when more than 40 percent of the
total available soil water has been depleted (p = 0.4).
The crop performance is sensitive to the irrigation practices. In general a prolonged
severe water deficit limits growth and reduces yields which cannot be corrected by heavy
watering later on. Highest demand for water is during flowering. However, withholding
irrigation during this period is sometimes recommended to force less mature plants into
flowering in order to obtain uniform flowering and ripening. Care should be exercised in
this to avoid damage to the mature plants.
Excessive watering during the flowering period has been shown to increase flower drop
and reduce fruit set. Also this may cause excessive vegetative growth and a delay in
ripening. Water supply during and after fruit set must be limited to a rate which will
prevent stimulation of new growth at the expense of fruit development.
15
Surface irrigation by furrow is commonly practised. Under sprinkler irrigation the
occurrence of fungal diseases and possibly bacterial canker may become a major
problem. Further, under sprinkler, fruit set may be reduced with an increase in fruit
rotting. In the case of poor quality water, leaf burn will occur with sprinkler irrigation;
this may be reduced by sprinkling at night and shifting of sprinkler lines with the
direction of the prevailing wind. Due to the crops specific demands for high soil water
content achieved without leaf wetting, trickle or drip irrigation has been successfully
applied.
2.6.1.Onion
Onion (Allium cepa) is believed to have originated in the Near East. The crop can
be grown under a wide range of climates from temperate to tropical. Present world
production is about 46.7 million tons of bulbs from 2.7 million ha.
Under normal conditions onion forms a bulb in the first season of growth and
flowers in the second season.
The production of the bulb is controlled by daylength and the critical day length
varies from 11 to 16 hours depending on variety. The crop flourishes in mild
climates without extremes in temperature and without excessive rainfall. For the
initial growth period, cool weather and adequate water is advantageous for proper
crop establishment, whereas during ripening, warm, dry weather is beneficial for
high yield of good quality. The optimum mean daily temperature varies between
15 and 20°C. Proper crop variety selection is essential, particularly in relation to
the day length requirements; for example, a long day temperate variety in tropical
zones with short days will produce vegetative growth only without forming the
bulb. The length of the growing period varies with climate but in general 130 to
175 days are required from sowing to harvest.
The crop is usually sown in the nursery and transplanted after 30 to 35 days. Direct
seeding in the field is also practised. The crop is usually planted in rows or on
16
raised beds, with two or more rows in a bed, with spacing of 0.3 to 0.5 x 0.05 to
0.1 m. Optimum soil temperature for germination is 15 to 25°C. For bulb
production the plant should not flower since flowering adversely affects yields.
Bulbs are harvested when the tops fall: For initiation of flowering, low
temperatures (lower than 14 to 16°C) and low humidity are required. Flowering is,
however, little affected by day length.
Onion, in common with most vegetable crops, is sensitive to water deficit. For high
yield, soil water depletion should not exceed 25 percent of available soil water. When
the soil is kept relatively wet, root growth is reduced and this favours bulb
enlargement. Irrigation should be discontinued as the crop approaches maturity to
allow the tops to desiccate, and also to prevent a second flush of root growth.
The growth periods of an onion crop with a growing period of 100 to 140 days in the
field are: establishment period (from sowing to transplanting, 0) 30 to 35 days;
vegetative period 25 to 30 days; yield formation (bulb enlargement, 3) 50 to 80 days;
and ripening period (4) 25 to 30 days.
The crop is most sensitive to water deficit during the yield formation period,
particularly during the period of rapid bulb growth which occurs about 60 days after
transplanting. - The crop is equally sensitive during transplantation. For a seed crop,
the flowering period is very sensitive to water deficit. During the vegetative growth
period the crop appears to be relatively less sensitive to water deficits.
For high yield of good quality the crop needs a controlled and frequent supply of
water throughout the total growing period; however, over-irrigation leads to reduced
growth.
To achieve large bulb size and high bulb weight, water deficits, especially during the
yield formation period(bulb enlargement, should be avoided. Under limited water
supply small water savings can be made during the vegetative period and the ripening
17
period. However, under such conditions water supply should preferably be directed
toward maximizing production per hectare rather than extending the cultivated area
with limited water supply.
The crop has a shallow root system with roots concentrated in the upper 0.3m soil
depth. In general 100 percent of the water uptake occurs in the first 0.3 to 0.5rn soil
depth (D = 0.3-0. 5 m). To meet full crop water requirements (ETm) the soil should be
kept relatively moist; under an evapotranspiration rate of 5 to 6 mm/day, the rate of
water uptake starts to reduce when about 25 percent of the total available soil water
has been depleted (p = 0.25).
The crop requires frequent, light irrigations which are timed when about 25 percent of
available water in the first 0.3 m soil depth has been depleted by the crop. Irrigation
application every 2 to 4 days is commonly practised. Over-irrigation some-times cause
spreading of diseases such as mildew and white rot. Irrigation can be discontinued 15
to 25 days before harvest. Most common irrigation methods are furrow and basin.
2.6.1.Potato
Potato (Solanum tuberosum) originates in the Andes from the tropical areas of
high altitude. The crop is grown throughout the world but is of particular
importance in the temperate climates. Present world production is some 308
million tons fresh tubers from 19 million ha. (FAOSTAT, 2001).
Yields are affected by temperature and optimum mean daily temperatures are 18 to
20°C. In general a night temperature of below 15°C is required for tuber initiation.
Optimum soil temperature for normal tuber growth is 15 to 18°C. Tuber growth is
sharply inhibited when below 10°C and above 30°C. Potato varieties can be
grouped into early (90 to 120 days), medium (120 to 150 days) and late varieties
(150 to 180 days). Cool conditions at planting lead to slow emergence which may
18
extend the growing period. Early varieties bred for temperate climates require a
day length of 15 to 17 hours, while the late varieties produce good yields under
both long and short day conditions. For tropical climates, varieties which tolerate
short days are required for local adaptation.
Potato is grown in a 3 or more year rotation with other crops such as maize, beans
and alfalfa, to maintain soil productivity, to check weeds and to reduce crop loss
from insect damage and diseases, particularly soil-borne disease. Potato requires a
well-drained, well-aerated, porous soil with pH of 5 to 6. Fertilizer requirements
are relatively high and for an irrigated crop they are 80 to 120 kg/ha N, 50 to 80
kg/ha P and 125 to 160 kg/ha K. The crop is grown on ridges or on flat soil. For
rainfed production in dry conditions, flat planting tends to give higher yields due to
soil water conservation. Under irrigation the crop is mainly grown on ridges. The
sowing depth is generally 5 to 10 cm, while plant spacing is 0.75 x 0.3 m under
irrigation and 1 x 0.5 m under rainfed conditions. Cultivation during the growing
period must avoid damage to roots and tubers, and in temperate climates ridges are
earthed up to avoid greening of tubers.
The crop is moderately sensitive to soil salinity with yield decrease at different
levels of ECe: 0% at 1.7, 10% at 2.5, 25% at 3.8, and 50% at 5.9 and 100° / at ECe
10 mmhos/cm.
Potato is relatively sensitive to soil water deficits. To optimize yields the total
available soil water should not be depleted by more than 30 to 50 percent.
Depletion of the total available soil water during the growing period of more than
50 percent results in lower yields. Water deficit during the period of stolonization
and tuber initiation and yield formation have the greatest adverse effect on yield,
whereas ripening and the early vegetative periods are less sensitive. In general,
water deficits in the middle to late part of the growing period thus tend to reduce
yield more than in the early part. To maximize yield, the soil should be
maintained at relatively high moisture content. This, however, can have an
19
Water supply and scheduling are important in terms of quality. Water deficit in the early
part of the yield formation period increases the occurrence of spindled tubers, which is
more noticeable in cylindrical than in round tubered varieties. Water deficit during this
period followed by irrigation may result in tuber cracking or tubers with black hearts. Dry
matter content may increase slightly with limited water supply during the ripening period.
Frequent irrigation does reduce occurrence of tuber malformation.
Good yields under irrigation of a crop of about 120 days in the temperate and subtropical
climates are 25 to 35 ton/ha fresh tubers and in tropical climates yields are 15 to 25
ton/ha. The water utilization efficiency for harvested yield (Ey) for tubers containing 70 to
75 percent moisture is 4 to 7 kg/m3.
adverse effect when frequent irrigation with relatively cold water may decrease
the soil temperature below the optimum value of 15 to 18°C for tuber formation.
Also, soil aeration problems can sometimes occur in wet, heavy soils.
Since the potato is a relatively sensitive crop in terms of both yield and quality,
under conditions of limited water supply the available supply should preferably be
directed towards maximizing yield per ha rather than spreading the limited water
over a larger area. Savings in water can be made mainly through improved timing
and depth of irrigation application.
20
3. METHODOLOGY AND SOURCE OF DATA
3.1 Location and physiographic
The study area is found in small micro earth dam, called grebe Beat Dam in the
Southern zone of Tigray region. It lies between latitude of 13°44 '67” E and 39°47
'70 "N longitude about 3.14 km, west Aynalem town. The elevation of the area
ranges from 2144 to 2155 m ASL. The topography of the area is not uniform. The
catchment area of the study consists; gentle slope, considerably plain and hilly
slopes. The gentle and hilly slope areas are mainly used for agricultural
production. The reservoirs is constructed on a gentle slope and situated on
farmlands causing displacement of a number of farmers. The irrigation and
drainage infrastructure in the dam is open canals made of earth.
Figure 1: location of Gereb Beati
21
3 .2 Methodology
3.2. 1 Collection of agro-climatic data
Tigray is located at the northern limit of the central highlands of Ethiopia. The
landform is complex composed of highlands (in the range of 2300 to 3200 meters
above sea level, (masl), lowland plains (with an altitude range of <500.to 1500
masl), mountain peaks (as high as 3935 masl) and high to moderate relief hills
(1600 to 2200 masl). The climate condition in the study area can be described as
dry and hot typical of subtropical Regions.
3.2.2 Geology and Soil
The soils of this site are Liptosoils, consist 50 of clay and sand 20%, 31 volume
gravel, having small amount of salt around 0.1%. This type of soil a very
shallow over hard or highly calcareous material or a deeper soil that is
extremely gravelly or stony. It is graduàùally transported from the surrounding
mountainous area. Leptosols are unattractive soils for rain fed agriculture because
of their inability to hold water.
22
Sources: Soil water character
Table 1: soil mapping unit
23
3.2.3 Water source
Reliable water source is essential for sustainable production and the amount of
water that is available determines the area to be irrigated. Its gets water from the
Gereb Beati Dam found in Aynalem city. Gereb-Beati present reservoir capacity
is 85000m³ the source of water utilize rain water/runoff, diversion of floods from
the highland and two rivers, there is 90 ha planned command area but the actual
command area under irrigation is 36 ha and 440 actual beneficiaries (Aster et al.,
2007).
3.2.4. Climate
The area has a monomodal rainfall pattern that the main rainy season is during
summer from June to August. The remaining months are dry. A shorter rainy
season and such climate variability represent major challenges for the population.
The temperature and rainfall data was obtained from CLIMWAT 2.0
The annual rainfall data were obtained directly by the software
New_LocClim_1.10 from the interpolation done on the basis of data from
meteorological stations nearby.
Figure 2: Vegetation period of Gereb beati
Source: New-LocClim analysis
24
3.3. Determination of tomato, onion, pepper) grown crops water
requirement
Water requirement of tomato, onion, pepper) grown crops were determined using
the software CROPWAT 8.0developed by FAO. The crop coefficient Kc,
however, was adjusted to bring them closer to tropical conditions.
3.3.1 The crop coefficient Kc
The Kc integrates the characteristics of the crop that distinguish it from the
reference crop (usually a short, green, well-watered crop that completely shades
the ground) used to estimate reference ET .
Table 2: Tomato Growth Stages and Crop Coefficient Kc
Crop Init.
(Lini)
Dev.
(Ldev)
Mid
(Lmid)
Late
(Llate)
Total Plant
Date
Region
Tomato 30 40 40 25 135 January Arid Region
35 40 50 30 155 Apr/May Calif., USA
25 40 60 30 155 Jan Calif.
Desert, USA
35 45 70 30 180 Oct/Nov Arid Region
30 40 45 30 145 April/May Mediterrane
an
Crop
Coefficient,
Kc
0.6 >> 1.15 0.7-0.9
Source: http://www.fao.org/nr/water/cropinfo_tomato.html
25
Table 3: onion Growth Stages and Crop Coefficient Kc
Source: FAO, 2009
Table 4 : Potato Growth Stages and Crop Coefficient Kc
Source: http://www.fao.org/nr/water/cropinfo_potato.html
Init.
(Lini)
Dev.
(Ldev)
Mid
(Lmid)
Late
(Llate)
Total Plant
Date
Crop Region
15 25 70 40 150 April Onion (dry) Mediterranean
20 35 110 45 210 Oct; Jan. Arid Region;
Calif.
0.7 >> 1.05 0.75- Crop
Coefficient,
Kc
Crop Init.
(Lini)
Dev.
(Ldev)
Mid
(Lmid)
Late
(Llate)
Total Plant
Date
Region
Potato 25 30 30/45 30 115/130 Jan/Nov (Semi)
Arid
Climate
25 30 45 30 130 May Continental
Climate
30 35 50 30 145 April Europe
45 30 70 20 165 Apr/May Idaho,
USA
30 35 50 25 140 Dec Calif.
Desert,
USA
Crop
Coefficient,
Kc
0.5 >> 1.15 -0.5
26
Table 5: Climate data
Source: cropwat analysis
Table 6: monthly Rainfall
Source: cropwat analysis
27
3.4. Design Software
9 programs were used to design the irrigation system:
1.Google Earth is a virtual globe, map and geographical information program that
was originally called Earth Viewer 3D, and was created byKeyhole, Inc, a Central
Intelligence Agency (CIA) funded company acquired by Google in 2004 (see In-
Q-Tel).
It maps the Earth by the superimposition of images obtained from satellite
imagery, aerialphotography and GIS 3D globe
https://en.wikipedia.org/wiki/Google_Earthacessed 6/17/2013.
2.Harmonized World Soil Database is a 30 arc-second raster database with over
16000 different soil mapping units that combines existing regional and national
updates of soil information worldwide. The HWSD contributes sound scientific
knowledge for planning sustainable expansion of agricultural production to
achieve food security and provides information for national and international
policymakers in addressing emerging problems of land competition for food
production, bio-energy demand and threats to biodiversity (FAO, 2009). Soil
3.water characteristics program estimates soil water tension, conductivity and
28
water holding capability based on the soil texture, organic matter, gravel content,
salinity, and compaction. The result analysis from this gives very low infiltration
rate and used the associated soil for the analysis because this is not the actual data
from local the software may not give me perfect results of actual area.
4 Cropwat is a decision support system developed by the Land and Water
Development Division of FAO for planning and management of irrigation.
CROPWAT is meant as a practical tool to carry out standard calculations for
reference evapotranspiration, crop water requirements and crop irrigation
requirements, and more specifically the design and management of irrigation
schemes. It allows the development of recommendations for improved irrigation
practices, the planning of irrigation schedules under varying water supply
conditions, and the assessment of production under rainfed conditions or deficit
irrigation (FAO, 2013).
6. CLIMWAT 2.0 is an extensive climatic database of more than 5,000 stations
worldwide which is directly linked to the irrigation model AQUACROP. The
combination of both allows users to calculate crop water requirements, irrigation
supply and irrigation scheduling for various crops for a range of climatologically
stations. Climate data: maximum and minimum temperature, mean daily relative
humidity, sunshine hours, wind speed, precipitation and calculated values for
reference evapotranspiration and effective rainfall as input data for cropwat
7. EPANET is software that models water distribution piping systems. EPANET
is public domain software that may be freely copied and distributed. It is a
Windows 95/98/NT/XP program. EPANET performs extended period simulation
of the water movement and quality behavior within pressurized pipe networks.
EPANET was developed by the Water Supply and Water Resources Division
(formerly the Drinking Water Research Division) of the U.S. Environmental
Protection Agency’s National Risk Management Research
29
Laboratoryhttp://www.epa.gov/nrmrl/wswrd/dw/epanet.htmlacessed in 19 June
2013.
8 Ve.pro.LG.s is application software that performs the operation checks
dimensioning and design of systems of drip irrigation, with the aim to increase the
uniformity of distribution of irrigation, to save water and reduce energy
consumption. For the design of the distribution network at the sub-plot level,
namely drip lines system. The software Ve.Pro.L.G. s., name derived from the
initials of "Verification and Design of drip lines and areas of plant stems from
Ve.Pro.LG.s first version, released in 2003 and represents a substantial evolution,
being able to assess the functioning of entire planting areas and also extend the
application range of the horticultural industry and tree crops, even when grown on
sloping ground elevation along the line.
3.4.1. Choice of Plot
An area of 90 ha square shape was arbitrarily defined on the undeveloped area of
the plain of served as plot type. The choice was made on the agricultural area
which could potentially be attributed to farmers. This division is designed to
enable simultaneous operation or not of these three sub-plots, Allowing to vary the
crop pattern.
30
Figure 3: Plot division
Source: Google earth
Table 7: Felid measurements
Column Field 3 Field 2 Field 1
Tomato
(m)
Onion
(m)
Potato
(m)
Quote upstream 2136 2136 2136
Quote
downstream
2131 2131 2132
Length 270 200 160
Width 50 50 45
Slope 1.9 12.5 3.1
Area 7200 10000 13500
Total Area 30,700 m2
Area 44% 33% 23%
Source: Google Earth
31
4. Result and Discussion
4.1 Crop Water Requirements of Each Crop
Tomato crop has large area coverage than the other vegetable crops produce in
study area. Total water requirements (ETm ) after transplanting, of a tomato crop
grown in the field for 90 to 120 days is 525.8 mm, depending on the climate of the
study area. The average crop evapotranspiration under standard conditions,
denoted as Etc and average effective rainfall are 586.5 and 59.5 respectively.
Irrigation of tomatoes can result in higher and more consistent yields, better
quality, larger fruit, less blossom-end rot and less cracking. The use of drip
irrigation will to reduce the Phytophthora problems caused by furrow irrigation.
Table 8: Tomato crop water requirement
Month Decade Stage Kc Etc ETc Eff rain Irr. Req.
Coeff mm/day mm/dec mm/dec mm/dec
Dec 1 Init 0.6 2.14 21.4 0.7 20.7
Dec 2 Init 0.6 2.07 20.7 0.1 20.7
Dec 3 Deve 0.6 2.14 23.5 0.3 23.2
Jan 1 Deve 0.69 2.52 25.2 0.5 24.7
Jan 2 Deve 0.83 3.12 31.2 0.6 30.6
Jan 3 Deve 0.98 3.84 42.3 1 41.2
Feb 1 Mid 1.13 4.6 46 1.2 44.7
Feb 2 Mid 1.16 4.96 49.6 1.5 48.1
Feb 3 Mid 1.16 5.16 41.3 3.3 38
Mar 1 Mid 1.16 5.36 53.6 5.1 48.5
Mar 2 Mid 1.16 5.56 55.6 6.7 49
Mar 3 Late 1.14 5.58 61.4 8.6 52.8
Apr 1 Late 1.03 5.13 51.3 11.3 39.9
Apr 2 Late 0.91 4.63 46.3 13.6 32.6
Apr 3 Late 0.82 4.29 17.1 4.9 11
586.5 59.5 525.8
Source : cropwat analysis
Total water requirements (ETm ) after transplanting, of a potato crop grown in the
field for 90 to 120 days is 461.3 mm, depending on the climate station of the study
32
area. The average crop evapotranspiration under standard conditions, denoted as
Etc and average effective rainfall are 502.9 and 39.8 respectively.
Water quality and water scarcity issues and may lead some growers to adopt drip
irrigation for potato production. It’s part of the solution to being as conservative
and efficient with the water. Study in Drip irrigation of potato in arid farmlands
of China also sates that a feasible eco-technological and economically viable
technology Use of scarce water resources, in a sustainable way, in potato
cultivation to spread over a larger area. Higher productivity, quality tubers, food
security and increased income to farmers. The risk of foliar diseases is lower with
drip systems, and they can apply fertilizers and some pesticides effectively.
Table 9: Potato crop water requirements
From: Cropwat analysis
Month Decade Stage Kc ETc ETc Eff rain Irr.
Req.
Coeff mm/day mm/dec mm/dec mm/dec
Dec 1 Init 0.5 1.78 17.8 0.7 17.1
Dec 2 Init 0.5 1.73 17.3 0.1 17.2
Dec 3 Deve 0.54 1.93 21.2 0.3 20.9
Jan 1 Deve 0.76 2.76 27.6 0.5 27.1
Jan 2 Deve 0.98 3.66 36.6 0.6 36
Jan 3 Mid 1.15 4.52 49.7 1 48.7
Feb 1 Mid 1.17 4.77 47.7 1.2 46.4
Feb 2 Mid 1.17 4.97 49.7 1.5 48.1
Feb 3 Mid 1.17 5.17 41.4 3.3 38.1
Mar 1 Mid 1.17 5.37 53.7 5.1 48.6
Mar 2 Late 1.09 5.21 52.1 6.7 45.5
Mar 3 Late 0.95 4.64 51 8.6 42.4
Apr 1 Late 0.81 4.06 36.5 10.2 25.2
502.3 39.8 461.3
Total water requirements (ETm) after transplanting, of onion crop grown in the field for
100 to 140 days is 461.3 mm, depending on the climate station of the study area.
33
The average crop evapotranspiration under standard conditions, denoted as Etc and
average effective rainfall are 331.7 and 11.8 mm respectively.
Mohammad Quadir ,et al (2005 ) also state design drip irrigation for onion
production in arid regions allows very littile evaporation and runn off, save water by
directing it more precisely ,reduce the transmission of pathogens and produce fewer
weeds ,also has the ablity to meet crop requirements ,this is particular as the crop
matures as over watering on onon crop near harvest can damages the bulbs and reduce
shelf life , occur with furrow irrigations and also help can apply water uniformly
,alternative method for crop need high demand .
Table 10: crop water requirements of onion
Source: cropwat analysis
Month Decade Stage Kc ETc ETc Eff
rain
Irr.
Req.
coeff mm/day mm/dec mm/dec mm/dec
Dec 1 Init 0.7 2.5 25 0.7 24.3
Dec 2 Init 0.7 2.42 24.2 0.1 24.1
Dec 3 Deve 0.77 2.74 30.2 0.3 29.9
Jan 1 Deve 0.9 3.28 32.8 0.5 32.3
Jan 2 Mid 1.02 3.82 38.2 0.6 37.6
Jan 3 Mid 1.06 4.16 45.8 1 44.8
Feb 1 Mid 1.06 4.35 43.5 1.2 42.2
Feb 2 Late 1.06 4.52 45.2 1.5 43.7
Feb 3 Late 1.02 4.52 36.2 3.3 32.9
Mar 1 Late 0.98 4.5 22.5 2.6 19.9
343.5 11.8 331.7
34
4.2 Cropping pattern
Cropping pattern means the proportion of area under various crops at a point of time
in a unit area or it indicated the yearly sequence and spatial arrangements of crops and
follows in an area. Land resources being limited emphasis have to be placed for
increasing production from unit area of land in a year. Cropping systems based on
climate soil and water availability have to be evolved for realizing the potential
production levels through efficient use of availability use of available resources. The
cropping pattern, or cropping schedule of an irrigation area provides information, for a
period of at least one season, on three important elements, which crops are grown,
when are they cultivated, how many hectares of each crop are grown (FAO,1992).
Figure 4:area cropping pattern
44%
33%
23%
Area of crooping pattern %
Tomato
Onion
Potato
35
4.3. Schemes supply
Water supply networks usually represent the majority of assets of a water utility. One
of the most important factors that affect service delivery and the continued use of rural
water schemes is the quality of water the schemes deliver to users. The net scheme
irrigation need, is the amount of water needed to meet crop water needs of an entire
scheme minus the effective rainfall. Water supply schemes coverage has maxima net
irrigation requirement of 4.3 mm/day and minimum is 1.3 mm/day.
Table 11: scheme supply
From: Cropwat analysis
Lines available in the study area, 11 provide a uniform distribution over 93.5 (90%
being the acceptable threshold in drip irrigation). The first 11 drip lines ranking are
self-compensating, i.e. drip line whose discharge varies very little or not in case of
change of pressure (Emitter discharge exponent x close to zero). Another
characteristic of self-compensating drip lines is their relatively high cost due to
this particular characteristic. The area uniformity is 93.5 % and the area flow rate
is 15.3 l/s = 55.08 m3/hour and the inlet pressure is 8 mH2o.
36
Figure 5 :drip line for potato
Figure 6: checking drip
Having identified and ranked the drip lines available with the software
Ve.Pro.LG, the drip line best drip line from select 11 drip lines is stream line
,having uniformity of 93.6 ,spacing 0.4 inlet pressure 8 and discharge of 2.04l/hm
and irrigation intensity of 4.1mm/h .
37
Figure 7: pressure compensating
Pressure compensating drippers adjusted to provide a continuous wetting pattern
along a line. The use of pressure compensating dripline can simplify the design of
the entire irrigation system. With pressure compensating dripline water can be
applied uniformly on long rows and on uneven terrain.
38
Figure 8 :onion drip line
The emission uniformity is 92.5 % and the area flow rate is 11.2 l/s = 40.03
m3/hour and the inlet pressure is 8 mH2o, having annual water loss of 374m3/ha
and Considering that the system operates by rotational distribution of irrigation
water within the four sub-plots irrigation intensity is 4m3/ha .
39
Figure 9: Tomato
The area uniformity is 87.8 % and the area flow rate is 7.6 l/s = 27.36 m3/hour and
the inlet pressure is 8 mH2o, having annwater loss of 538m3/ha.
4.3 Network of the design
Figure 10: Network of the design
40
4.5 System in operation
Figure 11: system watering of field one
The system delivers to the field one a flow rate of 28.44m3/h and pressure of 4.4
mH2o and flow velocity of 0.46 m/s (figure 11).
Figure 12 : system watering of field two
The system delivers to the field two a flow rate of 40.32 m3/h and pressure of 8
mH2o and flow velocity of 0.66 m/s figure (12).
Figure 13: system watering of field 3 part lot 1
41
The system delivers to the felid d three part one a flow rate of 27.56 m3/h and
pressure of 8 mH2o and flow velocity of 0.45 m/s (figure 13).
Figure 14: system watering of field 3 part lot
The system delivers to the field one a flow rate of 27.56 m3/h and pressure of 8
MH2o and flow velocity of 0.45 m/s (figure 14).
The pipe line system was fully designed with pipe of 110.2 mm of diameter. The
diameter of the pipe was kept constant because the delivery system will be by
rotation among the 4 plots. Then all the water from the pump will be used by a
single sub-plot at a time.
Valves (PRV) with loss coefficient to obtain the desired pressure head at each plot
level have been also used. Indeed the 4 sub-plot receive a head pressure a little bit
higher than they need then the need to decrease this pressure to the desired
pressure.
42
4.2 Characteristics of system components Table 12: system components
Pipe
number
19
Diameter 110.2
roughness 140
43
6. Conclusion and recommendation
The efficient use of water is seen as a key to crop production in arid and semi-arid
areas in subSahara Africa. This is increasingly true because of ever-increasing
populations and demand for food production, coupled with growing competition
for water. For smallholder farmers, drip irrigation provides a means of maximizing
returns on their cropland by increasing the agricultural production per unit of land
and water and increasing cropping intensity by growing a crop during the dry
season.
Drip irrigation can help you use water efficiently. A well-designed drip irrigation
system loses practically no water to runoff, deep percolation, or evaporation.
Irrigated desert soils are commonly used for the production of high value
horticultural crops.
The study shows that the dam can conveniently supply the water required for
irrigation in the area used at present and also in the entire land area. The results
obtained from the study can be used as a guide by farmers for selecting the amount
and frequency of irrigation water for the crops studied under consideration but the
climate in the study was characterized shorter rainy season and climate variability
represent major challenges for the population , the water supply in the study area is
low due to a drought and water restrictions are applied, the inefficiencies of a
poorly designed and installed irrigation system quickly become apparent. For an
irrigation system to be successful, it must include proper design, correct
installation, the right component selection, the proper layout, and equally
important, appropriate maintenance, for this reason the software’s like Google
earth, CLIMWAT2.0, SPAW, the CROPWAT Ve.pro.LG.s, and EPANET was
44
used to evaluate field and coordinates, get climatic data, determine soil
characteristics, the crop water requirements, determine efficiency of the irrigation
system ,proper design of drip irrigation are used respectively in the selected
agricultural district in the study area. This technology could help a farmer to
overcome the worst conditions would have a substantial impact on crop yields,
improve food security, and increase the farmer’s potential for income.
The final system has an efficiency of 92 % and works without pumping, only by
gravity. This performance increases substantially water saving in irrigation,
therefore, allows extension of irrigated areas with the same resource and also its
sustainable use. Google Earth allows users to perform some basic measurements
(latitude and longitude, elevation, and size) but this all measurements do not mean
it is perfect. Some place marks or place mark collections are dynamic, in that they
contain information that changes through time.
45
5. Reference
A. Tagar, F. A. Chandio, I. A. Mari, B. Wagan, 2012, Comparative Study of Drip
Adeniran K.A Amodu M.F1, Amodu M. and Adeniji F.A, (2010), Water
requirements of some selected crops in Kampe dam irrigation project,
AJAE 1(4):119-125 ISSN:1836-9448
FAO, 2013, Crop Water Information, Potato water development and management
unit.
FAO,1992, Irrigation Water Management: Scheme irrigation water needs and
supply
FAO,2013,WaterDevelopmentAndManagementUnit,http://www.fao.org/nr/water/i
nfores_databases_cropwat.html accessed in June 19, 2013
FAO/IIASA/ISRIC/ISSCAS/JRC, 2009. Harmonized World Soil Database
(version 1.1). FAO, Rome, Italy and IIASA, Laxenburg, Austria
Furrow Irrigation Methods at Farmer’s Field in Umarkot, World Academy of
Science, Engineering and Technology
Girmay Tesfaye, Mitiku Haile, Berhanu Gebremedhin, J. Pender
and Eyasu
Yazew.2010. Small-scale irrigation in Tigray: Management and
institutional considerations
http://www.epa.gov/nrmrl/wswrd/dw/epanet.htmlacessed in 19 June 2013.
Jess Stryker, 2011 Drip Irrigation Design Guidelines
Kifle Woldearegay Woldemariam, 2012, Regreening Tigray - Up scaling 3R
Catchments
Langbein W. B. and Kathleen T.Iseri ,2013 General Introduction and Hydrologic
Definitions PAPER 1541
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Locascio, J.S. (2005) Management of irrigation for vegetables: past, present,
future, Hort Technology 15(3): 482–485.
Management in Ethiopia, world water in week in Stockholm
MARD, 2009. Agricultural Investment Potential of Ethiopia. Review rt. March,
2009, Addis Ababa
Mintesinot Behailu, Mohammed Abdulkedir., Atinkut Mezgebu, Mustefa Yasin,
2004.Community Based Irrigation Management in the Tekeze Basin:
Impact Assessment A case study on three small-scale irrigation schemes
(micro dams).
Mofoke, A. L. E., Adewumi, J. K., Mudiare, O. J. and A. A. Ramalan, 2004,
Design, construction and evaluation of an affordable continuous-flow drip
irrigation system, Journal of Applied Irrigation Science, Vol. 39. No
2/2004, pp. 253-269
Pascal Vagnat, 2013, Federal Democratic Republic of Ethiopia.
Seleshi Bekele Awulachew, Aster Denekew Yilma , Makonnen Loulseged
Willibald Loiskandl ,Mekonnen Ayana, Tena Alamirew, 2007 . Water
Resources and Irrigation Development in Ethiopia, Paper 123
Simonne Eric ,Hochmuth Robert, Brem Jacque an , Lamont William , Treadwell
Danielle , and Gazula Aparna , 2012 Drip Irrigation System for Small
Conventional Vegetable Farms And Organic Vegetable Farms
Suat Irmak, 2007, Drip Irrigation Design and Management Considerations for Windbreaks
Suhas P Wani ICRISAT, Johan Rockström SEI, n and Theib Oweis ICARDA,
2009 . Rainfed Agriculture
T.K. Hartz, 1999 Water Management in Drip-Irrigated Vegetable Production
University of California, Davis, CA 95616
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Yazewe (2005) Development and management of irrigated lands in Tigray,
Ethiopia PhD thesis UNESCO IHE Institute for Water E ducation. Delft,
the Netherlands: 265 p.
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Appendix
Annex 1:Soil mapping unit
Annex 2: Soil water character
49
Annex 3 Networki table of field one
Anex 4: Networki table of field two
50
Anex 5 : Networki table of field 3 part one
51
Anex 6: Networki table of field 3 part 2