ICRISAT AVRDC Niger Final Report AMIV Final 280910-2

8/6/2019 ICRISAT AVRDC Niger Final Report AMIV Final 280910-2

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Improving Livelihoods through Affordable Micro-Irrigation forVegetable (AMIV) in Western Africa

Final report

Niger component

ICRISAT/AVRDCNIGER

November 2009-May 2010

Lennart Woltering, Dov

Pasternak, Navid Dejwakh and

Sanjeet Kumar

August 2010


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Contents

1. Background............................................................................................................................... 12. Solar pumps for smallholder producers in Niger...................................................................... 3

IntroductionMaterial and Methods

Results and Discussion

Conclusions and recommendations

3. Low head drip irrigation for farmers in Niger: a technical evaluation ..................................... 8IntroductionMaterial and Methods



4. Economic performance of low pressure drip irrigation, hand watering and crophusbandry on production of onion and hot pepper in Niger .......................................................... 14

IntroductionMaterial and Methods



References......................................................................................................................................21


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ICRISAT/AVRDC Niger progress report AMIV project 1

1. BackgroundNiger has been rated among the least developed countries in the world for a long time. Morethan three-fifths of households live below the international poverty line of US$1 per day and40% of children are malnourished (UNCTAD, 2005). The large majority of the population

make their living from agriculture, mostly by production of rain fed staple crops. The rain fedproduction systems are neither sustainable nor profitable due to erratic rainfall, poorproductivity and low commercial value of staples and overexploitation of cultivable land.Total GDP generated by the agricultural sector is 24% of which more than half is generatedby less than the 1% of arable land that is the irrigated (World Bank, 2008). Most of that landis occupied by small-scale (0.1ha) privately-held gardens for the production of horticulturalcrops (Norman and Walter, 1994; Perry, 1997). Irrigation is essential in achieving foodsecurity, increasing household income and generating employment opportunities (Hussain,2005). Yet, less than one-fourth of total 270,000 hectares irrigable land in Niger is being fullyor partially irrigated, with easily exploitable water resources still abound along the Nigerriver and in the areas of the Dosso-Gaya Dallols, the Maradi Goulbis, and the ZinderKoramas, where ample renewable shallow aquifers remain largely untapped (World Bank,2004). Development of the irrigation sector is held back by a lack of technologies (storage,water abstraction and efficient field application), access to credit, poor marketingarrangements and weak institutional support (World Bank, 2004, 2008). This report describesinnovative technologies that demonstrate to save labour, water and other inputs, and improveprofitability for smallholder farmers in Niger and other countries in the Sudano Sahel of WestAfrica.

Major bottlenecks for smallholder farmers that are engaged in irrigated horticultureproduction are water abstraction, water application and crop husbandry.

Water abstraction:

Niger, and many other countries in the Sudano Sahel, has a large potential for furtherdeveloping irrigation using renewable water resources. A large part of this water can befound in the sandy permeable soil at shallow depths. The most common method ofabstracting water for irrigation in Niger is by hauling water from a well using a simple half-gourd with a long cord attached (Norman and Walter, 1994). This method is very labourintensive and often used when water is not deeper than 5 meters, because it will yield toolittle water at too much labour. Some farmers use small, gasoline-powered pump sets that canpump from maximum 7 meters deep. Fuel is not always available in rural areas and farmercooperatives often have difficulties collecting funds for fuel when sharing a pump. Solar

pumps, on the other hand, are independent of fuel availability and have hardly any operatingcosts. Submersible pumps are very efficient because they are placed under the water table andonly push up water instead of sucking and pushing water as other types of pumps do.Therefore they can pump water from much greater depth than pumps that are situated abovethe water table. Chapter 2 describes the results of an experiment where water is pumped upusing a submersible pump powered by solar panels.

Water application:

Surface irrigation methods are utilized in more than 80% of the worlds irrigated lands yet thefield level application efficiency is often only 4050%. In contrast, drip irrigation may havefield level application efficiencies of 8090%, as surface runoff and deep percolation losses

are minimized (Postel et al. 2001). Besides that, surface irrigation methods are very labourintensive, whereas when the garden is equipped with drip irrigation it requires no more than


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opening a tap. For the above and many other reasons, drip irrigation is fast becoming popularin the developing world. Drip irrigation is made available to smallholder farmers in the formof standard drip kits that constitute a water reservoir, drip laterals and connectors. Differentprice-quality categories of these drip kits are being promoted in Africa. In Chapter 3 we showthe results of an experiment where we compared 3 different types of drip laterals from 3

different sources.

Crop husbandry:

Another important determinant of a profitable gardening activity is the way farmers managethe crops. Knowledge on crop production is mostly based on their own initiative andknowledge sharing within the community. Generally in the region, extension services lackcapacity in terms of both staff numbers and horticultural expertise (Drechsel et al., 2006).Production is seasonal and limited to only a few leading species and varieties that aremarketed at times when supply is high and thus prices are low. Vegetable seeds are importedfrom abroad and therefore expensive and not always adapted to the hot and sometimes veryhumid climate of the region. Availability of farm inputs and knowledge on fertilizer use and

disease and pest control is limited (Pasternak et al, 2006). These constraints result not only inlow yields and low produce quality, but also lead to wastage of water, soil degradation andhealth hazard due to improper use of pesticides. ICRISAT in Niger developed the AfricanMarket Garden, that combines drip irrigation and improved crop husbandry practices in oneproduction system. In Chapter 4 we compare the performance of the AMG, the improvedmanagement and the farmer practice in production of onion and hot pepper.


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2. Solar pumps for smallholder producers in Niger2.1 IntroductionWater lifting is a major limiting factor for development of the irrigation sector in the Sahel.

Currently used technologies are expensive in operation as they require either a lot of labouror depend on fuel availability. Solar pumps have great potential in the Sahel. Solar pumpsrequire no fuel and demand little maintenance compared to motorized pumps. The lifetime ofsolar pumps is estimated almost twice the lifetime of manual and motor pumps (8 vs. 4-5years). However, solar pumps are more expensive than fuel based pumps. A solar pump setthat can give 30 m3/day at 10m imported from Europe was quoted at 4600 Euro (6800 US$),while a conventional fuel pump would cost 350 US$. In recent years, China and India haveemerged as big producers of solar panels and submersible pumps, bringing prices downdramatically. When asked for prices from China we found out that we could order a completesolar pumping unit with similar qualifications from China at only US$ 3800, almost half ofthe conventional price. The pumping system contains a submersible pumps that allowspumping water from deep wells. Manual lifting methods are used until a maximum depth of 5meters (Norman and Walter, 1994) and ordinary fuel based pumps can pump up water until 7m depth. The submersible pump opens up opportunities for farmers to irrigate areas wherethe water table was considered too deep to be used. In this experiment we tested this solarpumping system in terms of technical performance as well as socio-economic factorsaffecting potential adoption by smallholder farmers.

2.2 Materials and methodsThe solar pumping system was completely manufactured in China andwas sent as a kit that could be assembled by laymen. It consisted of:

Lorentz PS150-Centric centrifugal submersible pump (12.5 kg) Controller C-SJ5-8

Metal frame with screws and bolts

Cables, electrical floats, run-dry sensor and other accessories.

4 SUNPOWER SPJS075-12S 75W solar modules with 2modules connected in series and two sets connected in parallel

Figure 2.1: Submersible pump and control box

F

Figure 2.2:Solar pumping

system set up.

Four solar

panels, control

box and

testing the

pump (left).

Pumping from

the well to

higher

elevation

(right)


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The experiment was conducted on the outskirts of Niamey city in the direction of theICRISAT research station (South-East side) in a pilot farmers garden. The water table in thegarden was 3m deep. The pumping system was lowered into a well, keeping 0.75m clearance

from the bottom of the well to prevent any dirt from being sucked in. A water meter wasinstalled to allow discharge measurements. The discharge was recorded hourly until the 4 th ofJune and daily afterwards. The water was elevated another 2 meters to simulate a pumpingdepth of 7 meters. At this pumping depth people generally abandon irrigation as it is tooheavy to lift water by hand and ordinary motor pumps cannot pump from this depth. Solarradiation data from the Agrhymet meteorological station 3.5 km west of the garden was usedto correlate the pumping rate to solar activity.

2.3 Results and discussionTechnical performance

The solar pumping system was fairly simple to install. It can be lifted by two persons, moved

around in the field, and transported in a pick-up. The connections from the solar panels to thecontroller appeared to be faulty, and the pumping data collected until the faulty connectionwas discovered (about one month) had to be discarded. The connectors could be easilyreplaced by simple connectors widely available in the market. Solar radiation data from theweather station was only available until the 16th of June 2010. Only the data collectedbetween the 21st of May and 16th of June was used in this analysis. Figure 2.3 shows that thepump pumps between 9 and 21 cubic meter per day depending on the solar radiation. Thecorrelation coefficient between pump discharge and solar radiation was found to be 0.87.Figure 2.4 shows the hourly solar radiation and pump discharge between 7h in the morninguntil 21h in the evening. The pumping is irregular, it stops when clouds block the sun, andreaches a maximum (2.5-2.8 m3/hr) between 11h and 16h, after which it decreases to zero at18h. This irregular flow over the day and dependence on solar radiation requires the pumpingsystem to be connected to a reservoir. This reservoir can be filled over the day, and used atonce, especially in combination with a drip irrigation system. At the same time the waterstored in the reservoir will function as a battery - storage of energy for a later time. In thepumping set-up there is no battery- as this requires maintenance and has proved to be theweakest link in many solar projects. The solar radiation peak is reached at 14h, while thepump pumps more or less constant between 11h-16h. The solar radiation is effectivelyconverted to pumping energy up to 2.5 MJ, after that the maximum pumping rate of 2.8 m 3/hris reached and the additional radiation is not used. This suggests that with anotherconfiguration of panels and pumps the performance of the solar pumping system might

improve.

Figure 2.3: Daily

solar radiation and

pump discharge (7

meters head)

0

5

10

15

20

25

30

5-21

5-23

5-25

5-27

5-29

5-31

6-2

6-4

6-6

6-8

6-10

6-12

6-14

6-16

Pum p discharge (m 3/day) Solar radiation (MJ/m2/day)


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0

1

2

3

4

24-5 26-5 28-5 30-5 1-6 3-6

Date and time of day

Pump discharge (m3/hr) Solar radiation (MJ)

Figure 2.4: Hourly solar radiation and pump discharge (22

ndMay to 4

thJune 2010)

The pilot farmer testing the solar pumping unit was impressed by the silent running of thepump, and was happy with the savings in fuel cost. The submersible pump could be easilyinstalled in existing wells that were used for water abstraction by small gasoline poweredpumps. The well had to be cleaned and covered to prevent any dirt from blocking thesubmersible pump. Operation was very easy as the pumping system was always switched

ON, so that it starts pumping in the morning and automatically switches off in the evening.The farmer and experts were wary that the control box contained too much electronics thatwould be vulnerable to the many dust storms and extreme heat of Niger. It is recommendedto use submersible pumps that have in-built control boxes in the pumping unit, so that thecontrol box is under the water table at a constant temperature and away from shocks at thesurface (for example the Grundfos SQF pumps).

Economic analysis

The solar pumping system pumps about 20 cubic meters per day. The irrigation requirementfor vegetables in Niger is commonly set at 8 mm/day. This means that this solar pumpingsystem can provide water for about 0.25 hectare intensive vegetable production. Table 2.1

compares the 3 most common methods of water abstraction in Niger, that is, manual waterlifting, using a treadle pump and using a motor pump to costs for using the solar pumpingsystem. In this case it is assumed that a producer irrigates 200 days per year. Two alternativelabour costs are included in the analysis, that is labour at 2 and 1 US$ per day. The annualamortization of the solar pumping system is lower than when lifting water by hand, or usingmotor pumps. The treadle pump is the most economic alternative at current cost levels.However, costs of solar pumping systems are expected to decrease even more. At a cost of2800 US$ for the solar pumping system it becomes more economic than the treadle pump (atlabour cost of 2 US$ per day).


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Table 2.1: Economic comparison of different water supply alternatives used in Niger forirrigation at two labour costs: 2 and 1 US$ per man day

qty

unit

cost total amortz qty

unit


unit


unit

cost total amortz

$ $ $/year $ $ $/year $ $ $/year $ $ $/year

Equipment 3 10 30 15 1 70 70 18 1 400 400 80 1 3,800 3,800 380

Well 3 30 90 23 1 100 100 10 1 200 200 20 1 200 200 20

Water distr. network 0 0 1 75 75 8 1 100 100 10 1 100 100 10

Maintenance 3 11 40 10

Fuel 0 0 480 0

Labor@2 $/manday 556 2 1,111 139 2 278 20 5

Labor@1 $/manday 556 1 556 139 1 139 10 3

Total 1,152 324 660 428

@Labor 2$/day

Total 596 185 640 423

@Labor 1$/day

eneral assumptions

Water need: 80 m3/day/hectare for 200 days/year equals 4,000 m

3/year

Site characteristics: assume >40 m3/hr well recharge, water table at 5m depth

Well types: Hand dug well at 30US$ lifetime 4 years; Washboard well 50 US$; Tube well at 200 US$ lifetime 10 years

Water distribution network: Underground pvc pipe system from pump to multiple field outlets used to irrigate 800 m2

area

Hand Lifting: at 5m depth Q= 0.25 L/s= 7.2 m

3

/day/person. Hand dug well. Require 3 water lifting points.Treadle pump: Q= 1 L/s= 28.8 m

3/day/person. Washboard well. Requires 1 water lifting point.

Moto r pump: 3 hp uses 0.12 Liter of fuel to move 1m3

water. Fuel cos t 1 US$/liter. Tube well. Labor 1h/day

Solar pump: Tubewell. Ins tallation cos t 3800US$ incl import, t ransport and ins tallation. Labor 0.25h/day

Lifetime Hand lifting 2, Treadle pump 4, Motor pump 5 and Solar pump 10 years

1 US$= 500 CFA

Hand lifting Treadle pump Motor pump Solar pump

apptechdesign.org

Table 2.2 shows the enterprise budget for a smallholder producer cultivating vegetables on0.25 ha. Apart from the solar pumping system the producer needs a fence, reservoir tools andother equipment to set up a vegetable garden. Then he saves fuel costs, but still needs to payfor farm inputs, maintenance and labour. Gross revenues from the sales of vegetables areassumed 5500 US$ per year. In the second column, it is assumed that the producer uses the

African Market Garden (AMG) production system developed by ICRISAT in Niger. Thissystem is based on low pressure drip irrigation. The AMG requires a higher investment indrip kits and a reservoir, and higher cost for farm inputs. However labour cost is significantlylower. In both cases the payback period is 2 years.


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Table 2.2: Enterprise budget for a 2500 m2 vegetable garden using the solar pumpingsystem and irrigated traditionally by hand or using the African Market Garden (AMG)technology

Traditional AMG

US$ US$Investment

Solar pumping system 3800 3800

Fence, well, reservoirs, tools, etc 1522 3372

Production cost

Farm inputs, maintenance, etc 676 1293

Labour 2025 675

Gross revenues

Vegetable production 5500 5500

Payback period (years) 1.9 2.0

2.4 Conclusion and recommendationsThis study focused on the experience in designing, installation and operation of solar pumpsfor smallholder farmers. A mobile solar pumping system developed for smallholder farmerswas tested in Niger and found economically and technically feasible. The system can beconsidered cheap at half the conventional price of a solar pumping system. The pump deliver20 m3 /day at a 7m pumping head, this is enough to irrigate 0.25 ha intensively. Solarpumping systems can and should be kept as simple as possible, this means with as littleelectronic components as possible (batteries, control box, automatic switch, etc). The flow isirregular over the day and therefore the solar pump should be combined with a reservoir. Thereservoir serves as battery- storage of energy in the form of water elevated above the field.Under current prevailing prices, the solar pumping system would be economically morefeasible than manual water lifting and motor pumps. The payback period of the solarpumping system is 2 years.


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3. Low head drip irrigation for farmers in Niger: a technical evaluation3.1 IntroductionDrip irrigation offers a viable alternative to traditional, inefficient, irrigation practice of

vegetable producers in the developing world. Drip irrigation allows uniform and efficientdistribution of water and nutrients to all plants in the irrigated field. Uniform irrigationimproves crop yields because it averts adverse effects of under- or over- watering, such asplant stress or leaching of plant nutrients, in certain parts of the irrigated area. Besides that,energy, fertilizer and other chemicals are used more efficiently when the correct amount ofwater is applied everywhere in the field. Because irrigation uniformity relates to crop yieldand the efficient use of resources and energy (i.e. to pump water), engineers regard it as animportant factor to be considered in the selection, design and management of irrigationsystems. Other important factors that influence the performance of a drip kit are emitter flowrate, occurrence of clogging, maximum lateral length, costs, lifetime and ease ofoperation/installation.

Conventional drip irrigation systems are fairly complex and expensive, mainly becausehardware components are optimized for fields of four hectares or larger and designed tominimize labour and management costs (Postel et al., 2001). Furthermore, the drip lines arerelatively long (200400 meters) and the drip emitters are designed to be compact and to notinterfere with mechanical cultivation of fields. This requires: relatively large-diameter dripline tubing; sophisticated emitters that operate at relatively high pressures (2 bar) whilehaving flow paths that are large enough so they do not clog easily, and expensive filters tominimize clogging of the emitters. Drip systems on larger fields also require carefulengineering and design to assure that the relative pressure differences among the emitters are

small so that the application (drip rate) throughout the field is uniform. By contrast, early dripsystems were simple and used micro-tubes instead of sophisticated emitters. These simpledesigns were abandoned because they did not fit the needs of modern medium- and large-scale farming in the developed countries.

Since the 1970s, experiments have been carried out on drip kits that serve small areas forsmallholder farmers. These kits have short drip lines and pressure is provided by watercontainers elevated 1 meter above the field. The elevation difference within the plot istypically minimal, so pressure losses are small. IDE is the largest promoter of drip kits forsmallholder farmers. Drip kits, suitable for 10-500 m2 are made available for smallholderfarmers. The major differences between the kits are in the quality of the laterals and

connectors, and command area. IDE incorporated the micro-tubes in their drip kit. ICRISATin Niger is promoting the use of high quality drip lines with in-build drippers that arenormally used for high pressure drip systems. A third major type of drip lines is drip tape,where in-build drippers are incorporated in thin-walled PE laterals.

ICRISAT in Niger is designing drip irrigation systems for smallholder farmers.Technological features of drip kits that are important to smallholders include low investmentand operation cost, and simple operation and maintenance. Obviously one should find theright balance between affordability and simplicity on the one hand and quality and longevityof equipment on the other. This study will evaluate the technical performance of these threemain types of drip laterals and give recommendations on application in West Africa. The

effect of water supply head, lateral length and other parameters important in design of dripirrigation systems will be evaluated. The results of this study will be of interest to farmers,


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NGOs and decision makers that have a range of options to invest in several types of drip kitsin Niger.

3.2 Materials and methodsExperimental set-up

The field experiment was conducted at the ICRISAT Sahelian research station (1315N.217E) in Niger, situated 40 km South East of the capital Niamey. Three different driplaterals were tested; Micro tubes, in-line emitters and drip tape. Micro tubes are beingpromoted by the biggest supplier of small scale drip kits, the International DevelopmentEnterprise (IDE). IDE has one representation in West Africa in Ghana that sells very low costdrip kits for 10-1000 m2 command area using micro tubes. The NaanDan-Jain company inIsrael is providing its high quality in-line drip laterals in a 500 m 2 drip kit through theMANOMA Company in Niger. MANOMA sells the kits mainly in Niger, Burkina Faso andMali. Drip Tape (D Tape or T Tape) is a third drip line brand being evaluated. It is made ofthin flexible PE material with built-in low quality drip emitters.

Table 3.1: Characteristics of three different drip laterals tested

The drip laterals are connected to an open 200 litre barrel on an adjustable stand. The heightof the barrel can be varied from 0.5m, 1m, 1.5m to 2m to give different hydraulic pressures.The operating head is a measure for the pressure in the irrigation system. At high pressure,we expect less difference in pressure along the lateral length due to hydraulic losses, andhence, higher uniformity of water distribution. The barrel is kept full at all times to have aconstant water level, as water is released by gravity at thebottom of the barrel into the drip line lateral. The lengthof the laterals was varied from 5m to 30m in steps of 5mby simply folding and tying the line securely. The emitterdischarge was measured by catching water in recipients

placed under the drip emitters every 1.5m for laterallengths less or equal to 15m and every 3m for longerlateral lengths. The first emitter discharge was measuredat 0.3m from the source. Volume measurements weretaken over 15 minute time periods. For each combinationof drip line type, hydraulic head and lateral length, themeasurement is repeated 3 times.

Criteria

The emission uniformity (EU) is the most widely used indicator for drip line efficiency. Itgives an indication of the uniformity of the discharge of all emitters in a drip system

(Senzanje et al., 2004). Irrigation uniformity is related to crop yields through the agronomiceffects of under- and over-watering.

Supplier Origin Irrigatedarea forkit

Cost inNiger

Emittertype

Wallthickness

Lateraldiameter

Emitterspacing

4. 5. 6.Per meter mm mm cm

Jain Israel/India 500m2 0.3 USD In-line 1.2 12 30

IDE India 100m2 Micro- tube 0.17 16 30

DTape Thailand Laterals 0.04 USD Drip tape 0.26 16 30


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The emission uniformity is dependent on the combined effects of:1. The water supply head available;2. The elevation differences throughout the irrigated area;3. The friction losses in the pipe distribution network; and

4. The discharge characteristics and uniformity of the water emission device

EU = Qmin/Qmean (1-1.27CV) * 100

WhereEU is the Emission Uniformity in %,Qmin is the average of 25% emitters with lowest discharge,Qmean is the average discharge, andCV is the coefficient of variation of emitter discharge

The flow variation (Qvar) measures the variation in emitter discharge rates throughout a drip

system (Senzanje et al, 2004). The emitter flow variation Qvar is defined as:

Qvar = Qmax - QminQmax

where:Qmax = average of 25% of emitters with highest dischargeQmin = average of 25% of emitters with lowest discharge

The equations have been widely used in evaluation of different drip irrigation systems

(American Society of Agricultural Engineers (ASAE), 1999; Senzanje et al., 2004).

The ASAE general performance evaluation criteria for EU values are: >90%, excellent; 8090%, good; 7080%, fair; and


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fertilizers are unavailable and low solubility NPK fertilizer is applied as a basic dressingtogether with manure to provide all nutritional needs for a whole production cycle.

0

0,5

1

1,5

2

2,53

3,5

4

4,5

5

0 3 6 9 12 15 18 21 24 27 30

emitterdischarge(L/hr)

distance along lateral (m)

IDE Microtubes (H=1m)

30 25 20 15 10 5

0

0,5

1

0 3 6 9 12 15 18 21 24 27 30

emitterdischarge(L/hr)

distance along lateral (m)

D-Tape (H=1m)

Jain in-line emitters (H=1m)

30 25 20 15 10 5

Figure 3.1: Emitter discharge at 1 meter hydraulic head for three different lateral types and

laterals varying from 5 to 30 meter in length

The discharge decreases at lower hydraulic head. Figure 3.2 shows that at 5m long lateral the

discharge of the IDE microtubes goes down from 6 L/hr to 3 L/hr when the hydraulic head isdecreased from 2m to 0.5m. This trend is much less apparent for the DTape and Jain inlineemitters; the average discharge stays rather constant for all lateral lengths. This is due to thefact that the emitters function as resistors, forcing the water to build up pressure before wateris released through the emitters.

0

1

2

3

4

5

6

5 10 15 20 25 30

q(L/hr)

Lateral Length (m)

(a) H=2m

Jain

Dtape

IDE

0

1

2

3

4

5

6

5 10 15 20 25 30

q(L

/hr)

Lateral Length (m)

(b) H=1.5m

Jain

Dtape

IDE

0

1

2

3

4

5

6

5 10 15 20 25 30

q(L/hr)

Lateral Length (m)

(c) H=1m

Jain

Dtape

IDE

0

1

2

3

4

5

6

5 10 15 20

q(L/hr)

Lateral Length (m)

(d) H=0.5m

Jain

D Tape

IDE

Figure 3.2.Plots of average emitter discharges along 5, 10, 15, 20, 25 and 30m lateral

lengths with hydraulic heads (pressure) H of 2m (a), 1.5m (b), 1m (c) and 0.5m (d) for dripline types of Jain (squares), D Tape (triangles) and IDE (crosses).


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The emission uniformity (EU) for all laterals were within the good (EU=80-90%) toexcellent (EU>90%) ASAE performance labels for all lateral lengths and hydraulic heads(Figure 3.3). It can be seen that EU generally decreases at increasing lateral length anddecreasing hydraulic head. The IDE curves followed the most expected trends with clear EU

decreases with both lateral length (~10% decrease with 5-30m lateral length increase) andhydraulic head (~10% decrease with overall hydraulic 2-0.5m head decrease). These EUdecreasing patterns were less evident with the DTape drip line and even less evident withJain. Jain drip line had the highest EU values at H=1.5, reaching 100% at 5m lateral length.The highest EU values for DTape were measured at a 2m and 1m heads (highest of 95%).Overall, Jain and DTape had higher EU than IDE drip lines.

80%

85%

90%

95%

100%

5 10 15 20 25 30

Emissionuniformity

EU(%)

Lateral Length (m)

(a) H=2m

Jain

Dtape

IDE

Good

Excellent!

80%

85%

90%

95%

100%

5 10 15 20 25 30

EmissionuniformityE

U(%)

Lateral Length (m)

(b) H=1.5m

Jain

Dtape

IDE

Good

Excellent!

75%

80%

85%

90%

95%

100%

5 10 15 20 25 30

EmissionuniformityEU(%

)

Lateral Length (m)

(c) H=1m

Jain

Dtape

IDE

Good

Excellent!

Fair

70%

75%

80%

85%

90%

95%

100%

5 10 15 20

EmissionuniformityEU(%)

Lateral Length (m)

(d) H=0.5mJain

Dtape

IDE

Good

Excellent!

Fair

Figure 3.3. Emitter emission uniformity along 5, 10, 15, 20, 25 and 30m lateral lengths withhydraulic heads (pressure) H of 2m (a), 1.5m (b), 1m (c) and 0.5m (d) for drip line types of

Jain (squares), D Tape (triangles) and IDE (crosses).

3.4 Conclusions and recommendationsIn this experiment it was expected that emitter discharge and emission uniformity woulddecrease at longer lateral length and lower pressure. This was clearly the case for the IDEmicrotubes where discharge from a 5 meter long lateral was found more than 2 times higherthan for 25m long laterals. At the same time emitter discharge halved when the hydraulicpressure was reduced from 2 to 0.5 meter. The IDE microtube emitters gave 2 to 10 timeshigher discharge than D-Tape (~0.7 L/hr) and Jain emitters (~0.4 L/hr). High discharge canlead to excessive leaching of nutrients and reductions in yields, especially in poor sandy soils.


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4. Economic performance of low pressure drip irrigation, handwatering and crop husbandry on production of onion and hot pepperin Niger

4.1 IntroductionLow pressure drip irrigation kits are promoted in Sub Saharan Africa as an alternative toinefficient traditional methods of irrigating vegetables on small plots. Commonly citedadvantages of drip irrigation over hand watering methods of irrigation are higher crop yieldsand savings in water and labour. The few studies performed in Africa concluded that the dripkits did save water, but that technical, agronomic and marketing support were more importantfor improved returns from vegetable production (ITC, 2003; Kulecho and Weatherhead,2006; Belder et al., 2007). Since 2001, the International Crops Research Institute for theSemi-Arid Tropics (ICRISAT) in Niger and partners invested in the development of anintegrated horticultural production system called the African Market Garden (AMG)

(Pasternak and Bustan, 2003). The AMG combines low-pressure drip irrigation withimproved crop management. The latter helps the producer to apply the right amount of water,use improved vegetable varieties for year round production, and improve soil fertility, amongothers. This study assesses and compares the returns to investment on the African MarketGarden (AMG), and watering can irrigation methods for vegetable production in Niger. Thespecific objectives of this experiment are to determine labour, production cost and water useof the AMG and the local hand watering vegetable production system. In addition, theperformance of the improved crop husbandry package used in the AMG will be evaluated incombination with drip irrigation (AMG) and with hand watering. The results of this studywill contribute to a better understanding of the advantages and disadvantages of the AMG,and the drip technology in general, and will be of interest to farmers, NGOs and decision

makers that focus on income generation and improved nutrition in West Africa.

4.2 Materials and methodExperimental set-up

The field experiment was conducted between November 2009 and April 2010 at theICRISAT Sahelian research station (1315N. 217E) in Niger, situated 40 km South East ofthe capital Niamey. Evapotranspiration rates average 8 mm day-1 and no rain fell during theexperimental period. Two irrigation methodswere used in combination with two crophusbandry practices. Three 500 m fields (20mx 25m) with ten planting beds each were

prepared. The planting beds were 25 m longand 1.8 m wide, separated by a 0.2 m path.Onion and hot pepper were grown at the sametime on five beds each, the two outer bedswere considered border and not included in theanalysis (Figure 4.1 and 4.2). Each field wasconsidered a treatment, with each planting beda repetition in a randomized complete blockset-up.

Figure 4.1: Onion and hot pepper in the AMG with dripirrigation (front) with watering cans (back) and farmer

practice (far back)


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The treatments are summarized in Table 4.1 and defined as follows:

1. African Market Garden (AMG): Improved crop husbandry package and irrigationwith low pressure drip irrigation. Drip laterals were 12 mm diameter in line drip

emitters spaced at 30 cm interval. The daily water application is set at 8 L m-2

according with the maximum local evapotranspiration rate (Pasternak et al., 2006).The water is collected in a 4 m3 reservoir before it gravity feeds to a 500 m drip kit.Crops are planted on elevated planting beds that are prepared with a basic dressing of4 kg/m manure and 0.1 kg m-2 NPK (15-15-15) before planting. Urea (0.8 gr m-2) ismixed daily with the water in the reservoir. Crops are irrigated by hand for the first 3days after planting at 4 L m-2. Planting density is according to internationalguidelines.

2. Improved Management (IM): Improved crop husbandry package and irrigation withwatering cans. The daily water application quantity, planting bed preparation andplanting density is similar to the AMG treatment. However, water is applied by

watering cans two times per day, two thirds in the morning (5.3 L m-2) and one thirdin the afternoon (2.7 L m-2). The total amount of urea applied per crop is equal to thequantity applied for the AMG, but it is applied through broadcasting and only twiceduring crop development, half is applied 21 days after planting and the other half atflowering stage.

3. Farmer practice (FP): Local crop husbandry practices and irrigation with wateringcans. Information on water application regime, fertilizer use, planting density andother variables was collected through surveys in and around Niamey city. About 10producers were interviewed per crop. Vegetable producers apply on average 12 L m -2for hot pepper, and 10 L m-2 for onion (Table 4.1). Manure and urea is applied at thefirst grubbing, about three weeks after planting, and at flowering stage. For onion,

producers use NPK instead of Urea.

8 m 8 m 8 m

25 m

2 m3 water basin

crop 1 crop 2

8 m 8 m 8 m

25 m 25 meter

20 m

2 m3 water basin 4 m3 water basin

Farmer Practice Improved Management (IM) AMG drip

borderPlan ting beds: Figure 4.2: Schematic layout of treatments showing planting beds for two different crops and

water basins used for irrigation


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Figure 4.4: Breakdown of production cost in drip irrigation (AMG) and hand watered (FP)

garden for production of onion

4.4 Conclusions

The AMG technology holds great promise to increase profitability of smallholder vegetableproducers due to a combination of drip irrigation and improved crop management. Dripirrigation saves labour, water and energy, bringing production costs down, and improved cropmanagement guidelines help the producer to improve growing conditions of the vegetables.In this experiment, the AMG did not perform better than alternative methods of irrigationbecause drip irrigation in combination with daily application of urea in the water amplifiedacidification in an already acid soil (pH 4.1), in turn having a detrimental effect on cropyields. Onion and hot pepper are sensitive to acid soils, while crops like okra and eggplantproved to do very well in previous experiments.

Improved management through more intensive use of fertilizer, use of less water and

respecting planting densities did improve crop productivity over the traditional farmerpractice. Production costs for the improved management are only less than 5% moreexpensive. This way vegetable producer can already improve their productivity withouthaving to invest in a new irrigation technology.

Production costs in vegetable production are considerable and dominate over the amortizedvalue of the investment cost. Labour takes up 44% of the production cost in vegetablegardens irrigated by hand. It was recorded that 85% of the producer time is spent onirrigation. Drip irrigation delivers water directly to the root zone of the crops without the needfor manual labour. The average labour requirement for cultivation of onion on 500 m2 in theAMG is 0.8 man hours per day against 5.2 man hours per day for the Farmer practice. The

comparative advantage of drip irrigation over hand watering is proportional to the labour thatcan be saved to irrigate the crop area. Hence, the larger the area the producer irrigates themore benefits he/she will get from drip irrigation.

The returns to land, water and labour were negative for all treatments due to very low cropyields. However, in acid sandy soils, improved crop management strategies can improveprofitability from vegetable production by smallholder producers.


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ICRISAT AVRDC Niger Final Report AMIV Final 280910-2

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