Hernaude Agossou, Janos Bogardi, Bernhard Tischbein · 2017-09-15 · loss during irrigation, and...
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RESEARCH POSTER PRESENTATION DESIGN © 2015 www.PosterPresentations.com In the context of water resources expected to become more scarce and variable in future due to climate and land-use changes versus a rising water demand driven by increasing food needs of a growing population, drip irrigation is potentially a very promising approach to raise irrigation efficiency and improve water productivity of cultivated crops. Yet, in West-Africa as in many developing regions of the world, the lack of financial resources for establishing, operating and maintaining drip systems is the main reason for their non-adoption by smallholder farmers. A promising attempt to step out of this dilemma is an innovative bamboo-drip system that would have the advantages of conventional plastic systems, but be less costly. Construction of the bamboo-drip system Bamboo culms were harvested in the wild, selected for good condition and cut to remove nodes. 20 cm internodes were selected for adequate inner diameters, treated to increase durability and reduce friction head loss during irrigation, and glued one to the other (with strong and waterproof glue) to construct drip pipes. Emitters were hand-made from 2 mm ID ball pen tube pieces. Basal opening was closed and three tiny V- openings made alongside to regulate flow by up and down movement into bamboo pipes. INTRODUCTION CONCLUSION ACKNOWLEDGEMENTS Center for Development Research (ZEF), University of Bonn [email protected] Hernaude Agossou, Janos Bogardi, Bernhard Tischbein MATERIALS AND METHODS Selected and treated internodes (used to form main and lateral pipes) Emitters Test of bamboo laterals : volumetric method Test set-up Testing heads: 20, 40, 60 and 80 cm Bamboo laterals (junctions are protected to ease handling and prevent breaking during future transportation to the field) Weighing of empty cans before test Test of emitters: volumetric method Weighing of collected water Assessment of inherent variabilities in hydraulics Harvested culms Distribution of Oxytenanthera abyssinica (A.Rich.) Munro in Africa Water collection - How would water flow in the bamboo system be affected by its two main components (i.e. bamboo material and emitters)? ( need to assess inherent variabilities in hydraulics) - As a result of this influence, how uniformly could the bamboo system supply water to the plants? ( need to assess emitter flow uniformity in the system as a whole) RESEARCH QUESTIONS Assessment of emitter flow uniformity (Christiansen uniformity coefficient) RESULTS AND INTERPRETATION Inherent variabilities in hydraulics Emitter flow uniformity Figure 1. Emitter flow variations due to bamboo material, emitters’ precision and emitter plugging Table 1: Criteria for micro-irrigation component manufacturing variability values. Adapted from ASAE EP405.1 (2000) Interpretation In the bamboo-drip system, flow variations due to bamboo material and emitters’ precision can be assessed as excellent at four pressure heads, whereas that due to emitter plugging kept unacceptable overall. Emitter plugging is the strongest factor causing emitter flow variation in the bamboo system, as in conventional plastic drip systems. Emitters plugging is due to flow velocity variations at emitter positions, resulting from singularities in bamboo internodes. Interpretation criteria Parameter Formula Expresses … Test Collected Unit Unit number Process UCC UCC = 1- ∆ ∆ being mean deviation of emitter flow from the average … how much water flow differs from one emitter to another Entire bamboo system (32 emitters) 01 One 30 minutes test (at each pressure head) Emitters outlet flow Parameter Formula Expresses … Test Collected Unit Unit number Process CV(H) CV(H) = Sl and being respectively standard deviation and average of lateral outlet flow … how much of emitter flow variation is caused by the bamboo material 5 m bamboo lateral (without emitter) 03 Three 30 minutes tests per lateral (at four pressure heads) Lateral outlet flow Parameter Formula Expresses … Test Collected Unit Unit number Process CV(M) CV(M) = Se and being respectively standard deviation and average of emitter outlet flow … how much of emitter flow variation is caused by emitters’ precision Emitter alone 03 Three 30 minutes tests per emitter (at four pressure heads) Emitter outlet flow Parameter Formula Expresses … Test Collected Unit Unit number Process CV(P) CV(P)= − , with CV(HMP) = CV 2 (H)+CV 2 (M) 1−P + P 1−P and CV(HM) = CV 2 H −CV 2 M CV(H) and CV(M) being as previously defined. P is the highest value of emitter flow reduction … how much of emitter flow variation is caused by emitter plugging 5 m bamboo lateral (with 08 emitters) 03 Six 15 minutes tests per lateral (at four pressure heads) Emitters outlet flow Ball pen ink tube Bamboo plants in the wild 80 cm 60 cm 40 cm 20 cm 0.89% 0.91% 1.39% 4.00% 0.003% 0.004% 0.006% 0.014% 16.72% 23.54% 33.28% 57.50% CV Bamboo material - CV (H) Emitter precision - CV (M) Emitter plugging - CV (P) 80 cm 60 cm 40 cm 20 cm 87.33% 86.35% 77.21% 69.42% UCC Figure 2. Emitter flow uniformity in the bamboo-drip system Interpretation criteria Table 2: Standards for uniformity in micro-irrigation systems. Adapted from ASABE EP458 (1999) Coefficient of variation Interpretation Below 5% Excellent 5 – 10% Average 10 – 15% Marginal Above 15% Unacceptable Uniformity coefficient Classification Above 90% Excellent 90 – 80 % Good 80 – 70 % Fair 70 – 60 % Poor Below 60 % Unacceptable Interpretation Emitter flow uniformity in the bamboo system is at least fair, but becomes poor at 20 cm pressure head. Pressure head being directly proportional to water flow velocity, this means flow velocity in the system at 20 cm head varies too much from an emitter position to another. This again is due to singularities in bamboo internodes and junctions, which become relevant at 20 cm head. Getting a good uniformity would imply to reduce these singularities by using more uniform bamboo internodes, or running the system at higher pressure heads. This research was funded by the Deutscher Akademischer Austauschdienst (DAAD) and the Stiftung Fiat Panis foundation. We warmly thank the Center for Development Research (ZEF) for their valuable assistance, and the European Alliance on Agricultural knowledge for Development (Agrinatura) for supporting our travel to Tropentag Conference. Bamboo-drip system Test set-up ; Testing heads: 20, 40, 60 and 80 cm The bamboo drip system is workable. It has good and similar hydraulic characteristics as conventional plastic drip systems under suitable pressure conditions. Its emitter flow variation is essentially due to emitter plugging, which can be reduced by running the system at high pressure heads, or improving internodes uniformity. But although this system works well, questions remain regarding its real life performance, economic profitability, durability and fertigation potential. These issues should be addressed by further researches. 15% Unacceptance threshold 70% Failure threshold Hydraulics and uniformity performance of an innovative bamboo-drip system
Transcript of Hernaude Agossou, Janos Bogardi, Bernhard Tischbein · 2017-09-15 · loss during irrigation, and...
RESEARCH POSTER PRESENTATION DESIGN © 2015
www.PosterPresentations.com
In the context of water resources expected to become more scarce and variable in future due to climate andland-use changes versus a rising water demand driven by increasing food needs of a growing population, dripirrigation is potentially a very promising approach to raise irrigation efficiency and improve water productivity ofcultivated crops. Yet, in West-Africa as in many developing regions of the world, the lack of financial resourcesfor establishing, operating and maintaining drip systems is the main reason for their non-adoption bysmallholder farmers. A promising attempt to step out of this dilemma is an innovative bamboo-drip system thatwould have the advantages of conventional plastic systems, but be less costly.
Construction of the bamboo-drip system
Bamboo culms were harvested in the wild, selected for good condition and cut to remove nodes. 20 cminternodes were selected for adequate inner diameters, treated to increase durability and reduce friction headloss during irrigation, and glued one to the other (with strong and waterproof glue) to construct drip pipes.
Emitters were hand-made from 2 mm ID ball pen tube pieces. Basal opening was closed and three tiny V-openings made alongside to regulate flow by up and down movement into bamboo pipes.
INTRODUCTION
CONCLUSION
ACKNOWLEDGEMENTS
Center for Development Research (ZEF), University of Bonn
Hernaude Agossou, Janos Bogardi, Bernhard Tischbein
MATERIALS AND METHODS
Selected and treated internodes
(used to form main and lateral pipes)
Emitters
Test of bamboo laterals : volumetric method
Test set-up
Testing heads: 20, 40, 60 and 80 cm
Bamboo laterals
(junctions are protected to ease handling and prevent
breaking during future transportation to the field)
Weighing of empty cans before test
Test of emitters: volumetric method
Weighing of collected water
Assessment of inherent variabilities in hydraulics
Harvested culms
Distribution of Oxytenanthera
abyssinica (A.Rich.) Munro in Africa
Water collection
- How would water flow in the bamboo system be affected by its two main components (i.e.bamboo material and emitters)? ( need to assess inherent variabilities in hydraulics)
- As a result of this influence, how uniformly could the bamboo system supply water to the plants?( need to assess emitter flow uniformity in the system as a whole)
RESEARCH QUESTIONS
Assessment of emitter flow uniformity (Christiansen uniformity coefficient)
RESULTS AND INTERPRETATION
Inherent variabilities in hydraulics Emitter flow uniformity
Figure 1. Emitter flow variations due to bamboo material, emitters’ precision and emitter plugging
Table 1: Criteria for micro-irrigation component manufacturing variability values.
Adapted from ASAE EP405.1 (2000)
Interpretation
In the bamboo-drip system, flow variations due tobamboo material and emitters’ precision can beassessed as excellent at four pressure heads, whereasthat due to emitter plugging kept unacceptable overall.Emitter plugging is the strongest factor causing emitterflow variation in the bamboo system, as inconventional plastic drip systems.
Emitters plugging is due to flow velocity variations atemitter positions, resulting from singularities inbamboo internodes.
Interpretation criteria
Parameter Formula Expresses …
Test
CollectedUnit
Unitnumber
Process
UCC
UCC = 1- ∆𝒒
𝒒
∆𝑞 being mean deviation of emitter
flow from the average
… how much water flow differs
fromone emitter to
another
Entire bamboo system (32 emitters)
01
One 30 minutes test (at
each pressure
head)
Emittersoutlet flow
Parameter Formula Expresses …
Test
CollectedUnit
Unitnumber
Process
CV(H)
CV(H) = 𝑺𝒍
𝒒𝒍
Sl and 𝑞𝑙 being respectively standard deviation and average of lateral outlet flow
… how much of emitter flow
variation is caused by the bamboo
material
5 m bamboo lateral
(without emitter)
03
Three 30 minutes tests per lateral (at four pressure
heads)
Lateral outlet flow
Parameter Formula Expresses …
Test
CollectedUnit
Unitnumber
Process
CV(M)
CV(M) = 𝑺𝒆
𝒒𝒆
Se and 𝑞𝑒 being respectively standard deviation and average of emitter outlet flow
… how much of emitter flow
variation is caused by emitters’
precision
Emitter alone 03
Three 30 minutes tests
per emitter (at four pressure
heads)
Emitter outlet flow
Parameter Formula Expresses …
Test
CollectedUnit
Unitnumber
Process
CV(P)
CV(P) = 𝐂𝐕𝟐 𝐇𝐌𝐏 − 𝐂𝐕𝟐 𝐇𝐌 ,
with
CV(HMP) =CV2(H)+CV2(M)
1−P+
P
1−P
and
CV(HM) = CV2 H − CV2 M
CV(H) and CV(M) being aspreviously defined. P is the highestvalue of emitter flow reduction
… how much of emitter flow
variation is caused by
emitter plugging
5 m bamboo lateral
(with 08 emitters)
03
Six 15 minutes tests per lateral (at four pressure
heads)
Emitters outlet flow
Ball pen ink tube
Bamboo plants in the wild
80 cm 60 cm 40 cm 20 cm
0.89% 0.91% 1.39% 4.00%0.003% 0.004% 0.006% 0.014%
16.72%23.54%
33.28%
57.50%
CV
Bamboo material - CV (H) Emitter precision - CV (M)
Emitter plugging - CV (P) 80 cm 60 cm 40 cm 20 cm
87.33% 86.35%
77.21%
69.42%
UCC
Figure 2. Emitter flow uniformity in the bamboo-drip system
Interpretation criteria
Table 2: Standards for uniformity in micro-irrigation systems. Adapted from ASABE EP458 (1999)
Coefficient of variation Interpretation
Below 5% Excellent
5 – 10% Average
10 – 15% Marginal
Above 15% Unacceptable
Uniformity coefficient Classification
Above 90% Excellent
90 – 80 % Good
80 – 70 % Fair
70 – 60 % Poor
Below 60 % Unacceptable
Interpretation
Emitter flow uniformity in the bamboo system is atleast fair, but becomes poor at 20 cm pressure head.Pressure head being directly proportional to waterflow velocity, this means flow velocity in the system at20 cm head varies too much from an emitter positionto another. This again is due to singularities in bamboointernodes and junctions, which become relevant at 20cm head. Getting a good uniformity would imply toreduce these singularities by using more uniformbamboo internodes, or running the system at higherpressure heads.
This research was funded by the Deutscher Akademischer Austauschdienst (DAAD) and the Stiftung Fiat Panisfoundation. We warmly thank the Center for Development Research (ZEF) for their valuable assistance, and theEuropean Alliance on Agricultural knowledge for Development (Agrinatura) for supporting our travel to TropentagConference.
Bamboo-drip system
Test set-up ; Testing heads: 20, 40, 60 and 80 cm
The bamboo drip system is workable. It has good and similar hydraulic characteristics as conventional plastic dripsystems under suitable pressure conditions. Its emitter flow variation is essentially due to emitter plugging, whichcan be reduced by running the system at high pressure heads, or improving internodes uniformity.
But although this system works well, questions remain regarding its real life performance, economic profitability,durability and fertigation potential. These issues should be addressed by further researches.
15% Unacceptance
threshold
70% Failure
threshold
Hydraulics and uniformity performance of an innovative bamboo-drip system
