Valet S. Valet S. 1 , M. Motélica-Heino , M. Motélica-Heino 2 2 & Ph. Le Coustumer & Ph. Le Coustumer 3 & P.S. Sarr & P.S. Sarr 4 1 Consultant. PASSERELLES, 9, rue du Bât d’Argent, 69001, Lyon France, Email : Consultant. PASSERELLES, 9, rue du Bât d’Argent, 69001, Lyon France, Email : [email protected] ; 2 2 UMR6113 Institut des Sciences de la Terre d'Orléans (ISTO) , France, , France, stefan.motelica-heino @ univ-orleans.fr ;. ;. 3 3 Université de Université de BordeauxI, av. BordeauxI, av. France France 4 4 ISRA (Institut Sénégalais de la Recherche Agronomique) BP199, Kaoloack, Sénégal ISRA (Institut Sénégalais de la Recherche Agronomique) BP199, Kaoloack, Sénégal papsar2000@ yahoo.fr . THE « THE « SUDANO SAHELIAN GROVE SUDANO SAHELIAN GROVE » : » : A multi-scale ecological alternative A multi-scale ecological alternative face to climatic face to climatic change change 13th World Water Congress"Changements Globaux et Ressources en Eau : face à des pressions toujours plus nombreuses et diversifiées". 1 au 4 septembre 2008. Montpellier (France) The problems of the 21th century in the sahelian to tropical zone, besides food sovereignty, are ecological and socio- ecological. The elaboration of new modes of environmental management has become a major priority of public policies. Some of ecological biotechniques have been largely used by peasants of all continents that control the runoff and valorize the runon. Runon is defined as « a natural irrigation, complementary and simultaneous to the rain that as generated it as a function of the evolutive states of surface and depth , with a transfer and sequestration of nutrients ”. (Valet, 1995). The goal of this study is the elaboration of the traditional and innovative biophysical techniques typology based on the runoff control and runon valorization. This typology supply to Ecologists and agronomists the most biophysical techniques adequate to resolve the degradation problems: A) techniques of total or partial control of the runoff (Ridges, mulch, RCW);B) techniques of sustain of a controlled non- erosive runoff (Quickhedge, rings of stones) and C) techniques of a total trapping of the runoff (1/2 moon, Zaï). 2 4 2 3. RESULTS 1. GOAL A- Techniques of total or partial control of the runoff C- Techniques of total trapping of the runoff 2. Perpendicular mulch effect on soil losses 1. Traditional quickhedge in West Cameroon The main results of this study showed the necessity of this traditional and innovating biotechniques typology based on the runoff control and the runon agroforestry valorization because of the drought increasing. Face to climatic change it will be more and more important to know the agrosystems hydrological functionning to choose the best traditional and innovating biotechniques to ensure an ecological sustainable management adapted to the 3. CONCLUSION RCW effect on soil aggradation (humus, N, P) & rye biomasse (root, straw, grain) increasing. « zaï » or “Tassela” 2. Sudan Sahelian zone: Soil losse decreasing and runon mainta Half moon *BP: phosphate naturel du Burkina. Zaï : 9,5 Tha-1 de manure (ox). 1. Ridges effect on runoff 3. Mulch effect on water soil storage at three d SENEGAL 0 2,5 5 7,5 1982 1984 1986 1988 1990 1992 Years K r% etsoillosses T/h Quickhedge im plantation Kr% T/ha/an Mali-Niger R 2 Up= 0,85 R 2 M id=0,98 R 2 Dow n= 0,59 0 5 10 15 20 25 30 35 300 400 500 600 700 Rain m m Runoff% Upslope Midslope Dow nslope Upslope-M anag M idslope-M anag Dow nslope-M anag B- Techniques of sustain of a controlled non-erosive runoff Burundi R 2 = 0,83 0 25 50 75 100 0 5 10 15 20 25 Kram % S o il lo sses T /h Bare soil (W ischm eier) Bare soil +Crust Perpendicularleaves Leaves in round Leaves in round+m ulch Thyssé-Sénégal 0 5 10 15 20 25 30/11/1983 19/01/1984 09/03/1984 28/04/1984 17/06/1984 Dates H um idité vol.m Cnu-30 M ulch-30 C-60 M -60 C-120 M -120 Field Village field *Varieties : Fusarium sp., a. et g.; Altermana a. ; Mycelia st. ; Nigrospora o. ; Macor h. et Acromoniella a. Initial crust state New crust and runoff - reduces considerably the erosion; - sustains of a non-erosive runoff; - maintains a runon; - stops the transfer of eroded sediments up to 95%; - amelioration of fertility and yield by uptake of nutrients; - increases biomass yield. No management No crust and no runoff Niger 0 200 400 600 800 1000 1200 Test Quickhedge M illetgrain kg/ Before Below Millet yield increasing Half moon Quick hedge Billons Mulch Treatments Soi l Grain Straw C%0 Cam/ l 1998 1999 1998 1999 Test 6.4 1.44 0 0 0 0 Z. Tradit. 9.2 2.23 3.75 2.06 21.3 0,73 Z+staw 7.5 1.73 4.38 1.8 24 7.4 Z. +straw+BP 9.9 2.54 7.08 6.94 39.1 16.2 Zougmoré & al., 1999 Treatments Soi l Grain Straw C%0 Cam/ l 1998 1999 1998 1999 Test 5.1 1.44 0 0 0 0 ½ moon 4.6 1.54 0.83 1.46 3.02 5.1 ½ moon+compost 4.6 2 9.3 11 27.3 25 ½ moon+manure 5.4 2.48 16.1 11.1 42.9 25.4 **BP: natural phosphate of Burkina. ; ½ moon : 14,6 Tha-1 of Manure et de compost. RCWs Fungi* Yiel d Qx ha 1 ROOT SOIL pecies Attack %* Grai n Straw Ms% Humus N P K TEST 78 12 27.8 91.4 1.91 7 2 10 2 8 0 Betula V. 63 14.9 30.4 92.6 2.75 7 3 10 6 8 5 Salix a. 88 14.5 30.6 92.2 2.92 7 3 10 4 7 4 Ramial Chipped Wood With mulch, the water loss is about 15% during drought season & 60% for crusted soil . = 56mm saving Each water mm = 7 to 11kgha -1 for millet grain. Valet., 1999 (Valet., 1999) Valet., 2004 Valet & al., 2008 Kalifa & al.,2005; Rockström & Valentin,1997 Quansah and al., 1999 Chervonyl, 1999; Domenech & al., 2008 The Ramial Chipped Wood is the ≤7cm diameter branches of trees and brushes. ridges reduce dramatically the runoff but not totally Leaves around Banana with mulch are the best to limite strongly OC, Nutrients and soil losses So, Half-Moon and Zaï ensure a signicative and stable production of sorghum (IRAT 204 of 90 days duration) because of a significative increasing of Ca ++ , P 2 O 5 , OC and water. Thecomplete runon infiltration ensures a better water satisfaction and limits the development of crusts For a long time the effect of these two techniques may be the same on the soil aggradation and biomass production RCW increases bacteries & mycellia quantity & kinds and their eficacity Dodelin & Valet, 2007 It spread 3cm thickness of RCW
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Valet S.Valet S.11, M. Motélica-Heino, M. Motélica-Heino2 2 & Ph. Le Coustumer & Ph. Le Coustumer33& P.S. Sarr& P.S. Sarr44
11Consultant. PASSERELLES, 9, rue du Bât d’Argent, 69001, Lyon France, Email : Consultant. PASSERELLES, 9, rue du Bât d’Argent, 69001, Lyon France, Email : [email protected] ; ; 2 2 UMR6113 Institut des Sciences de la Terre d'Orléans (ISTO), , France, France, [email protected];.;. 3 3 Université de BordeauxI, av. Université de BordeauxI, av. FranceFrance4 4 ISRA (Institut Sénégalais de la Recherche Agronomique) BP199, Kaoloack, Sénégal ISRA (Institut Sénégalais de la Recherche Agronomique) BP199, Kaoloack, Sénégal papsar2000@
yahoo.fr..
THE «THE «SUDANO SAHELIAN GROVESUDANO SAHELIAN GROVE» : » : A multi-scale ecological alternativeA multi-scale ecological alternative face to climaticface to climatic changechange
13th World Water Congress"Changements Globaux et Ressources en Eau : face à des pressions toujours plus nombreuses et diversifiées". 1 au 4 septembre 2008. Montpellier (France)
The problems of the 21th century in the sahelian to tropical zone, besides food sovereignty, are ecological and socio-ecological. The elaboration of new modes of environmental management has become a major priority of public policies. Some of ecological biotechniques have been largely used by peasants of all continents that control the runoff and valorize the runon. Runon is defined as « a natural irrigation, complementary and simultaneous to the rain that as generated it as a function of the evolutive states of surface and depth , with a transfer and sequestration of nutrients”. (Valet, 1995). The goal of this study is the elaboration of the traditional and innovative biophysical techniques typology based on the runoff control and runon valorization. This typology supply to Ecologists and agronomists the most biophysical techniques adequate to resolve the degradation problems: A) techniques of total or partial control of the runoff (Ridges, mulch, RCW);B) techniques of sustain of a controlled non-erosive runoff (Quickhedge, rings of stones) and C) techniques of a total trapping of the runoff (1/2 moon, Zaï).
2 4 2
3. RESULTS
1. GOAL
A- Techniques of total or partial control of the runoff
C- Techniques of total trapping of the runoff
2. Perpendicular mulch effect on soil losses
1. Traditional quickhedge in West Cameroon
The main results of this study showed the necessity of this traditional and innovating biotechniques typology based on the runoff control and the runon agroforestry valorization because of the drought
increasing.
Face to climatic change it will be more and more important to know the agrosystems hydrological functionning to choose the best traditional and innovating biotechniques to ensure an ecological
sustainable management adapted to the degradation intensity and the peasants need.
3. CONCLUSION
RCW effect on soil aggradation (humus, N, P) & rye biomasse (root, straw, grain) increasing.
« zaï » or “Tassela”
2. Sudan Sahelian zone: Soil losse decreasing and runon maintaining
Half moon
*BP: phosphate naturel du Burkina. Zaï : 9,5 Tha-1 de manure (ox).
1. Ridges effect on runoff 3. Mulch effect on water soil storage at three depths
SENEGAL
0
2,5
5
7,5
1982 1984 1986 1988 1990 1992
Years
Kr%
et so
il los
ses T
/ha/a
n
Quickhedge implantationKr%T/ha/an
Mali-Niger
R2 Up= 0,85
R2 Mid= 0,98
R2 Down= 0,59
0
5
10
15
20
25
30
35
300 400 500 600 700Rain mm
Runo
ff %
UpslopeMidslopeDownslopeUpslope-ManagMidslope-ManagDownslope-Manag
B- Techniques of sustain of a controlled non-erosive runoff
Burundi
R2 = 0,83
0
25
50
75
100
0 5 10 15 20 25Kram %
Soil
loss
es T
/ha/a
nBare soil (Wischmeier)Bare soil +CrustPerpendicular leavesLeaves in roundLeaves in round+mulch
Thyssé-Sénégal
0
5
10
15
20
25
30/11/1983 19/01/1984 09/03/1984 28/04/1984 17/06/1984Dates
Hum
idité
vol. m
m
Cnu-30 Mulch-30C-60 M-60C-120 M-120
Field Village field
*Varieties : Fusarium sp., a. et g.; Altermana a. ; Mycelia st. ; Nigrospora o. ; Macor h. et Acromoniella a.
Initial crust state
New crust and runoff
- reduces considerably the erosion;- sustains of a non-erosive runoff; - maintains a runon;- stops the transfer of eroded sediments up to 95%; - amelioration of fertility and yield by uptake of nutrients;- increases biomass yield.
No management
No crust and no runoff
Niger0
200
400
600
800
1000
1200
Test Quickhedge
Mille
t gra
in kg
/ha
BeforeBelow
Millet yield increasing
Half moon
Quick hedge
Billons Mulch
Treatments Soil Grain Straw
C%0 Cam/l 1998 1999 1998 1999
Test 6.4 1.44 0 0 0 0
Z. Tradit. 9.2 2.23 3.75 2.06 21.3 0,73
Z+staw 7.5 1.73 4.38 1.8 24 7.4
Z.+straw+BP 9.9 2.54 7.08 6.94 39.1 16.2
Zougmoré & al., 1999
Treatments Soil Grain Straw
C%0 Cam/l 1998 1999 1998 1999
Test 5.1 1.44 0 0 0 0
½ moon 4.6 1.54 0.83 1.46 3.02 5.1
½ moon+compost 4.6 2 9.3 11 27.3 25
½ moon+manure 5.4 2.48 16.1 11.1 42.9 25.4
**BP: natural phosphate of Burkina. ; ½ moon : 14,6 Tha-1 of Manure et de compost.
RCWs Fungi* Yield Qx ha1 ROOT SOIL
pecies Attack %*
Grain Straw Ms% Humus N P K
TEST 78 12 27.8 91.4 1.91 72 102 80
Betula V. 63 14.9 30.4 92.6 2.75 73 106 85
Salix a. 88 14.5 30.6 92.2 2.92 73 104 74
Ramial Chipped Wood
With mulch, the water loss is about 15% during drought season & 60% for crusted soil . = 56mm saving
Each water mm = 7 to 11kgha-1 for millet grain.
Valet., 1999
(Valet., 1999)
Valet., 2004
Valet & al., 2008Kalifa & al.,2005;Rockström & Valentin,1997
Quansah and al., 1999
Chervonyl, 1999; Domenech & al., 2008
The Ramial Chipped Wood is the ≤7cm diameter branches of trees and brushes.
ridges reduce dramatically the runoff but not totally
Leaves around Banana with mulchare the best to limite stronglyOC, Nutrients and soil losses
So, Half-Moon and Zaï ensure a signicative and stable production of sorghum (IRAT 204 of 90 days duration) because of a significative increasing of Ca++, P2O5, OC and water.
Thecomplete runon infiltration ensures a better water satisfaction and limits the development of crusts
For a long time the effect of these two techniques may be the same on the soil aggradation and biomass production
RCW increases bacteries& mycellia quantity & kinds and their eficacity
Dodelin & Valet, 2007
It spread 3cm thickness of RCW
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