Lowland
development
in M ali
In the Sudanian area
o f western Africa,
the ag ricultural
po tential
o f flo o d basins
can be very high.
Local inhabitants
and researchers
are co m b in in g
their efforts
to develop
this po tentia l
in the lesser lowlands
o f southern M ali.
T
he Sikasso region in s o u t h e r n M a l i , representing 10% of the country's area, is home to m o r e th a n 3 0 % o f its 8 million inhabitants (Fig. 1). The clim ate o f the region is Sudano-Sahelian in the north and Sudano-Cuinean in the south. It plays a vital role in M ali's production of several r a i n f e d c r o p s : 1 0 0 % f o r cotton, 63% for maize and 3 7 % f o r m i l l e t and s o rg h u m . E n c o u ra g e d b y th e C om pagnie m alienne pour le d év e lo pp em e nt des tex tiles (CMDT), farmers have, for the most part, adopted d r a f t a n i m a l s f o r c r o p cultivation. N . A H M A D I, F. B LANCHET, C IR A D -C A , 1ER, BP 1 8 3 , Sikasso, M a li M . S IM P A R A , B. TR A OR E, ' 1ER, BP 1 8 3 , Sikasso, M a liLowland
development
The flood basins, p rim a rily low lands and small plains, h ave n o t b e n e f i t e d fr o m the d e v e lo p m e n t p ro je c ts that focus on co tto n c r o p ping. They make up nearly 5% of the total area of sou thern M a li, about a fifth of w h ic h is under c u ltiv a tio n (Table 1 ). W ith limited rain- f a l l , th e s e f l o o d b a s in s , w h e r e r a in a n d g r o u n d w ater run off converge, are p o t e n t ia l sites fo r s ecure and diversified farming.Figure 1. Position of Mali's Sikasso region and the catchment basin of the Kobani.
Table 1. Southern M ali's flood basins: utilization (in km 2).
area and
Total area Cultivated area
Region 122 724 28 206
Flood basins 5 325 973
Lowlands 740 199
A griculture et développem ent ■ Special issue - December 1994
0* > A LGERIA MAURITANIA BAMAKO MALI NIGER BURKIN A G H A N A § BENIN NIG E R IA
Catchment basin and lowland crop shares for the total cultivated area
Basin
63 %
Basin
50.1 %
Potato
Figure 2. Catchment basin of the Kobani and M'pegnesso lowlands.
Fruit Related crops Cassava Sweet potato Rice Low land 49,9 %
Catchment basin and lowland crop shares for the area cash income
Basin
4 2 % Cotton 22 .7 % Sweet potato ■ basin 4 .7 % Miscellaneous 14.6 % Potato 10.8% Fruit 16.8%
Sweet potato - lowland 24.2 % R¡ce
¿
2 % Low land58%Figure 3. M'pegnesso area in 1 993. Distribution o f land types and crop revenues.
An important
source of income
T h e i m p o r t a n c e o f l o w lands in the re g io n 's p r o d u c t i o n syste m s is o fte n u n d e re s tim a te d : o n ly rice growing is counted in agri c u lt u r a l statistics. Rice is p r i m a r i l y c u l t i v a t e d b y w o m e n w h i c h p r o v id e s extra income and meets the f a m i l y ' s n e e d s f o r r ic e . Rice, however, is only offe red to guests and eaten on fe s tiv e o c c a s io n s , and in th is r e g io n r ic e g r o w i n g therefore has a limited role in f a r m o p e r a t i o n s . In c o n t r a s t , f r u i t c r o p p i n g , market gardening and tuber p ro d u c tio n (sweet potato, cassava, potato), all of w h i ch take p la c e in th e l o w la n d s a n d s u r r o u n d i n g areas, are very important to regional p ro d u c tio n . They a c c ou nt for a large part of th e rest o f th e c o u n t r y ' s s u p p lie s o f th es e s ta ple s and a ls o e x p o r ts to C ôte d'Ivoire are being developed. L ow land villa g e field s can be as i m p o r t a n t as la n d s above flo o d level. Such is the case, for instance, in thev i l l a g e o f M 'p e g n e s s o , 20 km north o f the regional capital Sikasso (Figs. 2 & 3). Lowlands make up 37% of the village's cultivated area. They contribute 50% of the a re a 's n e t i n c o m e and a lm o s t 7 0 % o f its cash i n c o m e . R ic e g r o w i n g a c c o u n t s f o r 3 8 % o f lo w la n d fa rm in g and p r o duces 16% o f farm ers' net income.
Actions taken
D u r i n g t h e 1 9 7 0 s and 1980s, a c tio n s and d e v e l o p m e n t p r o j e c t s in t h e f l o o d b a s in s s o u g h t to e n c o u r a g e in t e n s iv e ric e growing on the floodplains. However, rarely more than half of the planned capacity o f these p ro je c ts to be in actual use. This low success rate is m ost often b la m e d on the projects' unsuitabili t y to th e s o c i o e c o n o m i c e n v iro n m e n t, the fact that they were exclusively desi gned for rice growing, and an in s u ffic ie n t k n o w le d g e on the physical characteris tics o f the sites, in particular soil permeability.Catchment basin and lowland crop shares for the total area income
M o r e r e c e n t l y , s in c e th e 1980s research and d eve lo p m e nt efforts have f o c u sed on projects to improve the w ay small low land plots are farm ed. This had been o ne o f the m a in p la n n in g concerns voiced by the v il lagers themselves. The idea b e h in d these p ro je c ts has b e e n to i n v o l v e fa r m e r s more closely in flood basin development and to induce
them to speculate on some thing other than rice, and to f u r t h e r i n v e s t i g a t e th e hydrological and agricultu ral features o f the area. In the field, the result has been t h a t n o n - g o v e r n m e n t a l organizations (NG O s) and t h e M a l i a n g o v e r n m e n t have carried o ut many pro jects w ith the assistance of the specialized services of C M D T (Table 2). Potato 1.6 % Fruit 11.3 % Related crops 1.8 % Cassava 1.6 % Sweet potato 7.2 % Rice 13.6 % Low land 3 7 %
lo w la n d s in M a li
Table 2. Sikasso region development projects: background and outlook.
Period Number of projects Area involved (ha) Total Average Sponsor pre-1983 27 15 800 585 CMDT/EDF local development committees 1983 - 1992 45 1 500 33 CMDT/IBRD various NGOs; CMDT with Dutch cooperation 1993 - 1997 100 12 50 1 800 about 18 about 10 about 5 CMDT/ADB Rural engineering/ADB CMDTAVorld Bank 20 about 5 Various NGOs EDF: European D e v e lo p m e n t Fund; IBRD: In te rn a tio n a l Bank fo r R e co n stru ctio n and Development. ADB: African Development Bank.
These projects have all built up a fund of experiences that should now be pooled. Moreover, because of the uncertain economic clima te farmers are in need of new solutions that can be ra p id ly im p le m e n te d . Research is seeking to fulfil both of these expectations.
Research
thrusts
Action is required at several l e v e l s i n o r d e r t o implement these projects. At the regional level there is a need for consistency bet ween actions undertaken in the field in response to one time village requests. At the local level, the project must be suited to the constraints and advantages of the farms concerned. For this purpo se, a rapid analysis of the physical, social and econo mic factors is carried out. A technical lowlands deve lo p m e n t p ro je c t is then designed (management and farming systems). Progress is monitored and assessed in relation to the economic and social environment.
The overall results vary for the different sites, but they g e n e ra lly focus on the h y d ro lo g ic a l regim e of lo w la n d s and c r o p p in g systems.
Management and
the hydrological
regime
The im p ortant feature of lowland soils of the Sikasso region is that they are extre- m ely p e rm e a ble: w ater sinks in at the rate of 35-75 m illim e te r s per day, as compared to 3-20 mm in a typical rice paddy. Hence, when there is no ground water as much as sixfold the maximum évapotrans piration may be required in o rd e r to keep a la yer of water on the rice crop. Accordingly, groundwater fluctuations must be regula ted if lowland water mana gement is to be improved. It is mainly because this prin ciple was ignored that there were difficulties with flood- p la in projects (diversion dams, rudimentary irriga tion networks) carried out in southern Mali during the
1970s. Conversely, the suc cess of half-sunk dams in managing small lo w la n d plots like those of Kambo (Fig. 4) can in a large mea sure be explained by the attention paid to ground water circulation.
Three factors are directly in volved in choosing the water management approach and dam size:
- the m orphological cha* racteristics of the c a tc h ment basin, w h ich affect flood forecasting;
- the depth of the im per meable soil layer, w h ich determines to what extent lo w land drainage can be regulated;
- deferred flo w s — it is impossible to tell how large an area can be supported by g ro u n d w a te r outsid e flood periods, or for how long, unless these are known.
These factors can be taken into account in simulation models, and the effects of lo w la n d d e v e lo p m e n t under v a ria b le r a in fa ll c o n d itio n s can now be forecast. Spillway (cross-sectional view) Spillway w all (concrete) -Embankment (rip-rap) W ater A Anti-drainage barrier (rammea clay)
Figure 4. Half-sunk microdam.
low lands in M a li
Many management possibilities
In southern Mali, three kinds of water management projects have been built:- Weirs in the mean-water bed. These weirs are constructed in compact lowland areas but serve a relatively large area, generally more than 200 ha.
- Weirs with hydro-agricultural areas. The idea is to absorb floodwaters and ensure even submer sion of downstream plots (Fig. 5). This type of weir has proved effective especially for year-round watercourses, as dry-season crops also benefit from irrigation.
- Half-sunk microdams constructed in the high-water bed (Fig. 4). These dams, which are smaller and do not involve any change in rice growers' farming techniques, serve to regulate water flow in various parts of the lowlands during the rainy season. The secure water supply this affords allows more intense rice cropping in the flooded areas and also helps sweet potato, groundwater-fed rice and maize production in areas dependent on groundwater. At the outset of the dry season, these dams slow the fall of the water table and make it possible to grow certain out-of-season crops (mar ket gardening, potato) as well as fruit (banana, papaya and pineapple).
P: Irrigation canal in let «> Plot feed in let *• C om p artm en t feed in let *■ Inter-co m p a rtm e nt sp illw a y
Low d ik e between com partm ents
Figure 5. Weir development with a hydro-agricultural area.
Farming system
improvements
D u r i n g th e r a in y season, fa rm e rs use th e m e d iu m - and low-elevation zones of t h e l o w l a n d s , w h i c h are subject to flooding, for rice gro w in g; yields are around 1 t/ha w h e n m an ua l w e e din g is carefully done. The higher gro und, rarely f lo o ded b u t w it h g ro u n d w a te r near the surface, is used for tubers and f r u i t orc h ards . V e r y l i t t l e r ic e is g r o w n th e re fo r la c k o f s u it a b le varieties.
During the dry season, mar ket g a r d e n in g and p o ta to g ro w in g are carrie d o u t in
Table 3. Profitability of various crops. 1992 growing season, Kléla site. Yields (kg/ha) Margin (CFA francs) Working time (days) Pay per working day (CFA francs) Rainfed crops Cotton 1 800 95 225 99 962 Sorghum 1 200 35 420 45 787 Maize 2 000 63 335 60 1 055 Lowland crops Flood rice 3 000 141 120 93 1 517 Groundwater rice 2 750 109 850 75 1 465 Groundwater maize 2 000 40 700 35 1 163 l o w - l y i n g a re as, w h i l e g r o u n d w a t e r is s till s u f f i cien t for manual irrigation fro m w e lls . P r o d u c tio n is in flu e n c e d by the level o f t h e w a t e r t a b l e , w h i c h determines h ow long irriga tio n can be c a rrie d o n ; it may therefore be irregular. E x p e r i m e n t s c o n d u c t e d o v e r m ore than fiv e years at s e v e r a l s ite s in th e S ik a s s o r e g io n ( K lé la , Bamadougou) have shown t h a t te c h n iq u e s are a v a i la b le f o r i m p r o v i n g r ic e - g r o w i n g p r o d u c t i v i t y w i t h o u t n e c e s s a rily b u i l d i n g h y d r o - a g r i c u l t u r a l structures. P r o d u c t iv it y o f tra d itio n a l rice paddies can be increa sed by 40-50% using relati v e l y s i m p l e t e c h n i q u e s : im p ro v e d varietie s, better s o il p r e p a r a t i o n . A p p r o p ria te m a n u r in g , in a d d i t i o n to th e s e o t h e r t e c h niques, can double yields. E a rly w e e d c o n t r o l is crucial for rice production. U n d e r t h e t r a d i t i o n a l broadcast s o w in g m ethod, about 60 days o f w o r k per hectare was re q uired , b ut th is can be c u t in h a lf by fu rro w sowing and using a s m a ll m u l t i - r o w p la n t e r , w h i c h m a k e s m a n u a l weeding easier.
There can also be substan t i a l s a v in g s b y u s in g a 3-year schedule of fertiliza tion w ith natural phosphate produced in northern Mali. A t h ig h e r e le v a t io n s , th e use o f n e w ric e v a rietie s , i n t e r m e d i a t e b e t w e e n a q u a t i c t y p e s a n d t r u e rainfed rice, promises p ro duction equal to that o f rice g r o w n on f l o o d p l a i n s . M o r e o v e r , c r o p s c a n be diversified when maize and groundnuts are introduced.
low lands in M a li
There are also good pros pects fo r im p r o v e m e n t in p o ta to g r o w in g . A lh o u g h a v e r a g e y i e l d s are n o w around 16 t/ha, yields of as much as 35 t/ha have been obtained.
Hence, w it h o u t any d eve l o p m e n t , b u t o n l y a f e w innovations done in coope r a tio n w it h fa rm e rs , l o w la n d c r o p s c a n b e c o m e c o m p e t i t i v e w i t h c o tt o n , the m ain cash c ro p in the reg io n (Table 3). Some of the techniques rec o m m en d e d are a c t u a l l y b e i n g a p p li e d b y p ro d u c e r s on e x p e r i m e n t a l s ite s a n d , o u ts id e these sites, b e ing prepared for w id e r dissemi nation by C M D T.
However, much progress is s t ill r e q u ir e d in l o w l a n d a g r i c u l t u r e : t h e r e is no re a d y -m a d e a n s w e r to its v e ry diverse p h y s ic a l and social situations. Research is therefore continuing.
A new concept
A new concept fo r agricu l t u r a l m a n a g e m e n t and d e v e lo p m e n t o f th e l o w la n d s has e m e r g e d f r o m knowledge acquired on the v a r i o u s s t u d y s ite s : an attem pt is made to a ccen tuate the natural hydrologi cal features o f the various low land zones.Former creekbed
Creek
Downstream
V
C d check d a m ., I: inlet, D: d ike , Fc: feed c an al, Sc: see pa g e c an a l, M e : m ainte na nc e c an a l, S: spillw ay
In a s im p le n e w a rr a n g e ment being implemented in t h e K o b a n i l o w l a n d (on M 'p eg ne sso v illa g e land), water is diverted by means o f a w e i r and c h e c k dam into a netw ork o f recycling c a n a ls . T h e f i l t e r i n g s o il layers are very deep and the h a l f - s u n k d a m s a lr e a d y c om m on elsewhere cannot be used here. Groundwater f lu c tu a tio n s are regulated by rec y c ling so as to safe guard and increase the pro duction potential of dow ns tr e a m c r o p s . T h e d e v e lop m e nt, w h ic h in all w il l cost 7 m illio n CFA francs, is b e in g f i n a n c e d b y th e villagers, w h o are supplying the labour and have under taken to finance and m ain t a i n it t h a n k s to a l o c a l investment fund u nd erw rit te n b y th e F re n c h F onds d 'a id e et de c o o p é r a t i o n (FAC). The per-hectare cost of the developm ent w ill be 280 0 0 0 CFA francs. This model may be progressive ly extended to the w h o le of the Kobani lo w la n d , some 30 km in length.
This experience is of interest to t h e C M D T f o r th e p o s s i b l e f u t u r e d e v e l o p m e n t o f so m e t w e n t y l o w l a n d a reas b y t h e African Development Bank.
References
ALBERCEL J., LAMACHERE J.- M ., L ID O N B., M O K A D E M A., V A N DRIEL W ., 1 993. M is e en va le u r ag rico le des bas-fonds au Sahel. Typologie, fonctionnement hyd ro lo g iq u e , potentialités a g ri coles. Final project report CORAF- R3S. Ouagadougou, Burkina Faso, CIEH, 355 pp..
L I D O N B., S IM P A R A M ., 1993. Contraintes du milieu natu rel et in té rê t de l'a m é n a g e m e n t des bas-fonds : cas du sud du Mali.
In «Bas-fonds et Riziculture», pro
c e e d in g s o f th e s e m in a r at A n t a n a n a r iv o , M a d a g a s c a r, 9 -1 4 D e c e m b e r 1991, pp. 4 5 1 - 4 6 7 . M o n t p e l l i e r , F ra n c e , CIRAD-CA, 514 pp. PO ISSO N C., A H M A D I N ., 1993. Amélioration variétale pour la riziculture de bas-fond à l'IRAT : de la situation de nappe à l'in o n datio n profo n d e et de 0 à 2 000 mètres d'altitude. In «Bas-fonds et R iz ic u ltu re» , proceedin gs o f the s e m i n a r at A n t a n a n a r iv o , M a d a g a s c a r, 9 - 1 4 D e c e m b e r 1991, pp. 393-4 0 1 . M o n tp e llie r, France, CIRAD-CA, 514 pp.
Réseau Riz de la C O R A F , 1991. Report o f the CORAF rice N e tw o rk W o rk s ho p on the créa tio n -d iffu s io n process, Korhogo, Côte d 'Iv o ir e , September 1991. M o n tp e llie r, France, CIRAD-CA, 1991, 15 pp.
Figure 6 . Plan of the experimental development at M'pegnesso. Total a re a 2 5 ha, 1 0 at high elevation, 15 at low.
W h o is involved
This research project, on the development of village land in southern Mali with a lowland component, is being carried out jointly by the Institut d'économie rurale du Mali, CIRAD and the Compagnie malienne pour le développement des textiles (CMDT). ORSTOM and the U niv e rs ité des Sciences et Techniques du Languedoc (Montpellier, France) are also involved.
The study of southern Malian lowlands was begun in 1985 and is continuing with the current project, which has been receiving funding since early 1993 from the French Fonds d'aide et de coopération as part of the 'Mali-Sud' programme.
low lands in M a li
Abstract... Resumen... Résumé
N. A H M A D I, F. BLANCHET, M . S IM P A RA , B. TRAORE - Development of lowlands in Mali.
In areas with limited rainfall, lowlands (flood basins) w h e re r u n -o ff w aters converge a r e econ om ically im p o rta n t agricultural zones. Lowlands account for 5% o f the su rfa ce area in southern M ali and only 1 / 5 o f this is cultivated. It is essential th a t im p ro v e m e n t projects on agricultural w ater m o n a g e m e n l and cropping systems involve in te r ventions at m a n y levels (e.g. regional and local) and ta k e th e physical a n d social d iv e r s it y in to a c c o u n t. W a te r m a nag em e nt decisions should be guided by three factors: the morphometric features o f the w atershed (qu an titative flood forecasting), the thickness of the im p e rm eab le soil la y e r (p o ssib ility o f c o n tro llin g w a t e r leve ls w h e n the ground is highly porous), and delayed ru n -o ff (soils with a g r ic u l t u r a l p o t e n t i a l ) . In t h e M ' p e g n e s s o l o w la n d (Sikasso reg io n), rice cropping has been intensified in low areas using im pro ved varieties, better tillage and suitable fertilizatio n . In hig hlan d areas, hybrids o f pure rain fe d ond w etlan d rice varieties produce the sam e yields as in flood areas. M aize , groundnut and potato could be grown as co m p a n io n crops to im p r o v e a g r ic u ltu r a l div e rs ity . L o w la n d c ro p s c o u ld t h u s b e c o m e as p r o f i t a b l e as cotton crop.
Key words: soil, cropping system, rice grow ing, lowland, m a n ag em e n t, diversification, Mali.
N. A H M A D I, F. BLANCHET, M . S IM P A R A , B. TRAORE - La valorización de las hondonadas en Mali. En un contexto de pluviosidad lim itad a, las hondonadas (tierras inundadas) donde convergen los flugos de aguas constituyen zonas de agricultura económ icam ente im po r tantes. Dichas zonas rep rese ntan el 5% de la superficie del sur del M alí, la quinta parte de la cual es cultivada. Los proyectos de m ejo ra de la gestión del ag ua y de los siste m as de cultivo deben conciliar varias categorías de inter vención - la región y el terruñ o - y to m a r en cuenta la diversidad de las situaciones físicas y sociales. En la selec ción de los dispositivos de gestión del ag u a in terv ie n en tres factores: las características m o rfom étricas de la cuen ca v e r tie n te (pre visión c u a n tita tiv a de las crecidas), la p ro fun dida d de la capa de suelo im p e rm e a b le (posibili dades de regulación del nivel de ag u a cuando los suelos son m u y filtrantes), los flujos diferidos (superficies va lo - rizables potencialm ente). En la hondonada de M 'p e g n es so (reg ió n de Sikasso), el cultivo de arro z es intensificado en las zonas bajas con variedades m ejoradas, una mejor p re p a ra c ió n del suelo y un a fe rtiliza c ió n a d a p ta d a . En zonas altas, las variedades de arro z interm edias entre los tipos acuático y pluvial estricto son tan productivas como en las zonas inundadas. El maiz, el cacahuete y la patata son producciones interesantes para diversificar los cultivos. Los cultivos de hondonada pueden ser tan rentables como el algodón.
Palabras clave: suelo, sistema de cultivo, cultivo de arroz, h o ndonada, ordenación, diversificación, M alí.
N. A H M A D I, F. BLANCHET, M . S IM P A R A , B. TRAORE - La mise en valeur des bas-fonds au Mali. D an s un c o n te x te d e p lu v io s ité lim it é e , les b a s -fo n d s (terres inondables) où convergent les écoulements d'e a u x c o n s titu e n t des zo n e s d 'a g r i c u lt u r e é c o n o m iq u e m e n t im portantes. Ces zones représentent 5 % de la surface du sud du M ali, 1 / 5 est mis en culture. Les projets d 'a m é lio ration de la gestion de l'e a u et des systèmes de culture d o iv e n t co nc ilier plu sieurs n iv e a u x d 'i n t e r v e n t io n , la rég io n et le te rro ir, et te n ir co m pte d e la div ersité des situations physiques et sociales. Trois facteurs interv ie n nent dans le choix des dispositifs de gestion de l'eau : les caractéristiques m o rphom étriques du bassin versant (p r é vision quantitative des crues), la profondeur de la couche de sol im p e rm éab le (possibilités de régulation du niveau d 'e a u lorsque les sols sont très filtrants), les écoulements différés (surfaces po ten tiellem e n t valorisables). Dans le bas-fond de M'pegnesso (région de Sikasso), la riziculture est in ten sifié e dans les zo nes basses avec des va rié té s am éliorées, une m eilleure préparation du sol, une fertili sation ad ap té e. En zones hautes, des variétés de riz inter m édiaires en tre les types aq u a tiq u e et pluvial strict sont aussi productives que dans les zones inondées. Le maïs, l'arachide et la p o m m e de terre sont des productions inté ressantes pour diversifier les cultures. Les cultures de bas- fond peuvent être aussi rentables que le cotonnier. Mots-clés : sol, système de culture, riziculture, bas-fond, a m én a g e m en t, diversification, Mali.
