PILIOSTIGMA RETICULA TUM USED FOR SOIL ORGANIC ...
PILIOSTIGMA RETICULA TUM USED FOR SOIL ORGANIC
MATTER WlLD UP: EFPKTS ON TKE SOIL QUALLTY AND
CROI’ YIELD IN THE PEANUT BASIN OF SENEGAL
M. Diack, M. Sène and A. N. Badiane
ISRA, SENEGAL
Paper pre:pared for the fust Annual Workshop of InterCRSP
West Afi-ica Group
Kaolack, 11-14 January 1999
PILIOSTIGMA RETICULA TUM USED FOR SOIL ORGANIC
MATTER BUILD UP: EFFECTS ON THE SOIL QUALITY AND
CROP YXELD IN THE PEANUT BASIN OF SENEGAL
M. Diack, M. Sène and A. N. Badiane
Soi1 Scientists, ISRA, Senegal
ABSTRACT
Given the high demand for trop residues and the insufficiency of animal manure,
the use of native vegetation could be an alternative solution for improving soi1 quality
and trop productivity. This study was conducted to determine the effect of Piliostiptr
reficulafwn (PR), a native shrub, in improving the soi1 properties of a degraded soi1 and
to develop management systems that effectively utilize the species ta maximize input
efficiency and trop productivity. The experiment was conducted at Nioro, Kaolack, on a
Deck Dior loamy sand (fine sandy, rnixed Haplic Ferric Lixisol), Eeached ferrugeneous
soi1 tropical soil, where peanut and millet were grown. The above-ground biomass of PR,
collected alter each cutting from the field was applied at the soi1 surface, at a rate of 2
tia on the dry matter basis. The study compared a control (TO), PR biomass from
weeding (Tl), Tl + minera1 fertilizer (T2), at recommended rate for the growing trop,
T2 + biomass from cutting afier harvest (T3), PR biomass fi-om clear cutting during soi1
preparation (T4), and T4 + minera1 fertilizer at recommended rate for the growing trop
(T5). As treatment application was sequential, partial results showed slight increases of
21 and 26% for Tl and T2 respectively in peanut plant population, 6 and 17% for TI
and T2 respectively in pods. As for millet, increases in stalk of 8 and 188% for T 1 and
T2 respectively were recorded. For both crops, these increases in yield components were
more likely due to the chemical fertilizer that is more available to plants SO ,faàr.
Key words: Piliostigma reticulatum, biomass, soi1 organic matter, soil quality, trop productivity.
2
UTILISATION DE PILIOSTIGMA RETICULA TUM POUR
RECONSTITUER LE STOCK DE MATIERE ORGANIQUE: EFFET
SUR LA QUALITE DES SOLS ET DU RENDEMENT DES
CULTURES DANS LE BASSIN ARACHIDIER DU SENEGAL
M. Diack, M. Sène et A. N. Badiane
Pédologues, ISRA, Sénégal
RESUME
Devant la forte demande des résidus de cultures et 1’insufflsa:nce des déchets
animaux, l’utilisation de biomasse produite par la végétation naturelle pourrait constituer
une alternative & l’amélioration de la qualité des sols et de leur productivité. Cette étude
a été menée pour déterminer l’influence de Piliostigma reticulatum (PR), un arbuste
local, sur l’amélioration des propriétés d’un sol dégradé et développer un mode de
gestion qui maximiserait la productivité du sol. L’essai a été conduit à la station de
Nioro, (Kaolack), sur un sol Deck Dior, sableux fin, ferrugineux tropical lessivé, où
l’arachide et le mil sont en rotation. La biomasse aérienne de PR, ramassée du champ
après chaque coupe, était appliquée à la surface du sol pour les traitements concernés à
la dose de 2 t/ha de matière sèche. L’étude compare un témoin absolu (TO), une
biomasse de PR. coupée au sarclage (Tl), Tl + (N)PK à la dose recommandée pour la
culture (T2), T2 + biomasse de PR coupée après récolte (T3), une biomasse de PR
coupée pendant la préparation du sol (T4) et T4 + (N)PK, à la dose recommandée pour
la culture (TS). Etant donné que l’application des traitements a été séquentielle, les
résultats partiels montrent une légère augmentation de 21 et 26% respectivement pour
les traitements Tlet T2 en terme de population des plants d’arachide, et 6 et 17%
respectivement pour les traitements Tlet T2 en terme de gousses. Quant au mil, une
augmentation de 8 et 188% de paille produite respectivement pour Tlet T2 a été
obtenue. Pour les deux cultures, ces augmentations seraient plutôt imputables à l’effet
des engrais minéraux qui pour le moment, sont plus disponibles.
Mots clés: Piliostigma reticulatum, biomasse, matière organique du sol, qualité du sol, productivité.
Introduction
With 1/3 of the country’s area, the Peanut Basin provides 75% of the peanut and
80% of the millet production of the country. However, while the soils are intensively
cultivated with a. high degree of land utilization (land in fallow less than 3%), trop
production is still low. Soils are degraded.
Degradation of the soi1 resource, in Senegal, has resulted from the combination
of decreases in rainfall, inappropriate land management practices (less land in shorter
fallow periods, removal of nearly a11 trop residues from fields), and declining numbers of
trees from traditional parkland agroforestry systems. Consequently, there has been an
intense nutrient extraction of primarily N and P, and a decrease in overall soi1 organic
matter (decreased fiom naturally occurring 2% down to 0.3%). The changes to the soi1
resource have caused decrease in food production and reduced rural income. Therefore,
efforts must be re:doubled to replace nutrients that have been lost from the farms through
the use of fertilizers and organic matter.
Given the high demand for trop residues and the insufficiency of animal manure,
the use of native vegetation could be an alternative solution for improving soi1 quality
and thereby increasing trop productivity.
Piliostigma reticulatum, an endophitic legume, with no nodules, non-fixing N,
fiom the Cesalpiniaceae family, is usually a shrub but cari occasionally be a tree. lt
grows on sandy, clayey and lateritic soils, During the dry season, it cari regrow up to 90
cm with a canopy diameter of 100 to 175 cm. Annually, 1268 g of dry weight biomass
per shrub are produced, for an average density of 317 shrubs per ha (Diack et al., 1998).
In some areas, these shrubs nearly caver the landscape but in others, there is a less dense
distribution. This difference in density is due to dEerences in soi1 types. If left uncut,
these shrubs continue to grow, but in fat-mers’ fields they are tut at the soi1 surface and
burned just prior to the rainy season.
A survey was conducted (Diack et al., 1998) to determine the level of appreciation
and use that farmers make of P. reticulatum within the parkland system. The survey
showed that P. reticîrlatum was the third most important species that farrners would like
to conserve in the fields after two tree species: Cordylapinnata and Acacia albida. The
reasons for the choice these three species were fruit production, nutrient value of theïr
biomass and forage for livestock. For P. reticulatum, fat-mers admitted that it cari play an
important role in soi1 fertilization and help protect soi1 against erosion. The population of
P. reticulatum is still acceptable despite a decrease during the past ten years, due to
mecanization. The management system of P. reticulatum consists of cutting the shrub
(april-june) for soi1 preparation and cutting 2 to 3 times more, depending on the trop,
during the growing season. Ash as minera1 fertilizer is the main product that farmers get
from the manage:ment system. According to farmers, the effect of P. reticulatum on trop
productivity is showed by the good response of crops such as peanut, millet and to some
extend cowpea, under the shrub canopy. These information collected from the survey
show that Piliostigma reticulatum plays an important role in the farming system and has
a potential of improving the soi1 productivity.
A decomposition study of Piliostigma reticulatum biomass (Diack et al., 1998)
showed a greater mass loss under field conditions than under controlled ‘conditions. This
was probably due to the role of soi1 fauna which may have been involved under field
conditions but would have been excluded under laboratory conditions. With such fast
decomposition rate under field conditions, accumulating residue biomass at the soi1
surface would certainly avoid a discontinuous distribution of organic resource for the
microbial activity. The specific surface area-to-mass ratio, obtained for P. reticukatum,
should allow such a continuous application of the biomass to the soi1 for both caver and
organic matter build up.
The objectives of this study are to determine the influence of P. reticulatum on
the soi1 physical, chemical and biological properties and the trop yield.
Materials and Methods
&e
The experiment is being carried out in Paoskoto (Kaolack) in two farmers’fields
which are under a two-year rotation of peanut (Arachis hypogaea) and millet
(Pennisetum glaucum L.). The soil is a Deck Dior loamy sand (fine-sandy, mixed Haplic
Ferric Lixisol), leached ferrugeneous tropical soi1 @robably Ultisol). The soi1 has a pH
varying from 5.7 to 6.7 and a low fertility status (OC: 0.47%, N: 0.45%).
.-_-.“--.--.---
-m
W-I-
-___
--
. .-.--
.l_l_~~
Plant materiais:
The above-ground biomass (leaves and stems) of Piliostigma reticulatzm were
collected afier each cutting from the field.
Experimental des@
It is a randomized complete block design with 6 treatments replicated 4 times.
The treatments are the following:
TO = Control;
Tl = Biomass fiom cutting (weeding) and application between rows and at the soi1
surface, at a rate of 2 ton/ha of dry matter;
T2 = Tl + minera1 fertilizer at the recommended rate for the growing trop;
T3 = T2 + bioma.ss from cutting after harvest and application at the soi1 surface, at a rate
of 2 ton/ha of dry matter;
T4 = Biomass fiom clear cutting (soi1 preparation) and application at the soi1 surface, at
a rate of 2 ton/ha of dry matter;
T5 = T4 + minera1 fertilizer at the recommended rate for the growing trop.
Peanut, a 73-33 variety, Will be planted with interrows of 0.50 m while millet (Souna 3)
Will be planted with interrows of 0.90 m, in an experimental unit area of 45 m2.
Measurements
1. On plants: N, P, K, Ca, Mg and S contents Will be determined at the maximum
vegetative stage and before harvesting for each trop.
2 . On soils: samples Will be collected before and &er each growing season to monitor
soi1 moisture in relation to soi1 physical, chemical, biological properties and C
dynamics. The following properties Will be measured:
a)
Physical c.haracteristics: moisture content, bulk density, infiltration rate, soi1
resistance to penetration and sealing index as a measure of aggregate stability;
b)
Chemical characteristics: total C and N, NO<, NJ&‘, PzOS, K’, Ca”’ and Mg” ;
4
Biologica! characteristics: microbial biomass C, particulate organic C (POC) and
enzyme activity (P-glucosidase).
Partial Results ad Discussion
Since the application of Piliostigma reticulatum biomass is sequential, treatment
T3 has been applied right alter harvest while T4 and T5 Will be apphed early next season.
Therefore, the yield components presented in Tables 1 and 2 are only for treatments TO,
Tl and T2. The yield components recorded for T3, T4 and T5 treatments could be
considered as control for the first year.
For peanut (Table l), even though yields were relatively low, P. reticulaturn
application has showed a slight increase in yield components. For plant population at
harvest, there is an increase of 2 1 and 26% for Tl and T2 respectively. For pods, there
has been an increase in yield of 6 and 17% for Tl and T2 respectively whereas 6 and
29% were the respective increases in hay yield for Tl and T2.
As for millet, yields in general are low (Table 2). However, while treatment Tl
has not yet shown any increase, T2 in the other hand has strongly responded in yield.
Plant population has increased from 1 to 6% and stalk from 8 to 188% for Tland T2
respectively. For both crops, increases in yield components were more liltely due to the
chemical fertilizer that was added to P. reticdatum biomass for its greater availability.
Perspectives
Since the experimentation is a Lt-year program, we need to complete first the
treatment applications and then monitor the soi1 property changes over time.
Table 1. Yield components of the peanut as affected by Piliostigma reticdatwn
Treatment
Plant population
Pod + Hay (kg/ha)
T O
44480
1250
Tl
54060
1320
T2
55980
1530
Mean
53300
1460
Table 2. Yield components of the millet as affected by Piliostigma retimkrtm
Treatment
Plant population
Number
St.& (&$a)
Grain @@ha)
of
spikes /ha
T O
8240
11140
1240
210
Tl
8320
8170
1340
150
T2
8700
27170
3560
660
MeaIl
8380
18650
2040
410
---.-
--
.-“-v--B.
FIRST ANNUAL INTERCRSP WORKSHOP
West Africa Group
Field Trip Report on January 13, 1999
bY
Dr. Mateugue Diack
As part of the workshop program, the field trip gave an opportunity to the participants
to visït the Koutango and Nïoro sites where the InterCRSP experïmental plots were located.
7H 30 am. The vïsïtors left Kaolack for the Koutango site, 69 km, South-west from Kaolack
9H 05 am. They arrïved at the site and were introduced to Mr. Mansour Dème, field worker
and owner of the field by Dr. Modou Sène. A nutrient management progam ïs
beïng carrïed out on rice under rainfed. Rock phosphate and phosphogypsum as P
and Ca sources and manure are the fertïlizer forms used in the experiment (see
papers).
Several questions about the perception that farmers have on the phosphogypsum
progam, ïnïtïated by the Government of Senegal, were asked
U’as the phosphogypsum efflcient as fet-tïlïzer?
Yes, and 1 am also usïng it to control salinïty, replïed Mr. Dème.
What if the Government stopped providïng fertïlizer fi-eely?
1 Will purshase it, he saïd.
Beside rïce, Mr. Dème grows vegetables because water ïs avaïlable.
The site ïs wïthïn an interesting valley for whïch ISRA intends to run a research and
development program under lowland conditions. Dr. Dïack, coordïnator of that
program, presented prelïminary data obtained from both socio-economïc and
hydrologie surveys conducted in the valley. The data showed a great agricultural
potential of the valley. However, soi1 constraints such as salinizatïon, acïdity and
water management need to be addressed. From the socio-economïc standpoint,
villages established arround the valley are organized into 57 groups based on
economic ïnterest. The R and D program Will be carried out by a multïdïscïplinary
team composed of scientists fiom ISRA, the University of Dakar and an NGO.
9H 45 am. The participants left Koutango for the Nioro Research Station, second site
1 1 H 45 am. As they arrived at the Research Station, the participants were introduced to,the
local staff by Dr. Modou Sène. The visit started with experimental plots among
which the Piliostigma reticdatztm tria1 under peanut/millet rotation, a second tria1
where rock phosphate and phosphogypsum as P and Ca sources and manure were
compared under a peanut/millet rotation and a third experiment combining
nutrient management and water balance (see papers). The participants also visited
the small dam implemented to control runoff/erosion in the watershed.
For each trial, several questions were asked, leading to important discussion.
From the discussion, one could appreciate the amount of work done SO far,
meaning the InterCRSP program in Senegal is going well.
1 H 20 pm. The participants 1eR Nioro for Kaolack.
2H 15 pm. Arriva1 at Kaolack.
The following participants took part to the field trip:
1. Russe1 YOST
2 . Gaoussou TRAORE
3 . Samuel BRIJCE-OLIVER
4 . Aminata SIDIBE
5 . Isuarina BAPTISTA
6 . Aminata BADIANE
7 . Abou BERTHE
8 . Mamadou DOUMBIA
9. Kevin BRANNAN
1 0 . Richard KABLAN
1 1 . Mouhamed KEBBEH
1 2 . Babou JOBE
1 3 . Cheikh NDIAYE
1 4 . Modou SENE
1 5 . Mateugue DIACK
me--
-.,..
--
----
-.-.W.-*
7
Field Operations during the first year
Field Operations
Dates of Implementation
-
Peanut
Millet
-
Sowing
0712 1
0712 1
15’ weeding
-
08/18
08107
-
-
Thinning
08107
N-P-K application
08119
08/13
-
-
1 st urea application
08/19
-
2”d urea applicatio*l
09/04
-
P. reticulatum application
9/04
9104
2nd weeding
Harvest
P. reticulatum application
MATTER WlLD UP: EFPKTS ON TKE SOIL QUALLTY AND
CROI’ YIELD IN THE PEANUT BASIN OF SENEGAL
M. Diack, M. Sène and A. N. Badiane
ISRA, SENEGAL
Paper pre:pared for the fust Annual Workshop of InterCRSP
West Afi-ica Group
Kaolack, 11-14 January 1999
PILIOSTIGMA RETICULA TUM USED FOR SOIL ORGANIC
MATTER BUILD UP: EFFECTS ON THE SOIL QUALITY AND
CROP YXELD IN THE PEANUT BASIN OF SENEGAL
M. Diack, M. Sène and A. N. Badiane
Soi1 Scientists, ISRA, Senegal
ABSTRACT
Given the high demand for trop residues and the insufficiency of animal manure,
the use of native vegetation could be an alternative solution for improving soi1 quality
and trop productivity. This study was conducted to determine the effect of Piliostiptr
reficulafwn (PR), a native shrub, in improving the soi1 properties of a degraded soi1 and
to develop management systems that effectively utilize the species ta maximize input
efficiency and trop productivity. The experiment was conducted at Nioro, Kaolack, on a
Deck Dior loamy sand (fine sandy, rnixed Haplic Ferric Lixisol), Eeached ferrugeneous
soi1 tropical soil, where peanut and millet were grown. The above-ground biomass of PR,
collected alter each cutting from the field was applied at the soi1 surface, at a rate of 2
tia on the dry matter basis. The study compared a control (TO), PR biomass from
weeding (Tl), Tl + minera1 fertilizer (T2), at recommended rate for the growing trop,
T2 + biomass from cutting afier harvest (T3), PR biomass fi-om clear cutting during soi1
preparation (T4), and T4 + minera1 fertilizer at recommended rate for the growing trop
(T5). As treatment application was sequential, partial results showed slight increases of
21 and 26% for Tl and T2 respectively in peanut plant population, 6 and 17% for TI
and T2 respectively in pods. As for millet, increases in stalk of 8 and 188% for T 1 and
T2 respectively were recorded. For both crops, these increases in yield components were
more likely due to the chemical fertilizer that is more available to plants SO ,faàr.
Key words: Piliostigma reticulatum, biomass, soi1 organic matter, soil quality, trop productivity.
2
UTILISATION DE PILIOSTIGMA RETICULA TUM POUR
RECONSTITUER LE STOCK DE MATIERE ORGANIQUE: EFFET
SUR LA QUALITE DES SOLS ET DU RENDEMENT DES
CULTURES DANS LE BASSIN ARACHIDIER DU SENEGAL
M. Diack, M. Sène et A. N. Badiane
Pédologues, ISRA, Sénégal
RESUME
Devant la forte demande des résidus de cultures et 1’insufflsa:nce des déchets
animaux, l’utilisation de biomasse produite par la végétation naturelle pourrait constituer
une alternative & l’amélioration de la qualité des sols et de leur productivité. Cette étude
a été menée pour déterminer l’influence de Piliostigma reticulatum (PR), un arbuste
local, sur l’amélioration des propriétés d’un sol dégradé et développer un mode de
gestion qui maximiserait la productivité du sol. L’essai a été conduit à la station de
Nioro, (Kaolack), sur un sol Deck Dior, sableux fin, ferrugineux tropical lessivé, où
l’arachide et le mil sont en rotation. La biomasse aérienne de PR, ramassée du champ
après chaque coupe, était appliquée à la surface du sol pour les traitements concernés à
la dose de 2 t/ha de matière sèche. L’étude compare un témoin absolu (TO), une
biomasse de PR. coupée au sarclage (Tl), Tl + (N)PK à la dose recommandée pour la
culture (T2), T2 + biomasse de PR coupée après récolte (T3), une biomasse de PR
coupée pendant la préparation du sol (T4) et T4 + (N)PK, à la dose recommandée pour
la culture (TS). Etant donné que l’application des traitements a été séquentielle, les
résultats partiels montrent une légère augmentation de 21 et 26% respectivement pour
les traitements Tlet T2 en terme de population des plants d’arachide, et 6 et 17%
respectivement pour les traitements Tlet T2 en terme de gousses. Quant au mil, une
augmentation de 8 et 188% de paille produite respectivement pour Tlet T2 a été
obtenue. Pour les deux cultures, ces augmentations seraient plutôt imputables à l’effet
des engrais minéraux qui pour le moment, sont plus disponibles.
Mots clés: Piliostigma reticulatum, biomasse, matière organique du sol, qualité du sol, productivité.
Introduction
With 1/3 of the country’s area, the Peanut Basin provides 75% of the peanut and
80% of the millet production of the country. However, while the soils are intensively
cultivated with a. high degree of land utilization (land in fallow less than 3%), trop
production is still low. Soils are degraded.
Degradation of the soi1 resource, in Senegal, has resulted from the combination
of decreases in rainfall, inappropriate land management practices (less land in shorter
fallow periods, removal of nearly a11 trop residues from fields), and declining numbers of
trees from traditional parkland agroforestry systems. Consequently, there has been an
intense nutrient extraction of primarily N and P, and a decrease in overall soi1 organic
matter (decreased fiom naturally occurring 2% down to 0.3%). The changes to the soi1
resource have caused decrease in food production and reduced rural income. Therefore,
efforts must be re:doubled to replace nutrients that have been lost from the farms through
the use of fertilizers and organic matter.
Given the high demand for trop residues and the insufficiency of animal manure,
the use of native vegetation could be an alternative solution for improving soi1 quality
and thereby increasing trop productivity.
Piliostigma reticulatum, an endophitic legume, with no nodules, non-fixing N,
fiom the Cesalpiniaceae family, is usually a shrub but cari occasionally be a tree. lt
grows on sandy, clayey and lateritic soils, During the dry season, it cari regrow up to 90
cm with a canopy diameter of 100 to 175 cm. Annually, 1268 g of dry weight biomass
per shrub are produced, for an average density of 317 shrubs per ha (Diack et al., 1998).
In some areas, these shrubs nearly caver the landscape but in others, there is a less dense
distribution. This difference in density is due to dEerences in soi1 types. If left uncut,
these shrubs continue to grow, but in fat-mers’ fields they are tut at the soi1 surface and
burned just prior to the rainy season.
A survey was conducted (Diack et al., 1998) to determine the level of appreciation
and use that farmers make of P. reticulatum within the parkland system. The survey
showed that P. reticîrlatum was the third most important species that farrners would like
to conserve in the fields after two tree species: Cordylapinnata and Acacia albida. The
reasons for the choice these three species were fruit production, nutrient value of theïr
biomass and forage for livestock. For P. reticulatum, fat-mers admitted that it cari play an
important role in soi1 fertilization and help protect soi1 against erosion. The population of
P. reticulatum is still acceptable despite a decrease during the past ten years, due to
mecanization. The management system of P. reticulatum consists of cutting the shrub
(april-june) for soi1 preparation and cutting 2 to 3 times more, depending on the trop,
during the growing season. Ash as minera1 fertilizer is the main product that farmers get
from the manage:ment system. According to farmers, the effect of P. reticulatum on trop
productivity is showed by the good response of crops such as peanut, millet and to some
extend cowpea, under the shrub canopy. These information collected from the survey
show that Piliostigma reticulatum plays an important role in the farming system and has
a potential of improving the soi1 productivity.
A decomposition study of Piliostigma reticulatum biomass (Diack et al., 1998)
showed a greater mass loss under field conditions than under controlled ‘conditions. This
was probably due to the role of soi1 fauna which may have been involved under field
conditions but would have been excluded under laboratory conditions. With such fast
decomposition rate under field conditions, accumulating residue biomass at the soi1
surface would certainly avoid a discontinuous distribution of organic resource for the
microbial activity. The specific surface area-to-mass ratio, obtained for P. reticukatum,
should allow such a continuous application of the biomass to the soi1 for both caver and
organic matter build up.
The objectives of this study are to determine the influence of P. reticulatum on
the soi1 physical, chemical and biological properties and the trop yield.
Materials and Methods
&e
The experiment is being carried out in Paoskoto (Kaolack) in two farmers’fields
which are under a two-year rotation of peanut (Arachis hypogaea) and millet
(Pennisetum glaucum L.). The soil is a Deck Dior loamy sand (fine-sandy, mixed Haplic
Ferric Lixisol), leached ferrugeneous tropical soi1 @robably Ultisol). The soi1 has a pH
varying from 5.7 to 6.7 and a low fertility status (OC: 0.47%, N: 0.45%).
.-_-.“--.--.---
-m
W-I-
-___
--
. .-.--
.l_l_~~
Plant materiais:
The above-ground biomass (leaves and stems) of Piliostigma reticulatzm were
collected afier each cutting from the field.
Experimental des@
It is a randomized complete block design with 6 treatments replicated 4 times.
The treatments are the following:
TO = Control;
Tl = Biomass fiom cutting (weeding) and application between rows and at the soi1
surface, at a rate of 2 ton/ha of dry matter;
T2 = Tl + minera1 fertilizer at the recommended rate for the growing trop;
T3 = T2 + bioma.ss from cutting after harvest and application at the soi1 surface, at a rate
of 2 ton/ha of dry matter;
T4 = Biomass fiom clear cutting (soi1 preparation) and application at the soi1 surface, at
a rate of 2 ton/ha of dry matter;
T5 = T4 + minera1 fertilizer at the recommended rate for the growing trop.
Peanut, a 73-33 variety, Will be planted with interrows of 0.50 m while millet (Souna 3)
Will be planted with interrows of 0.90 m, in an experimental unit area of 45 m2.
Measurements
1. On plants: N, P, K, Ca, Mg and S contents Will be determined at the maximum
vegetative stage and before harvesting for each trop.
2 . On soils: samples Will be collected before and &er each growing season to monitor
soi1 moisture in relation to soi1 physical, chemical, biological properties and C
dynamics. The following properties Will be measured:
a)
Physical c.haracteristics: moisture content, bulk density, infiltration rate, soi1
resistance to penetration and sealing index as a measure of aggregate stability;
b)
Chemical characteristics: total C and N, NO<, NJ&‘, PzOS, K’, Ca”’ and Mg” ;
4
Biologica! characteristics: microbial biomass C, particulate organic C (POC) and
enzyme activity (P-glucosidase).
Partial Results ad Discussion
Since the application of Piliostigma reticulatum biomass is sequential, treatment
T3 has been applied right alter harvest while T4 and T5 Will be apphed early next season.
Therefore, the yield components presented in Tables 1 and 2 are only for treatments TO,
Tl and T2. The yield components recorded for T3, T4 and T5 treatments could be
considered as control for the first year.
For peanut (Table l), even though yields were relatively low, P. reticulaturn
application has showed a slight increase in yield components. For plant population at
harvest, there is an increase of 2 1 and 26% for Tl and T2 respectively. For pods, there
has been an increase in yield of 6 and 17% for Tl and T2 respectively whereas 6 and
29% were the respective increases in hay yield for Tl and T2.
As for millet, yields in general are low (Table 2). However, while treatment Tl
has not yet shown any increase, T2 in the other hand has strongly responded in yield.
Plant population has increased from 1 to 6% and stalk from 8 to 188% for Tland T2
respectively. For both crops, increases in yield components were more liltely due to the
chemical fertilizer that was added to P. reticdatum biomass for its greater availability.
Perspectives
Since the experimentation is a Lt-year program, we need to complete first the
treatment applications and then monitor the soi1 property changes over time.
Table 1. Yield components of the peanut as affected by Piliostigma reticdatwn
Treatment
Plant population
Pod + Hay (kg/ha)
T O
44480
1250
Tl
54060
1320
T2
55980
1530
Mean
53300
1460
Table 2. Yield components of the millet as affected by Piliostigma retimkrtm
Treatment
Plant population
Number
St.& (&$a)
Grain @@ha)
of
spikes /ha
T O
8240
11140
1240
210
Tl
8320
8170
1340
150
T2
8700
27170
3560
660
MeaIl
8380
18650
2040
410
---.-
--
.-“-v--B.
FIRST ANNUAL INTERCRSP WORKSHOP
West Africa Group
Field Trip Report on January 13, 1999
bY
Dr. Mateugue Diack
As part of the workshop program, the field trip gave an opportunity to the participants
to visït the Koutango and Nïoro sites where the InterCRSP experïmental plots were located.
7H 30 am. The vïsïtors left Kaolack for the Koutango site, 69 km, South-west from Kaolack
9H 05 am. They arrïved at the site and were introduced to Mr. Mansour Dème, field worker
and owner of the field by Dr. Modou Sène. A nutrient management progam ïs
beïng carrïed out on rice under rainfed. Rock phosphate and phosphogypsum as P
and Ca sources and manure are the fertïlizer forms used in the experiment (see
papers).
Several questions about the perception that farmers have on the phosphogypsum
progam, ïnïtïated by the Government of Senegal, were asked
U’as the phosphogypsum efflcient as fet-tïlïzer?
Yes, and 1 am also usïng it to control salinïty, replïed Mr. Dème.
What if the Government stopped providïng fertïlizer fi-eely?
1 Will purshase it, he saïd.
Beside rïce, Mr. Dème grows vegetables because water ïs avaïlable.
The site ïs wïthïn an interesting valley for whïch ISRA intends to run a research and
development program under lowland conditions. Dr. Dïack, coordïnator of that
program, presented prelïminary data obtained from both socio-economïc and
hydrologie surveys conducted in the valley. The data showed a great agricultural
potential of the valley. However, soi1 constraints such as salinizatïon, acïdity and
water management need to be addressed. From the socio-economïc standpoint,
villages established arround the valley are organized into 57 groups based on
economic ïnterest. The R and D program Will be carried out by a multïdïscïplinary
team composed of scientists fiom ISRA, the University of Dakar and an NGO.
9H 45 am. The participants left Koutango for the Nioro Research Station, second site
1 1 H 45 am. As they arrived at the Research Station, the participants were introduced to,the
local staff by Dr. Modou Sène. The visit started with experimental plots among
which the Piliostigma reticdatztm tria1 under peanut/millet rotation, a second tria1
where rock phosphate and phosphogypsum as P and Ca sources and manure were
compared under a peanut/millet rotation and a third experiment combining
nutrient management and water balance (see papers). The participants also visited
the small dam implemented to control runoff/erosion in the watershed.
For each trial, several questions were asked, leading to important discussion.
From the discussion, one could appreciate the amount of work done SO far,
meaning the InterCRSP program in Senegal is going well.
1 H 20 pm. The participants 1eR Nioro for Kaolack.
2H 15 pm. Arriva1 at Kaolack.
The following participants took part to the field trip:
1. Russe1 YOST
2 . Gaoussou TRAORE
3 . Samuel BRIJCE-OLIVER
4 . Aminata SIDIBE
5 . Isuarina BAPTISTA
6 . Aminata BADIANE
7 . Abou BERTHE
8 . Mamadou DOUMBIA
9. Kevin BRANNAN
1 0 . Richard KABLAN
1 1 . Mouhamed KEBBEH
1 2 . Babou JOBE
1 3 . Cheikh NDIAYE
1 4 . Modou SENE
1 5 . Mateugue DIACK
me--
-.,..
--
----
-.-.W.-*
7
Field Operations during the first year
Field Operations
Dates of Implementation
-
Peanut
Millet
-
Sowing
0712 1
0712 1
15’ weeding
-
08/18
08107
-
-
Thinning
08107
N-P-K application
08119
08/13
-
-
1 st urea application
08/19
-
2”d urea applicatio*l
09/04
-
P. reticulatum application
9/04
9104
2nd weeding
Harvest
P. reticulatum application