EFFECT OF MANURE AND P-SOURCE FERTILIZER ON THE ...
EFFECT OF MANURE AND P-SOURCE FERTILIZER ON THE
OPTINIIZATION OF SOIL WATER ANE) NUTRIENT USE FOR THE
MAIN CROPPING SYSTEM IN SENEGAL PEANUT BASIN
M.SEA?E, M.DIACK, andA. N. BADIANE
T!%A, SENEW ,L
Paper prepared for the fïrst annual workshop of InterCRSP, West
Afi-ica Group.
Kaolack, 1 l-1 4 Jammry 1999
”
_..._ . .-
-..
INTRODUCTION
In the Senegal peanut basin, fallow practices have almost disappeared fi-om the farmers land
use system. This situation is strongly related to the introduction of peanut as a cash cror. but
also results fi-om an increased demand for food crops by an increasing population. The high
pressure on the naturally fragile soils combined with the drought problem observed durin?, the
last 30 years is detrimental to the ammal and perennial vegetation caver. Therefore, through
soi1 organic matter loss and acidification due to continuous cropping andlor grazing, the jood
production system has lost its resilience. In most farmer’s field situations, the degradatio*l of
soi1 water characteristics favors an important deep water percolation beyond the rooting depth,
even under moderate rainfall conditions. This also increases nutrient leaching risks. Manure
applications and plowing are very efficient in reducing the water and nutrients loss through
deep percolation by promoting a rapid trop root grovdh (Cissé, 1986).
Many studies have con&med the efficiency of natural rock phosphate (RP) amendment at an
appplication rate of 400 to 500 kg/ha every 4 to 5 yaars to correct soil P defiencies. (sources
). On sois1 with low pH, the agronomie efficiency of the rock phosphate ran,ges from 82 to 91
% compared with the triple super phosphate (Bationo et al, 1990). This value depends on the
chemical characteristics of the rock phosphate mines for which comparison results of the study
are available (Ndiaye, 1978 ; Cissé, 1980).
However, for phosphogypsum (PG) or the combination of RP and PG IWW being used in
Senegal in the national 4-year prograq there is little information in terms of agronomie L;ilue
or soi1 P and Ca amendment efficiency. The on-going experimentation comparing those ‘:wo
minera1 compound is set to fOcus on that aspect. Assuming a positive effect of the combinal:;on
of RP and PG, the objective of this study is to analyse for the main cropping system:i. rhe
efficiency of appplying combined P source material and manure to a degraded soil to optimize
water and nutrient plant uptake in order to attain a sustainable trop production increase.
.
.--
-- ------
3.-
MATERLALS AND METHODS
Experimental sites
The sites are selected according to the existing main cropping systems.Within the Peanut
Basin. the improvement of food security cari be achieved in three cropping systems. In the
northem part of this agroecological zone, peanut followed by millet is the predominant if not
the unique trop rotation, whereas in the southem part, peanut followed by cor-n is a common
practice. In the low lands of the latter zone, continuous riçe is practiced.
One site for long terme experiment is selected in each of these representive çrop systems : one
site for peanutkrillet rotation at Ouadior (Gossas Department) in the north, two site; for
peanut/corn rotation in Nioro area (one at the ISBA Reseach Station and one on farm field
near the station), and one site for continuous rice in the Koutango valley (west part of the
Nioro Department).
Al1 the selected sites under the upland conditions are çontinously cropped fields with degra ded
soi1 fertility status, as illustrated by Nioro soi1 analyses data (table 1).
‘Table 1 : Soi1 pysical and chemical characteristics (0- 10 cm). Nioro
Tremnents
Five teatments compared are shown in table 2.
For cropping systems where com or rice are involved, plowing is performed when
implementing the treament, including the control. In fact, these two crops require deep tillage
in order to express their potential. For the peanutlmillet system only a shallow hoeing is
applied to prevent fertilizer loss Çom wind blow.
.
-
-.’ ------
Fii 3a: CHANGE iN SOIL WATER CONTENT IN THE PROFJLE
TREATMENTi: comwL
VCXUMETRIC VVATER CONTENT (%)
2
4
6
8
10
12
14
0
I
I
I
-50
Dl : Q7114m
-100
-150
-200
-250
Fg. 3b : CHANGE IN SOIL WATER CONTENT IN THE PROFILE
TREATMENTZ: MAMJRE
VOLUMETRIC SOIL WATER CONTENT (%)
2
6
10
14
I
I
I
i
I
I
I
0
Pi..
-50
Dl : 07/14/lQQS
D2 : 07m1998
D3 : 0#24/198s
h6 -100
D4:oQm/lw8
;
Ds : 1o/l!mBQ8
k
B
-150
D6 : 11/17/19@8
g
-200
-250
-300
Table 12 : Treatment description in the different cropping systems
Treatments
- -_--
_-----
Crop rotation Tl
T 2
T 3
T4
T 5
- - - -
- -
~-
Millet/peanut N K
N P K
O.M.
RP+PG -
-
-
O.M. + RP-PG
- - -
_~
Com/peanut
P + N K P + N P K
P + O.M.
P-;-RP + PG P + O.M. + RP-PG
Continuous
P + N K P + N P K
P + O.M.
!?-;RP + PG P + O.M. + RP-PG
rice
- - -
-
- - - -
N and K for Tl, and N, P and K for T2 are applied annually as urea , ammonium phosphate or
KCI accordingly, the recommended rates are applied for the diEerent crops.
T3 consists of manure application at the rate of 5 tons/ha every two years for the 2 first
çropping systems, and at 3 tons/ha for the continuos rice system, whereas T4 refers to the
application at the rate of 700 kg!ha every four years of RP and PG mix. La$ T5 is the
combination of T3 and T4.
For a11 treaments fiom T3 to T5, N and K have been added on an annual basis prio~ to
sowing. :
The experiment installed at Nioro station in 1997 does not include the T2 treatment, therelore
only four treatments are compared.
The experimental design is a randomized complete bloc design with five treatments repezed
fôur times.
The varieties used for the difberent crops are as follows :
a) for peanut : variety 55-437 at Ouadiour for short cycle duration (maturity at 90 days after
sowing ; variety 73-33 at Nioro sites for 105 DAS or medium cycle ;
b) for com : var. Synthetic C (90 DAS)
c) for rice : upland rice variety DJ-684D (maturity at about 90 DAS). Besides this rice
variety, the farmers was provided with two other sait tolerant varieties (Rock 5, and Var-1 ).
The agronomie behavior of those varieties cultivated according the farmers practices in the
bottom of the valley in submerged conditions have also been evahlated for general
assessment of the Koutango lowlands tith respect to rice production. In the farmer tice
field, six microplots were randomly harvested for lield determinations.
Measurements and monitoring
Sites çharacterization
Soi1 samples have been collected for the characterization of the sites : Ouadiour, on-farm site
at Nioro, and Koutango. For the on-station experiment at Nioro installed in 1997, site
chararacterisation data done in 1995 (Agetip, 1995) are used. Another soi1 sa.mp1in.g was made
aRer the corn harvest in december 1997. All the experirnental plots have been sampled ar the
following depths (O-10, 10-20 and 20-40 cm). Some laboratory analysis data now available are
presented in this report.
Soi1 water balance
This monitoring is done for plant water uptake but also for the pur-pose of nutrient balance.
Soi1 water content in the soil profile is measured 0nc.t: a week at Nioro station site, and once
every ten days elsewhere. Three methods are used : neutron probe, and TDR probe at Nioro
station site, and the auger method elsewhere. Access tubes for neutron probe readings are
installed at the depth of 265 cm ; i.e. deeper than the maximum trop root depths. As for the
TDR method, the probe installation depth is limited by the probe length provided ( 120
cm).Conceming the soil water content measurement method using the auger, the depth of
augering is limited by the wetting fiont as it avances in the profile during the rainy season.
Tensionics are used to determine the soil water suction at the depth supposed to be the
maximum rooting depth which is about 150 cm in sandy soils for peanut (Chopa& 1980). ‘T’he
longest tensionics available are 100 cm long, This exylains the actual field installation depth in
a11 experimental plots : 100 cm for plots having an installed actes tube, and 85 cm for the other
plots. Daily tensionic: readings started in 1998, but late (on september 23 until november 1 1)
due to equipment availabihy.
The water balance monitoririg is not conducted for the on-farm experiment at Diamaguene site
(near Nioro Research Station).
The soi1 water balance equation stated below allows the determination of the soi1 plant
evapotranspiration for spec%ed time increment duram +:he cropping season.
R-D-r+AS=ETR
ft =: ralnfall, D = drainage, r = runoff, AS = variation of stock, and ETR = evapotranspiration.
Al1 these components are in mm of water.
For drainage estimation, the Darcy law will be used. Soil hydraulic: conductivity is calcufated
using existing soil water characteristic studies for Nioro site (Cissé etal, 1990).
- classe A ; A + L = 20 % K(8) = 7.54*ZOg*t313.270
- classe B ; A + L = 21,5 % K(8) = 2.31*10’“*814.5’;
- classe A ; A + L = 20 % K(B) = 6.29*10’“*815.708
where A + L = elay + silt content ; K = hydraulic conductivity ; 8 = volumetric water content.
Darcy’s Law equation Will be used to determine the water drainage.
Nutrient balance
This is closely linked to soil water balance in general, and to soi1 water stock and drainage
components in particular. It requires the use of the tensionics to sample soil solution at
speeified depths. Weekly soi1 solution samples have heen taken, starting late september. The
nutrients of interest analysed are nitrates, ammonium, and Ca. The results are not yet available.
The nutrients lost through drainage, as part of the nutrient balance components. w-i11 be
calculated by multiplying the water drainge and the ehemical concentration of the different
elements analyzed.
Soi1 samples with deph at the biginning and at the eud of each cropping season plant samples
at harvest will be collected for analysis. This Will allow the determination of nutrient dynimics
in root zone and plant nutrient uptake.
Plant sampling
Plant samples were collected at flowering/pegging stage, around 60 days after sowing for foliar
diagrrosis. The sampling fiom each plot occurred alter noticeable leaf chlorosis was observed
7
on few treatment plots. Analysis of the plant samples is done for the following elements : lu, P,
K P, Ca The plant analysis results are presented.
‘E’ield operations
lbe multi-location experiment started in 1997 on two sites ; i.e. Koutango I(continuous rice)
and Nioro (peanutkorn rotation at research station). The other sites were implemented in
1998. The cropping operations are presented (table 3 ).
Table 3 : Field operation scheduling in the three selected sites.
-_--
Nioro
Koutango -
Chtadio&-
- - -
Gperation
COlIl
Peanut
Rice
) Rice
Peanut -
(1997)
(1998) (1997)
1 (1998)
(1998)
-~
RP, PG or Lime 061’30
07/19
- - 08/10
07123
--
application
l
Plowing
06130
06123
07/22
--1 0800
-
--
- - _ -
Sowing
08/05
07/20
07/24
- ’ 08/21
08/5
--
--
- - . -
N-K application
07127
--
i 08/21
08/05
Thinning
08/05
-
07/31
- 09/17
-
--
Pre-emergence
-
08/06
-
weeding
-~
1’ weeding
08122
07127
08/19
-- 09/15
08/15
--
- - _ -
1’ urea pplication
09105
-
08/19
- - 09/17
-
--
- - - -
2”d urea application
09/20
-
09/14
- - 10/02
-
--
!ind weeding
09/10
08/22
09/19
- - lO/Ol
09105
-
--_-
--
Redding
09/10
Harvest
11/3
11/5
11/15
1 Of26
11/5
--
-
Rainfall input
Rainfall patterns are difberent for the 2 years (1997 and 1998) in figure 1.
Fig. Nioro Fig.w Cumulative Rainfali by Decade - 1997 and 1998
140
120 -..
r-1 1 9 9 8
100
E
E
T:0 80
B
.
m
c
.-
60
2P
.-
m
5E
40
3
d
20
0
June
July
August
Sept
Months
Fig.&: Koutango Cumulative Rainfall per Decade - 1998
160
Annual Rainfall: 611 mm
140 -j
120 -_
100 -..
80
60
40
__
20 -_
l
0
1-
-
June
July
August
Sept Oct
Months
Fig. 1 c : Ouadiour Curnulative Rainfall - 1998
180
Annual Rainfall 1998: 391,4 mrss
160
140
Ê
g 120
!
% 100
.
=CO
?j
80
z'Z
$
60
3
40
20
0
June
July
Auyust
Sept
Oct
Mcrnths
In fact, we have experienced one early rainy season in 1997 as opposed to a late rainy seany in
1998. In Nioro, the total annual rainfall is about the same for the 2 cropping seasons (580
mm). However, While the rainy season started early june 1997, the first important rain was
recorded late July 1998. Although characterized by a rather short rainy season, the 1998
cropping season has a much better rainfall distribution. A long drought period (over 30 days)
occurred early during the 1997 cropping season, causing a severe plant water stress, while in
1998 there were no major water stress problem, except at the trop maturity phase.
In Koutango unlike in Nioro or Ouadiour, heavy storms were recorded (160 mm on august 23
1997, and 100 mm on sepember 1998). Eventhough the soil vegetation caver at that time was
well established, a important part of the water from this rainfall event is lest through runoff ;
the soi1 profile being near saturation at this time of the rainy season. This positive aspect of this
is the important input water to refill the Koutango river valley.
Data interpretation
This concerns the yield data, and the nutrients and water data. For most data, ANOVA
tnethods Will be implemented to compare treatement effects, whenever it is possible.
Otherwise, comparison of mean Will be used
Most of the experiments have started in 1998. Therefore, only partial data are available.
RESULTS AND DISCUSSION
a) On-Station experiment at Nioro
The yield components data (corn in 1997, and peanut in 1998) are presented in table 4 For
cor-n, the ANOVA indicates no significant effect on grain yield or stalk, despite the difference
of mean between the control and the other treatments. This is largely do to important
variability within treatments. The cor-n grain yields obtained are low but higher than those
obtained for phosphogypsum efficiency study (also presented in this workshop). It is assurned
that the manure application the key factor to that d.ifTerence. The soils samples collected ficm
a11 plots down to the depth of 40 cm indicates an enrichment of the nutrient content (table 5)
but also a downward movement of elements such as Ca (figure 2)
EL0 z. ’ Exchangeable Ca (meqil00 g soil)
0 . 4
0 . 6
0 . 8
1.0
-10
-t OM
-15
- 2 0
- 2 5
-30
-35
-40
PG + RP
-45
Figure 2. Ca dynamics along the soi1 profile - Corn 1997
Table 5 : Soi1 chemical analysis results afier harvest in 1997. Nioro
-_ ._
‘Samples Soi1 depth pHwater pHKc1 C
a
Mg
S
T- V
Tl cmtrol O-10
10-20
5,2
20-30
5,0
10-20
4,9
4,3
076
0,l
W3
0,X
84,s
20-40
4,9
4,2
078
1323
170
1,2
82,7
For peanut in 1998, the plant population was close to the optimum in a11 plots. The o\\wall
mean yields are good compared to the average jield observed this year. Howeveï, no
significant treatment effect for any yield component was obtained through the ANO‘\\‘A.
Around the middle of the rainy season, plant chlorosis were observed. Plant samples collelzted
on each plot were analysed. The foliar diagnosis results (data not presented) show no
significant Werence between treatments.
Table : yield components at Nioro Station in 1997 anC: 1998
corn 1997
Treatment Stand
TI 16800
‘I-2
33230
- - - -
T3 34690
-_-_-
‘l-4 36420
Mean
30290
Sign.
N S
Level
C V ( % ) 3 2
From the soil water monitoring done dming 1998 growing season, changes in water content in
the profile are shown (figure 3). Two major results cari be drawn fi-om the these figures.
First of all, regardless of the treatment, the water (content values are well below the wzter
saturation values for this type of soi1 (Cissé, 1990 ; Sene, 1995). This could. mean that wster
infiltrated in the soi1 is being used as long as the rains are falling.
Secondly, the wetting front has gone deep in the soi1 profile (below 2 na), SO that w.3t.er
drainage has occurred. Soi]. water balance requit-es then an estimation of the drained water.
b) On-farm experiments
On-farm
--.--
exneriment in the corn/neanut croppinn svstem Near Nioro Station
Yields components are shown in table 6. The plant population lower than that mentioned
above for the on-station experiment is common in farm cropping situation. The ANOVA
performed shows no signifkant treatment effects on peanut yield components.
Table 6: Peanut y-ield for on-farm experiment near Nioro. 1998
Treatment Plant
pod + hay
population
haY
7’1
70620 -
2430
1380
T 2
74270
2290
1260
- - -
7’3
61930 -
1830
1080
7’4
-
71405
-
2430
1340
T5
71400
2260
1310
Mean
69930
2240
1270
Fig 3~ CHANGE IN SOIL WATER CONTENT !N THE PROFILE
TREATMENTI : CONTROL
VOLUMETRIC WATER CONTENT (%)
2
4
6 8
6 8
10
12 14
0
-.----A--I’L -. ._A
-L--.---~ _i.-.-
-50
Dl : 07/‘14/98
D2 :07/20/1998
-100
D3 : 08/24/1998
D4 : 09/28/1998
-150
D5 : 10/1!5/1998
D6 : 1 l/l Y/1998
-200
-250
-300
Fig.3 b : CHANGE IN SOIL WATER CONTENT IN THE PROFILE
TREATMENT2: MANURE
VOLUMETRIC SOIL WATER CONTENT (%)
2
6
10
14
0
I
I
I
I
-L--I~----l.-.--.-
L.~I----.l.-.--.-
-50
Dl : 07/14/1998
Dl :
D2 : 07/20/1998
D2 :
D3 :
D3 OW24ll998
g
-100
04 :
04 09/28/1
:
CM8
D5 : 1 0/15/7
D5 : 1
$98
E
3
-150
D6 : 11/17/1CQ8
D6 :
$
-200
-250
-300
No ma.jor water stress has occurred during the rainy season, ‘due to the good rainfall
distribution. In this degraded soi1 fertility situation of the continuously cropped field (Diack
etal, 1998) the lack of direct effect of P amendment application on peanut could indicate that
nutrients added are not readily available for trop. As for the manure application, the lack of
direct effect confirms research findings indicating that peanut respond better to residual effet.
On-farm exueriment
_-----
a&Ouadiour for the peanut/millet-c,roppiw sv stem
The effect of PG and RP mix and/or manure on yields for the peanut/millet cropping system is
shown (table 7). Despite the fairly good plant population obtained, the yield components
namely hay and peg yields are low. There is no significant effect of the treatments. From the
water balance measurements (data not shown), a ver-j Seep water percolatjon is observed. This
indicates a low water use efficiency which also occurs in the sandy soil.
Table 7: Peanut yield for on-farm experiment at Ouadiour.
Level
I
On-farm
.-_ _.-- experiment & Koutango for the continuous&e cropping_ qslem
in the vallev bottom,
-
-
The yield components obtained using an upland rice variety are shown in table 8. The ANOVA
shows no significant effect of the treatments. The paddy yields values with a mean of about 5
tonsIha show a real rice production potential in the vahey.
The soi1 water profile monitoring indicates a fairly good water availability to trop, (datp not
shown). The water ,table during the cropping season has remained shallow (< 1 m ) (data not
shown). Therefore, chances are that the groundwater through capillary rise participates in ,:lant
water uptake when a drought period occurs.
Table 8: Effect of treatments on Rice Yield (var. DJ-684D) at Koutango. 1998
--_
Treatment
PG-
Paddy
Stalk
Panicle
-
WToflOOgr
population
Fi-
325000
4463
4989
5264
-
2 . 3 2 - ~ -
-1--
~_-----~_-
l-2
316666
4692
5320
5254
2.35
-
-
- -
l-3
350625
4102
4267
4616
-
2.35---
- -
_--
r4
304375
4440
5083
4983
-
2.T---
r5
324791
4006
4286
4481
-
2.3------
Wean
324292
4381
4784
4920
-
2.34-p
-
-
_.---
Sign. L e v e l N S
N S
NS --
NS
- NS
_..-
IV (%)
12.5
18.1
143 -
18.1
-
4 . 8
- -
-
- -
.-_-
CONCLUSION
The long ter-m experiments installed in three difExent cropping systems in the peanut 5asin
address the sustainabilty of the food production increase, by means of the enhancement o!’ soi1
fertility. It is assumed that the key factor there is the optimization of water and nutrien: use.
The results obtained fi-om the first year of implementation must the consideried as the basi\\ for
a necessary continuation of the work underway. For the next cropping season, focus Will be
put on the determination of the diffèrent components of water and nutrient balanc,e. Soi1 water
percolation (drainage) for upland cropping systems and upward water flow in the rice root
zone in the lowland system must be determined as accurately as possible. This poses the
problem of required equipment. The additional needs in that regard concern the tensiometers
for soi1 water pressure monitoring.
OPTINIIZATION OF SOIL WATER ANE) NUTRIENT USE FOR THE
MAIN CROPPING SYSTEM IN SENEGAL PEANUT BASIN
M.SEA?E, M.DIACK, andA. N. BADIANE
T!%A, SENEW ,L
Paper prepared for the fïrst annual workshop of InterCRSP, West
Afi-ica Group.
Kaolack, 1 l-1 4 Jammry 1999
”
_..._ . .-
-..
INTRODUCTION
In the Senegal peanut basin, fallow practices have almost disappeared fi-om the farmers land
use system. This situation is strongly related to the introduction of peanut as a cash cror. but
also results fi-om an increased demand for food crops by an increasing population. The high
pressure on the naturally fragile soils combined with the drought problem observed durin?, the
last 30 years is detrimental to the ammal and perennial vegetation caver. Therefore, through
soi1 organic matter loss and acidification due to continuous cropping andlor grazing, the jood
production system has lost its resilience. In most farmer’s field situations, the degradatio*l of
soi1 water characteristics favors an important deep water percolation beyond the rooting depth,
even under moderate rainfall conditions. This also increases nutrient leaching risks. Manure
applications and plowing are very efficient in reducing the water and nutrients loss through
deep percolation by promoting a rapid trop root grovdh (Cissé, 1986).
Many studies have con&med the efficiency of natural rock phosphate (RP) amendment at an
appplication rate of 400 to 500 kg/ha every 4 to 5 yaars to correct soil P defiencies. (sources
). On sois1 with low pH, the agronomie efficiency of the rock phosphate ran,ges from 82 to 91
% compared with the triple super phosphate (Bationo et al, 1990). This value depends on the
chemical characteristics of the rock phosphate mines for which comparison results of the study
are available (Ndiaye, 1978 ; Cissé, 1980).
However, for phosphogypsum (PG) or the combination of RP and PG IWW being used in
Senegal in the national 4-year prograq there is little information in terms of agronomie L;ilue
or soi1 P and Ca amendment efficiency. The on-going experimentation comparing those ‘:wo
minera1 compound is set to fOcus on that aspect. Assuming a positive effect of the combinal:;on
of RP and PG, the objective of this study is to analyse for the main cropping system:i. rhe
efficiency of appplying combined P source material and manure to a degraded soil to optimize
water and nutrient plant uptake in order to attain a sustainable trop production increase.
.
.--
-- ------
3.-
MATERLALS AND METHODS
Experimental sites
The sites are selected according to the existing main cropping systems.Within the Peanut
Basin. the improvement of food security cari be achieved in three cropping systems. In the
northem part of this agroecological zone, peanut followed by millet is the predominant if not
the unique trop rotation, whereas in the southem part, peanut followed by cor-n is a common
practice. In the low lands of the latter zone, continuous riçe is practiced.
One site for long terme experiment is selected in each of these representive çrop systems : one
site for peanutkrillet rotation at Ouadior (Gossas Department) in the north, two site; for
peanut/corn rotation in Nioro area (one at the ISBA Reseach Station and one on farm field
near the station), and one site for continuous rice in the Koutango valley (west part of the
Nioro Department).
Al1 the selected sites under the upland conditions are çontinously cropped fields with degra ded
soi1 fertility status, as illustrated by Nioro soi1 analyses data (table 1).
‘Table 1 : Soi1 pysical and chemical characteristics (0- 10 cm). Nioro
Tremnents
Five teatments compared are shown in table 2.
For cropping systems where com or rice are involved, plowing is performed when
implementing the treament, including the control. In fact, these two crops require deep tillage
in order to express their potential. For the peanutlmillet system only a shallow hoeing is
applied to prevent fertilizer loss Çom wind blow.
.
-
-.’ ------
Fii 3a: CHANGE iN SOIL WATER CONTENT IN THE PROFJLE
TREATMENTi: comwL
VCXUMETRIC VVATER CONTENT (%)
2
4
6
8
10
12
14
0
I
I
I
-50
Dl : Q7114m
-100
-150
-200
-250
Fg. 3b : CHANGE IN SOIL WATER CONTENT IN THE PROFILE
TREATMENTZ: MAMJRE
VOLUMETRIC SOIL WATER CONTENT (%)
2
6
10
14
I
I
I
i
I
I
I
0
Pi..
-50
Dl : 07/14/lQQS
D2 : 07m1998
D3 : 0#24/198s
h6 -100
D4:oQm/lw8
;
Ds : 1o/l!mBQ8
k
B
-150
D6 : 11/17/19@8
g
-200
-250
-300
Table 12 : Treatment description in the different cropping systems
Treatments
- -_--
_-----
Crop rotation Tl
T 2
T 3
T4
T 5
- - - -
- -
~-
Millet/peanut N K
N P K
O.M.
RP+PG -
-
-
O.M. + RP-PG
- - -
_~
Com/peanut
P + N K P + N P K
P + O.M.
P-;-RP + PG P + O.M. + RP-PG
Continuous
P + N K P + N P K
P + O.M.
!?-;RP + PG P + O.M. + RP-PG
rice
- - -
-
- - - -
N and K for Tl, and N, P and K for T2 are applied annually as urea , ammonium phosphate or
KCI accordingly, the recommended rates are applied for the diEerent crops.
T3 consists of manure application at the rate of 5 tons/ha every two years for the 2 first
çropping systems, and at 3 tons/ha for the continuos rice system, whereas T4 refers to the
application at the rate of 700 kg!ha every four years of RP and PG mix. La$ T5 is the
combination of T3 and T4.
For a11 treaments fiom T3 to T5, N and K have been added on an annual basis prio~ to
sowing. :
The experiment installed at Nioro station in 1997 does not include the T2 treatment, therelore
only four treatments are compared.
The experimental design is a randomized complete bloc design with five treatments repezed
fôur times.
The varieties used for the difberent crops are as follows :
a) for peanut : variety 55-437 at Ouadiour for short cycle duration (maturity at 90 days after
sowing ; variety 73-33 at Nioro sites for 105 DAS or medium cycle ;
b) for com : var. Synthetic C (90 DAS)
c) for rice : upland rice variety DJ-684D (maturity at about 90 DAS). Besides this rice
variety, the farmers was provided with two other sait tolerant varieties (Rock 5, and Var-1 ).
The agronomie behavior of those varieties cultivated according the farmers practices in the
bottom of the valley in submerged conditions have also been evahlated for general
assessment of the Koutango lowlands tith respect to rice production. In the farmer tice
field, six microplots were randomly harvested for lield determinations.
Measurements and monitoring
Sites çharacterization
Soi1 samples have been collected for the characterization of the sites : Ouadiour, on-farm site
at Nioro, and Koutango. For the on-station experiment at Nioro installed in 1997, site
chararacterisation data done in 1995 (Agetip, 1995) are used. Another soi1 sa.mp1in.g was made
aRer the corn harvest in december 1997. All the experirnental plots have been sampled ar the
following depths (O-10, 10-20 and 20-40 cm). Some laboratory analysis data now available are
presented in this report.
Soi1 water balance
This monitoring is done for plant water uptake but also for the pur-pose of nutrient balance.
Soi1 water content in the soil profile is measured 0nc.t: a week at Nioro station site, and once
every ten days elsewhere. Three methods are used : neutron probe, and TDR probe at Nioro
station site, and the auger method elsewhere. Access tubes for neutron probe readings are
installed at the depth of 265 cm ; i.e. deeper than the maximum trop root depths. As for the
TDR method, the probe installation depth is limited by the probe length provided ( 120
cm).Conceming the soil water content measurement method using the auger, the depth of
augering is limited by the wetting fiont as it avances in the profile during the rainy season.
Tensionics are used to determine the soil water suction at the depth supposed to be the
maximum rooting depth which is about 150 cm in sandy soils for peanut (Chopa& 1980). ‘T’he
longest tensionics available are 100 cm long, This exylains the actual field installation depth in
a11 experimental plots : 100 cm for plots having an installed actes tube, and 85 cm for the other
plots. Daily tensionic: readings started in 1998, but late (on september 23 until november 1 1)
due to equipment availabihy.
The water balance monitoririg is not conducted for the on-farm experiment at Diamaguene site
(near Nioro Research Station).
The soi1 water balance equation stated below allows the determination of the soi1 plant
evapotranspiration for spec%ed time increment duram +:he cropping season.
R-D-r+AS=ETR
ft =: ralnfall, D = drainage, r = runoff, AS = variation of stock, and ETR = evapotranspiration.
Al1 these components are in mm of water.
For drainage estimation, the Darcy law will be used. Soil hydraulic: conductivity is calcufated
using existing soil water characteristic studies for Nioro site (Cissé etal, 1990).
- classe A ; A + L = 20 % K(8) = 7.54*ZOg*t313.270
- classe B ; A + L = 21,5 % K(8) = 2.31*10’“*814.5’;
- classe A ; A + L = 20 % K(B) = 6.29*10’“*815.708
where A + L = elay + silt content ; K = hydraulic conductivity ; 8 = volumetric water content.
Darcy’s Law equation Will be used to determine the water drainage.
Nutrient balance
This is closely linked to soil water balance in general, and to soi1 water stock and drainage
components in particular. It requires the use of the tensionics to sample soil solution at
speeified depths. Weekly soi1 solution samples have heen taken, starting late september. The
nutrients of interest analysed are nitrates, ammonium, and Ca. The results are not yet available.
The nutrients lost through drainage, as part of the nutrient balance components. w-i11 be
calculated by multiplying the water drainge and the ehemical concentration of the different
elements analyzed.
Soi1 samples with deph at the biginning and at the eud of each cropping season plant samples
at harvest will be collected for analysis. This Will allow the determination of nutrient dynimics
in root zone and plant nutrient uptake.
Plant sampling
Plant samples were collected at flowering/pegging stage, around 60 days after sowing for foliar
diagrrosis. The sampling fiom each plot occurred alter noticeable leaf chlorosis was observed
7
on few treatment plots. Analysis of the plant samples is done for the following elements : lu, P,
K P, Ca The plant analysis results are presented.
‘E’ield operations
lbe multi-location experiment started in 1997 on two sites ; i.e. Koutango I(continuous rice)
and Nioro (peanutkorn rotation at research station). The other sites were implemented in
1998. The cropping operations are presented (table 3 ).
Table 3 : Field operation scheduling in the three selected sites.
-_--
Nioro
Koutango -
Chtadio&-
- - -
Gperation
COlIl
Peanut
Rice
) Rice
Peanut -
(1997)
(1998) (1997)
1 (1998)
(1998)
-~
RP, PG or Lime 061’30
07/19
- - 08/10
07123
--
application
l
Plowing
06130
06123
07/22
--1 0800
-
--
- - _ -
Sowing
08/05
07/20
07/24
- ’ 08/21
08/5
--
--
- - . -
N-K application
07127
--
i 08/21
08/05
Thinning
08/05
-
07/31
- 09/17
-
--
Pre-emergence
-
08/06
-
weeding
-~
1’ weeding
08122
07127
08/19
-- 09/15
08/15
--
- - _ -
1’ urea pplication
09105
-
08/19
- - 09/17
-
--
- - - -
2”d urea application
09/20
-
09/14
- - 10/02
-
--
!ind weeding
09/10
08/22
09/19
- - lO/Ol
09105
-
--_-
--
Redding
09/10
Harvest
11/3
11/5
11/15
1 Of26
11/5
--
-
Rainfall input
Rainfall patterns are difberent for the 2 years (1997 and 1998) in figure 1.
Fig. Nioro Fig.w Cumulative Rainfali by Decade - 1997 and 1998
140
120 -..
r-1 1 9 9 8
100
E
E
T:0 80
B
.
m
c
.-
60
2P
.-
m
5E
40
3
d
20
0
June
July
August
Sept
Months
Fig.&: Koutango Cumulative Rainfall per Decade - 1998
160
Annual Rainfall: 611 mm
140 -j
120 -_
100 -..
80
60
40
__
20 -_
l
0
1-
-
June
July
August
Sept Oct
Months
Fig. 1 c : Ouadiour Curnulative Rainfall - 1998
180
Annual Rainfall 1998: 391,4 mrss
160
140
Ê
g 120
!
% 100
.
=CO
?j
80
z'Z
$
60
3
40
20
0
June
July
Auyust
Sept
Oct
Mcrnths
In fact, we have experienced one early rainy season in 1997 as opposed to a late rainy seany in
1998. In Nioro, the total annual rainfall is about the same for the 2 cropping seasons (580
mm). However, While the rainy season started early june 1997, the first important rain was
recorded late July 1998. Although characterized by a rather short rainy season, the 1998
cropping season has a much better rainfall distribution. A long drought period (over 30 days)
occurred early during the 1997 cropping season, causing a severe plant water stress, while in
1998 there were no major water stress problem, except at the trop maturity phase.
In Koutango unlike in Nioro or Ouadiour, heavy storms were recorded (160 mm on august 23
1997, and 100 mm on sepember 1998). Eventhough the soil vegetation caver at that time was
well established, a important part of the water from this rainfall event is lest through runoff ;
the soi1 profile being near saturation at this time of the rainy season. This positive aspect of this
is the important input water to refill the Koutango river valley.
Data interpretation
This concerns the yield data, and the nutrients and water data. For most data, ANOVA
tnethods Will be implemented to compare treatement effects, whenever it is possible.
Otherwise, comparison of mean Will be used
Most of the experiments have started in 1998. Therefore, only partial data are available.
RESULTS AND DISCUSSION
a) On-Station experiment at Nioro
The yield components data (corn in 1997, and peanut in 1998) are presented in table 4 For
cor-n, the ANOVA indicates no significant effect on grain yield or stalk, despite the difference
of mean between the control and the other treatments. This is largely do to important
variability within treatments. The cor-n grain yields obtained are low but higher than those
obtained for phosphogypsum efficiency study (also presented in this workshop). It is assurned
that the manure application the key factor to that d.ifTerence. The soils samples collected ficm
a11 plots down to the depth of 40 cm indicates an enrichment of the nutrient content (table 5)
but also a downward movement of elements such as Ca (figure 2)
EL0 z. ’ Exchangeable Ca (meqil00 g soil)
0 . 4
0 . 6
0 . 8
1.0
-10
-t OM
-15
- 2 0
- 2 5
-30
-35
-40
PG + RP
-45
Figure 2. Ca dynamics along the soi1 profile - Corn 1997
Table 5 : Soi1 chemical analysis results afier harvest in 1997. Nioro
-_ ._
‘Samples Soi1 depth pHwater pHKc1 C
a
Mg
S
T- V
Tl cmtrol O-10
10-20
5,2
20-30
5,0
10-20
4,9
4,3
076
0,l
W3
0,X
84,s
20-40
4,9
4,2
078
1323
170
1,2
82,7
For peanut in 1998, the plant population was close to the optimum in a11 plots. The o\\wall
mean yields are good compared to the average jield observed this year. Howeveï, no
significant treatment effect for any yield component was obtained through the ANO‘\\‘A.
Around the middle of the rainy season, plant chlorosis were observed. Plant samples collelzted
on each plot were analysed. The foliar diagnosis results (data not presented) show no
significant Werence between treatments.
Table : yield components at Nioro Station in 1997 anC: 1998
corn 1997
Treatment Stand
TI 16800
‘I-2
33230
- - - -
T3 34690
-_-_-
‘l-4 36420
Mean
30290
Sign.
N S
Level
C V ( % ) 3 2
From the soil water monitoring done dming 1998 growing season, changes in water content in
the profile are shown (figure 3). Two major results cari be drawn fi-om the these figures.
First of all, regardless of the treatment, the water (content values are well below the wzter
saturation values for this type of soi1 (Cissé, 1990 ; Sene, 1995). This could. mean that wster
infiltrated in the soi1 is being used as long as the rains are falling.
Secondly, the wetting front has gone deep in the soi1 profile (below 2 na), SO that w.3t.er
drainage has occurred. Soi]. water balance requit-es then an estimation of the drained water.
b) On-farm experiments
On-farm
--.--
exneriment in the corn/neanut croppinn svstem Near Nioro Station
Yields components are shown in table 6. The plant population lower than that mentioned
above for the on-station experiment is common in farm cropping situation. The ANOVA
performed shows no signifkant treatment effects on peanut yield components.
Table 6: Peanut y-ield for on-farm experiment near Nioro. 1998
Treatment Plant
pod + hay
population
haY
7’1
70620 -
2430
1380
T 2
74270
2290
1260
- - -
7’3
61930 -
1830
1080
7’4
-
71405
-
2430
1340
T5
71400
2260
1310
Mean
69930
2240
1270
Fig 3~ CHANGE IN SOIL WATER CONTENT !N THE PROFILE
TREATMENTI : CONTROL
VOLUMETRIC WATER CONTENT (%)
2
4
6 8
6 8
10
12 14
0
-.----A--I’L -. ._A
-L--.---~ _i.-.-
-50
Dl : 07/‘14/98
D2 :07/20/1998
-100
D3 : 08/24/1998
D4 : 09/28/1998
-150
D5 : 10/1!5/1998
D6 : 1 l/l Y/1998
-200
-250
-300
Fig.3 b : CHANGE IN SOIL WATER CONTENT IN THE PROFILE
TREATMENT2: MANURE
VOLUMETRIC SOIL WATER CONTENT (%)
2
6
10
14
0
I
I
I
I
-L--I~----l.-.--.-
L.~I----.l.-.--.-
-50
Dl : 07/14/1998
Dl :
D2 : 07/20/1998
D2 :
D3 :
D3 OW24ll998
g
-100
04 :
04 09/28/1
:
CM8
D5 : 1 0/15/7
D5 : 1
$98
E
3
-150
D6 : 11/17/1CQ8
D6 :
$
-200
-250
-300
No ma.jor water stress has occurred during the rainy season, ‘due to the good rainfall
distribution. In this degraded soi1 fertility situation of the continuously cropped field (Diack
etal, 1998) the lack of direct effect of P amendment application on peanut could indicate that
nutrients added are not readily available for trop. As for the manure application, the lack of
direct effect confirms research findings indicating that peanut respond better to residual effet.
On-farm exueriment
_-----
a&Ouadiour for the peanut/millet-c,roppiw sv stem
The effect of PG and RP mix and/or manure on yields for the peanut/millet cropping system is
shown (table 7). Despite the fairly good plant population obtained, the yield components
namely hay and peg yields are low. There is no significant effect of the treatments. From the
water balance measurements (data not shown), a ver-j Seep water percolatjon is observed. This
indicates a low water use efficiency which also occurs in the sandy soil.
Table 7: Peanut yield for on-farm experiment at Ouadiour.
Level
I
On-farm
.-_ _.-- experiment & Koutango for the continuous&e cropping_ qslem
in the vallev bottom,
-
-
The yield components obtained using an upland rice variety are shown in table 8. The ANOVA
shows no significant effect of the treatments. The paddy yields values with a mean of about 5
tonsIha show a real rice production potential in the vahey.
The soi1 water profile monitoring indicates a fairly good water availability to trop, (datp not
shown). The water ,table during the cropping season has remained shallow (< 1 m ) (data not
shown). Therefore, chances are that the groundwater through capillary rise participates in ,:lant
water uptake when a drought period occurs.
Table 8: Effect of treatments on Rice Yield (var. DJ-684D) at Koutango. 1998
--_
Treatment
PG-
Paddy
Stalk
Panicle
-
WToflOOgr
population
Fi-
325000
4463
4989
5264
-
2 . 3 2 - ~ -
-1--
~_-----~_-
l-2
316666
4692
5320
5254
2.35
-
-
- -
l-3
350625
4102
4267
4616
-
2.35---
- -
_--
r4
304375
4440
5083
4983
-
2.T---
r5
324791
4006
4286
4481
-
2.3------
Wean
324292
4381
4784
4920
-
2.34-p
-
-
_.---
Sign. L e v e l N S
N S
NS --
NS
- NS
_..-
IV (%)
12.5
18.1
143 -
18.1
-
4 . 8
- -
-
- -
.-_-
CONCLUSION
The long ter-m experiments installed in three difExent cropping systems in the peanut 5asin
address the sustainabilty of the food production increase, by means of the enhancement o!’ soi1
fertility. It is assumed that the key factor there is the optimization of water and nutrien: use.
The results obtained fi-om the first year of implementation must the consideried as the basi\\ for
a necessary continuation of the work underway. For the next cropping season, focus Will be
put on the determination of the diffèrent components of water and nutrient balanc,e. Soi1 water
percolation (drainage) for upland cropping systems and upward water flow in the rice root
zone in the lowland system must be determined as accurately as possible. This poses the
problem of required equipment. The additional needs in that regard concern the tensiometers
for soi1 water pressure monitoring.