Nutrient Constraints in a Sahel Valley Land For Irrigated Rice Cultivation
Transcript of Nutrient Constraints in a Sahel Valley Land For Irrigated Rice Cultivation
Koné et al., / Advances in Applied Agricultural Science 03 (2015), 02: 65-74
65
ARTICLE INFO
ABSTRACT
Article history: Received: August 20, 2014
Revised: December 02, 2014
Accepted: December 05, 2015
Available online February 23, 2015
Missing tool for site specific nutrient management can impaired the sustainability of
rice (Oryza sativa L.) production. To improve knowledge of nutrient constraints in
irrigated plain of the Sahel zone in West Africa, an omission trial was conducted in
2007 and 2008 in Baguenida (Mali). The experiment design was a randomized
complete block consisting of complete fertilizer treatment-Fc (nitrogen [N],
phosphorus [P], potassium [K], calcium [Ca], magnesium [Mg] and zinc [Zn]) and
treatments with specific nutrient excluded from the complete fertilizer treatment (Fc-
N, Fc-P, Fc-K, Fc-Ca, Fc-Mg and Fc-Zn) with four replications. Respective rates of 30
kg N ha-1, 100 kg P ha-1, 50 K kg ha-1, 50 kg Ca ha-1, 50 kg Mg ha-1 and 10 kg Zn ha-1
were applied as basal fertilizer. Rice variety WITA 12 was used and additional rate of
urea was applied at 35 kg N ha-1 at rice tillering and panicle initiation stages excluding
Fc-N and the control (no fertilizer). Results revealed significant (P<0.05) decreasing
effect of N and Ca deficiencies on the grain yield and additional effects of K and Zn
deficiencies occurring occasionally. A synergistic interaction of soil nutrients and the
change of soil pH after flooding were likely to be useful tools for irrigated soil fertility
management in a way of sustainable rice production in the irrigated plain of Sahel in
West Africa.
© 2015 AAAS Journal. All rights reserved.
Keywords:
Fertilizer
Irrigated plain
Rice yield
Sahel
Soil nutrient deficiency
* Corresponding Author; E. Mail: [email protected]
Tel: +225 06546189
n West Africa, the declining rainfall (Barnett
& Schlesinger, 2012) is reinforcing the
suitability of lowlands for crop production due
to preferential drainage of surface water in this ecology
as compared to upland: Lowlands have higher potential
for rice production (6 t ha-1) compared with the
production of the upland (1 t ha-1) though it represents
only about 5% to 10% of the total land surveyed in Africa
(Giertz et al., 2012). Therefore, the restriction of lowland
area can limit rice production. Thus, the use of lowland
areas should be optimized for the needs of the sub-region
(Harsh, 2004). To achieve this, strengthening water, land
and soil fertility management strategies are required.
I
Advances in Applied Agricultural Science
Volume 03 (2015), Issue 02, 65-74
Journal homepage: www.aaasjournal.com
ISSN: 2383-4234
Research Article
Nutrient Constraints in a Sahel Valley Land for Irrigated Rice Cultivation
Brahima Koné 1*, N’guessan Kouamé Antoine 2, Touré Natari 1, Doumbia Yacouba 3, Sié Moussa 4
1 Soil Science department, Earth Science Unit, Felix Houphouet Boigny University, Cocody, 22 BP 582 Abidjan 22, Côte d’Ivoire.
. 2 Biology Science department, Peleforo Gon Coulibaly University, Korhogo, Biology Sciences, BP 1328 Korhogo. Côte d’Ivoire.
. 3 Agronomy department, Institue d’Economie Appliquée-IER, BP 16 CRRA, Sikasso, Mali.
. 4 Lowland rice breeding, Africa Rice Center, 01 BP 2031 Cotonou, Bénin.
.
Koné et al., / Advances in Applied Agricultural Science 03 (2015), 02: 65-74
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Most of the studies conducted in the inland valleys
(including lowland) of West Africa are related to agro-
ecological characterization (Ogban & Babalola, 2009),
impact of irrigation on rice productivity (Kebbeh et al.,
2003) and rice response to fertilizer (Segda et al., 2005).
The characterization of soil from irrigated plains in West
Africa showed low C, N, P, Ca and Mg contents (Buri et
al., 2010). Apart from Zn deficiency and iron toxicity in
rice production in the valley of Niger River
(Hägnesten,2006), there is scant evidence of soil nutrient
constraints on rice production inland valleys, especially,
for the irrigated plains of the Sahel zone as early
mentioned by Haefele et al. (2002). Indeed, existing data
collected from the temporarily flooded lowlands of the
humid zone in West Africa (Buri et al., 2010; Abe et al.,
2010) cannot be extrapolated to irrigated plains due to
the effect of submersion on soil properties and soil
nutrient flows in rice roots (Le Mer & Roger, 2001):
water displaces oxygen and CO2, affecting redox
conditions in soil with negative consequences for rice
growth (Thein, 2004). Furthermore, difference in climate
effects can be of concern from the humid zone to the
Sahel ecology. The use of soil testing (chemical analysis)
and rice yield for a specific fertilizer treatment can
underline site specific soil nutrient constraints on rice
production as illustrated for upland rice in the derived
savanna zone across the Dahomey gap of West Africa
(Koné et al., 2009; 2011) as well as in the humid forest
zone (Koné et al., 2013; 2014).
The current study was therefore conducted on the
irrigated plain of the Niger River at Baguenida (Mali) to
judge the level of deficiency of some soil major nutrients
(N, P, K, Ca, Mg and Zn) for rice production. The
objective was to identify the required nutrients for
sustainable rice production in an irrigated plain of the
Sahel zone in West Africa.
Materials and Methods
Experimental Site
Baguenida (12º35´05.89´´N; 7º42´05.40´´W; 357 m) is
located 30 km East of Bamako (Mali) on the plain of the
Niger River. It is within the Sahel zone where the
cropping period duration is 90 days with about 800 mm
total annual rainfall amount. The experiment was
conducted in an irrigated plain (2450 ha) along the Niger
River. The experimental site was established 200 m from
the valley fringe. It was preceded by two years fallow
period having vegetation composed exclusively by
annual grasses (Ischaemum rugosum Salisb.,
Echinochloa colona (L.) Link and Oryza barthii A.
Chev.). The soil was a Fluvisol having a loamy sandy
texture (40% sand; 35 % silt and 25 % clay) in the
surface soil depth (0 – 20 cm).
Experiment Layout
In 2007, the land was cleaned, flooded, ploughed and
manually leveled. A randomized complete block design
with four replications and eight treatments was laid out.
Plot size was 3 m × 5 m with spacing of 0.75 m between
plots and a distance of 1.5 m was maintained between
blocks as replications.
Each plot as well as the complete blocks were bunded
(0.30 m high, 0.20 m wide). Irrigation (0.20 m depth) and
drainage (0.20 m depth) canals were also made. A
complete fertilizer treatment (Fc) composed of nitrogen
(N), phosphorus (P), potassium (K), calcium (Ca),
magnesium (Mg) and zinc (Zn) was used. A specific
nutrient was excluded from Fc in each of other
treatments (Fc-N, Fc-P, Fc-K, Fc-Ca, Fc-Mg and Fc-Zn).
A non-fertilized treatment (0) was used as the control.
Fertilizers were applied as basal fertilizer according to
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Dobermann and Fairhust (2000), at rates of 30 kg N ha-
1 (Urea), 100 kg P ha-1 (Super triple phosphate), 50 kg K
ha-1 (potassium chloride) and 10 kg Zn ha-1 (zinc sulfite).
The rates of 250 kg ha-1 were applied as magnesium
sulfate (20% Mg) and calcium sulfate (23% Ca)
respectively. Each micro-plot was re-ploughed before
the transplanting rice of 21 days old seedling. One of the
popular, locally-adopted rice varieties, WITA 12, was
used. Additional urea was applied at a rate of 35 kg N ha-
1 as top dressing at maximum tillering stage (21 days
after transplanting-DAT) and again at panicle initiation
of rice (40 DAT) respectively excluding the treatments
Fc-N and the control. About 5-15 mm of water depth was
maintained weekly from transplanting to heading, and
the water was drained off field 2 days before applying N-
fertilizer (21 DAT and 40 DAT) and ten days before the
harvest.
Soil Sampling and Analysis
Soil samples were taken at 0 – 20 cm depth using an
auger before (2007) fertilizer application. Five samples
were taken in the four corners and the centre of every plot
for 3 kg of composite sample. A total of 32 composite
samples were taken for analysis of soil pH (water), soil
content in organic carbon (C), total nitrogen (N),
available phosphorus (P) and free iron using the methods
described by the International Institute of Tropical
Agriculture (IITA,1989).
Data Collection
At 30 DAT, the total number of tillers was counted
within in one square meter (1 m2) of each plot. Plant
height and panicle number were also collected at rice
maturity. The plot size harvested was 8 m2, with two
border lines eliminated from each side of the plot in order
to avoid a border effect. The rice was threshed and the
grains were sun dried and weighed. The moisture content
of the grain was measured and grain yield (GY) was
determined at 14% of moisture content.
Statistical Analysis
General linear model (GLM) analysis was used to
generate effect of the treatment on the grain yield and to
generate the mean values of grain yield obtained in each
treatment per year. The average mean of grain yield of
the two years experiment was also generated through
analysis of variance. In the same manner, means plant
height, tiller and panicle numbers per square meter were
determined. The least significant difference (LSD.05) was
used to separate the mean values. Existing synergistic or
antagonistic relationships between rice grain yield
production and the native soil contents of C, N, P and Fe
as well as with soil pH were explored in each treatment.
For this purpose, Pearson correlation analysis was used.
SAS software (SAS, 2001) was used for all statistical
analyses.
Results
Treatment Effects on Rice growth and Yield
No significant difference was observed between the
mean values of plant height (1.10 to 1.20 m) per
treatment meanwhile, the rice height was almost twice
higher in the treatments Fc-Zn and Fc-N than Fc-Ca, Fc-
Mg and the control plots as illustrated by a sharp
decreasing trend observed in Figure 1. But, there was
significant difference in treatment effects during the
tillering stage as noticed in Figure 2: Extreme values of
tiller numbers accounted for treatments Fc-Zn and the
control as highest and lowest values respectively while,
moderate effects were observed for treatments Fc-Ca and
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Table 1. The grain yields per treatment in 2007 and 2008 and the average mean grain yield for the year’s
period. Grain yields (t ha-1)
Treatments 2007 2008 Mean
Fc-Zn 3.55aA 3.46bA 3.50ab
Fc-Mg 3.29aA 3.66abA 3.47ab
Fc 3.28aA 3.49abA 3.39abc
Fc-Ca 3.24aA 2.84cA 3.04c
Fc-K 3.18aA 3.44bA 3.31abc
Fc-P 3.10aB 3.99aA 3.54a
Fc-N 2.43bB 3.73abA 3.08bc
Control 2.20bA 1.78dA 2.00d
GM (t ha-1)
LSD.05
P>F
3.03A
0.521
0.0003
3.30A
0.519
<0.0001
3.16
0.432
<0.0001
a, b, c and d: significant different mean values according to the LSD value in column as A and B in the line
between the two years.
Table 2. Chemical characterization of soil (0 – 20 cm depth) in each treatment plot
Plots pHw C
(g kg-1)
N
(g kg-1)
P
(mg kg-1)
Fe
(cmol kg-1)
Fc Mean 5.1 4.2 0.3 23.2 77
SE (4) 0.34 2.04 0.04 5.32 19.25
Fc-Ca Mean 5.1 4.9 0.3 18.7 49.2
SE (4) 0.37 0.92 0.07 5.37 14.27
Fc-K Mean 5.3 4.5 0.2 20.5 48.7
SE (4) 0.25 1.79 0.04 3.28 17.3
Fc-Mg Mean 5.3 4.3 0.2 17.5 43.2
SE (4) 0.36 1.33 0.02 1.55 15.52
Fc-N Mean 5.1 5.5 0.3 25.0 67.5
SE (4) 0.25 1.07 0.04 4.02 17.58
Fc-P Mean 5.3 5.0 0.27 22.5 66
SE (4) 0.22 0.81 0.02 4.25 18.94
Fc-Zn Mean 5.2 5.0 0.3 23.0 60.2
SE (4) 0.20 0.54 0.04 4.02 16.03
Control Mean 5.2 3.9 0.3 16.0 60.7
SE (4) 0.25 1.07 0.04 1.73 7.53
SE : Standard error; (4): sample size
Fig 1. Across years mean values of plant height per treatment (Letter “a”
is indicating no significant different between mean values).
Koné et al., / Advances in Applied Agricultural Science 03 (2015), 02: 65-74
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Fc-Mg and the number of tillers was reduced in treatment
Fc-P close to that of the control plot. Similar trend was
observed for panicle numbers as induced by treatments
with major difference in treatment Fc-P which induced
moderate panicle number (Figure 3) contrasting with the
tiller number previously presented.
Treatment Fc-Zn presented the highest effect on rice
vegetative development among the studied treatments
indifferently to the parameters (height, tillers and
panicles) considered.
Treatments Effects on the Yields
In 2007, the results (Table 1) showed significantly (P =
0.0003) similar lower yields in the treatment Fc-N (2.43
t ha-1) and the control treatment (2.20 t ha-1). The highest
yields were observed in the range of 3.10 t ha-1 (Fc-P) to
3.55 t ha-1 (Fc-Zn) contrasting with the results observed
in 2008 for treatments Fc-Zn (3.46 t ha-1) and Fc-K (3.44
t ha-1) characterized by yield reduction. Lowest yields
were obtained in the control treatment (1.78 t ha-1)
followed by treatment Fc-Ca (2.84 t ha-1). The yield
observed in treatment Fc-P (3.99 t ha-1) still remained
high in 2008 while treatment Fc-N (3.73 t ha-1) did not
induce significant yield decrease as observed in 2007:
The yields were significantly increased in both
treatments (Fc-P and Fc-N) from 2007 to 2007. Despite
of this increasing trend of grain yield in treatment Fc-N,
its overall grain yield (3.08 t ha-1) accounted among the
lowest similarly with the treatment Fc-Ca (3.04 t ha-1)
when excluding the control treatment (2.00 tha-1).
Indeed, the initial soil pH was low (< 5.5) indifferently
to the plots of which, Fc-N and Fc-Ca showed the lowest
values (5.1). In contrast, soil contents of available P (>
10 mg kg-1) and C (> 1 g kg-1) were ranging in acceptable
ranges for most of the crop growing (Table 2). There was
also interaction between soil nutrients with consequence
on rice grain yield: Significantly (P<0.10) higher
positive coefficients of Pearson correlation are observed
in the plots Fc (0.92) and Fc-N (0.93) between soil pH
and the grain yield in 2007 (Table 3). Similar
observations can be made in the treatment Fc-Mg for soil
contents of N (0.96) and P (0.94) as well as in treatment
Fc-N for soil content of N (0.93).
Discussion
Treatment Effects on Rice Growth as Affected by Sahel
Ecology
No significant difference was observed between the
mean values of plant height meanwhile, it has been
reported leaf chlorosis and plant height reduction should
have occurred in N-deficient (Fc-N) condition
(Dingkuhn et al., 1992). This was not the case, however,
in Sahelian conditions studied. The intensity of daylight
and/or photoperiodism characterizing this ecology
(Seaquist & Olsson, 1999) may have contributed to this.
Indeed, environment factors affect plant mineral
nutrition requirement as well as the symptoms of nutrient
deficiency (Ames & Johnson, 2013). However, these
processes are not well documented enough for rice
cultivation, especially in West Africa.
Despite the high content of P (22.5 mg kg-1) in the soil of
treatment Fc-P, a significant reduction of the plant tillers
number was observed as compared to Fc-Zn (Figure 2).
This is a typical symptom of P-deficiency as described
by Dobermann and Fairhust (2000) allowing the
suspicion of a certain level of P-deficiency in the studied
soil. However, this observation was not reflected by the
grain yield.
The highest significant tiller (Figure 2) and panicle
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(Figure 3) numbers that were observed in the Fc-Zn
treatment were contrasting with the work done by
Dobermann & Fairhust (2000) in Philippines. Ecological
differences may have contributed to the differences
observed.
These results are supported by the study done by Makino
(2011) showing the effect of climate on photosynthesis
of rice. Furthermore, Lawlor (2002) stated that
environmental conditions can affect the growth
characteristics and nitrogen response of a crop. Our study
highlighted some differences in N and Zn effects on rice
growth in the Sahel zone of West Africa compared with
existing knowledge of studies performed in Asia.
Nevertheless, S released by fertilizer materials including
magnesium sulphate and calcium sulphate could have
interacted with the indigenous-N for mitigating N
deficiency as reported by Choudhury et al. (2009).
Flooding as Key Practice in Rice Production
There was yield increasing for treatments Fc-P and Fc-N
Fig 2. Across years mean values of tiller number in a square meter per
treatment (a, b and c are indicating mean values with significant
difference).
Fig 3. Across years mean values of rice panicle number in a square meter
per treatment (different letters (a and b) are related significant different
mean values).
Koné et al., / Advances in Applied Agricultural Science 03 (2015), 02: 65-74
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from 2007 to 2008 as probable consequence of the
improvement of bunds consistency in 2008, reducing the
loss of water and nutrients (Touré et al., 2009). In fact,
N loss can be minimized by maintaining soil
continuously flooded (Khind & Ponnamperuma, 1981)
coupled with more availability of soil P for crop uptake
(Lindsay, 1979). However, the effect of flooding could
reduce Zn availability, affecting the rice yield
(Veldkamp et al., 1991) as observed in treatment Fc-Zn
(in 2008). Furthermore, cations (K+, Ca2+, and Mg2+) can
be displaced from clay exchangeable site by Fe2+, Mn2+
and NH4+ under conditions of soil submersion (Sahrawat,
2012). Therefore, flooding can reduce soil supplying
capacity of K+, Ca2+, and Mg2+ to crop, affecting yields
as observed for Fc-Ca and Fc-K in 2008. The yield
decrease was not, however, significant in treatment Fc-
Mg compared with the highest yield of Fc-P in 2008.
Hence, there is opportunity to assert mitigated effect of
flooding in Mg2+ nutrition of rice compared to that of
other cations (K+ and Ca2+) in soil. Other process than
those related to soil inherent fertility may explain this
result: The high yields observed for Fc-P and Fc-Mg
may be due to the high soil P inherent content (Table 2)
and to a synergistic effect observed in treatment Fc-Mg
(Table 3) respectively. In fact, soil P content was high
(22.5 mg kg-1) despite the relatively low pH (5.3) of the
soil. The relatively high C (organic carbon) content (3.9
– 5.5 g kg-1) in the soil may explain this result according
to isomorphic exchange between HCO2- and P2O5
2- . This
process can induce P release from hydroxide iron
fixation, increasing soil available P content and blocking
iron components during the experiment (Olk et al., 1996;
Bennani et al., 2005; Seng et al., 2006).
In the light of these analyses, we assert the possibility to
increase the yield of rice variety WITA12 in Mg-
deficient soil when applying N or P, while applying N or
raising soil pH can do so, in N-deficient soil. In fact, long
term flooding (2 to 4 weeks) can help to increase the pH
in acidic soil resulting from redox process
(Ponnamperuma, 1972; 1985) and contributing to yield
increase by 0.8 to 1 tha-1 as observed in treatment Fc-N
characterized by 1.3 tha-1 of yield increase in 2008 close
to that of Fc because of bounds and flooding effect
improvement. However, these synergistic effects could
be observed only for specific nutrient deficient condition
(Table 3) of which K and Zn were concerned and the use
of flooding can be cited as a nutrient management
strategy in the Baguenida irrigated plain.
The current study confirmed soil Zn-deficient as early
reported by Hägnesten (2006) in a plain of “Office du
Niger” and underline this occurrence as a consequence
of inadequate duration of soil submersion according to
our interpretations of the results obtained in 2008. To
avoid such constraints, there is a need to generate
knowledge of the effects of flooding duration on tropical
soil contents of K, Ca and Zn in rice cultivation,
particularly, for K which has been neglected in this agro-
ecology (Greenland & De Data, 1985).
The Fluvisols of irrigated plains in Sahel can be
characterized by N and Ca deficiencies’ effects on rice
grain yield without any symptomatic effect on rice
Koné et al., / Advances in Applied Agricultural Science 03 (2015), 02: 65-74
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growth. Furthermore, K and Zn deficiencies can be
observed under certain conditions that were probably
related to water management. Additional knowledge
concerning the effects of flooding duration on K and Zn
is required for improving fertilizer and water
management in this agro-ecology.
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Table 3. Pearson correlation coefficients (R) and its probabilities (P) showing relationship between soil characteristic
and the grain yield obtained in 2007.
Coefficient of Pearson correlation
pH water C N P Fe
R P R P R P R P R P
Fc 0.92 0.08 0.29 0.70 0.79 0.21 -0.29 0.71 0.65 0.35
Fc-Ca 0.50 0.41 0.32 0.67 0.48 0.52 0.12 0.67 0.34 0.43
Fc-K 0.14 0.85 0.58 0.42 0.42 0.58 0.56 0.44 0.58 0.49
Fc-Mg 0.63 0.47 -0.02 0.98 0.96 0.04 0.94 0.06 0.08 0.94
Fc-N 0.93 0.07 0.51 0.49 0.93 0.07 0.82 0.17 -0.42 0.58
Fc-P 0.42 0.57 0.37 0.63 -0.55 0.43 0.82 0.18 0.83 0.16
Fc-Zn -0.16 0.84 0.24 0.76 -0.24 0.76 0.11 0.89 -0.29 0.70
Control 0.89 0.10 0.92 0.26 0.84 0.15 0.71 0.29 -0.56 0.42
R: Pearson coefficient of correlation; P: Probability of correlation
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