Influence of Climate Variability on Seasonal Rainfall Patterns in South-Western DR Congo

Tu The drought susceptible génotypes hâve a longer flowering period compared to tolérant varieties (Edmeades et al., 1994). Maize improvement for drought résistance related to the flowering interval reflects fertilization problem (Gardner et al., 1991; Schussler et al., 1988). Approaches used to reduce the effects of drought include the development of lines and populations with proper synchronization between male and female flowering dates, whose interval is an important informative parameter in a sélection strategy for drought tolérance (Wesgate and Boyler, 1986; Hema et al., 2001).

The objective of this study was to increase knowledge about the use of direct measurement parameters such as flowering interval, régression and corrélation in the sélection of drought résistant génotypes in a savannah région in DRC.

MATERIALS AND METHODS

The trial was conducted during the growing season B (mid-March to mid-May) in 2013 in the Research Centre INERA Mvuazi. This season with < 60 rainy days was chosen in order to synchronize the flowering period with the cessation of rainfall. Nine maize varieties from HTA (EVDT-W99STRQPMC0, EVDT-W2008STR, EVDT- Y2000STRC0, EVDT-Y2000STRQPMC0, IAR-DENT-Q, IAR-FLINT-Q, MultiobEarlyDT, TZE-WDTSTRQPMCO, TZE- YDTSTRQPMCO) were evaluated under agro- ecological conditions of Mvuazi (DR-Congo) and compared to other varieties that include Mudishil, Mudishi3, Musl, Samaru, 07SADVE, and ZM523. These varieties were selected for seed production in DR. Congo (INERA, 2013). Génotypes (ZM523 and 07SADVE) developed by CIMMYT – Zimbabwe in 2007 for their drought tolérance and tested in Malawi and Angola (Girma et al., 2012) and the Africa région and Eastern South (CIMMYT, 2008, 2009) were used as Controls.

The experimental design was randomized complété block with four réplications. The land was plowed and harrowed in February 2013. After délinéation of the plots, sowing was done with two grains per hoie, for a density of 53333 plants per hectare with spacing of 0.75 m x 0.25 cm. Urea (46% nitrogen) and NPK 17-17-17 bought on the local market were used as fertilizers. NPK (250 kg.ha-1) was applied at planting. Urea (120 kg) was applied by fractionation into two halves of the dose at 15 days and 30 days after sowing. Maintenance care consisted of manual weeding. At harvest, the ears of corn were harvested on two central lines and yields were calculated at 14% moisture content. During the growth, data were collected on végétative parameters proposed by Vasal et al. (1997), the number of days to 50% of the male flowering (Mf), the number of days to 50% silking (Slk), the interval between male and female flowering (IFM). At maturity, the data were collected on percentage of stérile plants (Sp), the ear aspect (Ea) according to the rating scale of 1 to 5 (where 1 = excellent, 2 = very good, 3 = good, 4 = poor, 5 = very poor), weight of 100 grains (W100) and grains yield (Yld).

Statistical analyses

Data were subjected to analysis of variance (Under R Î3.1.3 software) using the general model « AnovaModel <- aov (y ~ variety) to détermine the significant différences between treatment means. A linear régression was established between IFM and yield; the model Im (Yield = IFM * Variety) to show the general évolution of varietal performance against the flowering interval. The principal component analysis (PCA) was also performed to show the level of dependence between factors and variables studied. Pearson détermination coefficients were calculated to show the levels of corrélations between variables.

RESULTS AND DISCUSSION

Analysis of variance

The mean values obtained on the parameters observed during growth are presented in Table 1. The results of the analysis of variance for these parameters showed highly significant différences among varieties {P<0.0001) with very distinct homogeneous groups.

The averages obtained for the percentage of stérile plant, ear appearance performance and weight of 100 grains are shown in Table 2. The test results showed highly significant différence among means for percent of stérile plants, grain yields, weight of 100 grains and ear appearance (P<0.001).

Table 1. Comparative analysis of maize varieties based on days to male and female flowering (Fm and Ff), and interval between flowerings (IFM).

Variety Fm (Days) Ff(Days) IFM (Days)
07SADVE 64,000 abc 65,000 a 1,000 a
EVDT-W2008STR 62,500 ab 68,250 ab 5,750 cde
EVDT-W99STRQPMC0 63,250 abc 69,750 b 6,500 de
EVDT-Y2000STRC0 62,000 a 68,500 ab 6,500 de
EVDT-Y2000STRQPMC0 62,500 ab 67,500 ab 5,000 bcd
IAR-DENT-Q 61,500 a 70,000 b 8,500 e
IAR-FLINT-Q 62,000 a 66,000 ab 4,000 abcd
Mudishil 66,750 c 68,750 ab 2,000 ab
Mudishi3 66,500 bc 69,000 ab 2,500 abc
MultiobEarlyDT 62,750 abc 66,500 ab 3,750 abcd
Mus1 63,000 abc 67,500 ab 4,500 bcd
SAMARU 66,250 bc 68,750 ab 2,500 abc
TZE-WDTSTRQPMCO 63,750 abc 67,500 ab 3,750 abcd
TZE-YDTSTRQPMCO 62,750 abc 66,750 ab 4,000 abcd
ZM523 64,500 abc 65,250 a 0,750 a
Pr>F 0,0001 0,003 0,0001

 

Kabongoetal. 814

Table 2. Comparative analysis of maize varieties based on % of stérile plants (Sp), the appearance of ears (Ea), grain yield (Yld), and weight of 100 grains (W100).

Variety Sp (%) Ea(1-5) Yld(t /ha) W100 (gr)
07SADVE 3,000 bc 1,000 a 9,053 d 35,000 ef
EVDT-W2008STR 1,000 ab 2,250 a 4,524 ab 29,250 abcde
EVDT-W99STRQPMC0 10,250 d 1,500 a 5,141 bc 32,250 cdef
EVDT-Y2000STRC0 0,750 ab 2,250 a 4,461 ab 26,500 abc
EVDT-Y2000STRQPMC0 4,750 c 3,000 a 3,290 ab 26,750 abcd
IAR-DENT-Q 11,750 d 2,500 a 3,596 ab 25,500 ab
IAR-FLINT-Q 11,250 d 2,750 a 4,271 ab 27,250 abcd
Mudishil 0,500 ab 2,000 a 5,784 bc 33,000 def
Mudishi3 0,000 a 2,500 a 3,873 ab 27,500 abcd
MultiobEarlyDT 1,250 ab 2,000 a 3,701 ab 31,750 bcdef
Mus1 0,000 a 1,250 a 4,254 ab 34,250 ef
SAMARU 0,000 a 2,000 a 5,272 bc 35,000 ef
TZE-WDTSTRQPMCO 1,750 ab 3,250 a 2,064 a 24,000 a
TZE-YDTSTRQPMCO 0,000 a 2,750 a 3,532 ab 29,750 abcdef
ZM523 0,000 a 1,000 a 7,352 cd 36,000 f
Pr> F 0,0001 0,011 0,0001 0,0001

 

 

Table3. Matrix of corrélation.

Variable Mf Ff IFM Sp Ea Yld
Ff 0,036
IFM -0,628 0,755
PS -0,502 0,065 0,380
AE -0,223 0,614 0,624 0,173
Rdt 0,327 -0,716 -0,772 -0,111 -0,821
P100g 0,444 -0,620 -0,774 -0,348 -0,872 0,756

Bold values are different from 0 to a level of significance alpha = 0.05.

 

the weight of 100 grains (r = 0.756).

 

 

 

Linear régression between the flowering interval and performance shows that the values of the flowering interval are negatively correlated to performance (grain yield) with a coefficient R2 = 0.226 (Figure 1). Thus a short interval between male and female flowering results in a high yield. Potentially, productive varieties hâve a flowering interval equal to or less than 2 days.

Corrélation between variables

Corrélations were observed between the flowering interval and male flowering (r = -0.628), the interval between flowering and silking (r = 0.755) between the flowering interval and grain yield (r = -0.772), between the flowering interval and weight of 100 grains (r = – 0.774), between silking and grain yield (r = -0.716), between silking and weight of 100 grains (r = -0.774), between the appearance of ears and grain yield (r = – 0.821), between the appearance of the ears and weight of 100 grains (r= -0.872), and between grain yield and

Principal component analysis (PCA)

Eigenvalues and vectors of factors

Only three of the six axes hâve eigenvalues greater than 1 (Figure 2). The first and second axes provide 80.86% of the total variation (Figure 3). The first axis is defined by the yield, the weight of 100 grains and flowering interval. This dimension opposes high yielding varieties with low IF to low yielding varieties with high IF. The second dimension defined by tasselling Fm, opposed by early varieties and by the rate of stérile plants. The first axis categorizes the varieties (07SADVE and ZM523) obtaining high yields with high individual weight of 100 grains (> 35 g). Percentage of stérile plants correlates positively with higher flowering interval. This suggests that a long flowering period resulted in a higher percentage of stérile plants (> 10%). This axis defines ail varieties with low grain yield and small weight of 100 grains <28 g (IAR-FLINT-Q, IAR- DENT-Q).

 

 

 

 

eigenvalues                            ~                                       ViddâW
Eigenvalues                    —o—% cumulative
Fl                    F2                  F3                   F4                   F5                   F6

axe

Figure 2. Scree plot.
Figure 3. Vectors projection from ACP.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Kabongo et al. 816

 

‘3        -2.5         -2        -1.5         -1        -0.5          0         0.5          1         1.5           2         2.5           3         3.5

Fl (60,24 %)

Figure 4. Biplot (axes F1 et F2: 80.86%).

 

 

 

Figure 3 shows the combinations of varieties based on dominant agro-morphological characters.

The results showed that parameters related to flowering and yield (Tables 1 and 2) and the ACP (Figures 2, 3, and 4) hâve generated three distinct group of varieties. The first group, consisting of two varieties (07SADVE and ZM523), was characterized by a rate of stérile plants below 5%, a weight of 100 grains of 35 grammes and a grain yield than 6 t/ha with an interval of less than two days flowering.

The second group of three varieties (Mudishil, Mudishi3, Mus1 and Samaru) was characterized by a very low rate of stérile plants (<1%), an average grain yield from 5.14 to 5.78 t. ha’1 and a lower interval of flowering less or equal to 3 days. The third group of varieties rich in amino acids (EVDT-W99STRQPMC0, EVDT-Y2000STPQPMC0, IAR-DENT-Q, IAR-FLINT-Q, TZE-WDTSTRQPMCO, MultiobEarlyDT and TZE- YDTSTRQPMCO,  EVDT-W2008STR), was

characterized by intermediate values to yield low (<4 t ha’1), a flowering interval greater than 3 days and a high stérile plant rate. The corrélations between pairs of variables (Table 3) and linear régression (Figure 1) showed that the flowering period is negatively related to grain yields. According to Edmeades et al. (1997c), this applies not only for dry but with irrigated conditions. Edmeades et al. (1992) showed that at low yield levels, the genetic corrélation between yield and flowering interval was quite high (about -0.70). Hema et al. (2001) showed that the drought tolérant lines were characterized by a flowering interval between 1 and 2 days and had a high weight of 100 grains and a high yield of grain. Magorokosho et al. (2003) obtained similar trends; the phenotypic corrélation coefficients between yield and flowering interval increased from r = – 0.08 to -0.21 * in favorable conditions of humidity and r = -0.40** to -0.43 ** in conditions of water stress. According to Vasal et al. (1997) négative corrélation existed between the appearance of ears and performance. This is consistent with the results obtained for the first and second group of varieties. Data on genetic corrélation between flowering period and amino acid content corroborate with other studies. The high amino acid content lines were vulnérable to dry conditions (Hema et al., 2001). Since Banziger et al. (2000), and Wesgate and Boyler (1986) indicated that the range of flowering was a very important parameter in the sélection of varieties for drought tolérance, the varieties of the first and second groups hâve potential for a maize improvement program.

Conclusion

There are three groups of maize. The first group and the second group include 07Sadve varieties, MZ523, Samaru, Mudishil Mudishi3 and which hâve proved promising, with yields of over 5 t/ha against a shorter

 

flowering period (0-3 days). The third group includes the QPM varieties other than Mudishil and Mudishi3. This group was vulnérable to drought, with yields of less than 5 t/ha against a longer flowering period (> 3 days). The results of the présent study showed that grain yields and flowering intervals are highly correlated, and dry conditions increase the time between male and female flowers. Interval between the male flowering silking allowed the identification of sensitive maize varieties and not susceptible to drought. In drought conditions, sensitive cultivars hâve a long flowering period with adverse effects on grain yield, while a short flowering period is correlated with drought tolérance.

REFERENCES

Ashley J (1999). Food Crop and Drought. In. CTA Macmillan
Education Limited, London and Basingtoke. Pp. 133.
Bànziger M, Edmeades GO, Beck D, Bellon M (2000). Breeding

for drought and nitrogen stress tolérance in maize: From theory to practice. Mexico, DF. International Maize and Wheat Improvement Centre (CIMMYT).

Bànziger M, Diallo AO (2004). Progress in developing drought and N stress tolérant maize cultivars for eastern and Southern Africa. In: D.K. Friesen and A.F.E. Palmer (Eds.). Integrated Approaches to Higher Maize Productivity in the New Millennium. Proceedings of the 7th Eastern and Southern Africa Régional Maize Conférence. Pp. 5-11

Bolanos J, Edmeades GO (1993). Eight cycles of sélection for drought tolérance in lowland tropical maize. II. Responses in reproductive behaviour. Field Crops Res. 31: 253-68.

CIMMYT (2008). Characterization of Maize germoplasm Grown in Eastren and Southern Africa. Results of yhe 2008 Régional Trial coordinated by Cimmyt. Pp. 16-17.

CIMMYT (2009). Characterization of Maize germoplasm Grown in Eastren and Southern Africa. Results of yhe 2008 Régional Trial coordinated by Cimmyt. Pp. 18.

Diallo AO, Kikafunda J, Welde L, Odongo O, Mduruma ZO, Chivatsi WS, Friesen DK, Mugo S, Bànziger M (2004). Water stress and low nitrogen tolérant hybridsfor the moist mid altitude ecology of eastern Africa. In: D.K. Friesen and A.F.E. Palmer (Eds.). Integrated Approaches to Higher Maize Productivity in the New Millennium. Proceedings of the 7th Eastern and Southern Africa Régional Maize Conférence. 5-11 February 2002, CIMMYT/KARI, Nairobi, Kenya. Pp. 206-^212.

Edmeades GO, Champman SC, Bolanos J, Bànziger M, Lafitte HR (1994). Recent évaluations of progress in sélection for drought tolérance in tropical maize. Fourth Eastern and Southern Africa Régional maize conférence. Harare/Zimbabwe.

Edmeades GO, Bànziger M, Chapman SC, Ribaut JM, Bolanos J (1995). Recent Advances in Breeding for Drought Tolérance in Maize. Paper presented at the West and Central Africa Régional Maize and CassavaWorkshop, May 28-June 2 1995, Cotonou, Bénin Republic.

Edmeades GO, Bolanos J, Lafitte HR (1992). Progress in breeding for dought tolérant in maize. In D Wilkinson,ed. Proc. 47th Ann. Corn and Sorghum Ind. Res. Conf., Chicago, Illinois, Dec. 1992, Washigton, DC, ASTA. Pp. 93-111.

Edmeades GO, Bolanos J, Bànziger M, Chapman SC, Ortega A, Lafitte HR, Fischer KS, Pandey S (1997). Récurrent

sélection under managed drought stress improves grain yields in tropical maize. In: Developing Drought and Low-N Tolérant Maize. Edmeades, G.O., Bànziger, M., Mickelson, H.R. and Pena-Valdivia C.B. (Eds.), CIMMYT, El Batân, México. Pp. 415-425.

FAOSTAT(2010). Statistical Database of the Food and Agriculture Organization.

Gardner CO, Stevens J(1988). Breeding for stress tolérance in maize. In: Workshop on maize breeding production. Belgrade, Yugoslavia : Euromaize. Pp. 59-67.

Girma T, Kassie L, Olaf E, Wilfred M, Peter S, Augustine L, Kaonga KK (2012). An Innovation Learning Platform for Drought Tolérant Maize in Malawi: Lessons Learned and the Way Forward. Pp. 23.

Hema D, Kim SK, Mondeil F, Tio-Toure BB, Tapsoba A (2001). Intervalle entre floraison mâle et femelle chez le maïs: son importance en sélection pour la tolérance à la sécheresse. Cahiers Agricultures Août. 10(4): 255-260.

Langyintuo AS, Mwangi W, Diallo AO, MacRobert J, Dixon J, Bànziger M (2010). Challenges of the maize seed industry in eastern and Southern Africa: A compelling case for private-public intervention to promote growth. Food Policy 35: 323-331.

Magorokosho C, KPixIey KV, TONGOONA P (2003). Sélection for drought tolérance in two tropical maize populations. Afr. Crop Sci. J. 11 (3): 151-161.

NATIONAL RESEARCH COUNCIL (1988). Quality Protein Maize. National Academy of Sciences: Washington, DC.

Schussler JR, Westgate WE. 1991. Maize kernel at low potential II. Sensitivity to reduced assimilâtes at pollination. Crop Sci. 31:1196-1203.

SENASEM (2009). Politique nationale du développement du sous-secteur de semences, Projet « Appui au Secteur Semencier », Ministère de l’agriculture, Kinshasa.

Smalberger S, Du Toit AS (2001). Identification of maize cultivars tolérant to low soil fertility in south africa, seventh eastern and Southern africa régional maize conférence 11th – 15th february, 2001. Pp. 202-205.

USDA (2013). Les céréales dans le monde. http://www.passioncereales.fr/dossier-thematique/les-

céréales-dans-le-monde-en-europe-et-en-

france#sthash.XsDJ1XeR.dpuf

Vasal SK, Cordova H,. Beck DL, Edmeades GO (1997b). Choices among breeding procedures and strategies for developing stress tolérant maize germplasm. In: G.O.Edmeades, M. Bànziger, H.R. Michelson and C.B. Pena-Valdiva (Eds.). Developing Drought and Low N-Tolerant Maize. Proceedings of a Symposium. 25-29 March 1996, Mexico, D.F., Mexico. Pp. 336-347.

Westgate ME, Boyer JS (1986). Silk and pollen water potential in maize. Crop Sci. 26:947-951.

 

Open Access Library Journal

2016, Volume 3, e2952 ISSN Online: 2333-9721

ISSN Print: 2333-9705

Influence of Climate Variability on Seasonal Rainfall Patterns in South-Western DR Congo

Kabongo Tshiabukoïe1*, Pongi Khonde1, Muliele Muku1, Kizungu Vumilia12, Kiasala Lunekua1, Mbuya Kankolongo1

‘Institut National Pour l’Etude et la Recherche Agronomiques (INERA), Kinshasa, Gombe

2Biométrie et Expérimentation, INERA DG & Université de Kinshasa, Kinshasa, Gombe

Ematk                                               gctouslr2002@gmail.com, tonymuliele@yahoo.fr, kizunguvumilia@yahoo.fr, lunekua75@gmail.com,

mbuyakanko@gmatkcom, sgramer2003@yahoo.fr

Abstract

Climate variability in DR Congo in general and in the Kongo Central Province in particular is well established. However, rains related to variables such as frequency of rainy days and duration of the rainy seasons was generally very little studied. This study aims to investigate the influence of the climate event on rainfall patterns in the south-western of the DRC. This is firstly to characterize the climate event from the analysis of the air température, the frequency of rainy days and duration of the rainy seasons. Furthermore compare the normal monthly rainfall over the period 1962- 2012 to clear the behavior of seasonal rainfall patterns. Climate variability is mani- fested by temporal dynamic régressive températures, annual rainfall and a decrease in the number of rainy days. A température increase of around 1°C was observed from 1992 and the thermal peak was recorded in 1994 (>28°C). The highest rainfall was recorded in 2006 (>2400 mm). These variabilities cause short periods of intense rainfall leading to early droughts of the end of season.

Subject Areas

Environmental Sciences

Keywords

Climate Variability, Rainfall Régime, Drought Index, DR Congo, INERA Mvuazi

  1. Introduction

In the province of Kongo Central in the Démocratie Republic of Congo (DR Congo), rainfall is generally abundant due to the influence of warm winds from the Southwest

DOI: I0.4236/oalib.ll02952 September 28, 2016

 

and condensation caused by cold currents Benguela [1]. They are short-term and fo- cused on ten days per month and total for the rainy season, an average monthly height of about 130 mm, with a maximum exceeding 230 mm in December or April. Ail these supposed phenomena known by locals are very few argued objectively on science. Aguilar et al. [2] State that lack of information on trends in rainfall variables and cli- mate extremes in many régions across the developing world. SOLOMON et al. [3] also believe that the rainfall indexes are still too few studies in sub-Saharan Africa.

Despite the often dramatic conséquences of the rainfall fluctuation on agriculture and the environment Mvuazi, variability remains unclear as outliers in its time sériés. The daily rainfall sériés analyzed in this area only covers the period 1990-2008 [4]. On the other hand, note that the strong human impact in Mvuazi zone followed by a noti- ceable dégradation of natural resources would only increase this climate variability and/or impacts in the région.

It is therefore necessary to thoroughly analyze the seasonal cycle of Mvuazi rainfall. Indeed, the interest in this type of study lies in the fact that extreme events may become more frequent due to global warming [5] and it is appropriate to consider them now. There is currently a strong scientific interest in the field of analysis of climate extremes because they reflect some important nonlinearity and their économie and social consé­quences of human activity are potentially huge [6].

This study addresses a characterization of Umbro-thermal Mvuazi events. Thus time sériés at different time were formed. The results of this study may find direct applica­tion locally including démonstrations of érosion phenomena, the landslides, and oc­currences of floods and in the context of agriculture-related activities. The study will generate strategies to lead by farmers to consider the notion of seasonal hydrological risks in the development of the agricultural calendar.

  1. Materials and Methods
    • Data

The analysis of rainfall and température dependence of the INERA Mvuazi station (5’21’S, 14°5’E and altitude of 470 m above sea level) was conducted from rainfall data available daily from 1 January 1962 to 31 December 2012.

  • Approach

The approach is based on a global study based on statistical methods, and the calcula­tion of the few meteorological indexes.

Analysis of drought by using meteorological drought indexes.

Drought indexes and the most commonly used for monitoring and forecasting tools are following.

  • Gap Index Average (Em)

The déviation from the average is the différence between the annual amount of precipi-

 

tation (Pi) and the average annual précipitation amount (Pm). This is the index most used to estimate the rainfall déficit throughout the year. However, the gap in the middle is the most used by agro meteorologists, obviously, when the data sample is asymme­trical, the différence between the mean and the médian is great.

Em = Pi — Pm                                                              (1)

The gap is positive for the wet year and négative for the dry year. There is talk of déficit year when rainfall is below average and over-year when the average is exceeded. This in­dex allows visualizing and determining the number of loss-making years and their estate.

  • Compared to Normal Rainfall (RN)

This index is expressed mathematically as a percentage as follows:

RN(%) = (Pi/Pm)xlOO                                                           (2)

where

Pi: précipitation of the iyear;

Pm: the average précipitation for the same time period studied.

This report makes a point estimate rainfall compared to normal: A year is classified as dry if rainfall is below normal; that is to say when the RN is less than 100% [7].

  • Rainfall Déficit Index (IDP) or Index of the Déviation from Normal (En)

To locate rainfall in a long sériés of rainfall records, proportional to the average dévia­tion is used. This index (Equation (3)) allows visualizing and determining the number of loss-making years and their estate. A positive value indicates a wet year while a négative value indicates a dry year. The accumulation of years of successive indexes serves to iden- tify the major trends in isolation from small fluctuations from one year to another. When the sum of the différences increases, it is a wet tendency. The trend is a “dry” otherwise.

IDP(%) = (Pi-Pm)/Pmxl00                                                         (3)

where:

IDP: rainfall déficit index (percentage).

Pi: annual rainfall (mm).

Pm: average rainfall (mm).

  • Standardized Précipitation Index (SPI)

Standardized Précipitation Index (SPI) created by MCKEE et al. [8]

SPI =(Xi-Xm)/Si                                               (4)

where Xi is the cumulative rainfall for i year; Xm and Si are the mean and the standard déviation of annual rainfall observed for a given set respectively.

Adopted by the World Meteorological Organization (WMO) in 2009 and approved during the Congress World Meteorological Congress in 2011, the standardized précipi­tation index is a simple, powerful and flexible both based on rainfall data [8] [9] and allow as well checking the periods/dry cycles that periods/dry cycles. SPI compares

 

rainfall over a certain period (usually 1 – 24 months) to long-term average rainfall ob­served on the same site [10] [11] (Table 1).

  1. Results and Discussion
    • Evolution of Rainfall

Analysis of the characteristics of rainfall sériés of Mvuazi (Table 2) shows that they are relatively unbalanced. There is a non-significant différence between positional pa- rameters (mean, médian). The gap between the minimum and the maximum is very important. The coefficient of variation (CV) for annual précipitation sériés is characte- rized by strong fluctuations. Based on the observed seasonal and annual data, one can notice the irregularities in rainfall and rising trends (Figure 1).

The big trend is clear from the accumulated différences in rainfall (Figure 2) disre- garding the slight fluctuations of successive years over the entire period.

According ROGNON [7], a year is classified as dry if rainfall is below normal; that is to say when the RN is less than 100%. On the last 2 décades only six years 1997/98, 1999/2000, 2000/01, 2007/08, 2010/11, 2012/13 were classified as dry (Figure 3).

Although the trend of rainfall is on the rise, the pace of daily précipitation shows a decrease in the number of days of rainfall from 1999 to 2012. In other words, it rains

Table 1. Values of the SPI.

from 2.0 to more Extremely W etter
from 1.5 to 1.99 Very’ wet
from 1.0 to 1.49 Moderately moist
from -0.99 to 0.99 Near normal
from -1.0 to -1.49 Moderately dry
from -1.5 to -1.99 Very dry
from -2 to less Extremely dry

 

Table 2. Characteristics of statistical annual rainfall data.

Stalistics Annual rainfall (mm) Season A SeasonB
Means 1506.3 598.2 577.3
Minimum 1029.1 314.1 360.1
Maximum 2428.10 1228.1 802.3
Médiane 1513.5 594.1 578.8
Standard déviation 265.3 163.6 119.0
Variance 70,373 26,754.1 14,157.7
Standard error 37.1 22.9 16.6
CV (%) 17.6 27.3 20.6

Season A (starts from mid-October to end January) and season B (lasts from mid-March to mid-May).

 

Figure 1. Evolution of annual rainfall in the Mvuazi station from 1962 to 2012.

 

—♦ Annual ———— (Annual)

Year

Figure 2. Evolution of the différence cumulative rainfall compared to normal Mvuazi.

 

RN

Year

Figure 3. Report to normal rainfall.

 

heavily but in very short time. This causes the shortening of the rainy season and late season drought (Figure 4).

The most persistent droughts occurred in the early décades, they are formed of two or three consecutive dry years (Figure 5). The différence analysis between dry and wet periods experienced periods presented in Figure 3 can show once again that the South­west région of the DR Congo undergoes a wet climate change trend. This was predicted bythe GIEC [12].

In order to characterize the level of severity of droughts experienced, we relied on the calculation of the index of standardized précipitation (SPI). As a resuit, the frequency of moderate drought is 18% while that of severe droughts is 0.2%.

 

•-Rainy days — (Rainy days)

Figure 4. Evolution of the annual number of rainy days.

 

Figure 5. Standardized Précipitation Index (SPI).

 

The most persistent droughts occurred in the first décades, they consist of two, three and four consecutive dry years (Figure 5).

The analysis of different experienced droughts and wet periods presented in Figure 5 can show once again that the South-west région of DR Congo undergoes climate dis- ruption wet trend:

  • Before 1994, rainfall was less abundant and well distributed; after 1995, by cons, we had more and more heavy rain for short periods.
  • The last two décades hâve seen a moderate drought, making it the wettest déc­ades.

The succession of dry years is 2 years while that of wet years is 6 years maximum.

  • Températures Evolution

Table 3 on the main characteristics of température data sets to Mvuazi station allows highlighting an increase in the average température of approximately 1°C, providing information about the global warming phenomenon [13],

The thermally absolute température record was broken in the period (2010 and 2011). This trend is consistent with global warming recorded during the last fifty years with the accélération of this process during the period 1993-2011 (Figure 6), which was named one of the hottest épisodes [13].

Figure 6. Evolution of the annual average température from 1962 to 2012.

 

Table 3. Statistical characteristics of annual and seasonal average températures for the period 1962-2012 to Mvuazi.

Statistics Annual température (°C) Season A Season B
Means 24.40 25.1 25.6
Minimum 23.5 28.8 24.2
Maximum 25.6 26.4 26.8
Médiane 24.4 25.1 25.6
Standard déviation 0.5 0.5 0.6
Variance 0.23 0.29 0.35
Standard error 0.07 0.08 0.08
CV (%) 2.0 2.1 2.3

Season A (starts frommid-October to end January) and season B (lasts from midMarch to mid-May).

 

The study of thermal sériés shows an asymmetry and a non-significant différence between positional parameters (mean, médian). The gap between the minimum and the maximum is very important (Table 3).

The annual and seasonal variation coefficient for average température sériés is cha- racterized by a low fluctuation of approximately 4.86%, 13.20% and 5.64% respectively for the annual, season 1 and season 2; which allows assessing the degree of variability and the dispersion of the values relative to the average.

  1. Conclusions

Several drought indexes to characterize meteorological drought in the savannah South- western DR Congo are proposed in this poster. Based on the analyzes and results pre­sented, based on data from the Mvuazi station, we can remember that the South-western DR Congo is likely to drought to wet dominant trend. Dry years consist of two or three consecutive dry years. Drought can occur throughout the year as it can last two or more consecutive years.

The index standardized précipitation shows that the frequency of occurrence of dry successive years is relatively low: over the last 50 years, 25 hâve experienced droughts.

 

The trend line confirms the general downward trend in the number of rainy days.

The trend line average annual température confirms a general upward trend, and therefore a significant warming. Shortening periods of rain combined with high inten- sity rainfall often causes the snap rains causing droughts early end to the season.

Référencés

  • PNUD/UNOPS (1998) Monography Bas Congo. Physical Description XXI, 361p.
  • Aguilar, E., Aziz Barry, A., Brunet, M., Ekang, L., Fernandes, A., Massoukina, M., Mbah, J., Mh Do Nascimento, D.J., Peteson, T.C., Thamba Umba, O., Tomou, M. and Zhang, X. (2009) Change in Température and Précipitation Extrêmes in Western Central Africa. Guinea Conakry, Zimbabwe, 1955-2006. Journal of GeographicalResearch,
  • Solomon, S., Qin, D., Manning, M., Alley, R.B., Berntsen, T., Bindoff, N.L., Chen, Z., Chid- thaisong, A., Gregory, J.M., Hegerl, G.C., Heimann, M., Hewitson, B., Hoskins, B.J., Joos, F., Jouzel, J., Kattsov, V., Lohmann, U., Matsuno, T., Molina, M., Nicholls, N., Overpeck, J., Raga, G., Ramaswamy, V„ Ren, J., Rusticucci, M., Somerville, R., Stocker, T.F., Whetton, P., Wood, R.A. and Wratt, D. (2007) Technical Summary. In: Solomon, S., Qin, D., Manning, M., Chen, Z., Marquis, M., Averyt, K.B., Tignor, M. and Miller, H.L., Eds., Climate Change 2007: The Physical Science Basis. Contribution of Working Group Ito the Fourth Assess- ment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge and New York.
  • Wamuini Lunkayilakio, S., Vreven, E., Vandewalle, P., Mutambue, S. and Snoeks, J. (2010) Contribution to the Knowledge of Fish Fauna of Inkisi in Bas-Congo (DR Congo). Cybium, 34,83-91.
  • Houghton, J.T.Y., Ding, D.J., Griggs, M., Noguer, P.J., Van Der Linden, X., Dai, K. and Maskell, C.A. (Eds.) (2001) The Scientific Basis: Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change. Climate Change, Cambridge University Press, 525-582.
  • Naveau, P., Nogaja, M., Ammann, C., Yiou, P„ Cooley, D. and Jomelli, V. (2005) Statistical Methods for the Analysis of Geophysical Extrême Events. Comptes Rendus de P Académie des Sciences, 337, 1013-1022. http://dx.doi.org/10.1016Zi.crte.2005.04.015
  • Rognon, P. (1997) Drought and Aridity: Their Impact on Désertification in North Africa. Sécheresse, 7, 287-297.
  • Mckee, T.B., Doesken, N.J. and Kleist, J. (1993) The Relationship of Drought Frequency and Duration Times Scales. American Meteorological Society. 8/7i Conférence on Applied Climatology, 17-22 Janvier, Anaheim, 179-184.
  • Mckee, T.B., Doesken, N.J. and Kleist, J. (1995) Drought Monitoring with Multiple Times Scales. American Meteorological Society. 9th Conférence on Applied Climatology, 15-22 Janvier, Dallas, 233-236.
  • Edwards, D.C. and Mckee, T.B. (1997) Characteristics of 20th Century Drought in the United States at Multiple Time Scales. Climatology Report Number 97-2, Colorado State University, Fort Collins.
  • Guttman, N.B. (1994) On the Sensitivity of Sample L Moments to Sample Size. Journal of Climatology, 7, 1026-1029.

http://dx.doi.org/10.1175/1520-0442(1994)007<1026:OTSOSL>2.0.CQ;2

  • GIEC (2007) Assessment Climate Change 2007: The Physical Science Basis. In Quatrième rapport d’évaluation de GIEC. 2 février 2007, France.

 

  • IPCC, Climate Change 2001 and 2007: Impacts, Adaptation and Vulnerability. Contribu­tion of Working Group II to the Third Assessment Report of the IPCC. In: McCarthy, J.J., Canziani, O.F., Leary, N.A., Dokken, D.J. and White, K.S., Eds., Cambridge University Press, 1032 p.

—————————————  Open Access Library ——————————————————-

Submit or recommend next manuscript to OALib Journal and we will provide best service for you:

  • Publication frequency: Monthly
  • 9 subject areas of science, technology and medicine
  • Fair and rigorous peer-review System
  • Fast publication process
  • Article promotion in various social networking sites (Linkedln, Facebook, Twitter, etc.)

° Maximum dissémination of your research work

Submit Your Paper Online: Click Here to Submit

Or Contact service@oalib.com

 

Nature & Faune

Enhancing natural resources management forfoodsecurityin Africa

Volume 30, Issue 2

Sustainable management of forests and wildlife in Africa:
Enhancing value, benefits and services

Editor: Foday Bojang
Deputy Editor: Ada Ndeso-Atanga
FAO Régional Office for Africa
nature-faune@fao.org

http://www.fao.org/africa/resources/nature-faune/en/

Régional Office for Africa

FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS
Accra, 2016

 

Substitution test of Nicotiana tabacum by forest tree species in bio-conservation of maize kernels in southwestern savanna of Démocratie Republic of Congo

Kabongo Tshiabukole, Pongi Khonde) Lubanzadio Nsunda) and BipiniMbula

Summary

A study was carried to détermine the efficacy of three plants (Nicotiana tabacum, Eucalyptus citriodora, Tephrosia vogilii) against pests of maize in storage. Leaves powderof these three plants were mixed for 27g at 270g of grain and tested in comparison with a synthetic insecticide (Actellic) during six months in real conditions of storage in Mvuazi (28- 32°C and 65-70% RH). Significant différences (p <0.05) were observed between treatments for the attack rates over time. Actellic recorded 0% of attack rates followed by Nicotiana tabacum with 12%, Eucalyptus citriodora with 14% and 16% of Tephrosia vogilii with emergence powers of80.5%, 71%, 70% and 67% respectively. Control recorded 40.75% of attack rates and 2% of emergence. These results suggest that eucalyptus and tephrosia could represent an alternative to the use of synthetic products which are généra lly expensive and scarce for tropical Africa.

Introduction

The conservation of food products in general and maize in particular, poses serious problems in tropical environments because insect pests by feeding destroy products and cause enormous damage. Worldwide, about 10% of the products are lost (Fleurât, 1982).These losses can reach 20 to 40% of stocks in the tropics (Foua-Bi K., 1992). Several inexpensive solutions hâve been proposed to reduce these losses in the respect and protection of the environment (Delobel et Malonga , 1987 ; Golob et Webley, 1980 ; Ivbijaro, 1983 Seck & al., 1996 ; Tamile, 2001 ). In most cases, tobacco was used to performances against infestations of postharvest insects (Danjumma et al, 2009). However, in the région of Mvuazi, tobacco powder is very popular with the public for its invigorating power. Therefore, use of some non-edible forest species can improve the quality of seed saving, replacing synthetic products and Nicotiana tabacum. The object of this study was to compare the quantitative and qualitative performance of some bio-insecticides from the forest to replace Nicotiana. tabacum and synthetic insecticides in the conservation of maize seed.

Materials and methods

The study was carried at INERA Mvuazi Research Centre (470 m, 14° 54’E and 21 ° 5’S) during the period from 13 January to 14 July 2011, this period corresponding to shelf life exit seed of the season A. Young leaves of Nicotiana tabacum, Eucalyptus citriodora, Tephrosia vogilii were harvested, dried in the shade to prevent loss of essential oils. After drying they were ground and passed to 0.5mm sieve to obtain a fine powder. Following the protocol of Kaloma et al. (2008)27 grams of the leaves powder were mixed with 270 grams of maize kernels (Variety Samaru appreciated by the people of Mvuazi) and placed in sealed polyethylene bags and placed in a previously arranged place imitating real conditions of conservation. During six months, two control samples (with and without AtéllicTM : pirimiphos-méthyl à 25%) were compared with bio­insecticides to assess the attack rates during storage; and the outcome of préservation, germination test was done in a randomized design with four replications.The data were submitted to variance analysis and the general linear model was analyzed. Significant différences to 5% hâve been observed (n = sample size)..

1

Kabongo Tshiabukole. National maize sélection programme of INERA Mvuazi.

Email: ipkabon2005@gmail.corn.

Tel.:+243815992827

2 __ Pongi Khonde. Agronomist, National maize programme INERA. Email: Mvuazigetousfr2002@gmail.com

Tel.:+243815184592

Lubanzadio Nsunda. Technician, National maize programme

INERA. Mvuazi

Hel.: +243815247106

Bipini Mbula. Infrastructure and maintenance personnel, INERA Mvuazi.

■’Email: timothebipini@gmail. com

Tel.:+243816535199

 

Analyses of variances hâve, over time, showed significant différences (p <0.05) between treatments. The attack rates were estimated at over 40% in the control without ActellicTM (Figure 1).

? *

J 30 ? w I io • o – Û

Figure 1. Evolution of conservation corn grain attack rate

When insecticides were applied, after 6 month the attack rates were reduced to 16%, 14%, 12% and 0% respectively fortephrosia, eucalyptus, tobacco and Actellic’ ».

A significant différence (p <0.05) was found between treatments for the emergence rate. At the end of the rétention period, kernels treatment germinated at 80.5% with Actellic followed by Nicotiana tabacum with 71%, Eucalyptus citriodora with 70%, Tephrosia vogilii with 67%andcontrolwith2%(Fiaure2).

 

Figure.2. Comparison of the germination after storage of 6 months

It appears from these results that ail the grains of the control hâve been destroyed at 40%. The same plant extractions effects against insects hâve been reported by Liu (1991) and by Ogendo et al.(2004). Golob & al.(1982) also reported that Nicotiana tabacum powder application provided protection of the grain of maize against maize weevil Sitophilus zeamais and the grain moth Sitotroga cerealella during storage. A similar situation was presented by Gakuru & Buledi (1993) when comparing the effects of tobacco powder and castor oil on weevils of Vigna unguiculata. Indeed, Actellic and Nicotiana tabacum are commonly used in the food crop seed conservation in tropical Africa (Danjumma et al ; 2009 ; Malik et Mujtaba, 1984). The repellency of Tephrosia vogilii against Sitophilus zeamais was reported by Ogendo et al (2004). Regarding Eucalyptus citriodora performance hâve been reported by Kaloma & al. (2008) and Tamil (2001) in the conservation of common bean and maize. After this study, it appears that maize weevil Sitophilus. zeamais actually colonize the land of Mvuazi causing damage. The insecticide and insect repellent effect of powdered tobacco leaves, eucalyptus and Tephrosia vogilii hâve been proven on Sitophilus zeamais. The effectiveness of these powders was demonstrated when applied to 10% of the seed weight. At these doses, these plants could validly replace standard products commonly used.

Recommendations and suggestions

Residues of Tephrosia vogilii leaves being harmful in the food and feed (Wilbaux, 1934), these would be indicated for the precious seeds not intended for later consumption. Regarding Eucalyptus citriodora, leaves residues are harmless (Kaloma et al., 2008). An économie analysis of the use of these leaves, taking into account the labor involved and the réduction in the cost of purchased inputs and alternatives is important to give récognition to the potential value of the use of these species to improve livelihoods. Such an assessment should also include the impact on the sustainability of using these forest species.

 

Twenty-two years of agroforestry in Mampu in Western Région of the Démocratie Republic of Congo: Lessons learned.

Cécile Diaka Pika) Tony Muliele Muku*, Jean-Pierre Kabongo Tshiabukole and Jean-Claude Muliele Lumbu

Summary

The sequentiat agroforestry System involving Acacia auriculiformis fallows associated with annual crops (namely cassava and maize), was implemented in Mampu, in the western région of the Démocratie Republic of Congo (DR Congo).

Twenty-two years later, a large Acacia auriculiformis multi­service forest is established in contrast with the natural végétation made up of an herbaceous savannah. Agroforestry practices improve soil fertility (especially the organic carbon, nitrogen and base cation content) and promote an increase in the production of cassava (20 to 25 MT/ha), of maize (1.7 to 2 MT/ha) and of honey (12 to 30 kg/hive) with net average profit gains amounting to three thousand hundred and fifty dollars, four hundred and fifty dollars, and twenty eight dollars (USD) respectively as compared to traditional practices. Charcoal production ( 1.5 ha) yields a net gain of two thousand seven hundred USD. An ecological living environment has been created, family farms with économie jobs were generated and a trade center has been set up around Acacia auriculiformis.

Introduction

The Mampu Agroforestry Center is located in the Batéké plateau, in the Kinshasa province région of the DR Congo, situated in the north-eastern part of Kinshasa between 4°19’S and 15°47‘E and spreading to the north of the large Kwango plateau.

The climate at the Batéké plateau is of a tropical-humid type with 4 months of dry season (June-September). The végétation is dominated by a savannah colonized by herbaceous (e.g. Loudetia arundinacea and Hyparrhenia diplandra) and tree species (e.g. Hymenocardia acida and Crossopteryx febrifuga) on the plateaus. The slopes of the valleys and their affluents used to be covered with thick forests which are now degraded by shifting agriculture. The soil (Rubic Ferralic Arenosols according to the Word Reference Base (WRB) classification hâve developed on ochreous sands of the Kalahari System) is chemically poor (pH <5.3; cation exchange capacity (CEC); <10 cmolc/kg soil, base cations status: <0.40 cmolc/kg soil) and has a low water rétention capacity. The organic carbon content (Corg) is low or very low (<1%), and uniformly decreases with depth in A horizon. The nitrogen content (0-50 cm) is highly déficient (<0.05%).The mineralogicalcomposition is essentially made up of quartz, kaolinite and some Al and Ti residual oxides (Kasongo et al., 2009). Despite this low potential for farming, the soil at the Batéké Plateau is largely exploited by farmers with limited means to improve soil fertility, especially for cassava, maize and groundnut production.

in orderto promote a productive, profitable and sustainable agricultural System in Mampu, the government of the DR Congo (former Zaïre), with help from the European Union and the Hanns Seidel Foundation (German political foundation) and the contribution of the Mbankana Centre for Integrated Development (CADIM, Congolese NGO), has introduced the Acacia auriculiformis-based sequential agroforestry System, in addition to its ability to grow on nutrient-poor soils through the symbiotic fixing of the atmospheric nitrogen with Rhizobium-type bacteria, this legume tree grows very fast, can produce abundant litter and has a thick forest conducive to carbonization.

This article, mainly based on the data obtained from documentation, will address the expérience of the Mampu agroforestry System, especially (i) the implémentation of agroforestry, (ii) the effect of agroforestry on the physicochemical quality of the soil, (iii) the impact of agroforestry on the productivity and social life of agroforesters, and (iv) on biodiversity.

‘Cécile Diaka Pika. Natural Resources Expert, Kasangulu Integrated Programme, World Vision. BP 942, Kinshasa/Gombe, Démocratie Republic of Congo. Tel : +243 97 00 10 655 ; Email : cecilediaka@yahoo. fr.

/Tony Muliele Muku (Correspondind Author), Pedologist and Natural Resources Manager. National Institute for Agricultural Studies and Research (INERA), B. P. 2037, Kinshasa/Gombe, Démocratie Republic of Congo. Tel: +243 85 315 88 22 ; Email : tonymuliele@yahoo. fr.

(Jean-Pierre Kabongo Tshiabukole, Plant sélection Expert, National Institute for Agricultural Studies and Research (INERA), B. P. 2037, Kinshasa/Gombe, DémocratieRepublicofCongo.

Tel: +24381599 28 27; Email : jpkabon2005@gmail.com. « Jean-Claude Muliele Lumbu, Sustainable Forest Management Expert, Mbankana Centre for Integrated Development (CADIM), Mbankana, Démocratie Republic of Congo. Tel: +243 81 839 46 31; Email: jcmuliele@gmail.com

A propos de inera21 24 Articles
admin

Soyez le premier à commenter

Poster un Commentaire

Votre adresse de messagerie ne sera pas publiée.


*