Global Leadership Training Programme in Africa 2015
2014
Activity Report of Field Research

Above/below ground ecosystems in Dambo (wetland) areas in Zambia
1

Toru HAMAMOTO

I.

Summary
English Summary (1 page)
This research aimed to investigate soil characteristics, soil insects and microbialcommunities and their potential changes due to the agricultural development in wetlands(Dambo). The soil samples were collected from cultivated (maize farms and watermelon
farms) and uncultivated (native trees and grasslands) sites. Soil pH, EC and moisture wasmeasured in Zambia. Soil insects’ diversity was also investigated at each sampling site by
pitfall traps and tullugren systems. This research is still ongoing. I have already applied to theJapanese government for the permission to import some of the sampled soils for further
analyses, particularly for soil microbiological data.
In future, after collecting soil animal/microbes data, small-scale soil animal/diversity
map will be created. There were previous studies investigated the relationships between soil
animal research and anthropogenic impact. However, in order to promote specific measures,
it is important to develop of spatial information combining GIS data and soil animal diversity
data.
The Dambo areas are often moist throughout the year and they are very important
ecosystems in the sub-Saharan Africa. Thus, this project will enable local agriculturalresearch sectors to evaluate what kind of soil animal/microbial/plant communities are
suitable or unsuitable for agricultural development in the Dambo areas in Zambia.

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2nd year Master’s student, Graduate School of Agriculture, Hokkaido University, JAPAN
Host University and the period of my field research: University of Zambia, 2016/1/12~3/18
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Japanese Summary (1 page)

本研究は、ザンビアの湿地帯（ダンボ）における、農業開発による土壌動物および土壌微
生物の多様性変化を調査することで、生態影響評価を行うものである。土壌サンプルは主に耕作地（メイズ、スイカ）と未耕作地（林、草地）から採取した。現地では、土壌 pH、EC、水分量を測定した。土壌動物の多様性については、ピットフォールトラップとツルグレンという方法によりそれぞれのサンプリングサイトで調査した。本研究は現在進行中であり、今後はザンビアから土壌サンプルを輸入し、さらなる化学的な土壌分析や土壌微生物群衆構造解析を行う予定である。
これらのデータ収集後、本研究は小さなスケールでの土壌動物および微生物多様性マップを作成し、今後の持続維持可能な農業開発の提言をするための材料となるように発展させる。
特にアフリカのような農業ポテンシャルが高いとされている地域で、その地域による具体的な環境保全対策を遂行するためには、地理的データと土壌サンプリングによって得たデータを結合した空間的情報に発展させていくことは重要である。
ダンボは一年を通して土壌水分が高く、サブサヘルアフリカにおいて特に重要な生態系が存在しているとされている。したがって、その貴重な地域においてサステイナブルな開発を推進していくことが重要だ。本研究によって、地元の農業開発部門に対して、どのような土壌動物・微生物・植物コミュニティが農業開発に適しているのかについて評価できるだろう。
さらに、本研究の結果から生態学的視点から農業開発に適した地域を提案することも可能になるだろう。

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II.

Research Activity

1. Introduction

In Zambia, water resources are generally limited due to a short raining season.
However, in wetland areas in Zambia, water is often abundant throughout the year. These
wetlands are called “Dambo”. We believe that these areas can potentially be used as
agricultural lands and the significant part of the Dambo area has been already cultivated.
However, Dambo areas contain important natural resources, including plants, soil animals
and microbes, but few studies have performed so far to investigate the changes in thenatural resources due to the cultivation of Dambo areas, particularly in relation to the thesoil ecosystems. The relevant study shows that where Dambos dry out permanently, theplant composition markedly changed but the changes in the soil ecosystems have not been
investigated [Burrough et al. 2015].
Thus, more studies are necessary for the investigate of the natural resources in Dambo
areas and their potential changes due to the agricultural uses of Dambo area. This research
aimed to investigate soil characteristics, soil insects and microbial community in Dambo area.

Photo; Dambo in Zambia

32. Study Area

My field work was conducted in the area stretching between Lusaka and Kabwe,
Kabwe whichis called "Chisamba" (14°59'S
14°59'S, 28°23'E) in Zambia. I sampled the soils from partly cultivatedfarm area. There were maize crops, watermelon and no agricultural area (native grasslandand trees). Dambo areas are located around farmlands and cultivation is performed near theDambos.

Photo; no agricultural area (left) and watermelon farm area (righ(right)t) in Chisamba

3. Methodology

Soil sampling site and Experimental site of pitfall traps
Soil
oil samples were collected from 10 sites,
namely native tree sites (t), native grasslands (g),watermelon farms (w), and maize farms (m). Fig.
1 shows that eachach soil sample w
was different incolor and texture (these will be investigated infuture).

Insecttrap

experiments

were

also

conducted in the same area. Two traps were set up
in “t” and “m” sites whereas four traps were set up

Figure 1; There were various soil
types.

in “g” and “w” area.

Soil Characteristic
Soil moisture contents were measured based on the dry soil weight after fresh
fsoils
were oven dried at 120°C°C for >24 hours. To measure soil pH, 10 grams of air-dried soils
were mixed with 25 mL of water and shaken for 30 minutes followed by the measurementmeas
4using a pH sensor (HI98129
HI98129, HANNA Co., Romania). In addition, inorganic-N
inorganic (NO3−-N and
NH4+-N), P and K will be analyzed in Japan.

Soil Insects
Soil insects’ diversity was investigated at each sampling site.. To achieve this,t“pitfalltrap” systems were used. They can trap small insects crawling on soil surfaces. Traps
consisted of a plastic cup containing a 70% ethanol to kill insects white plates covered
cover theplastic cups to avoid rainfall to be trapped within the cup (Fig. 2). A "tullgren method" wasalso used to extract living organisms from samples of soil. Comparedompared to pitfall traps, thismethod can catch smaller insects. In addition, Sticky sheets were used at thetDambo tocatch flying insects (e.g. A
Aphids, White Flies, and Stink Bugs). All visible
isible insects/soil animals
were collection and categorized by using a camera and note in Zambia. The small insects
will be divided at the order level (e.g. Beetles, Flies, Springtails, etc.).

Figure 2; Photos of pitfall trap system. Traps consisted of a plastic cup containing 70%
ethanol (left). After that, white plates cover the plastic cups (right)

Soil Microbial community
To analyze soil microbes (e.g. Bacteria), DNA samples will be extracted from soils andwill be analyzed using a next generation sequencer. This will be performed after we obtained
the import permission from the Japanese government (under process). We aimed to obtain
16S rRNA based bacterial community structure data for each sampling site.
The data for soil animals and microbes will be mapped based on the GPS data thus weunderstand the controlling factors (e.g. distances from the water source) of the plant/soil
animal diversities.

54. Research Findings

Soil Characteristic
Soil pH had, 5.75 ± 0.86, 5.51 ± 0.55,
6.38 ± 0.21 and 5.37 ± 0.21 for watermelon
farms, maize farms,, trees area and grasslands(no cultivation areas) respectively. All pH
were less than 6 except trees area. Especially,
the

soil

pH

in

watermelon

farm

was

sometimes less than 5 (Fig. 3a)3a).
Electric conductivity (EC) had, 43.5 ±
3.5, 69.5 ± 19.5, 45.5 ± 5.5 and 54.75 ±45.2 for watermelon farm
farms, maize farms,
trees area and grasslands respectively (Fig.
3b).
Figure 3; Soil pH(a) and EC(b) in soil
measured for each land use

Soil Insects
Fig. 4 shows some of insects
sampledthroughthepitfalltraps.

Tulllugren methods showed smaller soil
animals when compared to the pitfall
traps. Fig. 4 shows that tthey are

Tenebrionidae,

Staphylinidae,

Oligochaeta, Laccotrephes japonensis,
DiplopodaI from upper left, respectivelly.
Figure 4; Photos of some of the insect by pitfall

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Statisticalal analyses of soil animal community structures
To investigate the relationship between soil sampling sites (t, g, w and m) and soil
animal data, the data were analyzed using canonical correspondence analyses. It isconceptually similar to principal component analysis, but applies to categorical rather thancontinuous data. In a similar manner to principal component analysis, it provides a means ofdisplaying or summarizing a set of data in two-dimensional
dimensional graphical form (Fig. 5). The signs“ g”, “t”, “m”, “w” show land use ttypes
ypes (g=grasslands, t=trees, m=maize farm,
w=watermelon farm). Numbers mean the replication number. Capital characters mean eachsoil animal (Table 1).

Figure 5; Canonical Correspondence analyses

Table 1; The soil animal

between soil animals and land use. g, t, m, w shows

information of Fig. 5

land use types (g=grasslands, t=trees, m=maize
farm, w=watermelon farm). Numbers mean the7

5. Discussion

I note that this research is still ongoing. My Japanese supervisor and I have alreadyapplied to the Japanese government for the permission to import some of the sampled soils
for further analyses, particularly for soil microbiological data.

Natural diversity data map
The correspondence analyses show the effects of soil animal diversity by the land usechange (Fig. 5). The soil animals sampled through the pitfall trap, such as Lumbricina(Earthworm) and Geotrupidae (Earth-boring dung beetle), mainly eat fallen leaves, feces andcarcass. This means that the activities and numbers of these soil animals may influence soilorganic matter accumulation, consequently soil fertility. These insects are known as
indicators for the diverse soil animal communities [Ueda 2015].

Caelifera (Grasshopper) and Staphylinidae (Rove beetle) were mainly observed in themaize farm. On the other hand, there was no observation of the soil animals which
decompose soil organic matter, such as Lumbricina, Diplopoda (Millipede) and Geotrupidae,
in the maize farm. Thus, the maize farms might be lower in the soil organic matter contents
when compared to the watermelon farms and to the no cultivation areas. Measurements ofsoil structure and the analysis of total carbon and nitrogen contents are need to further
investigate the hypothesis and I will be performing these analyses when the soils areimported.
The g3 area was an uncultivated spot but was located on poorly drained soils, whencompared to g1 and g2 sites and its soil animal diversity was similar to that of watermelon
farm area (w1–3). It is difficult to fathom reasons for the similarity among w1–3 and g3 but
factors such as crop type and/or soil drainage capacity may influence the magnitude of theeffect of cultivation on soil animal diversities.
When compared to the watermelon sites and natural sites, maize cultivated areas hadcompletely different soil animal diversity and the abundance of the species was smaller. This
result may suggest that soil animal diversity was influence by maize cultivation but the
influence of watermelon farming activities has to be investigated in longer term because thewatermelon sites were relatively more recently cultivated.
In future, after collecting soil animal/microbes data, small-scale soil animal/diversity
map will be created. There were previous studies investigated the relationships between soil
animal research and anthropogenic impact. However, in order to promote specific measures,8

it is important to develop of spatial information combining GIS data and soil animal diversity
data.

Soil fertility
Generally it is though that African soil pH is low (acidic) and below optimum for thecrop growth, and this assumption is supported by my study. Additionally, the EC was also
very low for my site. The optimum EC value for crops is 200-400 µS/cm but my soils were all<100 µS/cm (Fig. 3b) [Kato 1996]. The EC indicates the total amount of the ion
concentration of the various substances in soils and the values are related to soil fertility.
Thus, the improvement of soil nutrients has to be achieved to increase the productivity of thesite. During my stay, I observed that a lot of maize residues were piled and unused invillages. Farmers always threw them away after cultivation. In Japan, plant residues are often
recycled on farm, some are returned as a charcoal. If these crop residues can be used to
improve soil pH and EC status, soil fertility improvement can be achieved using locallyavailable materials.

6. Conclusion

This project will help identifying soil animals/microbes living in the Dambo areas inZambia and their potential changes due to the agricultural development. The Dambo areas
are often moist throughout the year and they are very important ecosystems in the subSaharan Africa. Thus, this project will enable local agricultural research sectors to evaluate
what kind of soil animal/microbial/plant communities are suitable or unsuitable for
agricultural development in the Dambo areas in Zambia.

7. Acknowledgement

The technical assistance of Mr. Meki Chirwa is highly appreciated. I would also like tothank Prof. Imasiku A. Nyambe and Dr. Kawawa Banda for all assistance. This work was
financially supported by Global Leadership Training Program from UNU-IAS’s.

8. References

Burrough SL et al. 2015. Landscape sensitivity and ecological change in western Zambia:
The long-term perspective from dambo cut-and-fill sediments. Journal of Quality Science
Ueda A 2015. Tools for evaluating forest habitat using carrion silphid (Silphidae) andscarabaeoid dung beetles (coprophagous group of Scarabaeoidea) as indicators: Effects of9bait type, trap type, and trap number on beetle captures. Forestry and Forest Products
Research Institute．

Kato T et al. 1996. The methods and utilization of soil diagnosis Rural Culture Association
Japan

III.

Reflection to the GLTP in AfricaYour motivation to participate in the GLTP
I had been interested in Africa region for a long time and wanted to go there someday.
As I went on to university, transferred to the Faculty of Agriculture, and went on to graduate
school, I came to learn a lot about agricultural problems of the world. When I faced withthese global scale issues in relation to the future demand for food and its potential impacts
on the environment, I began to think that Africa had an important role for the world in near
future.
My purpose of this program was to see and to feel the current state of agricultural
technology in Africa. Also, I wanted to research its potential impacts on the environment. My
final goal is to help developing the foundation for future sustainable African agriculture.

Field experiences
Almost all of my Zambian research life was collecting/taking the photos of insects.
However, I had an opportunity to visit some places and to know a lot of Japanese people
living in Zambia. I also visited Zambia Agricultural Institute (ZARI). This institute is thelargest agricultural research entity in
Zambia. It has 10 research stations
and the institutes’ overall objectives
are to develop and adapt crop, soil
and plant protection technologies
and to provide a high quality,
appropriate

and

cost

effective

service to farmers. Soil lab in ZARI
has many kinds of machines. If

Figure 6; One of the researcher and I at ricethese machines are used effectively

field in ZARI

for local farmers, they will be able toimprove their farm managements.
10In addition, I joined a resilience workshop in Lusaka. It was held in collaboration withJapanese Universities. The theme was “Climate Change, Agricultural Production and
Nutrition: Towards Integrated Policy Design for Food Security”.
I also met a person who works for a trading company in Japan at the New Yearcelebration reception in the embassy of Japan in Zambia. We discussed about their crop
project. We may collaborate as industry-university cooperation. He and I went to Chirundu
area to observe the crop growth conditions and hold some meetings with farmers.
As stated above, I could get to know various places and people during my research.
These experiences and connection are irreplaceable and precious things to me.

Challenges
In future, I would like to propose suitable areas for agricultural development, in
relation to the ecological aspects in Zambia. However, doing ecological research means
understanding very complex food chains and the ecosystems of insects or microbes which
are very difficult. Also, crops’ disease causing mechanisms have to be further investigated inrelation to soil animal/microbes.
Thus, my study aims to propose an eco-friendly farming methods without using excess
pesticides but it is still difficult to identify the direct link among soil animal/microbial
diversities and crop disease.

How to make use of this experience to your future career development
I have a plan to write a peer-reviewed paper after further analyses of the sampled soils.
During my stay, I could meet a lot of Japanese in Zambia. These connections are still
remaining strong even after I came back to Japan. I hope to develop my career to deal withissues related to African in the future.

Encouragement to other students
If you are interested in Africa, you have to apply for this program. This program cansupport your trip to Africa financially as well as let you have a chance to communicate withstudents with different backgrounds. Actually I was able to meet students from Universityof Tokyo and Kyoto University in Zambia thorough this program. However, this program
does not include the fund to conduct a research. Thus it might be an issue for science
students.

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