A presentation by the BGBD Kenya team

1. 5/27/2010
Introduction
IMPACT OF LAND USE ON SELECTED SOIL • Conservation and sustainable use of biodiversity is one of
ORGANISMS IN TAITA AND EMBU BENCHMARK the pillars of development.
SITES, KENYA
• Ecosystem services such as decomposition, nutrient cycling
and disease/pest regulation are products of Biodiversity
• Sensitivity to loss of biodiversity is of great concern to the
world population
BGBD Kenya team • This has catalyzed the channeling of resources to research
hi h l d h h li f h
The BGBD National Office, on biodiversity.
University of Nairobi, Kenya, • However, soil biodiversity has not received adequate
Tel: 254-020-4442115, Email: attention despite its contribution to sustainable agricultural
bgbd@uonbi.ac.ke productivity
• This study was therefore undertaken to determine the effect
of land use on soil biota in Embu and Taita benchmark sites.
Benchmark sites Methodology
• The benchmark sites selected • Grid method was used to establish the sampling points
across land use intensification • Methods and criterion for soil sampling were as described
gradients were:
by Moreira et al. (2008).
– Embu - stretching from Irangi
forest into the adjacent farms.
• Samples were analysed for selected functional groups which
– Taita Hills stretching from included
Ngangao forest into the farms • Characterization, Micoregulators, Mesofauna, macroafauna
and plant pathogens
– Biodiversity hotspots,
supporting some endemic plant
and animal species.
Pitfalls
Transect
Nematode trapping Colembola Acari
fungi
Monolith
Nematode
Earthworm
Mycorrhiza
1

2. 5/27/2010
Trichoderma along land use types
Results
• There was a general change of soil biota with increased land
intensification.
• Soil pathogens (Pythium and Fusarium) and Plant parasitic
nematodes increased with increased land use intensity.
• Nematode trapping fungi increased with increase land
intensification
Land use types and Nutrients- Arbuscular Nematode destroying Fungi
Mycorrhizal Fungi (AMF)
Effect of land use on occurrence of nematode destroying fungi Parasitism index of plant parasitic nematodes in different land use types.
35
3.5
Frequency of occurrence %
30 3
2.5
25
Pa paras index
2
itc
20
1.5
nt
n
y
la
15 1
0.5
10
0
5 P lant at ion Nat ural Napier Fallow Coffee Maize Veget able
forest forest
Land use t ype
0
Forest Shrub Napier Maize/ beans Vegetables
Land use
2

3. 5/27/2010
Abundance of mites across land use types in dry and wet seasons in Embu Abundance of Collembola across land use types in dry and wet seasons in Embu
1000
Abundance of Collem bola
Mean abun dance of m ites
900
250 800
200 700
600
150
500
100 400
e
50 300
0 200
100
e
a
er
st
0
w
ak
ze
st
ffe
Te
llo
pi
re
re
ai
O
Co
Na
Fa
fo
M
fo
u
er
l
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us
e
a
er
w
us
x
ze
M
us
ff e
Te
tu
te
t
ll o
pi
yp
no
ai
Na
Vi
t
Co
Na
yp
Fa
l
M
ca
ge
l
ca
Eu
di
Eu
In
Land use types
Land use types
Bacteria in association with Legumes
Conclusion
• There was a general decline of soil biota
with increased land intensification.
• Soil pathogens (Pythium and Fusarium)
and Plant parasitic nematodes increased
Land use system No. of sampling Rhizobia populations
points (n) (cells g-1 soil) with increased land use intensity.
Coffee 8 1.1 × 102 ± 3.71
Tea 10 1.1 × 102 ± 3.32
• Nematode trapping fungi increased with
Maize, beans intercrop 8 1.1 × 102 ± 3.71 increase land intensification
Napier 6 6.1 × 10 ± 3.19
Fallow 7 2.3 × 102 ± 5.73
Indigenous forest 8 0
3

4. 5/27/2010
Nematode trapping Colembola Acari
fungi
Nematode
Earthworm
Mycorrhiza
ASANTE
4