PK06:Distribution of Soil Organisms in Diverse Tropical Ecosystems: The Impact of Land Use on Diversity
List of contributors
Distribution of Soil Organisms in
Diverse Tropical Ecosystems: The Peter Okoth, Joseph Mung’atu, Fatima
Moriera, Jeroen Huising, Fransis Susilo,
Impact of Land Use on Diversity Brazil
Mary Gikungu, Sheila Okoth, Brian Cote d’Ivoire
Isabirye, Juvenil E. Cares, Souleymane
Mexico Konate, Anne Akol, Si
K t A Ak l Simoneta N
Tropical Soil Biology and Fertility Institute of
Yankelevich, Nancy Karanja David
the International Centre for Tropical Uganda
Agriculture (TSBF-CIAT) Bignell, Chandrasekhara U.M, Maikhuri
Indonesia R.K, Jan Lagerlof, Joyce Jefwa
• Conclusions Macro and meso-fauna
• Need for better understanding of the relationship between soil
organisms and land use differences.
• Organisms could offer basis for regulating, suporting and
provisioning of ecosystem services (e.g. decomposition, pest
& disease control, food, carbon sequestration, etc)
• Need for increasing agricultural productivity through:
enhanced nutrient release, increased nutrient cycling,
decomposition, symbiosis (e.g. nitrogen fixation),
increased root surface area, fungal diseases control
(antagonistic fungi), enzyme production, pests control (e.g.
Isolation and testing
of effective AMF
Below-Ground Biodiversity Land Use
An assemblage of different soil biota Land use in this presentation is defined at
broad categories almost synonumous with
separated by taxonomic differences and
land cover definitions and include: forests
or functional differences and assessed tree-based systems (including agroforestry
by using diversity indicies. systems), grasslands, fallows and
• Create better knowledge and
understanding of the distribution of soil
organisms in different land use kinds.
• Use knowledge gained for designing
methods for supporting, regulating and
provisioning of ecosystem services.
Soil biological diversity decreases with
Hypothesis land use intensification & change
Forests Tree based
systems Grasslands Fallow Croplands
Land Use Change & Intensification
Methodology 13 cm
6 metres 6 metres
Macro and meso-fauna
Microbes, i.e, bacteria and fungi
from composite soil samples
For more details-see Manual on Tropical Soil Biology
Data Analysis Results & Discussions
Global analysis of data collected in Brazil, Cote
d'Ivoire, India, Indonesia, Kenya, Mexico & Uganda.
Comparison of means after an ANOVA
PCA for soil-biota analysis
The computation of means was done using the
GENSTAT software Version 10 (Rothamsted
Experimental Station, UK, 2007).
Relationship between BGBD and
soil chemical properties-Indonesia Soil organisms Vs Land Use
Eigenvalues d = 0.5
Sca Ant Nematode
Ca K Na CEC
Monte Carlo Significance test
Relationship with soil chemical
properties Fungi distribution
Beetles, ants and earthworms correlate more with
Calcium, Magnesium and high Base Saturation.
Termites are more associated with high organic
Nematodes associated more with Nitrogen.
Plant pathogenic fungi, arbuscular mycorrhizal fungi
and collembola associated more with Phosphorous.
Arbuscular mycorrhizal fungi (AMF) Plant pathogenic Fungi
AMF Plant Pathogenic Fungi
Pythium spp. tend to be very generalistic and
• Sensitive to human disturbance e.g.
unspecific in their host range.
higher sporulation and diversity in tree
based systems compared to forests. Phytophthora spp. are generally more host-specific.
• Sensitive to root turn-over i.e. comparing
turn over i e
For this reason, Pythium spp. and their relatives,
perrenials and annuals (grasslands (i.e., Rhizoctonia, Fusarium & Phytophthora spp) are
versus forests). more devastating in the root rot they cause in crops.
• Sensitive to intesity of chemical used
Crop rotation alone will often not eradicate the
(i.e., spores depressed in croplands). pathogen
Legume Nodulating Bacteria LNB
Distribution based on presence of
leguminous plants above-ground though
more in croplands and tree based systems
most probably due to introduced legumes
Macro-fauna in general Beetles & Earthworms
Earthworms, termites, ants, beetles, spiders, etc
Ants & Termites Macro-fauna
Distribution determined mainly by less
disturbed habitats and availability of food
sources and organic matter .
Meso-fauna Meso fauna & Nematodes
Inhabit fallows more than the other land use
Proliferation based more on less habitat
Nematodes are almost equally distributed in
forests, grasslands and in croplands. Their
distribution almost similar to the PPF.
Soil biota in general change with land use kinds.
The direction of change is however not in any one
direction. Tree based systems seems to favour the
The b o a see s to a g themselves with nutrients,
e biota seems o align e se es u e s,
land use, food chains, their individual functions and
The trends show that soil biota can be used to
further understand their niches including
opportunities in ecosystems services.
• Global Environment Facility (GEF) for the
• UNEP for implementation support.
• Diversitas for the conference organization.
• SIDA for the sponsoring this particular
• CIAT Director General and TSBF Director for
making the work possible in good environment.
• Countries and partners in: Brazil, Cote d’Ivoire,
India, Indonesia, Kenya, Mexico and Uganda