ASSESSMENT OF SOIL HEALTH USING NEMATODE ASSEMBLAGE AND SOIL CHARACTERISTICS IN

ARENOSOLS, CAMBISOLS AND VERTISOLS IN KENYA

Andrew Thuo Kariuki A56/77793/2012

Supervisors: Prof. J.W. Kimenju

Dr. G. KarukuDr. G.M. Kariuki

Prof. H. Melakeberhan

Introduction• Diminishing Cropland Productivity is threatened by excessive,

wanton cultivation and deforestation (Hill et al. 1995b).

• Cropland accounts for 31% of Kenya’s total area, contributing to 20% of GDP and 65% of Exports. (Republic of Kenya 2010)

• Soil should be perceived as a “Living Body” hence Soil health quality assessment requires a prompt and direct analyses technique (Torrion, 2002).

• Soil micro-organisms depict life processes taking place in soil (Neher, 2001).

• Soil Nematode Assemblages act as key bio-indicators of Soil life processes. (Neher,2001;Fiscus & Neher, 2002) .

Introduction (cont..)• Nematode Fauna Fluctuations indicate changes in soil

ecosystem functions (Kimenju et al. 2009).

• Past Soil health assessment via nematodes has focused “Primarily” on Plant Parasitic Nematodes (Urzelai et al., 2000).

• A New and Robust approach to assess entire soil food web via use of :-

» Bacteriovores » Fungivores» Herbivores» Predators»Omnivores (Ferris et al.,2005; Wardle et al., 2005).

Nematode Trophic LevelsNematode Trophic Levels

Justification

-Dwindling Cropland due to soil degradation in Kenya necessitate the Need to optimize on under-utilized available croplands in Kenya.

-Nematode Assemblages act as Viable, Rapid and Accurate Tool for Monitoring Soil Health in Kenya due to their:

• Presence in all Soil Trophic Levels• Change Sensitive Reaction (chemical & physical)• Differentiation btw Natural & Structural changes• Economical and Accessible

ObjectivesGeneral Objective:

To develop accurate and scalable soil health-based models that address soil degradation using Vertisols , Arenosols and Cambisols of Kenya.

Specific Objectives:1. To determine effect of seasonal variation and land use practices on

nematode assemblage of selected soil groups.

2. To determine how soil properties influence nematode assemblage in selected soil groups.

3. To determine how socio-economic & local customs influence land use practices in selected soil group regions.

Methodology

Total of 192 Geo-Referenced SamplesTotal of 192 Geo-Referenced Samples

2 Farms(24)

2 Farms(24)

2UD Zones

(8)

2UD Zones

(8)

2 Farms(24)

2UD Zones

(8)

2 Farms(24)

2UD Zones

(8)

2 Farms(24)

2 Farms(24)

2UD Zones

(8)

2UD Zones

(8)

2 Farms(24)

2 Farms(24)

2UD Zones

(8)

2UD Zones

(8)

2 Farms(24)

2 Farms(24)

2UD Zones

(8)

2UD Zones

(8)

VertisolsVertisols Cambisols ArenosolsArenosols VertisolsVertisols Cambisols ArenosolsArenosols

Soil Sites Identification(FAO 1974)

Soil Sites Identification(FAO 1974)

Central Province Sites(Makuyu)

Central Province Sites(Makuyu)

Lower Eastern Province Sites(Makueni)

Methodology….

Seasonal Sampling ScheduleSeasonal Sampling Schedule

Dry Hot Season(192)

Dry Hot Season(192)

Rainy Wet Season

(192)

Rainy Wet Season

(192)

Dry Cold Season(192)

Dry Cold Season(192)

11 22 33 44 55 66 77 88 99 1010 192192

200cm3 Soil for

nematode extraction

200cm3 Soil for

nematode extraction

200cm3 Soil Sample for

Soil Property Analyses

200cm3 Soil Sample for

Soil Property Analyses

Contingency Soil SampleContingency Soil Sample

Compilation of Soil VariablesCompilation of Soil Variables

Soil Information

Soil Information

Questionnaire Administered- Socio-Economic Survey

Questionnaire Administered- Socio-Economic Survey

Description of Lab Data to CollectNematode Data Microscopic Genus Level ID (×400) Trophic Levels Genus Richness Abundance Ratio Maturity Index Structure Index

Soil Properties -Physical Properties (Temperature, Sand%, Silt%, Clay%)

-Chemical Properties (pH, Ca, Mg, K, Na, Total N, Available P, Cation Exchange Capacity C.E.C., Organic Matter Content).

Socio Economic Survey- Land Use and Socio-economic info

Data Analyses

• Data will be subjected to Analysis of Variance (ANOVA) using SPSS, GenStat & SAS.

• Differences among the Soil Groups and Regions will be tested using ANOVA for the comparison if the F-value is significant.

Expected Output

• Effect of seasons, soil groups and land use practices on nematode assemblage established

• Effect of soil properties on nematode assemblage under different soil groups determined

• Msc Thesis

• Three scientific papers

Work Plan

Activities2012 2013

June July August Sep Oct Nov Dec Jan Feb Mar Apr May June July

Soil Identification

and 1st Season Sampling

Second Season Sampling

Socio Economic

survey

Nematode enumeration

Data compilation

Data Analyses and thesis Writing

Submission

Budget

Activity Quantity Unit cost Ksh Total cost (Ksh)

Data collection expenses /

Nematodes Count/Soil

Property Analyses

300,000

Subsistence and Travel 8 2000 16,000

Printing Papers Thesis 2 reams 500 1,000

Printing Draft Proposal &

Final Thesis

200 Pages 10 10,000

Photocopying 400 Pages 2 800

Binding 5 copies 50 250

GRAND TOTAL 328,050

Thank You