Andrew Thuo Kariuki A56/77793/2012 Supervisors: 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. Karuku Dr. 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) .

Nematode Trophic Levels 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 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

Objectives General Objective: Specific Objectives: 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 Soil Sites Identification (FAO 1974) Total of 192 Geo-Referenced Samples 2 Farms (24) 2UD Zones (8) Vertisols Cambisols Arenosols Soil Sites Identification (FAO 1974) Central Province Sites (Makuyu) Lower Eastern Province Sites (Makueni)

Methodology…. Questionnaire Administered- Socio-Economic Survey Seasonal Sampling Schedule Dry Hot Season (192) Rainy Wet Season Dry Cold Season 1 2 3 4 5 6 7 8 9 10 192 200cm3 Soil for nematode extraction 200cm3 Soil Sample for Soil Property Analyses Contingency Soil Sample Compilation of Soil Variables Soil Information Questionnaire Administered- Socio-Economic Survey

Description of Lab Data to Collect Nematode 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 Activities Soil Identification and 1st Season Sampling 2012 2013 June July August Sep Oct Nov Dec Jan Feb Mar Apr May 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

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