INFLUENCE OF LAND USE TYPES ON OCCURRENCE OF ARBUSCULAR MYCORRHIZAL FUNGI IN THE HIGH ALTITUDE REGIONS OF MT. KENYA

Abstract

"A survey was carried out to establish the effects of Land Use Types (LUTs) on Arbuscular Mycorrhiza Fungi (AMF). AMF spore abundance and colonization were evaluated. The percentage root colonization was assessed in trap plants only. AMF were identified and enumerated from spores extracted directly from field soils. Soils were sampled from 60 points occurring in central Kenya. A total of 17 AMF species were isolated and 14 identified to species level. The spore community was dominated by Acaulosporaceae, and Glomaceae. Land use type had no significant (p<0.05) effect on AMF spore abundance or root colonization. However, trends were observed in soil under napier (Pennisetum purpureum Schumach) and tea (Camellia sinensis (L.) Kuntze) recording the highest AMF spore abundance; in fallow/pasture, maize (Zea mays L.) and coffee (Coffea canephora L. var. robusta) with intermediate spore abundance while natural forest and planted forest had the least spore abundance. The reverse was observed for root colonization where the highest colonization were soils under natural and planted forest but tea maintained both high spore abundance and slightly high colonization. The relationship between spore abundance and soil nutrients was not statistically significant (p<0.05) although phosphorus and acidity gave negative, coefficient correlation values of -1.29 and -0.48 respectively, with AMF spore abundance. The similarity of land use types was high (r = 0.716) though this did not have similar spore abundance orsoil nutrient factors. This meant that other factors such as plant species and management played a major role in influencing AMF occurrence. The study maintains phosphorus and acidity to have negative influence on AMF, spore abundance and root colonization brought out similarities in land use intensities. There is a clear suggestion that spore abundance and AMF colonization were able to detect variations in land use intensity. There was also an indication that AMF species spore abundance was a response to stress with the Glomaceae and Acaulosporaceae responding to harsh conditions by producing spores, making them to persist and dominate disturbed landscapes longer."