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 (LUT) 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 three windows in central Kenya. A total of 16 AMF species were isolated and 15 distinguished to species status. 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 with land use with napier and tea recording the highest AMF spore abundance; LUT with fallow/pasture, maize and coffee with intermediate spore abundance and LUT with natural forest and planted forest with the least spore abundance. The reverse was observed for root colonization with highest colonization in natural and planted forest and the less in the remaining LUT. This is with the exception of LUT with tea which maintained both high spore abundance and slightly high colonization. Soil factors were significantly (p< 0.01) in LUT. However, the relationship between spore abundance and soil nutrients was not statistically significant (p<0.05). There was however a slight evidence of effect showing phosphorus and acidity, with coefficient values -1.29 and -0.48 respectively, to have negative relationship with AMF spore abundance. The similarity of land use types was high (r = 0.716) and was not by chance. However, similar LUT did not necessarily having similar spore abundance or soil nutrient factors. Hence implying the possibility of other factors such plant species and management as major in influencing AMF occurrence and soil nutrients factors. 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 are able to detect variations in land use intensity. There is also an indication that AMF species spore abundance is a response to stress with the Glomaceae and Acaulosporaceae responding faster to harsh conditions by producing spores, hence are able to remain and dominate disturbed landscapes longer