White and Brown Rot Fungi Associated with the Humus Layer Under Juniperus Phoenicea and Ceratonia siliqua Trees in Al-Jabal Al-Akhdar, Libya

Abstract

This study aimed to isolate and identify fungi associated with the residues of juniper (Juniperus turbinata) and carob (Ceratonia siliqua) and the humus layer at two sites in Al Jabal Al Akhdar, Libya. The study also determined the frequency of fungal genera during three different stages of plant residue decomposition and evaluated selected physical and chemical properties of the supporting soils. Plant residue and humus samples were collected from the study sites, and fungi were isolated using suitable culture media and identified based on morphological and microscopic characteristics. Four fungal genera were isolated: Pythium, Penicillium, Rhizopus, and Chaetomium, with clear differences in the number and distribution of isolates according to plant species, study site, and decomposition stage. Carob residues showed higher numbers of fungal isolates during several decomposition stages, with Rhizopus occurring at particularly high numbers during the second and third stages, whereas Chaetomium was more clearly associated with juniper residues. The soil analysis showed that the soils at both study sites had a clayey texture and were generally alkaline, with differences in some chemical properties. The mean soil pH was 7.87, mean organic matter content was 7.07%, and mean total nitrogen content was 0.15%. The results indicate changes in fungal community composition during plant residue decomposition, reflecting differences in substrate suitability and environmental conditions for the different fungal genera. This study provides preliminary information on fungi associated with juniper and carob residues and the humus layer in Al Jabal Al Akhdar and contributes to understanding their potential role in organic matter decomposition and nutrient cycling.