Comparing microbial community heterogeneity in soil under organic and conventional agricultural system cultivated with olive and peach trees in three fields differ with age at Al-Jouf Saudi Arabia

This research study was carried out at Al-Jouf region, north eastern Saudi Arabia, to investigate the differences in microbial community and density of microorganisms in the rhizosphere of olive (Olea europaea) and peach (Prunus persica) tree fields subjected to growth under organic and conventional agriculture systems. The soil analytical processes were conducted in three olive and three peach fields (9, 17, 27 years old and 20 ha in area) under organic fertilization, and three similar olive and peach fields under conventional fertilization system. The results indicated significant variations between the two agricultural systems in rhizosphere content of microbial and mycorrhizal colonization%. The highest percentages of actinomycetes, total fungi and bacteria (PSM) were recorded in the organically agricultural system (OAS) in olive fields in comparison to conventionally agricultural system (CAS). Regarding field ages OAS dominated CAS in total number of fungi under all olive fields ages, while under peach fields fungi counts were significantly high under CAS compared to OAS. Under peach fields OAS dominated giving the highest actinomycetes and bacteria and CAS dominated by giving the highest CFU and fungi count. The significantly highest counts of CFU and bacteria were attained under conventional farming system (CAS) in all of the different aged field compared to OAS. Actinomycetes and bacteria in young fields were significantly high under CAS, while in old fields actinomycetes and fungi counts were the highest under OAS.