Effect of soil Amelioration on Fungal and Bacteria Communities in Kurdistan Calcareous Land

Calcareous soils in Kurdistan pose significant challenges to agricultural productivity due to low fertility and poor structure,Calcareous soils are characterized by high pH and significant calcium carbonate content, which pose challenges for microbial activity due to their alkaline nature and limited nutrient availability. This study investigates the effect of soil amelioration practices, specifically organic matter (OM) and ash applications, on fungal and bacterial communities to improve soil health and functionality. The objective was to evaluate the diversity, phylogeny, and functional roles of soil microbes under varying levels of OM (0–6 t/ha) and ash (0–4 t/ha). Using 16S and 28S rRNA gene sequencing and phylogenetic analysis, microbial diversity and evolutionary relationships were assessed. The results demonstrated that high OM levels (6 t/ha) significantly enhanced microbial diversity, supporting nitrogen-fixing bacteria (Azotobacter chroococcum) and beneficial fungi (Trichoderma reesei). Ash applications influenced microbial composition, promoting resilient species such as Xanthobacter sp. and Sphingomonas sanguinis. Phylogenetic analysis confirmed close genetic relationships within microbial genera, reflecting their adaptability to calcareous soil conditions. Beneficial microbes played key roles in nutrient cycling, plant growth promotion, and soil resilience. In conclusion, integrating OM and microbial-based approaches can improve the fertility and biological health of calcareous soils. While ash can condition soil, its long-term impacts on microbial communities should be monitored. It is recommended to adopt regular OM applications and bio-inoculants containing Pseudomonas and Trichoderma to sustainably enhance soil productivity. These findings provide a foundation for tailored soil management strategies in the agricultural landscapes of Kurdistan.Keywords: Soil Amelioration, Fungal, Bacteria, Calcareous soil.