Biological Assessment and Soil Health Sustainability Using the Shannon Microbial Diversity Index in Al-Dulab Soils, Babylon, Iraq

Abstract

This study evaluates soil health in the Dulab region, Babylon, Iraq, using the Shannon microbial diversity index as a quantitative biological indicator. A total of 48 agricultural soil samples were collected and analyzed to determine microbial density (CFU/g). The results revealed values ranging from 1.08×10⁷ to 2.92×10⁷ CFU/g, with a mean of 1.99×10⁷ CFU/g. The Shannon index (H) was calculated based on relative microbial abundance. The relative proportions (pj) ranged from 0.0141 to 0.0380, while individual contributions (Hj) ranged from 0.0430 to 0.1264. The overall Shannon index reached H=3.63, approaching the theoretical maximum H_max=3.871. The normalized index value was B=0.94, indicating high microbial homogeneity and excellent soil health. The findings confirm that the studied soils exhibit high microbial activity and a well-balanced microbial community, reflecting strong ecological stability and sustainability.

The Shannon index (H) was calculated based on relative microbial abundance. The relative proportions (pj) ranged from 0.0141 to 0.0380, while individual contributions (Hj) ranged from 0.0430 to 0.1264. The overall Shannon index reached H=3.63, approaching the theoretical maximum H_max=3.871. The normalized index value was B=0.94, indicating high microbial homogeneity and excellent soil health.

The findings confirm that the studied soils exhibit high microbial activity and a well-balanced microbial community, reflecting strong ecological stability and sustainability.