Exceptional roles by protozoa on enhancing degraded soil quality

Degraded arable land globally results in soil aggregate breakdown and biodiversity loss. Protozoa, key consumers in soil microfood webs, have underexplored roles in improving soil quality. This study investigates for the first time the impact of three protozoa on soil aggregate formation, nutrient changes, and biome dynamics in eroded arable soil. Results show that Colpoda inflata , Blepharisma americanum , and Tetrahymena pyriformis significantly enhance aggregate formation. Colpoda inflata notably increases large macroaggregates (LMA) carbon content by 93.3 % and reduces acidification by 8.5 %. Blepharisma americanum significantly raises nitrate nitrogen and ammonium nitrogen levels by 1529.5 % and 215.1 %, respectively, compared to the control. Tetrahymena pyriformis contributes to an 18 % increase in total nitrogen. Colpoda inflata , Blepharisma americanum , and Tetrahymena pyriformis increase bacterial abundance by 8.4 %, 2.6 %, and 28.5 %, respectively, while reducing fungal abundance by 44.5 %, 90.8 %, and 74.2 %. The Chao1, Shannon, and Simpson indices of bacterial and fungal diversity did not change significantly ( p > 0.05). These findings underscore the crucial roles of protozoa in eroded soil ecosystems, offering significant insights into their potential to improve soil health and quality. Copyright © 2025. Published by Elsevier B.V.