Arbuscular mycorrhizal fungi (AMF) form mutualistic associations with terrestrial plant roots and play a key role in nutrient acquisition, soil structure and plant resilience. AMF hyphae extend beyond root systems, improving uptake of relatively immobile nutrients such as phosphorus, and contributing to soil aggregation through glomalin production. Agricultural soil fertility and pest management practices, including tillage and intensive chemical inputs, can alter soil biodiversity and microbial communities. This study tested two hypotheses: (1) frequent soil disturbance and management reduce AMF hyphal networks and population density compared with nearby uncultivated controls, and (2) maize croplands support higher AMF population density and species diversity than teff croplands. The objective was to evaluate the effects of farm and soil fertility management practices on AMF population density, species diversity, community composition and species richness in teff and maize croplands in East Gojjam Zone, Northwest Ethiopia.
Sampling was conducted in three districts of East Gojjam Zone: Aneded, Awabel and Gozamin. The districts are located in Northwest Ethiopia at geographic coordinates approximately 37°42'–37°45' E and 10°17'–10°21' N, with elevations between 2,350 and 2,500 meters above sea level. The area receives an average annual rainfall of about 1,380 mm and mean temperatures that range roughly between 12 °C and 25 °C. Major crops in the districts include teff, wheat, barley, maize and various legumes.
A preliminary survey documented farm and soil fertility management histories, including cropping history, chemical fertilizer and pesticide application, and lime amendment. Fourteen croplands were selected for soil sampling based on known teff and maize production: seven teff plots and seven maize plots. Plot sizes ranged from 0.5 to 2.5 hectares. At each farmland five points (north, south, east, west and center) were sampled to 30 cm depth, cleaned and composited into a single sample per plot. Nearby uncultivated farmlands that had been left fallow during the sampling season served as controls. Sampling occurred during the dry season (October–December 2023). Samples were transported in sterile bags to laboratories at Debre Markos University and Addis Ababa University for analysis. Each 1 kg composite was split into two 500 g subsamples for AMF spore extraction and soil parameter analysis. The study received ethical approval from the Department of Biology, Debre Markos University; informed consent was obtained from landowners.
Soil samples were processed at the designated university laboratories for both biological and physicochemical analyses. One subsample from each composite was allocated for AMF spore extraction and identification; the other subsample was retained for soil parameter analysis. All laboratory procedures, including spore extraction, counting and morphological identification, were conducted following the study methods described by the authors. The manuscript states that all data are included in the article and that the work is open access.
AMF spores were extracted from the field-collected soil samples, quantified as spores per 100 g dry soil and morphologically identified to morphotypes and, where possible, to species. The study compared average spore counts across districts, among individual sampling locations and between crop types (teff versus maize), as well as against uncultivated controls.
Average AMF spore populations varied significantly (p < 0.05) across districts, among specific sampling locations within districts, and between crop types. Controls exhibited a higher average AMF population density (63.33 spores per 100 g dry soil) than the combined croplands mean (47.59 spores per 100 g dry soil), indicating a reduction in AMF abundance associated with cultivation and soil management activities. Maize croplands showed the highest observed spore densities, with values reaching up to 112.67 spores per 100 g dry soil, and an average AMF density of 66 spores per 100 g dry soil. In contrast, teff croplands had a lower average AMF density of 30 spores per 100 g dry soil.
A total of 14 AMF morphotypes were identified across sampled sites, representing three genera. The genera Acaulospora and Pacispora were reported as dominant within the study area. Dominant species included Acaulospora myricarpa and Pacispora franciscana. The authors report that farm and soil fertility management practices were associated with decreases in both AMF population density and species diversity across cultivated plots relative to controls.
The findings align with the premise that agricultural disturbance and intensive soil fertility or pest management can reduce soil microbial diversity, including AMF. The higher AMF counts in uncultivated controls support the hypothesis that soil disturbance disrupts hyphal networks and reduces spore abundance. Differences between maize and teff croplands—maize sustaining higher AMF densities and spore counts than teff—were observed and consistent with the second hypothesis. The dominance of Acaulospora and Pacispora genera suggests particular community composition in these highland Ethiopian croplands, but the study is based on morphological identification of morphotypes and does not report molecular confirmation in the manuscript text.
The study concludes that cropland type and farm soil fertility management practices influence AMF population density and species diversity in North West Ethiopia. Cultivation and soil management practices in the sampled districts were associated with reduced AMF abundance and diversity compared with nearby uncultivated plots. The authors recommend maintaining AMF population density and species diversity as a strategy to improve soil health and crop productivity, particularly under climate change, to promote sustainable agriculture. The manuscript notes that all data are included in the article; no specific external funding was declared and no competing interests were reported.