Soil microbial biomass and oxy-hydroxides contribute to aggregate stability and size distribution under different land uses in the Central Andes
Bibliographic record
Abstract
Context Agricultural intensification leads to land use changes with potential consequences for soil aggregate stability and size distribution, affecting nutrient and water retention capacity, aeration, sequestration of soil organic carbon, and biogeochemical cycling. Aims This study evaluated soil aggregate stability and size distribution under potato, fallow and Eucalyptus globulus L. land uses in Cambisols of the eastern branch of the Central Andes, Bolivia. We also investigated the relation between aggregates and total C, extractable C, oxy-hydroxides, microbial biomass and activity. Methods Aggregate stability, size distribution and oxy-hydroxides were measured in soil samples from eight plots of each land use. Key results Compared to fields cultivated with potato (Solanum tuberosum L.), Eucalyptus increased aggregate stability, megaaggregate content, and C and N in the free silt + clay fraction. Fallow did not lead to significant changes in soil structure. Soil aggregate stability was related to both microbial biomass and oxy-hydroxides. Microbial biomass C, microbial activity and dithionite extractable Fe were positively related to megaaggregates and aggregate stability. Oxalate extractable Fe and Mn were related to microaggregates. Conclusions The plantation of Eucalyptus is suitable for soil structural amelioration and C sequestration, but its introduction to cultivated areas should be carefully evaluated due to its effects on soil chemistry and microbiology. Short-term fallowing did not contribute to the maintenance of soil structure. Implications In a context of land uses change, modifications of microbial biomass and activity would affect megaaggregate formation and stability. Alternative management practices are required to maintain soil structure and optimize sustainable land use of cultivated and fallow fields.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".