Soil quality and rehabilitation of tepetates using board-ditches

Resumen

Objective: Physical and chemical properties, as well as microbial respiration, were evaluated during the rainy and dry seasons in a vegetation-free tepetate treated with board-ditches and in a relic forest soil, in order to determine soil quality.

Design/methodology/approach: The study areas were: vegetation-free tepetate, tepetate with board-ditches, and relic forest soil. Within 625 m² of each area, a systematic sampling scheme was established to collect samples during the rainy and dry seasons. Data were analyzed under a randomized block experimental design with a 3 × 2 factorial arrangement. A Principal Component Analysis (PCA) was performed to determine the degree of association between soil properties and soil types by season.

Results: In tepetates treated with board-ditches, bulk density and electrical conductivity decreased, and a neutral pH was observed, with these effects being more evident during the rainy season. Cation exchange capacity, phosphorus, and inorganic nitrogen increased across all three soil types, particularly in the rainy season. PCA explained 75% of the total variation, accounted for by PC1 and PC2. The biplot graph showed that relic forest soil was associated with organic matter and calcium in both seasons, whereas tepetate with board-ditches, in both dry and rainy periods, was associated with the physical component.

Limitations of the study/implications: Physical and chemical properties in rehabilitated tepetates may take several years to exhibit significant changes compared to non-intervened sites.

Findings/conclusions: Three years after the establishment of the board-ditches, and together with the presence of herbaceous vegetation and grasses, a decrease in bulk density was observed during the rainy season, favoring increased porosity. Electrical conductivity also decreased, and the neutral pH indicates a reduction in soluble salts. PCA revealed that forest soil, in both seasons, is associated with organic matter and calcium; whereas tepetate with board-ditches, during the dry season, is associated with bulk density and sand content, and during the rainy season with particle density and silt, indicating that soil quality remains low.