Soil compaction and topsoil removal effects on soil properties and seedling growth in Amazonian Ecuador

Background

Soil properties affect plant growth including during germination and establishment. Topsoil loss, nutrient loss, and compaction due to industrial activity in forest may impact forest regeneration. This study reports on soil properties and seedling growth following topsoil removal in Amazonian Ecuador.

Research goals & methods

Soil properties were measured before and after bulldozer clearing of tropical moist forest during oil extraction activities. These activities resulted in a 70% increase in bulk density and significant decreases in SOM, soil nutrients, and total porosity, and an increase in cation exchange. Seedlings of three canopy tree species (Cedrelinga cateniformis, Caryodendron orinocense, and Virola elongata) were then planted in undisturbed soil, compacted subsoil, and uncompacted subsoil. Growth responses were not consistent among species. Height growth was reduced in all species but diameter growth decreased only in Cedrelinga cateniformis.

Conclusions & takeaways

Topsoil addition to compacted subsoil did not positively affect growth. Fertilizer addition had the most consistently positive effect on growth. This study confirms that many soil physical and chemical properties are changed with topsoil removal and compaction, but the effects of these changes on tree seedling growth remain unclear.