In tropical forests, a paradoxical relationship is commonly observed between massive biomass production and low soil fertility (low pH). The deficiency of soil nutrients generally constrains plant productivity. However, low pH can not always limit productivity of woody species. To acquire bases through cation exchange reaction and mineral weathering, plants promote acidification by nitric and organic acids even in highly acidic soils.

Low pH generally limits microbial activity and thus, affects nutrient cycles. However, in the highly acidic soils under dipterocarp forest, production of dissolved organic matter (DOM) is promoted by the specific fungal enzymes (peroxidase) in the organic layer. The organic acids in DOM facilitate nutrient transport in the soil profile. The specific strategies of plant and microorganism can render tolerance to low pH and mitigate nutrient deficiency.

There are several examples that both knowledge on plants and soils are needed to answer mysteries of plant-soil interactions. For example, stability of clay minerals (kaolinite vs. gibbsite) has been supported by considering plant Si cycles. The wet-dry cycles tied with global climate pattern can increase nutrient supply from soil microbial pools to plants. These are good examples that warrant collaboration of soil and plant ecologists.