Tree species effects on soil properties in experimental plantations in tropical moist forest

Background

Forest soil properties are influenced by the complex interactions of vegetation, soil type, geology, management, and climactic patterns. Tree species can differ in their long-term effects on soils. This study resamples one of the earliest replicated experimental sites at La Selva Biological Station, Costa Rica, used to examine the effects of native tropical tree species on soil properties, to examine longer term effects on soil properties.

Research goals & methods

The authors sampled soils to 1m depth in mono-dominant stands established in abandoned pasture in 1988 of six species: Pentaclethra macroloba; Hyeronima alchorneoides; Virola koschnyi; Vochysia ferruginea; Vochysia guatemalensis; and the exotic Pinus patula. Soil organic carbon (SOC) differed significantly among species, ranging from 44.5 to 55.1 g kg^-1, compared with 46.6 and 50.3 g kg^-1 in abandoned pasture and mature forest, respectively. The species differed in the quantity and chemical composition of their detrital production. Soil organic C was significantly correlated with fine-root growth, but not with aboveground detrital inputs. Soil organic C increased with potential C mineralization on a grams of C basis, indicating that species influenced both the quality and quantity of SOC.

Conclusions & takeaways

The authors hypothesize that differences among species in the capacity to increase SOC stocks involved fine-root traits that promoted soil microbial turnover and, thus, greater production of recalcitrant, microbial-derived C fractions.