Seasonal changes in soil respiration and microbial biomass in five tropical tree plantations in Thailand

Abstract

Since microbial biomass is a key factor controlling nutrient dynamics in the soil through mineralization of soil organic nutrients or microbial turnover, investigating the seasonal changes of microbial activities and biomass is essential for better understanding the nutrient dynamics in tree plantation. We investigated the seasonal changes in soil respiration, microbial biomass carbon (MBC), and microbial biomass nitrogen (MBN) in five tropical tree plantation stands. Although CO₂ emissions and MBN contents were high in hot-rainy season and low in cool-dry season, MBC contents in cool-dry season kept in the same level as rainy season. We assumed that the different response of MBC and MBN to cool-dry condition was because of the changes in microbial fauna or individual adaptation for drought. The influence of the microbial dynamics observed in the present study on soil nutrient dynamics needs to be studied in the future.