Termites are social insects of the infraorder Isoptera and are widely distributed across tropical and subtropical ecosystems. These insects are the most important soil bioturbators and have been called “soil engineers”. Phosphorus (P) concentrations are usually low in highly weathered tropical acidic soils, but termite nests form bioaggregates that serve as carriers for P protection and stabilization. However, few studies have focused on the changes in the composition and availability of aggregate-associated P within termite mounds.In a study published in Plant and Soil, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) showed that the presence or absence of fungus-growing termite nesting exhibited contrasting effects on soil aggregate stability and distribution of aggregate-associated P fractions in a mature rubber plantation.
The researchers studied fungus-growing termite mounds (active and abandoned) involving both above- and belowground locations in a 24-year-old rubber stand. They then measured the mass distribution and stability of aggregates and the P fraction concentrations in soil aggregates of termite mounds as well as their correlations with the main chemical properties.
Active belowground chambers exhibited stronger stability and less erodibility due to more aggregates？>1 mm size than aboveground mounds. In active aboveground mounds, the concentrations of labile P and non-labile P were higher than other types. However, H2O-Pi and NaHCO3-Pi in most aggregates were enriched in active belowground chambers relative to aboveground ones. Furthermore, middle-sized (0.25–2 mm) aggregates stored more P and represented the highest P storing capacity, especially for active belowground chambers.
The results suggest that although termite activity reduced aggregate stability aboveground, the effect of promoting P availability is beneficial.
“Our study provides an important reason why mound soils can be considered as fertility amendments for agroforestry practices in P-deficient tropical soils,” said LIU Chengang of XTBG.
Contact
LIU Chenggang Ph.D
Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun 666303, Yunnan, China
E-mail: liuchenggang@xtbg.ac.cn
