The researchers studied fungus-growing termite mounds (active and abandoned), both above- and below ground, in a 24-year-old rubber stand. They then measured the mass distribution and stability of the aggregates and the P-fraction concentrations in soil aggregates of termite mounds, as well as their correlations with key chemical properties.
Active belowground chambers showed greater stability and less erodibility due to more aggregates > 1 mm in size than aboveground mounds. In active aboveground mounds, the concentrations of labile P and non-labile P were higher than in other types. However, H2O-Pi and NaHCO3-Pi in most aggregates were enriched in active belowground chambers relative to aboveground ones.
Furthermore, middle-sized aggregates (0.25–2 mm) stored more P and represented the highest P storage capacity, especially for active belowground chambers.
The results suggest that although termite activity reduces aggregate stability above ground, 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.
52 Sanlihe Rd., Xicheng District,
Beijing, China (100864)