Retention of post-harvest residues enhances soil fungal biodiversity in Eucalyptus plantations

Abstract

Plantation forests have the potential to meet global economic and ecological objectives. The sustainability of plantations is influenced by a variety of above- and below-ground factors. Among these factors are soil-associated microbes, as they play a vital role in soil biogeochemical processes. However, when compared to natural forests, the microbial biodiversity associated with plantation soils is often less biodiverse due to anthropogenic disturbances. The loss of microbial biodiversity in plantation soils can be partially mitigated through better post-harvest residue management regimes. To study this hypothesis in South African plantation soils, the effects of three post-harvest residue management regimes on fungal diversity were compared: retained, removed, or removed and fertilized. We collected 108 soil samples from these treatments at three study sites planted with a single Eucalyptus genotype. Consequently, DNA was extracted from all soil samples and fungal amplicon libraries were constructed using the Illumina MiSeq platform. The bioinformatic and statistical analyses of the data indicated that the post-harvest residue management regimes, the location of the study sites, and their interaction (soil treatment × site) influenced the community composition of soil fungi. The plots retaining post-harvest residues had a higher diversity of saprotrophs and symbiotrophs and fewer pathotrophs. The results showed that retaining post-harvest residue can improve the diversity of beneficial soil fungi in South African plantation soil. In the future, the South African and global forestry sectors should consider retaining post-harvest residues to ameliorate the tree and soil health of their plantations.