Quantification of soil erosion dynamics in the hilly red soil region of Southeast China based on exposed roots

Abstract

The hilly red soil region (HRSR) of southeastern China is one of the most eroded areas in China. However, the knowledge on regional erosion dynamics and climate drivers still remains fragmental due to lack of long-term observations. Herein, exposed roots from endemic Pinus massoniana, Cunningh lanceolata, and Cinnamomum camphora trees were consulted to explore the evolution of local soil erosion across time and its linkages with climates. Results demonstrated that soil loss induced a distinct diminution in the lumen area of earlywood tracheids/vessels in the exposed roots. Based upon the signals in these root-ring records, we reconstructed average erosion rates for three sheet-erosion sites and found that local eroding conditions have been mitigated after decades-long protection. In addition, we built a chronology of sudden erosive activities since 1971 at the Benggang sites in HRSR with exposed roots. The El Niño-Southern Oscillation (ENSO) acted as a critical trigger for erosive events via modulations of spring-summer precipitation. Ongoing climate change may strongly modulate local soil erosion and an adjustment of mitigation strategies is highly desired to enhance climate change adaption for soil conservation.