Soil Hydrology Characteristics among Forest Type, Stand Age and Successive Rotation in <i>Eucalyptus</i> Plantations in Southern China

Abstract

The water holding capacity of forest soil plays a crucial role in ensuring forest productivity, particularly in Eucalyptus urophylla plantations. In this study, we investigated the soil water holding capacity and hydrological properties of Eucalyptus in a subtropical area of Guangxi, China. Different stand ages (five years old, seven years old, and 15 years old) and successive rotations (first, second, and third) of Eucalyptus plantations were compared, with Cunninghamia lanceolata (Chinese Fir) and Pinus massoniana (Pine) plantations serving as references. Soil physical properties, soil hydrological parameters, and litter characteristics were analyzed to assess soil water retention and conservation variations. Our findings revealed that Eucalyptus and Chinese Fir plantation forests exhibit superior soil physical characteristics compared to Pine plantations, resulting in better soil water retention. However, an increase in the age of Eucalyptus plantations significantly diminished the capillary water holding capacity of the soil, despite an increase in surface litter accumulation and litter moisture content. Furthermore, successive rotations led to a notable reduction in soil capillary porosity, soil moisture content, soil saturated permeability, and overall soil water holding capacity. In addition, soil bulk density emerged as a critical factor relating to the hydrological characteristics of Eucalyptus plantation forests. Decreasing soil bulk density in Eucalyptus forests may offer potential for optimizing their water retention function. These results reveal that Eucalyptus management practices significantly alter the hydrological properties of soil through their effects on soil and litter properties, and consequently, stand age, rotation, and species mixing should be given intensive attention in maintaining the maximization of soil water holding capacity.

Keywords

• successive rotation
• stand age
• soil water holding capacity
• soil property