Factors Limiting the Growth of Eucalyptus and the Characteristics of Growth and Water Use under Water and Fertilizer Management in the Dry Season of Leizhou Peninsula, China

Abstract

The growth rate of eucalyptus in the dry season was significantly lower than that in the wet season. However, the limiting factors of eucalyptus growth in the dry season are not clear. In this paper, through the continuous monitoring of the diameter growth and environmental factors of 5.5-year-old Eucalyptus urophylla S. T. Blake × E. grandis W. Hill ex Maiden in the dry season, the diameter growth characteristics of eucalyptus during the dry season were studied and the limiting factors of eucalyptus growth in the dry season were determined. The water and fertilizer management activities in the dry season were evaluated to verify the growth and water use characteristics of Eucalyptus urophylla × E. grandis in the dry season under the conditions of mitigation limiting factors and provide the basis for further increasing the growth rate of eucalyptus. The results show that the diameter fluctuation of Eucalyptus urophylla × E. grandis is cyclical and the diameter cumulative growth during the dry season monitoring is consistent with the Gompertz model. Atmospheric temperature and soil water content are the main factors limiting the growth of Eucalyptus urophylla × E. grandis in the dry season. Irrigation and fertilization in the dry season can significantly increase the growth of diameter at breast height (DBH) and biomass growth and significantly improve the water use efficiency in the dry season.