Impact of Initial Planting Density on Soil Water Resource use Limit by Plants

Guo ZS and Zhang WW

Abstract

Impact of Initial Planting Density on Soil Water Resource use Limit by Plants Soil Water Resource Use Limit by Plants (SWRULP) is one of the most important indexes to express whether or not plant overuses soil water resources. However, it is still unclear how the impact of initial planting density on SWRULP. In this study, we investigated the changes of plant growth with time and soil water content with soil depth and time in caragana shrubland at different planting density and the change of soil water content with soil suction in the semiarid Loess hilly region since 2002. The results shows that Caragana forests at higher initial planting density grew and covered land fast. At the same time, the depth of root to absorb soil water increased and soil water content in the root zone soil reduced. When soil water resources in the maximum infiltration depth (MID) reduced to SWRULP, Caragana growth reduced or stoped with tree age. The soil water resource in the MID in the Caragana shrubland at the highest initial planting density first reach the SWRULP and the time soil water resource in the shrubland at lower density reach the limit delayed. When the soil water resources in the MID approach to the limit, it is the start time to reduce Caragana density on soil water carrying capacity for vegetation to prevent further soil desiccation and soil degradation.