Air moisture and soil texture are crucial for the water dynamics of riparian bamboo in a subtropical region

Abstract

This study investigated the influence of soil properties and plant age on the water use pattern of Bambusa rigida at different distances from a river during the dry season. The oxygen and hydrogen isotope compositions (δ18O and δ2H) of soil water and culm water in B. rigida forests from sites located at different distances from a river (site A: beside the river with high air moisture; site B: 200 m from the river with high clay content; site C: 400 m from the river with low clay content) were measured. Water uptake was not affected by plant age during early summer. Bambusa rigida at site A were able to use water from the soil organic horizon and moist air contributed 26% and 16% of soil water in this layer during winter and early summer. Bambusa rigida mainly took up water from soil layers with a high clay content at a depth < 50 cm due to the high water storage of these layers, although a high clay concentration weakened water uptake of bamboo roots at greater depths. This study is the first to identify the importance of air moisture for water dynamics of riparian bamboo and offers new insights into water use strategies of riparian B. rigida.