The distribution of fine root length density for six artificial afforestation tree species in Loess Plateau of Northwest China

Aim of the study: Data about the distribution of fine root length density (FRLD) is important to understand the ecophysiology of vegetation. This is particularly true when models are applied to describe ecohydrology and vegetation function. However, there is yet limited knowledge of root distributions in semi－arid regions. The aim of this study is to investigate the distribution of fine roots for six typical afforestation tree species in Loess Plateau and its relationships with soil environmental factors.Area of study: Loess Plateau (NW of China).Material and methods: We quantified the fine root length density distribution of six typical afforestation tree species by soil core method, and the soil properties also were investigated.Main results: More than 50% of fine root length was concentrated at depths between 0 and 40 cm in vertical direction. In horizontal direction, most of fine roots concentrated near the trunk. Results showed a significant negative correlation between vertical distribution of FRLD and soil water content, a positive correlation between FRLD and organic matter and total N is significant, and a negative correlation with bulk density. No relationships were found with total C and particle size distribution in any soil layer for the six tree species. Stepwise multiple linear regression confirmed that changes in different soil properties significantly affected the variation in FRLD for each tree species, total N had strong and positive relationships with FRLD.Research highlights: These measurements provide valuable data for modelling of ecosystem water use and productivity.Keywords: Anjiapo catchment; Core method; Root distribution; Soil moisture; Soil properties