5 Conclusion
The results of this study suggest that increases in RFC promote deep
distribution of fine roots in the three woody species, mainly owing to
the low water and nutrient levels of the coarse soil and penetration
into the deep soil layer. High RFC also increased the biomass and length
density of fine roots in the soil profile, particularly in the soil
layer below 30 cm, which prompted plants to occupy deep soil spaces.
With increasing age, the changes in soil structure had a cumulative
decreasing effect on fine root vertical distribution; that is, the
increasing years of growth reduced the variation ranges in fine root
depth and biomass of the three woody species along the RFC gradient. The
RFC also influenced the decrease in range of fine root diameter over
years, with the greatest range observed under 75% RFC. We also found
that interspecific differences in root distribution and the dynamic
response to RFC gradient, fine root depth, and biomass of A.
vestita decreased with the increase in soil RFC and age, which was
inconsistent with the increasing trend in woody
species. These results provide
insight into the
adaptive
processes of plant under rocky soils and have profound management
implications for tillage in degraded ecosystems.