Soil heterogeneity and earthworms independently promote growth of two bamboo species

Abstract

Soils are commonly spatially heterogeneous and earthworms are widely distributed in terrestrial ecosystems. While both soil heterogeneity and earthworms can influence the performance of plants, whether they can interact to affect the growth of bamboo species has not been examined. In a greenhouse experiment, we planted two dwarf bamboo species, Sasa argenteosriata and Sasaella glabra, separately in a heterogeneous soil consisting of two different types of soil patches and in a homogeneous soil in which the two types of soil patches were evenly mixed. These soils were added with or without earthworms. Both S. argenteosriata and S. glabra grew more in the heterogeneous soil than in the homogeneous soil and in the soil with earthworms than in the soil without earthworms. Soil heterogeneity and earthworms did not interact to influence the performance of either bamboo species. Independent of the presence of earthworms, both bamboo species grew equally well in the two types of soil patches within the heterogeneous soil, indicating that the foraging behavior of bamboos is weak; this is likely because resource translocation between interconnected ramets located in different soil patches homogenized plant responses to different resource levels. These results indicate that a heterogeneous supply of nutrients may aid in the growth of bamboo species, and these actions should be integrated into the sustainable management of bamboo forests.