Biomass production and relative competitiveness of a C-3 legume and a C-4 grass co-dominant in the semiarid Loess Plateau of China (vol 347, pg 25, 2011)

摘要

This paper presents a displacement-based model for predicting the relationship between the increase in shear resistance and shear displacement for soils permeated with an entire plant root system. The root force in the root system is estimated based on the shear deformation developed in the soil. This displacement-based model takes a number of factors into account, including the distribution of the shear deformation in the soil, the root orientation, the mobilized root forces, and the root properties. The proposed model reasonably captures the relationship between the increase in the shear resistance (Delta S) and the shear displacement, as shown by a comparison of the predicted results with data from in situ shear tests. Major findings are the following: (1) the Delta S value increases considerably with increasing b coefficients, which are used to describe the deformed shape of the shear zone, and Young's moduli of roots at the early stage of shearing; (2) the Delta S value increases significantly with the tau value at large shear deformations; (3) short roots play an important role in the contribution of root systems to the shear resistance of the soil. However, the success of the model relies on the appropriate estimate of the deformation characteristics on the shear zone and the soil-root bond strength.