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Enhancement of wind erosion by fire‐induced water repellency
Author(s) -
Ravi Sujith,
D'Odorico Paolo,
Herbert Bruce,
Zobeck Ted,
Over Thomas M.
Publication year - 2006
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2006wr004895
Subject(s) - environmental science , aeolian processes , soil water , erosion , arid , surface runoff , nutrient , wind speed , wind tunnel , hydrology (agriculture) , soil science , geology , geotechnical engineering , ecology , paleontology , oceanography , geomorphology , biology , aerospace engineering , engineering
The occurrence of fire and the subsequent increase in wind erosion are known to affect vegetation dynamics in dryland landscapes. Fires act as a disturbance on shrubs and trees and expose the soil surface to the erosive action of wind, thereby affecting the loss and redistribution of soil nutrients. Despite the relevance of wind erosion and fires to the dynamics of arid ecosystems, the interactions between these two processes remain poorly understood. We have investigated how a representative water repellent organic compound released by burning biomass and absorbed in the soil may enhance soil erodibility. To this end, we carried out a series of wind tunnel experiments, laboratory tests, and theoretical analyses to assess the effect of fire‐induced water repellency on the soil susceptibility to wind erosion. The experiments were carried out using clean, well‐sorted sand which was artificially coated with palmitic acid, a common water repellency inducing fatty acid found in most plants. The results indicate that fire‐induced water repellency enhances soil erodibility, causing a drop in wind erosion threshold velocity. The results are explained by the effect of water repellent compounds on soil‐water contact angle and on the strength of interparticle wet‐bonding forces.