Land degradation from soil erosion has been considered by many to be a problem of significant proportion, affecting some 30-50% of the earth's land surface. At the time of the first publication of this book in 1993, estimates indicated that 10-15 million hectares of land were being lost each year through erosion and salinisation from irrigation and that at such a rate of loss, topsoil reserves on most sloping lands would be depleted within two hundred...