Advances in Soil Science: Volume 15 - Tapa blanda

The study of soils has taken on increased importance because a rapidly expanding population is placing demands on the soil never before experi­ enced. This has led to an increase in land degradation. Land degradation is one of the most severe problems facing mankind. Volume 11 of Advances in Soil Science was devoted entirely to this critical area of soil science. The editors of that volume, R. Lal and B.A. Stewart, defined soil degradation as the decline in soil quality caused by its misuse by humans. They further stated that soil degradation is a major concern for at least two reasons. First, it undermines the productive capacity of an ecosystem. Second, it affects global climate through alterations in water and energy balances and disruptions in cycles of carbon, nitrogen, sulfur, and other elements. Through its impact on agricultural productivity and environment, soil deg­ radation leads to political and social instability, enhanced rate of deforesta­ tion, intensive use of marginal and fragile lands, accelerated runoff and soil erosion, pollution of natural waters, and emission of greenhouse gases into the atmosphere. In fact, soil degradation affects the very fabric of mankind.

The study of soils is increasingly important due to growing demands on soils by rapidly expanding populations. Volume 15 of Advances in Soil Sciences is a mixed-topic volume in this series; consisting of five critical review articles: 1. VA Mycorrhizae as modifiers of soil fertility (J.M. Barea, Estacion Experimental del Zaidin, Granada, Spain) 2. Argillic horizons in modern loess soils in an ustic soil moisture regime? (A. Bronger, University of Kiel, FRG) 3. Myths and scientific realities of agroforestry as a strategy for sustaining management of soils in the tropics (R. Lal, Ohio State University, Columbus, OH) 4. Land evaluation: from intuition to quantification (C.A. van Diepen et al. Winand Staring Center for Integrated Land, Soil and Water Research, Wageningen, The Netherlands) 5. Crop residue management (R. Prasad, Indian Agri- cultural Research Institute, New Delhi, India)