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The review highlights the significant untapped potential for climate change mitigation and adaptation associated with improved management of grazing lands in pastoral systems and rangelands. Grasslands and rangelands deserve greater attention, not only for their large extent, widespread degradation and limited resilience to drought and desertification, but also for their potential capacity to sequester and store carbon in soils. Degradation of the land base negatively affects the accumulation of carbon in the soils. Thus, reversing land degradation in extensive dryland areas through improved pasture and rangeland management would contribute to restoring the soil carbon sink while also improving livelihoods of pastoral and agropastoral peoples. The review also highlights the multiple benefits of enhancing ecosystem services and processes for improving livelihoods while contributing to adaptation to climate change impacts. Realizing this potential will require increased awareness and coordinated global efforts alongside interventions that address associated socio-political and economic barriers, such as land tenure constraints and inadequate services for, and political marginalization of, pastoral and agropastoral communities. The opportunity to support climate change mitigation in drylands that will simultaneously contribute to climate change adaptation and reduced vulnerability of pastoral societies should be a key area of focus in post-Kyoto mechanisms.

El objetivo principal de la investigación en la ciencia del suelo es la comprensión de la naturaleza, propiedades, dinámicas y funciones del suelo como parte del paisaje y los ecosistemas. Un requerimiento básico para lograr ese objetivo, es la disponibilidad de información confiable sobre la morfología de los suelos y otras características obtenidas a través del estudio y la descripción del suelo en el campo. Es importante que la descripción del suelo sea hecha exhaustivamente; esto sirve como base para la clasificación del suelo y la evaluación del sitio, así como para realizar interpretaciones sobre la génesis y funciones medioambientales del suelo. Una buena descripción de suelos y el conocimiento derivado en cuanto a la génesis del mismo, son también herramientas útiles para guiar, ayudar en la explicación y regular el costoso trabajo de laboratorio.

A new database on the world’s soils improves knowledge of the current and future land productivity as well as the present carbon storage and carbon sequestration potential of the world’s soils. It helps to identify land and water limitations, and assist in assessing the risks of land degradation, particularly soil erosion risks. Derived from the soil database, FAO has produced a global Carbon Gap Map that allows for the identification of areas where soil carbon storage is greatest and the physical potential for billions of tons of additional carbon to be sequestrated in degraded soils. Soil information, from global to local scale, has often been the one missing biophysical information layer, which absence added to the uncertainties of predicting potentials and constraints for food and fibre production. The lack of reliable and harmonized soil data has hampered considerably land degradation assessments, environmental impact studies and adapted sustainable land management interventions.

Throughout Africa, degrading land resources and poor water management are serious impediments to the development of agriculture. Inappropriate farming practices result in soil erosion, a loss of soil organic matter and declining fertility and capacity to retain water. Once-fertile soils become compacted and crusted, causing valuable rainwater to run off rather than seep into the ground and carrying with it precious topsoil and nutrients. The results are unhealthy crops due to water and nutrient deficits and the build-up of weeds and diseases, poor and unreliable yields, and chronic water shortages due to lack of recharge of ground water. How to escape from this vicious cycle? FAO and other development organizations have been promoting farmer field schools – an innovative approach to adult education first developed in Southeast Asia for pest management – to improve land and water management in Africa.

The maintenance of good soil quality is vital for the environmental and economic sustainability of annual cropping. A decline in soil quality has a marked impact on plant growth and yield, grain quality, production costs and the increased risk of soil erosion. Therefore, it can have significant consequences on society and the environment. A decline in soil physical properties in particular takes considerable time and cost to correct. Safeguarding soil resources for future generations and minimizing the ecological footprint of annual cropping are important tasks for land managers. Visual Soil Assessment is based on the visual assessment of key soil ‘state’ and plant performance indicators of soil quality, presented on a scorecard. With the exception of soil texture, the soil indicators are dynamic indicators, i.e. capable of changing under different management regimes and land-use pressures. Being sensitive to change, they are useful early warning indicators of changes in soil condition and as such provide an effective monitoring tool.

Land evaluation is a vital link in the chain leading to sustainable management of land resources. There is a perceived need to update the FAO 1976 Framework for Land Evaluation to reflect current concerns related to climate change, biodiversity and desertification. The goods and services of the land that are related to its multiple functions or benefits as well as the sustainability of its use need to be addressed. New tools to conduct land evaluation have become available and the need for a participatory approach has been recognized.Many concepts and definitions of the original Framework remain valid; others evolved and new concepts arose over the past 25–30 years.