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Displaying 1561 - 1572 of 2001

Tracking desertification on the Mongolian steppe through NDVI and field-survey data

Journal Articles & Books
Dezembro, 2011
Mongólia
Ásia Oriental

Changing environmental and socio-economic conditions make land degradation, a major concern in Central and East Asia. Globally satellite imagery, particularly Normalized Difference Vegetation Index (NDVI) data, has proved an effective tool for monitoring land cover change. This study examines 33 grassland water points using vegetation field studies and remote sensing techniques to track desertification on the Mongolian plateau.

Natural and Fire-Induced Soil Water Repellency in a Portuguese Shrubland

Journal Articles & Books
Dezembro, 2011

Post-fire land degradation is often attributed to fire-induced soil water repellency, despite the fact that soil water repellency is a natural phenomenon in many soils and is therefore not necessarily caused by fire. To improve our understanding of the role of soil water repellency in causing fire-induced land degradation, a long-term monitoring study was performed in which the temporal variation of topsoil water repellency (0–2.5-cm depth) was captured in a Portuguese shrubland before and after fire between November 2007 and March 2010.

Integration of legume trees in maize-based cropping systems improves rain use efficiency and yield stability under rain-fed agriculture

Journal Articles & Books
Dezembro, 2011
Zâmbia
Nigéria
África

Water availability is a major constraint to crop production in sub-Saharan Africa (SSA) where agriculture is predominantly rain-fed. This study aimed to investigate the effect of the nitrogen-fixing legume tree Leucaena (Leucaena leucocephala) and inorganic fertilizer on rain use efficiency (RUE), a robust measure of productivity and land degradation, in three long-term (11–12 years) experiments conducted in Zambia and Nigeria.

Desertification and livestock grazing: The roles of sedentarization, mobility and rest

Journal Articles & Books
Dezembro, 2011

Pastoralism is an ancient form of self-provisioning that is still in wide use today throughout the world. While many pastoral regions are the focus of current desertification studies, the long history of sustainability evidenced by these cultures is of great interest. Numerous studies suggesting a general trend of desertification intimate degradation is a recent phenomenon principally attributable to changes in land tenure, management, and treatment.

Desertification and livestock grazing: The roles of sedentarization, mobility and rest

Journal Articles & Books
Dezembro, 2011

Pastoralism is an ancient form of self-provisioning that is still in wide use today throughout the world. While many pastoral regions are the focus of current desertification studies, the long history of sustainability evidenced by these cultures is of great interest. Numerous studies suggesting a general trend of desertification intimate degradation is a recent phenomenon principally attributable to changes in land tenure, management, and treatment.

Desertification assessment and mapping in the Russian Federation

Journal Articles & Books
Dezembro, 2011
Rússia

For the first time assessment and mapping of desertification have been performed in Russia at the 1 : 2500000 scale using data of geometrical sounding of the earth and in accordance with the approaches recommended by the United Nations Convention to Combat Desertification (UNCCD). It is shown that desertified areas, areas experiencing desertification, and areas threatened by desertification occupy about 1250000 km2. Nineteen causes of changes in natural and natural-artificial systems, seven degradation trends, and three progradation trends are recognized.

Numerical research of extreme wind-induced dust transport in a semi-arid human-impacted region of Mexico

Journal Articles & Books
Dezembro, 2011
México

A numerical research is carried out to investigate the regional impact of extreme wind-induced dust transport in the central-northern part of Mexico. In boreal winter, strong wind soil erosion processes occur in the arid zones of the Mexican highlands, as a consequence of land use change and land cover change. The effect of land use change and land cover change has consequences in the atmospheric circulation, by altering the balance in solar radiation, albedo, soil moisture and texture, aerodynamic roughness and other surface properties.

Oil content and lipid composition of safflower (Carthamus tinctorius) irrigated with saline water under greenhouse and field conditions

Journal Articles & Books
Dezembro, 2011
Usbequistão

An intensive process of land deterioration of some regions in Uzbekistan including the Aral Sea basin has led to a significant increase in soil salinity levels and consequently to a considerable reduction of total fertile soil area, as these lands are of little use for plant growth. The area is estimated to be more than 1.4 million ha of seabed. As a result, there was an immediate need to cultivate new crops capable of stopping the movement of sands and the enlargement of saline soils.

empirical approach to estimate soil erosion risk in Spain

Journal Articles & Books
Dezembro, 2011
Espanha

Soil erosion is one of the most important factors in land degradation and influences desertification worldwide. In 2001, the Spanish Ministry of the Environment launched the ‘National Inventory of Soil Erosion (INES) 2002-2012' to study the process of soil erosion in Spain. The aim of the current article is to assess the usefulness of this National Inventory as an instrument of control, measurement and monitoring of soil erosion in Spain. The methodology and main features of this National Inventory are described in detail.

Quantitative mapping of global land degradation using Earth observations

Journal Articles & Books
Dezembro, 2011

Land degradation is a global issue on par with climate change and loss of biodiversity, but its extent and severity are only roughly known and there is little detail on the immediate processes – let alone the drivers. Earth-observation methods enable monitoring of land degradation in a consistent, physical way and on a global scale by making use of vegetation productivity and/or loss as proxies. Most recent studies indicate a general greening trend, but improved data sets and analysis also show a combination of greening and browning trends.

dynamics of groundwater table and salinity over 17 years in Khorezm

Journal Articles & Books
Dezembro, 2011
Usbequistão
Ásia Central

Salinization of irrigated agricultural land threatens ecological sustainability and livelihoods of people. Salinization is especially severe in the dry lowlands world-wide and in Central Asia where large amounts of salts accumulated in the soil profile, originating from shallow saline groundwater (GW).

Analysis of trends in the Sahelian ‘rain-use efficiency’ using GIMMS NDVI, RFE and GPCP rainfall data

Journal Articles & Books
Dezembro, 2011
África
Global

Rain-use efficiency (RUE; the ratio of vegetation productivity to annual precipitation) has been suggested as a measure for assessing land degradation in arid/semi-arid areas. In the absence of anthropogenic influence, RUE has been reported to be constant over time, and any observed change may therefore be attributed to non-rainfall impacts. This study presents an analysis of the decadal time-scale changes in the relationship between a proxy for vegetation productivity (ΣNDVI) and annual rainfall in the Sahel-Sudanian zone of Africa.