How does degradation occur

Off-site eolic erosion was important in the Federal District D. This issue became aggravated when this zone was used for discharging wastewater from D. Chemical degradation is the most extensive soil degradation process in Mexico This type of degradation occurs in all states, the most affected being Yucatan The dominant chemical degradation type was the reduction in soil fertility This degradation type occurs in more than half of Yucatan and nearly one third of Tlaxcala, Chiapas, Morelos, Tabasco and Veracruz Table 3.

The other specific chemical degradation types pollution 4 , salinization and eutrophication are far less widespread, altogether representing 7. Chemical soil degradation derived from pollution is due to the presence, concentration and adverse biological effects of some chemicals.

Salinization or alkalinization is an increase in salt content in surface soil which leads to a decline in crop yield, among other effects. This occurs mainly in arid zones, closed basins and coastal areas with naturally saline soils. Irrigation systems using high-sodium water may cause the formation of a salt-deposit layer in the surface of soils with poor drainage, excessive irrigation or heavy evaporation. Eutrophication is the presence of excessive nutrients in soil that affect plant development.

The causes of chemical soil degradation involve a wide range of industrial and agricultural activities, including hydrocarbon spills, excessive fertilizer and pesticide application, poor materials management, hazardous and urban solid wastes.

Fertility drops when nutrient input, either by chemical or biological fertilization or retention of crop wastes, is lower than nutrient output as crop products or resulting from burning practices and leaching.

Physical soil degradation may occur as five different specific types: compaction, encrusting, flooding, water availability reduction and productivity loss.

Compaction is the destruction of soil structure 5 frequently associated with cattle trampling or the continued transit of heavy machinery, resulting in the rupture of soil aggregates. In encrusting, soil pores are filled with fine materials, preventing rainwater infiltration and leading to a rise in surface runoff and hydric erosion.

Soil encrusting is higher in sparsely vegetated areas with low organic matter content, thus increasing the mechanical damage of raindrops. Flooding derives from the presence of a surface water layer upon soil, frequently associated with the construction of irrigation dams. The opposite to flooding is the decrease in water availability resulting either from excessive water extraction for use in agriculture or population supply, or from the reduction in plant cover and soil organic matter.

Physical degradation is the less extended degradation process in the country, affecting only 5. Tabasco is the most severely affected state Encrusting, flooding and water availability reduction jointly affected 0.

The state most severely affected by compaction was Tabasco As for degradation levels, extreme physical degradation encompassed 1. Relationship between soil degradation and plant cover. Soil degrades as a result of a number of environmental and socioeconomic factors including topography, climate, production and land-owning systems, public policies and market. Soil degradation and vegetation cover loss are rarely triggered by a single factor, although the ultimate factors in nearly every case are human activities through changes in soil use, replacing natural vegetation by land dedicated to agriculture and cattle raising.

Despite no specific studies have been conducted to date to assess the relationship between soil degradation and vegetation cover in Mexico, the combination of the most recent national degradation Semarnat-CP, and land-use and vegetation charts INEGI, Serie III provide a good approximation of its status in Mexico.

According to this exercise, soil degradation was detected even in areas covered by natural vegetation. About soil maps. Laboratory soil test methods. Soil publications. Geodiversity expand Geodiversity. Karst and caves. Karst Management Advisory Committee. Topics Land and soil Soil degradation Soil degradation Understand how the quality of soil declines and what causes this decline. Soil Talk! The following buttons will open a feedback form below Was this page helpful?

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The world population is projected to increase by about 35 percent to 9. However, pressure on the global land resource is increasing due to other factors as well, such as agricultural production systems made less resilient by the loss of biodiversity, and natural factors such as climate variability and extreme weather events.

Climate change exacerbates variations in yields and income from agriculture, threatening the resilience of agro-ecosystems and stability of food production systems. The problems are particularly severe in the driest parts the planet. The vast majority of people who depend on drylands live in developing countries, where women and children are most vulnerable to the impacts of land degradation and drought.

The GEF recognizes that all productive landscapes, from the drylands of Africa and Asia to the sub-tropical grasslands of South America, and temperate forests in Europe must be managed carefully and sustainably. Our investments to arrest and reverse desertification and deforestation cover a wide range sectors — from crop and livestock production to water resource management.

The Conference of the Parties to the UNCCD recognizes Land Degradation Neutrality LDN as a concept that can help communities, businesses, and governments reconcile the need to intensify food production without degrading land resources.

Essentially, LDN is about managing land more sustainably to reduce degradation, while increasing rates of land restoration. The two ends converge to give a zero-net rate of land degradation.

Our investments have greatly enhanced the potential for restoring degraded land. And our work in land degradation supports other focal areas such as Biodiversity and Climate Change by generating multiple benefits. The GEF support helped to mainstream SLM into village development plans, develop conflict resolution systems, including specific financing mechanisms, and training.

The GEF is well-placed to help countries implement convention decisions and facilitate coordinated investments in sustainable land management practices, including LDN.

GEF investment will seek to address the drivers of land degradation, robust assessment of experience and existing knowledge, and knowledge and experience. The GEF strategy has two primary objectives:. The Food Systems, Land Use, and Restoration FOLUR Impact Program provides the opportunity for an integrated approach to implementing sustainable land management to increase the prospects for food security for smallholders and communities that are dependent on farming for their livelihoods.

The Sustainable Forest Management SFM Impact Program seeks to avoid further degradation, desertification, and deforestation of land and ecosystems in drylands through the sustainable management of production landscapes. Creating an enabling environment to support voluntary LDN target implementation. A conducive enabling framework and overarching political support through the Convention is essential for LDN investments.