Most commonly in drylands the salinity levels are always high and evenly dispersed due to this salinity levels the plant cultivated are usually tremendously affected. Normal plants cannot grow in soils with high salinity levels. In this book the authors would like to analyze the effects of human acticities on the salinity lebvels in drylands.
Dryland salinity is a natural process for soil, just like other processes such as wind erosion. Salinity degrades land by an increase in soil salt concentration in the environment, watercourse or soil in unirrigated landscapes, being in excess of normal soil salt concentrations in dryland regions.
Land productivity may be limited in salt-affected areas due to the toxicity of dissolved salts for plants or due to the destruction of soil structure that then restricts water infiltration capacity. Soil salinity is site-specific. Interventions may be prohibitively expensive and must be carefully managed. Saline soils may be treated by improving sub-surface drainage and applying sufficient water to move salts out of the root zone. Sodic or alkali soils can be treated through the application of chemicalbiological amendments, such as gypsum, along with organic manure.
Adoption of crop-rotation systems using salt-tolerant crops (halophytes), followed by legumes and avoiding fallow periods may improve the soil resource. For example, Quinoa (Chenopodium quinoa Willd), a salt-tolerant crop, is widely used in saline environments.
A large proportion of salt-affected soils in irrigated areas occur on small farms with limited access to resources. Many affected farmers must supplement their low on-farm income with off-farm economic activities. This potentially limits their ability to invest in many salinity management opportunities.
Although salt-affected soils are of low fertility and limited agricultural value, they can provide an alternative resource for growing biomass for renewable energy.
Authors and Publishers
The United Nations Convention to Combat Desertification in Those Countries Experiencing Serious Drought and/or Desertification, Particularly in Africa (UNCCD) is a Convention to combat desertification and mitigate the effects of drought through national action programs that incorporate long-term strategies supported by international cooperation and partnership arrangements.