There are many sever aboitic stresses threatening our environment and affecting humans in many ways. One of these major a biotic stresses that is a major problem in many areas of the world particularly in Bangladesh is the soil salinity. Also in Australia secondary soil salinity is a major problem. Soil salinity is defined as the content of soluble salt in the water or soil in arid areas. Such areas have insufficient rainfall or drainage to wash away the salt from the soil so that the plants don’t get affected. There are two major types of soil salinity. The primary or geological soil salinity and the secondary or dry-land soil salinity, the primary salinity is that the earth or soil was saline already before the human settlement. However the secondary soil salinity has been caused by human activities for agricultural purposes. Thus the water table rose close to the surface which affected the soil. Particularly in Australia It has been complicated to distinguish between primary and secondary soil salinity, when analysing a particular site, because the primary salinity has expanded due to human agriculture activities. Globally so many scientists have tried many techniques and strategies to reduce soil salinity, like developing salinity tolerant plants.
Cause of soil salinity
Soil became saline by two types of salinity. The primary and secondary salinity, primary salinity is the production of natural processes such as wind blow, weathering of rocks and rain depositing salt over thousands of years. In Australia salt has been naturally distributed unevenly throughout the country before the European settlements and its patterns or its impacts vary in eastern and western areas of the country Roberts AM et al 2009). In eastern areas the salinity is more restricted to that particular area, however in western regions the salinity is spreading widely throughout the landscape (Roberts AM et al 2009). In Australia secondary salinity is the major environmental problem which is the result of clearing the native vegetation for agriculture purposes or altering the form of the land (Roberts AM et al 2009). The main processes that cause secondary salinity are raising water tables, transient salinity and irrigation salinity.
Rising of the watertable by removing the deep rooted native plants and replacing them by shallow-rooted plants that requires less water Deep-rooted native plant like trees pushes and shrubs pushes the water table down and preventing them to come close to the surface (Roberts AM et al 2009). Due to vegetation imbalances more water passed through the soil raising the water table. Thus water table came close to the surface and that mobilised the salt to the soil surface (Roberts AM et al 2009). Transient salinity usually course in poor dry saline land where salts are seasonally moved in and out of the soil which was contained inside the root region of the crop (Ma C. et al 2012). The irrigation salinity is when plants are...