Natural accumulation of salt in soils is an outcome from previous cycles of drainage, desiccation and sea winds.
Factors such as climate, features of landscape, soils, drainage, aspect and the effects of human activities; all impact on the severity and occurrence of dryland salinity.
Dryland salinity effects human and natural resources, such as native vegetation and crops, animals, infrastructure, agricultural inputs, biodiversity, aquatic ecosystems and water supply quality in the environment.
Recharge may also occur by saturated flow when water bypasses the soil matrix as it moves to depth in macropores (e.g. root holes, fractures).
(Environment.nsw.gov.au, 2013) Evapotranspiration is reduced, as vegetation is lost, resulting in an imbalance in groundwater recharge and discharge, causing the water table to rise.
(Barry and Holwell et al., 2012) Prevention and alleviation of dry land salinity is a simplistic concept in theory however complex in application.
Ceasing the removal of deeply rooted vegetation in order to moderate unbalanced groundwater recharge and the replanting of deeply rooted vegetation such as Eucalyptus and salt tolerant species in regions where salinity is present, will start to alleviate the salt and ground water discharge problems.
Dryland salinity is a sign that the water balance of the nearby area of land or catchment has been altered.
Restoring the balance requires either the introduction of natural vegetation (e.g. mallee eucalyptus or perennial grasses), which intercepts and transpires most of the incoming rainfall; or by adapting agriculture to the increased area of shallow, saline groundwater.
The manifestation of dryland salinity is largely a problem of groundwater – however the accumulation of salt within the soil and at the surface due to proximity to or saturation by saline groundwater causes changes to the soil’s chemistry, structure and stability, and the plant life that it supports.
Engineering systems include deep open drains, pumps, siphons and various forms of surface water management.