Salinization in semi-arid irrigated agricultural regions

Abstract:

Large-scale introduction of canal irrigation systems across the semi-arid regions of the World has disturbed hydrologic equilibrium of many groundwater basins. This has resulted in rise of groundwater levels followed by degradation of soils through water logging and secondary saltbuild-up in many canal commands, and caused millions of hectares of irrigated agricultural land to go out of production. On the other hand, extensive pumping of groundwater for irrigation in some freshwater aquifers has lowered hydraulic heads and induced cross-formational flow from underlying highly mineralized older formations, which led to groundwater mixing between the formations and rise insalinity levels in the overlying fresh water aquifers over time. Some examples related to irrigation induced soil and groundwater salinization from India and the United States will be presented. Potential causes of salinization and possible solutions will be discussed.