Use of Geospatial Technology for Assessment of Waterlogging & Salinity Conditions in the Nara Canal Command Area in Sindh, Pakistan

摘要

Agriculture is being main stay of Pakistan economy and it’s very significant to monitor the existing agricultural areas and its changes, due to different aspects like salinity and waterlogging, which reduce the fertility of agricultural lands adversely. Managing salinity so as to minimize its environmental impact is a prerequisite for the long-term sustainability of irrigated agriculture. It is ironic that the irrigated areas are those that are afflicted most by the twin menaces of waterlogging and salinity. Geospatial technology was used to assess the waterlogging and salinity condition in Nara canal command area, during the last two surveys conducted in years 1977-1981 and 2001- 2003 respectively. After analyzing the results in detail, we obtain a clear relationship among salt affected soils, and waterlogged areas reveal that 0.2% to 1.25% of salt affected areas fall under the shallow zone with high water table. The spatial distribution of water table shows various trends among the water tables, and the surface salinity of surface saline areas has been increased due to waterlogging caused by unmanaged spatial drainage system.