ASSESSMENT OF SOIL DEGRADATION IN THE NORTHERN PART OF NILE DELTA, EGYPT USING REMOTE SENSING AND GIS TECHNIQUES

摘要

The present work aims at monitoring soil degradation process within the last two decades in the northern part of Nile Delta The investigated area lies between longitudes 31° 00" & 31° 15' E and latitudes 31° 00' & 31° 37' N., covering an area of about 161760 feddans. Detecting soil degradation and recognizing its various types is a necessity to take the practical measures for combating it as well as conserving and keeping the agricultural soil healthy. Land degradation was assessed by adopting new approach through the integration of GLASOD/FAO approach and Remote Sensing / GIS techniques The main types of human induced soil degradation that observed in the studied area are salinity, alkalinity (sodicity), compaction and water logging On the other hand water erosion because of sea rise is assessed. The obtained data showed that, areas that were affected by compaction increment have been spatially enlarged by 40.9 % and those affected by compaction decrease have been spatially reduced by 22.6 % of the total area meanwhile areas that have been unchanged were estimated by 36.5% of the total area. The areas that were affected by water logging increase have been spatially enlarged by 52.2 % and those affected by water logging decrease have been spatially reduced by 10.1 % of the total area, meanwhile the areas which have been unchanged were represented by 37.7 % of the total area. Areas that were affected by salinity increase have been spatially enlarged by 31.4 % of the total area and those affected by salinity decrease have been reduced by 43.3 % of the total area. An area represented by 25.2 % of the total area has been unchanged. Alkalinization (sodicity) was expressed by the exchangeable sodium percentage (ESP).Areas that were affected by sodicity increase have been spatially enlarged by 33.7 %, meanwhile those affected by sodicity decrease have been spatially reduced by 33 6 % of the total area. An area represented by 32.6 % of the total area has been unchanged. Multi-dates satellite data from Landsat TM & ETM+ images dated 1983 and 2003 were used to detect the changes of shoreline during the last two decades. The obtained results showed that, the eroded areas were determined by 547.4 feddans , meanwhile the accreted areas were detected by 476.5 feddans during the twenty years period.