Mapping soil salinity in the East Nile Delta using several methodological approaches of salinity assessment

Abstract

Soil salinization is one of the most serious problems facing soil fertility, crop productivity and sustainable agricultural development in Egypt. The risk of salinization is present, when it leads to toxicity. This study focuses on evaluation of soil salinization at East of Nile Delta to enhance management strategy program using geographical information system (GIS). Two different classifications of salt-affected soils, agronomic classification and Russian classification, were used. Ninety-two surface soil samples were collected at depth 0–30 cm. Inverse distance weighting (IDW) was used for spatial distribution mapping of soil salinity and salinization degree. Normalized Difference Vegetation Index (NDVI) was used to identify the correlation between vegetation density cover and soil salinity levels. The obtained data and salinity maps of the studied area presented that salinity levels according to agronomic classification occupied areas of 60% – non-saline, 15% slightly saline, 13% moderately saline, 2% strongly saline and 10% for extremely saline level. Nevertheless, soil salinization degrees according to Russian classification located 71% – non-saline, 10.5% – slight saline, 9% – moderate saline, 3.8% strongly saline and 5.7% for very strongly saline of the investigated area. On the other hand, the results showed reasonable correlation between NDVI, salinity (EC) and total toxic salts (%) (R2 = 0.58 with salinity and 0.65 with toxic salts). Finally, precise soil salinity management should consider the concentration of total toxic salts and chemical composition of salts.