Spatial Prediction of Soil Salinity and Its Impact on Land Evaluation in Some Areas of Menoufia Governorate Using Remote Sensing and Gis

Abstract

The current work aims to study the geomorphological and pedological characteristics including classification and land capability evaluation of soils in the area located at the northeastern part of El Sadat City, Menoufia governorate, Egypt. Soil water characteristic curve, validating Van Genuchten (VG) model in simulating SWCC, developing regression equations to predict the expected soil salinity over time and land use/land cover change detection within 20 years are also carried out. The integration of Remote Sensing (RS) and Geographic Information System (GIS) techniques was used to perform this work. The produced geomorphic map indicated that, there are three main identified geomorphic units namely Alluvial Plain, Pedi Plain and Aeolian Plain including eight landforms in this area. Nineteen soil profiles were selected representing these landforms. The land and site features are registered. Soil profiles were dug and morphologically described, and then disturbed and undisturbed samples were collected from the subsequent layers for integrated physical and chemical analyses. Also, irrigation water samples were collected and analyzed especially for land capability evaluation. The studied soils have almost flat to gently undulating topography. The elevation varies between 10 and 95 m above sea level. The soils are deep and well drained. These soils have mostly gravely sandy loam with rapid hydraulic conductivity and weak to moderate sub angular to granular structure and some layers have single grains. The analytical data revealed that, these soils have mostly slightly alkaline reaction. Most of them are non-saline and not sodic. Few soils have moderate alkaline reaction with sodicity effect. The soils are slightly to moderately calcareous having low organic matter and gypsum. Most of the studied soils were classified under Entisols order and the others that having sodic horizon are classified under Aridisols. Land capability evaluation indicated that, most of the studied soils (about 92%) are classified under fair class (C3). Soil water characteristic curves for the studied soils were produced and regression equations were developed to predict the expected soil salinity over the time. The overall changes in Land use/Land cover classes during 20 year indicated that, there is an increase in the agricultural area and built-up land at the expense of the barren land.