Environmental analysis of soil characteristics in El-Fayoum Governorate using geomatics approach

The present study aims at identifying the impact of wastewater irrigation on soil characteristics of El-Fayoum Governorate using Landsat images and geo-statistical techniques integrated with field investigation and soil analyses. Soil samples were collected from 40 representative sites during November/December 2016 and analyzed for pH, electric conductivity (EC), organic carbon (OC), total nitrogen (TN), total phosphorus (TP), Ca, K, Na, and Mg. Landsat images were processed to produce spectral indices of water (MNDWI), vegetation (NDVI), salinity (NDSI), and urban areas (NDBI). Inverse distance weighting in ArcGIS 10.1 was used for mapping soil characteristics. Results refereed to a fluctuation in soil characteristics among different districts, as a result of variation and severity of activities. High levels of OC (3.5-5.21%) were recorded in several scattered parts while northern parts showed high levels of TP and TN recording 0.8-1.7 mg/g and 1.7-2.4 mg/g respectively. A great fluctuation in salinity, Ca, K, and Na levels were detected among the collected soil samples. Southern and eastern borders of the governorate showed high levels of Ca (> 17.7 mg/g). The most alkaline soil samples (> 8) were mostly recorded in El-Fayoum and Tamia districts. Variation of soil characteristics is greatly impacted by irrigation using wastewater particularly from El-Bats and El-Wadi drains. A strong positive correlation (0.94) was observed between urbanization (NDBI) and land salinization (NDSI) which ensures the negative impact of residential areas on agricultural lands. It can be concluded that the agricultural land problems have greatly been impacted by the lack of sufficient water supply. Geospatial techniques along with soil analyses facilitate studying such problems.