Evaluation of Land Degradation in Agricultural Areas within Damietta Governorate, Egypt Caused by Urban Encroachment, Salinity, Sodicity and Loss of Fertility

Abstract

Land degradation is one of the most serious problems over time, where it is the main cause of declining agricultural productivity worldwide. The main objectives of this work were to monitor and evaluate land degradation of agricultural area in Damietta Governorate caused by urban encroachment, salinity, sodicity and loss of fertility. Accordingly, Landsat images were collected at four periods of time (1989, 2000, 2014 and 2019) to study the spatio-temporal changes in agricultural land over time. The soil adjusted vegetation index (SAVI) was used for studying the vegetation cover. Soil samples were also collected from 30 soil-profiles at three soil depth intervals (0-30, 30-60, and 60-90 cm). They were analyzed for pH, EC, ESP and available NPK values. Ordinary Kriging (OK) was used for the surface interpolation of these soil properties. The obtained results indicated a significant reduction in agricultural land within Damietta Governorate from 502.45 km2 (78.94%) in 2000 to 463.66 km2 (72.85%) in 2019. Salt affected soils (SASs) were dramatically increased (particularly in subsurface layers) due to the poor drainage in the area and sea-water intrusion either from the Mediterranean Sea and/ or Manzala Lake. The status of available nitrogen and phosphorous ranged between low and moderate, whereas available potassium was very high in most of the studied locations. In conclusion, agricultural lands in Damietta Governorate are seriously affected by land degradation resulted from urban sprawl, salinity, sodicity and loss of fertility. Therefore, they need to enact laws and develop a special program for their management and remediation.