Desertification of Agricultural Lands in Egypt by Remote Sensing
Principal Investigators: Dr. Curtis Woodcock, Dr. Hassan Hamdi
Collaborators: Soil and Water Research Institute, Remote Sensing Unit, Ministry of Agriculture, Giza, Egypt
Participants: Dr. Glen Green
Graduate Students: Mary Pax-Lenney, John Collins
Sponsors: USDA/OICD United States Department of Agriculture Office of International Cooperation and Development and NARP National Agriculture Research Project, Cairo, Egypt
Duration: October 1992-September 1993
The desertification of cultivated lands threatens agricultural productivity in Egypt by removing arable land from production. While remote sensing holds the potential to provide critical information on the location and extent of these phenomena, agrarian practices in Egypt preclude the use of traditional methods based on 1 or 2 images. The mild climate and ready access to irrigation water from the Nile permit fields to support 2 or 3 crops per year within a flexible cropping schedule. Under such circum stances, temporarily fallow yet healthy fields are indistinguishable from nonproductive lands in a single image.
The primary objective of this research was to develope and test new methods to identify and monitor the status of agricultural lands in Egypt. Special attention was given to the identification of fields of reduced productivity in the Delta, urban expansion onto previously productive agricultural lands, and the reclamation of desert and coastal lands for agricultural use. The study area covered the western Nile Delta and adjacent Western Desert.
A multitemporal NDVI dataset was created from 10 Landsat TM images acquired from June 1984 to April 1993. Productive lands showed both a higher maximum NDVI value and a greater range of values than fields subject to desertification processes such a eleva ted soil salinity levels or waterlogging. The results of the study show that as of 1993, 40,048 hectares (3.74%) of arable lands in the western Delta were nonproductive. From 1984 to 1990, land devoted to urban use in the western Nile Delta increased by 10.13%; this represents less than 0.4% of healthy agricultural lands. Reclamation of desert and coastal lands partially offset these losses; from 1986 to 1993, a total of 92,780 hectares of desert and coastal lands were converted to productive agricultur al use. Cultivated lands in the desert and coast increased by 43.3% during this time. The feasibility of detecting saline soils directly with remote sensing was also evaluated. Results showed that compounding factors masked all but the most severe salt encrusted soils.
This study shows that the status of agricultural lands can be assessed accurately using multitemporal NDVI features.
- Woodcock, CE., El-Baz, F., Hamdi, H. et. al (1994), Desertification of Agricultural Lands in Egypt by Remote Sensing. Final Report.
- Pax-Lenney, M., Woodcock, C.E., Collins, J. and Hamdi, H. (1996). The status of agricultural lands in Egypt: The use of multitemporal NDVI features derived from Landsat TM. Remote Sensing of Environment. In Press.
- Pax-Lenney, M., and Woodcock, C.E. (1996). Monitoring agrcultural lands with multitemporal Landsat TM imgaery: How many images are needed. Submitted to Remote Sensing of Environment.
- Pax-Lenney, M. and Woodcock, C.E. (1996). The effect of spatial resolution on the ability to monitor the status of agricultural lands. Submitted to Remote Sensing of Environment.