The geology of Jericho district is characterized by the Jordan rift valley deposits which are mainly composed of Marl & Pleistocene Alluvial formations. The geologic formations in the Jericho district, as shown in the geological map (Figure 3.1), are:

I. Alluvium Formation:

This formation covers the area adjacent to the Jordan Valley starting by a width of 1 km in the north and 5 kms in the south. It is of the Pleistocene to Recent in age. It is bounded structurally by the Jordan rift regional fault in the east and another fault of 12 km long in the west.

II. Lisan & Samra Formation:

This formation covers the greatest part of the Jericho district. It is of the Pleistocene to Recent age, and includes three local faults of up to 3 kms long. This area is bounded by the alluvium formation in the east and by a greater fault of about 13 kms long in the west. It is mainly composed of marl, chalk and conglomerates.

III. Chalk and Chert Formations:

These formations occupy the western part of the Jericho district. They are composed of the Senonian Chert and Chalk deposits and are covered structurally by minor faults.

IV. Metamorphic rock formations of Senonian to Neogene ages:

These formations are composed mainly of calcium silicates. They occupy small areas within the Chalk and Chart formations.

V. Dolomitic Limestone Formation:

This formation is composed mainly of limestone, dolomite and marl. It is of Cenomanian-Turonian in age, and occupies very small portions of the southwestern and northwestern parts of the Jericho district.

The system of faults distributed all over the district are responsible for the main emerged springs.

Land use

Jericho district has a total area of 35,330 hectares (353,300 dunums). Five major land use classes can be distinguished in the district. These are Palestinian built-up areas, Israeli settlements, closed military areas and bases, nature reserves and cultivated areas (Figure 3.2). Of the total area, the Palestinian and Israeli built up areas occupy approximately 1.7% and 1.5% respectively.

I. Palestinian built-up areas

There are seven Palestinian built-up areas in the district. The Jericho city is the only municipality in the district, while Dyouk El-Tahta, Dyouk El-Fuka, Nuwe'ma, Al-Auja are classified as villages. In addition there are Aqbat Jaber and Ein Al-Sultan refugee camps (Figure 2). These areas collectively account for approximately 591 hectares. The Palestinian built-up areas are located on either alluvial and brown soils, which are considered to be the most suitable soil for agricultural purposes in the district, or loessial serozems soils which are covered with pasture plants.

II. Israeli settlements

There are 14 Israeli settlements in the district. These are Gilgal, Netiv Hagedud, Niran, Yitav, Zori, Na'ma, Elisha', En Hogla, Bet Ha'erava, Lido Yehude, Atraqzia, Mizpe Yeriho, Vered Yeriho and Almog (Figure 2). These settlements occupy approximately 517.4 hectares of land, and are located on different soil associations. Elisha', for example, is found on alluvial arid brown soils, which are considered to be the most suitable soil for agriculture in the district, while Atraqzia is found on Solonchalks, which is used for agricultural purposes if intensively managed.

III. Closed military areas and bases

Closed military areas take up approximately 5,844 hectares in the district. The Israeli army claims these areas are of security importance and are used for military training purposes. In addition, there are six military bases with a total area of approximately 265 hectares. These closed military areas and bases extend along the western border of the district and are located on the following soil associations:

• Brown lithosols and loessial serozems, while not suitable for agricultural purposes, are important in terms of natural biodiversity and as a potential source for managed grazing.
  
• Brown lithosols and loessial arid brown soils, in which annual field crops, mainly wheat and barely, could be grown in these soils.

IV. Nature Reserves

Currently, there are four declared nature reserves in the Jericho district with a total area of about 1,965 hectares, mostly located within the declared closed military area in the district. Because of the Israeli government's history of confiscating land through declaring an area

a nature reserve, there is suspicion about the true Israeli intentions and the environmental importance of the areas currently declared.

V. Cultivated Areas

The cultivated areas in the Jericho district cover approximately 2419.4 hectares. Due to the limited rainfall combined with the hot weather, irrigated agriculture is dominant in the district. The cultivated areas are concentrated in Jericho city, Dyouk, Nuwe'ma and Al-Auja including the following major types of cultivation (Jericho Agricultural Station, 1994):

1. Fruit trees: The cultivated fruit trees occupy an area of 771.1 hectares. Most dominant are bananas and citrus covering an area of 560 and 136.9 hectares respectively.
2. Field crops and Forages: The total area of the cultivated field crops and forages occupy approximately 144.5 hectares and include barley, wheat and sudan grass.
3. Vegetables: The total cultivated area amounts approximately to 1,504 hectares, with 1,026 of the total area located at Jericho city and the rest distributed in Dyouk, Nuwe'ma and Al-Auja villages. For more information about cultivated areas see chapter five.

Soils

The Jordan Valley is the only ecosystem in Jericho district. Nine soil associations can be distinguished in this ecosystem (Figure 3.3).

1. Alluvial Arid Brown Soils

This type of soil association is located mainly in the Jericho city and Al-Auja areas. It covers an area of about 6,470 hectares. It is exists of alluvial fans and plains, formed as a result of erosion of calcareous silty and clayey materials. This soil type supports Herbaceous vegetation of desert annual halophytes and glycophytes and responds well to irrigation, producing various crops, mainly subtropical and tropical fruits, such as citrus, bananas, and dates, as well as winter vegetables. The American great group classifications that represent this soil association are Haplargids and Camborthids.

2. Loessial Arid Brown Soils

This type of soil association is found on moderate slopes to the west and northwest of the Jericho district, covering an area of about 1,290 hectares. The soil is formed originally from conglomerate and/or chalk and mainly found on gently sloping plateaux as well as dissected plateaux with locally hilly topography. The major vegetation type found in this region is Achillea santolina, and the main current land use consists of various field crops and some horticultural crops planted as irrigated crops. Wheat, barely, and sorghum are also grown under rainfed conditions. The American great group classifications that represent this soil association are Palexeralfs, Haploxeralfs and Xerochrepts.

3. Reg Soils and Coarse Desert Alluvium

This type of soil association is located in the southern part of the Jericho district. It is found in plains and dissected low plateaux and characterize large valleys and alluvial fans. The soil covers an area of approximately 800 hectares and it's parent materials are mainly of unconsolidated mixed stone and deposits. The vegetation on this soil is restricted in a few areas to rivulets. In most areas dwarf shrubs such as Anabasis articulata and Reaumuria are dominant. This soil is almost of no agricultural value and its native vegetation poor pastures for camels, goats and sheep. The American great group classifications that represent this soil association are Gypsiorthids and Camborthids.

4. Brown Lithosols and Loessial Serozems

This type of soil association is found on steep to moderate mountain slopes, in the areas southwest of Aqbat Jaber Camp and northwest of Nuwe'ma, covering an area of about 4,670 hectares. The soil is originally formed from limestone, chalk, dolomite and flint. The major vegetation types found on this soil are Anabasis articulata and Zygophyllum. The current land use is restricted to winter crops grown by Bedouins in some wadis. The American great group classification that represents this soil association is Haplargids.

5. Calcareous Serozems

This type of soil association is found southeast of Jericho city, northeast of Nuwe'ma and east of Al-Auja villages. It is formed mainly as a result of the flooding of the Jordan River. This soil covers an area of about 2,400 hectares and is originally formed from limestone, chalk and marl. The vegetation it hosts is restricted to Salsola vermiculata var vilosa and its current land use is limited to winter grazing. The American great group classifications that represent this soil are Xerochrepts, Calciothids and Gypsiorltids.

6. Solonchalks

This type of soil association is found in the south eastern part of the district. It covers an area of approximately 3,460 hectares. The soil occupies the drainage valleys and closed basins in the district, where the groundwater table is near the soil surface. The soil parent rocks are recent alluvial deposits ranging in texture form sand to clay. Its major vegetation cover is halophytic with species of Tamarix, Suaeda, and Nitraria being dominant. Without proper drainage this soil is of almost no agricultural value. In the Jericho district some dates are grown on the periphery of the depressions, where the ground water is still relatively fresh.

7. Loessial Serozems

This type of soil association dominates the areas of Nuwe'ma, north of Al-Auja and south of Aqbat Jaber camp covering an area of approximately 4,920 hectares. This soil is typical of plateaux and moderate slopes. The soil parent materials are loessial sediments, gravel and highly calcareous loamy sediments. Its major vegetation cover is an association of the Hammada scoparia. Most of the area covered by this soil is used for grazing and only part of it is dry-farmed. There are also some irrigated orchards. The American great group classification that represents this soil is Haplargids.

8. Regosols

This type of soil association characterize the eastern border of the Jericho district. It is found as badlands along terrace escarpments in the Jordan Valley, covering an area of approximately 8,880 hectares. The soil parent materials are sand, clay and loess. The soil dominant vegetation cover are Anabasis articulata, Salsola vermiculata and Salsola tetrandra, and are used primarily for grazing. The American great group classifications that represent this soil are Xerochrepts, Calciothids and Gypsiothids.

9. Brown Lithosols and Loessial Arid Brown Soils

This type of soil association characterizes the western part and covers an area of approximately 2,410 hectares of the Jericho district. These type of soils are mainly found on steep rocky and eroded slopes. Brown lithosols are found in the pockets among the rocks, while Loessial arid brown soils are found on flat hilltops, plateaux and foot-slopes. The parent rocks of this soil association are chalk, marl, limestone and conglomerates. Its major vegetation cover is Artemisia herba-alba. The American great classifications that represent this soil are Haploxeralfs and Xerochrepts.