Shortage of water resources in Jordan is a very severe problem due to the dominance of arid and semi-arid climate over about 90% of its area. Water recourses originate mainly from rainfall. Water Budget in Jordan for the past few years indicate that, the agricultural sector consumes about 70% of available water resources. Available surface water resources are almost exhausted and ground water abstraction has already exceeded the safe yield. It is estimated that, within two decades, the proportion of marginal water (saline and treated wastewater) will be more than 30% of the total available water resources for irrigation. Saline water will be highly valuable source of water for irrigation.

The Main objectives of the project are the following:

Conserve available water resources by optimum use and management of saline water for irrigation.

Increase agricultural production through widening the irrigated areas using saline water and decrease the dependence on good water quality in agriculture in Jordan.

Study the effect of using saline water on yield components and soil properties.

Two experiments were carried out at Al- Khaldiah Research Station in 1995/96 and 1996/97 seasons using Tomato and Sudangrass. For the first experiment, the main treatments were four levels of irrigation water amounts 50, 75, 100, 125% from evaporation class E-pan readings. Three levels of water quality treatments as sub-main treatments were used: Fresh water (0.7 dS/m), Saline water (5.4 dS/m), and Alternate irrigation with fresh water followed by saline water (1:1 ratio of the total amount of water applied). For the second experiment, four saline irrigation amounts (5.4 dS/m) were used (100%, 115%, and 130% of E-pan reading) as main treatments. Four N-fertilizations were used as sub-main treatments (0, 14, 20, 26 Kg N/du) in four replicates using basin irrigation system.

Tomato experiment results showed an increase in total production by increasing irrigation water amount for the three sub-main treatments. Total and marketable production increased significantly for the Fresh treatment (34.67 ton/ha) and Alternate treatment (31.96 ton/ha) over the Saline treatment (22.99 ton/ha) at the 125% irrigation level. Percentage of Total Soluble Solids (TSS) increased significantly for the Saline treatment (6.8%) over the Fresh (5.2%) and Alternate treatments (5.57%). Total Soluble Solids percentage decreased by increasing the amount of irrigation water. The highest TSS value (7.24%) was obtained under the Saline treatment at 50% irrigation level. Alternate water treatment was the lowest in decreasing fruit weight. Salinity development in soil profile was related to the amount of applied irrigation water. It has been found that salinity of the surface layers decreased under the 50% and 75% irrigation levels, while the decrease in salinity for the other depths was related to the higher levels of applied water (100% and 125%).

In the second experiment, the 1995/96 season results showed that biological yield of Sudangrass decreased with increasing the irrigation amount and the applied N-fertilizer. Biological yield increased significantly for all irrigation levels and reaches 101.9 ton/ha when 14 kg N/du was applied in comparison with 55.12 ton/ha production when 26 kg N/du was added. On the contrary, 94.75 ton/ha was gained in the second season 96/97 when 20 kg N/du was added and it under the 115% irrigation level. Percentage of dry matter weight increased throughout the season. The highest amount was achieved in the third cutting at the 130% irrigation level in both seasons 95/96 and 96/97 and reached 29.5% and 31.03% respectively. Protein percentage decreased throughout the growing season but increased when N-fertilization increased for all irrigation treatments. The highest protein percentage in both seasons was in the first cutting at 130% irrigation treatment and when 26 kg N/du was added. The amount in both seasons 95/96 and 96/97 reached 20.05% and 20.65% respectively. Salinity development depends on the applied amount of irrigation water. In both seasons, the effect of 100% irrigation level restricted in decreasing the salinity of the first layer (0-15 cm). While, decreasing the salinity of the deeper layers depended mainly on the higher irrigation levels, which are 115% and 130%.