AL-QAWASAMI, Walid, Ra'ed BADWAN and Amer Al NSOUR, 2003. Heavy metals content and soil fertility in irrigated agriculture Deir Alla area, Jordan Valley. Bulg. J. Agric. Sci., 9: 357–362
This study is aimed to assess potential productivity of soils in Deir Alla region (Jordan Valley) and to ascertain the current status of soil contamination with heavy metals (Ni, Cd, Pb and Co). Soil samples from surface and subsurface of the basin crop cultivated agriculture area in Deir Alla region were collected during the period 2001–2002. The 90 samples were analyzed for pH, EC, NO3, available P and K. Soils were extracted by DTPA. The extracted were analyzed for available heavy metal Cd, Ni.Co, and Pb. Cultivated soils in Deir Alla region have alkaline reaction, coarse or medium texture, and high concentration with CaCO3. Typical natural properties for this soil are low organic carbon, nitrogen, P and K.
The results have proved that pH values are varied from 7.1 to 8.4, with mean range from 7.5 to 7.8. The soil samples were characterized with moderate values of EC, range between 5–6 dS/m. Most of soil samples were characterized with high values of NO3, available P and K .The overall means and maximum values of heavy metals in Deir Alla region soils are very low and they are acceptable in all European Standard.
The present study concluded that the soils in Deir Alla region have alkaline reaction and moderate EC. The soils are characterized with high potential capacity of available nutrients as a result of over fertilization and the high content of irrigation water with nutrients. Òhe soluble forms of Cd and Ni in the soil studied prevail the established in some European countries Maximum Acceptable Concentration (MAC) for available forms of these metals in soils, but extracted amount of Pb with DTPA do not exceed the these values. The Deir Alla region soils could be able to produce high and safety yields. Therefore, a proper management of nutrient resources should be taken into consideration to maintain and enhance soil fertility without imposing environmental damages.