Accumulation of cadmium in arid soils as affected by intensive phosphorus fertilization

Amounts of P-fertilizers annually added to crops grown on soils of Saudi Ar abia are enormously increased, The environmental hazards of these fertilize rs worldwide, however, have become of great concern. As these fertilizers m ight hear rich content of detrimental elements typically like cadmium, that element's levels in the used, P-fertilizers and soil were pursued. Eleven wheat farms situated in Al-Kharj district were chosen to carry out this stu dy These farms represented a comparatively short period of cultivation (les s than 10 years) and a long one (more than 10 years). Soil samples represen ting three depths, 0-15, 15-30, and 30-40 cm, were taken from inside the ce ntral pivots and from its outer uncultivated sphere. The changes of soil to tal and extractable P and total Cd were measured and the effect of P fertil ization on the buildup of soil P and Cd was estimated. The results obtained revealed that buildup in P status of soil has occurred. P was accumulated in the surface soil layer elite to higher P applications. Its total content in the surface soil layer (0-15 cm) was raised from 254 to 482 mg kg(-1) e lite to long-term cultivation. Testing Cd content in the utilized P fertili zers indicated that it averaged 32.2 mg kg(-1). A positive significant rela tionship between total P and total Cd in soil was obtained. Nonetheless, th e results indicated that, a comparatively long-term application of P fertil izers only slightly elevated Cd content of the soil surface layer. The data made clear that Cd accumulation is associated with P accumulation. However , no harmful effect would be expected as Cd was accumulated in minute amoun ts.