Physical and chemical properties, plant growth, and radionuclide accumulation effects from mixing phosphogypsum with some soils

Large areas of salt-affected soils exists in Syria. Besides, large quantities of phosphogypsum (PG) are stacked in areas close to the fertilizer factories radioactivity 350 to 400 Bq kg(-1)) that may pose a negative impact on the environment. Different rates of PG (0, 0.25, 2.5, 5, and 25%) were mixed with three soils characterized by different level of salinity (ECe 5.25, 9.44 and 17.66 dS m(-1)) to monitor the effect of mixing PG on the physical and chemical properties of the soils, plant growth and the accumulation of radionuclides in soils and plants. The high PG application rates (2.5, 5, and 25%) were used to monitor the effects of adding the normal application rate of PG (5 T ha(-1)) for 10, 20, and 100 consecutive years. Soil-PG mixtures were put in 8.5 kg pots where trifolium (Trifolium pilulare) and barley (Hordium vulgare var. Arabi Abyad) were seeded. The results showed that mixing PG increased the saturated hydraulic conductivity, reduced Cl-1 and increased SO24- concentrations in the saturated extracts and increased the available phosphorus (P). Mixing PG increased plant height, shoot number and dry weigh of both plants. Barley grain weight increased by 62.0, 49.8, and 39.5% in Ramet-Leha, Maskane, and Beni-Taghleb soils, respectively. The radioactivity of barley grains and the vegetative parts of the two plants grown in these mixtures were below the detective level (1.1 Bq kg(-1) of dry weight).