The Effects of mixing phosphogypsum with some soils on their physical and chemical properties, plant growth and radionuclides accumulation

The effects of enhanced UVB (280-320 nm) on the different phenological stages of a drought resistant cultivar of wheat (Triticum durum var. Horani) and drought sensitive cultivar of broad beans (Vicia faba) under field conditions were investigated. Both species were exposed to a daily UVB dose of 20% above the ambient UVB simulating a 10% ozone reduction from germination to harvest. This dose ranged between 1.34 J/cm 2 in the beginning of study and 6.33 J/cm 2 at the end of it. The plant height, tiller number, number of flowers, spikelets, dry weight and leaf area in both species showed positive responses to UVB treatment. In contrast, the chlorophyll content showed a significant decrease in broad beams (10%) and a slight increase in wheat (6.6%). At harvest, the seed weight of broad beans was virtually equal in exposed and unexposed plants. Whereas the number of pods and seeds revealed decreases of 12.6% and 14.2% respectively, in wheat, seed weight and number of spikes exhibited significant increases of 15% and 15.9% respectively. In conclusion, despite the negative responses noted in chlorophyll content and the number of pods and seeds, broad beans can be considered as a tolerant cultivar to enhanced UVB since the yield was not different under UVB. In wheat enhanced UVB seemed to have stimulation effects in both vegetative growth and yield. (Author). 22 Tabs., 31 Refs