Effect of phosphogypsum application on the chemical properties of Andosols, and the growth and Ca uptake of melon seedlings

Abstract Allophanic Andosols are widely used as a major material in commercial nursery media for fruit vegetables in Japan because of their remarkable physical properties, such as a high water-holding capacity. In the present study, our objectives were: (1) to examine the effect of phosphogypsum (PG) on the chemical properties of Andosols, (2) to investigate the effect of PG on the growth and Ca uptake of melon seedlings. The effect of PG on chemical properties of Andosols was studied using five Andosols with different inorganic and organic colloidal components. The change in soil pH (H2O) was dependent on the soil samples; an increase was observed in the case of Kawatabi 3Bw soil; a sharp decrease in Kawatabi A2 soil; and almost no change or a slight decrease in Kameoka A1, A2 and Bw soils. The water-soluble Ca content was examined as an index of Ca availability in Andosols treated with PG. The increment in water-soluble Ca by PG application was depressed by allophane. The effect of PG application to the...