نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشجوی دکتری دانشگاه شهید چمران اهواز و کارشناسی ارشد سابق دانشگاه شیراز
2 استاد دانشگاه شیراز
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
To understand nutrient elements mobility and bioavailability in soils treated with sewage sludge, it is essential to know their chemical forms. To study the effect of sewage sludge application and soil textural classes on chemical forms and bioavailability of zinc (Zn) in two textural classes of a calcareous soil, and the relationship between soil Zn and its concentration in corn (Zea mays L.), a factorial experiment was carried out in a completely randomized design (CRD) with three replications under greenhouse condition. Treatments included five sewage sludge levels (0, 1, 2, 4, and 8 w/w) and two soil textural classes (sandy and clay loam). Sequential extraction procedure of Sposito et al. (1982) was used to determine the chemical forms of Zn in soil. Reduced partitioning index (IR) was employed to compare Zn bioavailability in the two soil textural classes. Results indicated that in both soil textures, Zn concentration in corn shoot increased significantly with increasing sewage sludge levels. In sandy soil, chemical forms of Zn in sewage sludge treated samples and the control treatment were in the order of: residual > carbonatic > organic > adsorbed and in clay loam texture were as: residual > carbonatic > adsorbed. In clay loam texture treated with sewage sludge, good correlations were observed between Zn concentration in corn shoot with carbonatic, adsorbed and residual forms and in sandy texture these relationships were significant for adsorbed, carbonatic, organic, and residual. Based on the calculated IR, bioavailability of Zn in sandy texture, in both the control and all sewage sludge treated samples were higher than those of clay loam texture. In sandy texture, increasing sewage sludge levels increased Zn bioavailability; however, this trend was not observed in clay loam texture. In general, influence of sewage sludge application on Zn chemical forms and its bioavailability and the relationships between these forms and Zn concentration in corn plant was different for the studied soil textural classes, which should be considered in the management and application rates of sewage sludge.
کلیدواژهها [English]