The Effect of Biosolids (Sewage Sludge, Urban Compost, Manure) On Soil Chemical Properties and Bioavailability of Micronutrients (zinc, iron) by Corn in two Calcareous Soils n)

The objectives of this research were to study the effect of three kinds of biosolids applications such as urban compost، sewage sludge، cow manure and chemical fertilizers (sulphates of Zn، Fe) concentration on soil and corn plant. Two calcareous soils having different textures (sandy loam and clay loam) were used in order to study the uptake of the above zinc and iron by corn. This study was carried out in pots in a greenhouse using a factorial experiment design which was block completely randomized and each treatment was replicated three times. The levels of biosolids used were 0، 25، 50 Mg ha-1 and chemical fertilizers applied were as (Zn and Fe) sulphates. Seventy five days after corn seeds were sown; young plants at 4 to 5 leaf stage were harvested and made ready for chemical analyses. Results of the soil analysis showed that in sewage sludge treatment (50 Mg ha-1) the CEC، and the DTPA extractable (Zn and Fe) increased significantly compared to control and other treatments in soils. Cow manure treatment (50 Mg ha-1) had a significant effect on OM، and EC. Result of the plant analysis showed that in the sewage sludge treatment the concentration of Zn in the roots، and the concentrations of Zn، Fe in the shoots increased significantly. In general، corn yields increased significantly in the sewage sludge treatment compared to the other treatments in clay loam soils. Generally، the results of this study showed that biosolid application including sewage sludge increased concentration of micronutrients (Zn and Fe) in soil and corn plant.