The effects of slag and converter sludge as an acid soils amendment on tea garden

The tea plant (Camellia sinensis (L.) Kuntze) is grows well in strongly acidic soils. The optimum pH for economic production is 5-5.5. In many reasons tea plantation in Iran tend to more acidic. Therefore amendment of soil acidity seems to be necessary. Liming is effective agricultural practice for correcting soil acidity and in general liming increase soil pH, Ca and Mg. Slag and converter sludge are by-products of steelmaking factories. In addition to their liming and corrective properties, these materials contain some plant nutrients such as Ca and Mg that can supply these elements for the deficient soils. To assessing the residual, cumulative effects of slag and converter sludge on a soil and tea plant chemical properties, 6 field experiments were conducted in Tea Research Institute of Iran sited in Fuman Station for there year. Each experiment was performed in completely randomized blocks design with 6 treatments (0.5% and 1% slag ,0.5% and 1% converter sludge ,0.5% slag + 0.5% converter sludge at dry soil weight & a control) and 3 replicates. Treatments were partially mixed in 15 cm depth of soil. Methodically, soil and plant sampling were done at 3 stages; spring, summer and autumn. The soil samples were routinely analyzed for ECe, pHH2O, pHCaCl2, and texture. Additionally some elements such as N, P, K, Ca, Mg, Cu, Zn, Fe, Mn and Al were detected in soil and tea green flash leaves. The results indicated that pH and ECe were increasing with increasing the levels of slag and converter sludge treatments. Slag treatments caused more pH increasing than converter sludge treatments. As long-term effects, all treatments significantly increased available Ca of soil and plant content. In contracts, Al and Mn of soil and plant were decreased by different percentages of slag and converter sludge treatments. Totally, ameliorants did not any significant effect on other soil/plant elements which is mentioned. At whole, the effect of ameliorants on tea green leaves yield was merely significant in one of six experiments, which was the most slag received.