Using by-products of steelmaking industry as soil pH corrective and their effects on Zn, Cu and Cd of soil and tea plant

S.F.Kiaee.Jamali1., A.Forghani2 1-MSc student of soil sci;. College of Agric. Guilan Univ. 2-Assis. prof of soil sci. College of Agric. Guilan. Univ.

Abstract: In the tea gardens of North of Iran, pH decreased by several reasons and reach to below 4 at some region. By-products of steelmaking industry such as slag and converter sludge that have alkaline pH, could be used as cheaper liming material for increasing pH and amendment these lands. So for determination of these substance's effects on soil and plant chemical properties, a field experiment has established. This design has performed in 18 plots with 40m2 area,6 treatments ( 0.5% and 1% slag ,0.5% and 1% converter sludge ,0.5% slag + 0.5% converter sludge at dry soil weight unit and control treatment ) with 3 replications on tea rows at Completely Randomized Design(CRD).Treatments were mixed with soil in 15 cm depth at Spring . After 2 month from mixing, soil sampling was done (5 stages and 1time/45days period and from 0-15 cm and 15-30 cm depths). However leafs plucking is performed at 3 stages (Spring, Summer and Autumn). Plant and soil samples were chemically analyzed in laboratory. Results showed that soil pH was increased at slag and converter sludge in both depth. Also pH is higher in slag treatment than converter treatment. In all treatments DTPA-extractable Zn was significantly decreased than control treatment and lower available Zn was recorded at 1% slag and converter sludge treatments. DTPA-extractable Cu in 1% slag treatment was significantly than control treatment. The DTPA- extractable Cd did not show any significant difference between all treatments and control. Leaf analysis showed that Zn, Cu and Cd concentrations were decreased significantly in all of slag and converter sludge treatments than control treatment.

Keywords: soil acidity, liming material, slag, converter sludge