Effects of rock phosphate added with farm yard manure or sugar juice residues on wheat growth and uptake of certain nutrients and heavy metals

Abstract

Rock phosphate (RP) and farm yard manure (FYM) can promote plant growth, but little is known about the effect of sugar juice residues (FMC) on Zn, Cu, Cd, and Pb phyto-availability. This study investigated the effects of FYM and FMC added alone or each in combination with RP on wheat growth and Zn, Cu, Cd, and Pb uptake. Wheat was grown in a soil amended with 0.25, 0.5, or 0.75 g RP or with 5, 10, or 20 g kg-1 soil of FYM, or FMC, added separately, or each in combination with 0.75 g P2O5-RP kg-1 soil. At harvest, shoot N, P, and K; soil pH; available P and DTPA-Zn, Cu, Pb, and Cd, dry matters of root, shoot, and grain; and heavy metals’ concentration in each organ were determined. RP addition increased growth and P and K uptake and reduced Zn, Cu, Cd, and Pb of wheat more at the high application rate compared to the low application rate. Compared to the control, FYM addition decreased soil pH, increased P and metals availability and uptake, and decreased plant biomass, whereas FMC addition increased soil pH, decreased P and metals availability and uptake, and increased plant biomass; these effects were maximized with increasing the application rate. The results revealed that FMC has the potential in limiting heavy metal uptake and that the combined application of FMC and RP is beneficial for wheat growth.