Cu and Pb accumulation in maize (Zea mays L.) and soybean (Glycine max L.) as affected by N, P and K application

Abstract

Nitrogen (N), phosphorus (P) and potassium (K) fertilizer application affects soil properties and processes in many ways that remain unclear. The effects of N, P, and K application on plant growth and copper (Cu) and lead (Pb) accumulation, as well as their differences in plant species were thus evaluated in soil-maize and soil-soybean systems. Five treatments were arranged: N, P, and K application (NPK), N and P application (NP), N and K application (NK), P and K application (PK), and CK (no fertilization). Results showed that N application could significantly increase maize shoot Cu concentration and translocation from soil to above ground tissue (p<0.05). However, soybean shoot Cu concentration could not increase with N application. Phosphorus application could effectively decrease the bioavailability of Cu and Pb in both systems. Under nutrients deficiency, soil dissolved organic carbon (C) significantly increased, showing difference in plant species (p<0.05), which further enhanced Cu and Pb mobility in soils. Copper removal from soil positively correlated with plant biomass production with the NPK and NP treatments showing the greatest in both crops. Our results show that, an appropriate increase in P application and decrease in N application are recommended to reduce agro-ecological risks associated with Cu and Pb in soil-plant systems. Key words: Soil-plant system, heavy metals, Cu and Pb mobility, ecological risk, translocation.