Biochar Amendment for the Alleviation of Heavy Metals Stress in Corn (Zea mays L.) Plants Grown in a Basic Soil

Since environmental contamination, by heavy metals (HMs), affects human health, crop growth and yield production, finding methods, which may mitigate HMs stress is of significance. Due to their chemical properties, biochars of rice straw and date palm, may ameliorate plant uptake of HMs, for example, in corn as the objective of this research. Incubation and greenhouse experiments were conducted. The greenhouse experiment was a factorial on the basis of a complete randomized block design with three replicates investigating corn uptake of HMs affected by biochar type and percentage (0, 4 and 8%), and HMs including cadmium, zinc, lead and copper, as the most important heavy metals. The experimental treatments significantly affected corn uptake of HMs, and depending on the type of HMs, the effects of biochars were different, as date palm was the more effective one. Nevertheless, with increasing biochar percentage, the effectiveness of rice straw increased even at twice the standard level of HMs (a 30% reduction of cadmium uptake). The second level of date palm significantly decreased corn Zn uptake (158.33 mg kg^− 1) compared with the first level (176.50 mg kg^− 1). There were positive and significant correlations among the investigated HMs. Soil HMs affected by biochar was also determined. Due to their physicochemical properties (high surface area and abundance of functional groups), the use of rice straw and date palm is recommendable for the amelioration of HMs uptake by corn, since they are able to immobilize HMs and decrease their concentration in the soil.