Evaluation of Cadmium Concentration in Wheat Crop Affected by Cropping System

Abstract

Background: Cadmium accumulation is a growing problem for foodstuff and the environment; it has negative impacts on humans including the damage to kidneys and liver tissue, as well as carcinogenesis, and emphysema. Objectives: The current research aimed at evaluating the effect of planting systems of agricultural products and different growth stages on cadmium concentration in wheat seed. Methods: The study was carried out as a split plot experiment based a randomized complete-block design with 3 replications in the seasonal year of 2014 - 2015. The main factor included 2 cropping systems (wheat-rice, fallow-wheat) and the subfactor were the growth stages (tillering, flowering, and maturity). Comparison of the amount of wheat seed cadmium concentrations between the 2 cropping systems was performed by t test. Results: The difference in seed cadmium concentration between the 2 cropping systems was significant (P < 0.01), and seed cadmium concentration in rice-wheat cropping system with an average of 0.31 mg/kg was higher than that of the fallow-wheat planting system (0.27 mg/kg) as well as the world health organization (WHO) standard (0.20 mg/kg). The ANOVA results showed the significant effect of cropping systems and different growth stages on the cadmium concentration of plant, root, stem, and soil phosphorus content (P < 0.01). Rice-wheat cropping system, due to high consumption of non-standard phosphate fertilizers (such as cadmium), higher soil phosphorus concentrations (9.03 mg/kg), and residues of the previous products had high cadmium concentration in plant (1.83 mg/kg), root (1.09 mg/kg) and stem (0.73 mg/kg) than those of the fallow-wheat cropping system. Conclusions: Due to high accumulation of cadmium in wheat yield, management of phosphate consumption based the standards of Soil and Water Research Institute is recommended.