Accumulation of heavy metals in dry beans sown on different dates

Apart from water, living organisms need minerals, i.e. nutritional compounds and vitamins, to survive. Demand for minor minerals in the human body is quite low but most of them are essential as well. Heavy metals are components of mineral substances that are widely used for medical, agricultural, industrial, technological and domestic purposes and have effects on the environment. The present research was conducted by sowing 7 dry bean genotypes on 6 different dates for 2 years (2010 and 2012) in Konya, Turkey, to determine changes in heavy metal concentrations. According to the results, differences statistically significant at a 1% significance level were found for all the factors and their interactions except for the year factor. Mean concentrations of the analysed minerals ranged as follows (in mg kg-1): 0.00-0.06 for Cd, 0.00-0.84 for Co, 0.36-10.47 for Cr, 1.06-14.17 for Cu, 6.81-59.71 for Fe, 1.65-12.31 for Ni, 0.00-0.44 for Pb and 2.31-26.27 for Zn. In summary, the content of Co, Cu, Ni and Zn showed a decrease in beans sown late, while Cr and Fe presented a decreasing tendency in general. Additionally, the content of Cd and Pb in beans sown on 15th May at the latest varied depending on the sowing dates. Consequently, delayed sowing of bean resulted in a significant decrease in the heavy metal content of dry bean seeds. Further studies into the nutritional quality and agronomic characteristics of plants are needed, including such aspects as well-balanced yield and quality traits, in order to ensure sustainable functional food production and sustainable agricultural systems.