The effect of cadmium contamination water and soil on corn yield components

Conservation of soil and water resources could be an important role in the health of crop. The use of wastewaters and the presence of heavy metals in these waters as well as the pollution of soil resources due to the entry of heavy metals can cause many problems for quantity and quality of crop. The high retention of heavy metals in the environment causes transfer to plants and food chains and cause irreparable damage to humans, plant growth, soil and the environment. This study was conducted to investigate the contamination caused by the application of different amounts of heavy metal Cadmium (Cd) in irrigation water and also in soil on its growth and accumulation in organs of corn variety (cultivar) 201 in Shahrekord University farm.

To this aim, the factorial test was done based on the completely randomized design with three replicates as a pot culture with Silt Loam texture. The first factor was the addition Cd in soil from the Cd Nitrate Salt at three levels (0 (control), 10 mg/kg soil, and 50 mg/kg soil) and the second was the Cd concentration in irrigation water from Cd Nitrate Salt at five levels (0 (control), 0.01, 0.05, 1, 2 mg/L).After using Cd treatments in the soil, corn was cultivated and irrigated with water with different levels of Cd during the growing period. At the end of the growing period, the concentration of Cd in different components of the plant (stem, leaves and seed), soil as well as the relative components of corn were determined. Also, the amount of evaporation and transpiration and water requirement were recorded during the experiment.

The results showed that water and soil contamination with Cd had a significant effect (at a1% level) on yield components including grain yield per plant unit, number of rows in corn, number grain at the row, dry leaf weight and dry stem weight. However, the effect of water and soil contamination with Cd was not significant on yield components. High levels of Cd in soil and water had the highest reduction in yield. The results showed that the stem had the highest (2.283mgkg-1) and the grain (undetectable) had the lowest Cd concentration. In this study, the highest and lowest yields of corn plant components due to the using of different levels of Cd in soil, in grain yield and the number of rows in corn obtained11.46%, 15.51% and 2.47%, 3.81%, respectively. Water and soil contamination with Cd had a significant effect (p < 0.05) level on water use efficiency in corn. Water use efficiency due to the using of high levels of Cd in water and soil decreased by 15.45% and 17.21%, respectively.

The results showed that the combined use of contaminated water and contaminated soil with Cd leads to a quantitative and qualitative reduction of corn yield. Therefore, efforts should be made to prevent the contamination of water and soil, to minimize the use of contaminated water in contaminated soil in order to protect soil resources as well as water. According to the results, the amount of Cd concentration in leaves and stem was higher than the allowable limit. Contamination of water with Cd also led to a further reduction in corn yield in contaminated soil.