چکیده:
Using plants for the remediation of soils contaminated with heavy metals is an economical, cheap, and effective strategy. The goal of this research was to study the effect of sewage sludge and drought stress on the remediation of cadmium in soil, root uptake by corn plant. This study was carried out on corn in factorial design experiment based on completely randomized design with three replications in three soil pollution levels, namely B1(control soil), B2 (Cd with soil, 20 mg.kg-1), B3 (Cd with sewage sludge with soil treated, 20 mg.kg-1), and two different irrigation regimes, including A1 (full irrigation) and A2 (limited irrigation). The research included two irrigation treatments at two levels of irrigation: 100% of field capacity (A1) and deficit irrigation at 80% of field capacity (A2). The results showed that the soil treated with cadmium and sewage sludge decreased dry and fresh wet weight plant. Sewage sludge increased the amount of cadmium concentration in shoot almost 21% toward the soil treated with cadmium (soil without cadmium); however, it could not increase cadmium uptake due to the decrease in shoot and root dry matter. In limited irrigation, cadmium concentration in shoot and root was reduced by 46 and 16% toward control treatment, respectively. With increasing irrigation and in the soil treated with sewage sludge, the transfer factor of cadmium from root to shoot dry matter increased. The translocation factors were 0.65, 0.5, and 0.13 for sewage sludge contaminated treatments, cadmium-contaminated treatments, and control treatments, respectively. Based on the results, growing plants at an irrigation level of 100% offered nest advantages in terms of higher biomass and efficient Cd removal.
خلاصه ماشینی:
The goal of this research was to study the effect of sewage sludge and drought stress on the remediation of cadmium in soil, root uptake by corn plant.
The results showed that the soil treated with cadmium and sewage sludge decreased dry and fresh wet weight plant.
With increasing irrigation and in the soil treated with sewage sludge, the transfer factor of cadmium from root to shoot dry matter increased.
In general, the availability of heavy metals relies on their physical, chemical, biological properties and their interaction such as soil texture, structure, permeability, organic material content, clay content, root system, calcium carbonate, oxidation-reduction potential, pH, salt, solubility, and concentration (Ali et al.
Therefore, the present study was carried out to investigate the effect of deficit irrigation, cadmium concentration in soil and soil contaminated with sewage on cadmium absorption by corn plant.
Maximum allowable concentration (MAC) in soil (Iranian Environmental protection Agency Iran, 2014) Parameter MAC value (mg kg-1) Cd 1 Zn 200 Pb 100 Cu 75 Ni 40 Cr 75 Co 30 Tables 4 and 6 present the effect of soil pollution and irrigation levels on the fresh and dry weights of shoots and roots of corn.
(A1: irrigation at 100% of FC, A2: irrigation at 80% of FC, B1: soil, B2: soil with Cd, B3: soil with Cd and sewage sludge) Table 5 indicates the significant impact of soil contamination and irrigation water amount treatments on cadmium concentration in the shoot and root.