Interaction Effect of Municipal Waste Compost and Pistachio Residues Biochar on Decreasing Cadmium Stress in Shallot (A Case Study: Zarandieh Municipal Waste Compost)

Abstract

Background & objectives: Today soil pollution by heavy metals especially in industrial regions is one of the major health problems. This research was done to investigate the effect of pistachio residues biochar on decreasing soil cadmium (Cd) stress in shallot in a soil treated with Zarandieh municipal waste compost. Methods: The present study is an experimental study has been done on the Cd polluted soil as a factorial experiment in the layout of randomized completely block design. Treatments were consisting of applying municipal waste compost at the rates of 0, 10 and 15 t ha-1 and applying pistachio residues biochar (0 and 15 gr kg-1) and the cd polluted soil at the rates of 0, 10, 20 and 30 mg cd kg-1 soil. The Zarandieh municipal waste compost and pistachio residues biochar were added to the soil and after the end of the experiment; root and shoot Cd concentration and catalase enzyme activity were measured. Means comparisons were done by LSD test at a probability level of 5%. Results: Applying 15 g kg-1 pistachio residues biochar in a Cd polluted soil (20 mg Cd kg-1 soil) treated with 15 t ha-1 municipal waste compost caused a significant decrease in root and shoot Cd concentration by 12 and 9%, respectively. In addition, the root and shoot catalase, enzyme activity was also decreased. Conclusion: The results of this experiment showed that applying Zarandieh municipal waste compost with pistachio residues biochar can decrease the plant Cd stress. However, the role of type and plant variety on the amount of decreasing Cd stress cannot be ignored

The Effect of Montmorillonite Nano-Clay on the Changes in Petroleum Hydrocarbon Degradation and Cd Concentration in Plants Grown in Cd-Polluted Soil

“…Considering the fact that the solubility of heavy metals such as Cd increases with decreasing pH (25), the use of montmorillonite nano-clay had no significant effect on decreasing soil pH (Fig. 1a) in the current study, which can be considered as an environmentally positive point.…”

“…In an experiment, Wang et al mentioned that the use of organic additives is an effective method for reducing the availability of heavy metals in soil (30). Baghaie investigated the role of organic amendment in decreasing the availability of heavy metals in soil and concluded that application of organic amendments such as sewage sludge increased the soil CEC, thereby reducing the availability of heavy metals in the plants (25). The result of a study by Kwiatkowska-Malina confirms this matter clearly (31).…”

“…Soil pH was measured in a 1:5 solid/liquid aqueous extract (24). Cation exchange capacity (CEC) of soil was measured by BaCl 2 method (25). The total petroleum hydrocarbons (TPHs) in soil were extracted from 30 g soil subsamples by Soxhlet using 150 mL of a mixture of dichloromethane and n-hexane (1:1, v/v) after 24 hours.…”