Stabilization of Zinc in Agricultural Soil Originated from Commercial Organic Fertilizer by Natural Zeolite

Exploring ways to reduce the risk of heavy metal pollution by organic fertilizer application is of vital importance. In the present study, by conducting a pot experiment, natural zeolite was applied together with pig manure based organic fertilizer to agricultural soil in order to test its possibility of reducing the risk of heavy metals originating from pig manure. The results showed that a low rate of organic fertilizer (10%) application increased the biomass of Chinese cabbage (by 57.2%), while a high rate of organic fertilizer (30%) decreased the biomass of Chinese cabbage (by 46.16%), and meanwhile a 3% zeolite addition increased the biomass of Chinese cabbage which was treated with 30% organic fertilizer. The organic fertilizer addition decreased soil pH and increased soil CEC, while zeolite addition increased soil pH and decreased the soil organic matter content. The concentration of Zn in Chinese cabbage shoots increased with the organic fertilizer addition from 4.46% to 48.27%, while the addition of 1% and 3% zeolite significantly decreased Zn in Chinese cabbage shoots by 15.53% and 14.08%, respectively. The concentration of DPTA-extractable and DGT-extractable Zn of soil was increased by organic fertilizer application, whereas zeolite addition decreased the concentration of DPTA-extractable and DGT-extractable Zn in soil treated with organic fertilizer. Our present study suggests that natural zeolite application could be a promising method to reduce the risk of heavy metals originating from organic fertilizers.