Accumulation of Heavy Metals in Soil Growing for Red Pepper (Capsicum annuum) with using Lime Bordeaux and Lime Sulphur Mixture

Abstract

Lime bordeaux mixture (LBM) and lime sulfur mixture (LSM) are representative environmental friendlyorganic materials for prevention of insect pests in South Korea. Recently, those have been widely used as analternative for chemical pesticides in eco-friendly farms. However, South Korea has not established evenrecommendation of LBM and LSM considering the stability of heavy metals in soil. The aim of this study wasto evaluate the accumulation of hazardous heavy metals in soil and plant with long-term application of LBMand LSM. Firstly, we investigated the amount of LBM and LSM used per year in several eco-friendly farms todetermine a standard application rate of both materials. The pepper plant was grown on the pot in greenhousefor 14 weeks. Both materials were applied at 0, 1, 3, and 9 times of standard application rates (2.56 and 1.28 Lha-1 of LBM and LSM per year, respectively). Dry matter yield of pepper and heavy metals (As, Cd, Cu, Hg,Ni, Pb, and Zn) concentration in soil and pepper plant were measured after 14 weeks. Yield of pepper plant didnot significantly chang with up to application rate of 1 times, thereafter it markedly decreased with more than3 times. With increasing LBM and LSM application, the concentration of Cu and Zn in soil significantlyincreased. Especially, Zn concentration in pepper significantly increased with increasing application rates ofboth materials. This might resulted in significant decrease in dry matter yield of pepper. The concentrations ofthose heavy metals in soil did not exceed safety levels (150 mg kg-1 for Cu and 300 mg kg-1 for Zn) establishedby the Korean Soil Environmental Conservation Act as well as concentration of heavy metals in pepper plantby Korean Ministry of Food and Drug Safety. However, particular attention should be paid for heavy metalsafety and crop productivity when using LBM and LSM in the organic farm.