Changes of soil chemical properties and heavy metal contents on periodical monitoring arable lands in ChungBuk, Korea

摘要

Studies were conducted to provide basic data for production of safe agricultural products by reducing soil and water pollution, and to establish soil improvement and fertilization policy for environmentally friendly agriculture. This is a long-term benchmark investigation of soil chemical properties and heavy metal contents in ChungBuk arable land. The obtained data showed the soil chemical properties and heavy metal contents of the same sites every 4 years since 1999. The investigated lands were upland(180), plastic film house(108), paddy (220 sites), and orchard soil(150) according to the form of agriculture. The chemical properties of upland soil in 2009 showed increases in pH, electric conductivity (EC), Ca, and Mg compared with 2001, and the organic matter (OM) contents were not changed, while Av. P_2O_5 and K decreased. The cadmium (Cd) had the same level, copper (Cu), nickel (Ni), zinc (Zn), arsenic (As) contents increased but lead (Pb), and chrome (Cr) decreased. The chemical properties ofplastic film house soil in 2008 showed increases in pH, OM and Ca compared with 2000, while EC, Av.P_2O_5, K, Mg, and NO_3-N had decreased. The As content increased, but Cd, Cr, Cu, Ni, Pb, Zn decreased in plastic film house soil. The chemical propertiesof paddy soil in 2007 showed increases in pH, OM, Av.P_2O_5, Av.SiO_2, Ca, and Mg compared with 1999, but K slightly decreased. The contents of Cu, Ni, Pb, Zn and As increased, but the Cd and Cr decreased in paddy soil. For orchard soil in 2006 pH, EC,OM, Av.P_2O_5, K, and Ca increased compared with 2002, but lime requirement decreased. Cd, Cr, Cu, Ni, Zn, and As increased, but Pb decreased in orchard soil. Soil fertility was improved by increasing pH, OM, Ca, and amounts of Av.SiO_2, and decreasing the lime requirement. Only 9-26% of investigated sites, however, remained in the optimum nutrient range, so nutrient imbalance of soil became more common. The heavy metal contents of the soils were less than amounts stipulated by regulation of the Soil Environment Conservation Law (SECL), but sustained soil monitoring should be carried out due to the gradual increase of heavy metal contents.