Status and Changes in Chemical Properties of Upland Soil in Gangwon Province between 2001 and 2017

Abstract

In order to obtain useful information for environment-friendly management of upland soils, the chemical characteristics of 170 upland fields in Gangwon province have been monitored every 4 years since 2001. In 2017, the pH, electrical conductivity (EC), organic matter (OM), and available phosphate (Avail. P2O5) of the soil samples were 6.4, 0.89 dS m-1, 32 g kg-1, and 742 mg kg-1, respectively. The values of exchangeable (Exch.) potassium (K), calcium (Ca) and magnesium (Mg) were 1.18, 7.6, and 2.0 cmolc kg-1, respectively. In terms of the long-term change, the contents of EC, OM, and Exch. cations in upland soils showed increasing tendency. However, significant changes in the contents of pH and Avail. P2O5 were not observed since 2013. The ratio of optimal range of pH and OM in upland fields reduced from 55% in 2001 to 36% in 2017 and from 33% to 27%, respectively. The ratio of excessive range of Exch. cations have increased. Therefore, it is necessary to apply the lime and fertilizers based on the soil test in order to properly manage the soil fertility of the upland soils. Meanwhile, average contents of Cd, Cu, Ni, Pb, Zn, and As were 0.23, 21.0, 13.5, 11.0, 82.6, and 4.8 mg kg-1, respectively. The results from the study imply that environment-friendly soil managements including the cultivation of green manure crop and application of organic composts are necessary to improve the soil chemical properties of upland fields. Excess, deficient and optimal range of chemical properties of upland soils in Gangwon Province (n = 170).