Variation of soil physical properties in paddy land in Gangwon Province from 2007 to 2023

The monitoring of soil physical properties is a field of agricultural environment change survey project, which started in 2007, and is conducted in accordance with the Rural Development Administration's notice in Korea.This study aimed to evaluate the annual trends and changes based on the results of the soil physical property survey in Gangwon, South Korea.The main soil series of the paddy soils surveyed in Gangwon were Sacheon, Namgye, and Gangseo, which have a large area distribution of paddy soils in Gangwon, and the main topographical characteristics were valleys/alluvial fan and river alluvium.The plowing depth of the paddy soils in Gangwon was less than the appropriate depth of 20 cm, but it had been continuously increased since 2015.The bulk density of the subsoil was found to be in the range of 1.46 to 1.57 Mg m -3 during the survey period, exceeding the appropriate standard.The organic matter content showed an increasing trend in both topsoil and subsoil, and the hardness of subsoil was lower than the appropriate standard of 20 mm until 2015, but then greater than the appropriate standard in 2019 and 2023.The main soil textures were sandy loam, loam and silt loam.The results of the physical characteristics of the paddy soil in Gangwon showed that the plowing depth and organic matter content were increasing, but the bulk density and hardness were deteriorating, implying that soil improvement was necessary to decrease the bulk density and hardness.