Soil moisture based spatio-temporal drought patterns for upland crops in South Korea

South Korea has experienced extreme droughts in the past decades. Recently, the spring 2017 drought, following the low precipitation that was recorded in the winter of 2016, affected a large portion of central and western South Korea. Climatologically, the spring (January to June) 2017 season was the driest spring recording less than 50% of the mean normal precipitation recorded over the 1961-2016 period. Generally, spring drought could cause several negative impacts on crop yield and agricultural ecosystem in South Korea. The objective of this study is to develop agricultural drought evaluation methodologies using soil moisture data for effective drought early warning and vulnerability assessment. In this study, we 1) constructed a database that includes observed soil moisture monitoring data and meteorological data for 4 years (2015-2018) from 59 different upland crop fields, 2) examined relationship between commonly used drought indices [Standardized Precipitation Index (SPI), Standardized Precipitation Evapotranspiration Index (SPEI), Self-Calibrated Palmer Drought Severity Index (SC-PDSI), and Evaporative Demand Drought Index (EDDI)] and observed soil moisture data, 3) evaluated which crops and regions are vulnerable to soil moisture agricultural drought for upland crops using soil moisture model, and 4) compared among soil moisture-based drought characteristics for upland crops, and actual drought damages. Results from this study can be used to improve the drought monitoring applications, as well as standardization of agricultural drought assessment, planning and preparedness in South Korea.