Korean Journal of Soil Science and Fertilizer ISSN:0367-6315(Print) 2288-2162(Online) 한국토양비료학회 학회지

This study aimed to identify the changing trends in the agricultural water quality of the major watersheds in Jeonnam Province over a 10-year period ranging from 2007 to 2016. The results of water quality analysis of the study sites revealed that the mean Chemical Oxygen Demand in April, July, and October was 3.20, 3.04, and 2.37 mg L^-1, respectively, with the median values being 2.85, 2.84, and 1.96 mg L^-1, respectively. The mean values of EC (Electrical Conductivity) in April, July, and October were 0.15, 0.15, and 0.17 dS m^-1, respectively. The mean EC values were lower in April and slightly higher in October, and there was no yearly fluctuation. The mean and median values of the T-N (Total Nitrogen) content were 3.41 mg L^-1 and 3.18 mg L^-1, respectively. A large deviation in the T-N content was only observed in April 2009 and July 2015. The mean and median values of the T-P (Total Phosphorous) content were 0.09 mg L^-1 and 0.05 mg L^-1, respectively. No fluctuations were observed in the T-P content in the months of April, July, and October, during the study period, with the exception of July 2016 and October 2016.

Changes in annual water quality index in April, July, and October.