Invited Speakers

Prof. Kei Nakagawa
Institute of Integrated Science and Technology, Nagasaki University, Japan

 

Speech Title: Time Series Analysis to Estimate Soil Water Content: A Case Study in Shimabara, Nagasaki, Japan

Abstract: Soil water content (SWC) plays a pivotal role in agriculture. The use of atmospheric data to predict soil water content in real-time will greatly facilitate agricultural management and effectively improve agricultural production. In this study, we applied an SWC model that includes three components (i.e., seasonality variations, environmental factors, and long-term trends) and used meteorological data as inputs to predict SWC at different depths (20, 40, 60, 80, and 100 cm) in a soil water content monitoring location in Shimabara, Japan. The prediction model uses singular spectrum analysis (SSA) and nonlinear least squares fitting (NLSF). This model achieved good prediction at soil depths of 20, 40, and 60 cm, and it was concluded that the soil water content in the study area had strong seasonal variations, and the impact of precipitation was stronger than that of other variables. The impact of global warming in this area is not dramatic in a short period of time. The results of this study show a promising application of the model for predicting the soil water content required in agriculture management and agricultural production.

 

Biography: Kei Nakagawa is a Professor of Environmental Groundwater Science with 30 years of research experience. He was first appointed as an Assistant Professor in Soil Science of the Department of Agricultural Chemistry in 1999 at Kyushu University and was promoted to Associate Professor in Water Use Engineering of the Department of Agricultural Engineering in 2002 at Kagoshima University. In April 2011, he was appointed Full Professor of Graduate School of Fisheries and Environmental Sciences of Nagasaki University. His main fields of research interest include reactive transport in groundwater, physical and chemical hydrogeology and heterogeneity, saltwater intrusion and performance evaluation of subsurface dams in coastal aquifers, groundwater modeling, and remediation of contaminated soils and groundwater (phytoremediation and electro-kinetic remediation of heavy metal-contaminated soils). Since being appointment at Nagasaki University in 2011, his main research topic has been nitrate pollution resulting from agricultural activities.