Drainmod-Linked Interface for Evaluating Drainage System Response to Climate Scenarios

Abstract

Abstract.This article presents the development of a drainage-climate interface that incorporates climatological data, crop drainage requirements, and drainage theory into a procedure for characterizing drainage system response under different climate scenarios. The drainage-climate interface is suitable for assessing potential county-level impacts of climate change on crop production, soil hydrology and subsequently on subsurface drainage design. Climate model projections from two general circulation models (GCMs), namely CCSM4 (Community Climate System Model) and MIROC5 (Model for Interdisciplinary Research on Climate), were used to create the climatological database for the drainage-climate interface. DRAINMOD was integrated into the Visual Basic for Applications (VBA) portion of the interface to simulate the performance of subsurface drainage systems in Illinois for the near future (2040 to 2069) and the far future (2070 to 2099) periods. Case studies were developed with the interface for Adams and Champaign Counties in Illinois for their predominant soil types. Hydrologic simulations from the interface were used to determine the optimal depth and spacing of tile drains that maximize crop yield for corn and soybean during the mid and late 21st century. Drainage water management (DWM) was incorporated into the drainage-climate interface to investigate the potential of DWM in the future climate scenarios to maintain water quality, reduce nutrient losses and minimize pollutant loading from drained fields by controlling the timing and amount of water discharged from agricultural drainage systems. Results from DRAINMOD simulations with MIROC5 show a significant decline in crop yield due to extreme heat stress. Corn yield in the future showed a severe reduction while the yield for soybean demonstrated a gradual decline over the years. DWM had only a minimal effect on future crop yield trends. The drainage-climate interface simulated subsurface drainage conditions and made evident the consequences of environmental conditions on crop physiological processes under scenarios of climate change predicted by MIROC5. Keywords: Agricultural system models, Climate change impacts, Drainage-climate interface, Drainage water management, Subsurface drainage, Tile drain depth, Tile drain spacing.