Drainage water management impacts soil properties in floodplain soils in the midwestern, USA

Authors: KAUR, HARPREET - University Of Missouri; NELSON, KELLY - University Of Missouri; SINGH, GURBIR - University Of Missouri; Veum, Kristen; DAVIS, MORGAN - University Of Missouri; UDAWATTA, RANJITH - University Of Missouri; KAUR, GURPREET - University Of Missouri

Submitted to: Agricultural Water Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/25/2023
Publication Date: 2/7/2023
Citation: Kaur, H., Nelson, K.A., Singh, G., Veum, K.S., Davis, M.P., Udawatta, R.P., Kaur, G. 2023. Drainage water management impacts soil properties in floodplain soils in the midwestern, USA. Agricultural Water Management. 279. Article 108193. https://doi.org/10.1016/j.agwat.2023.108193.
DOI: https://doi.org/10.1016/j.agwat.2023.108193

Interpretive Summary: Subsurface drainage is used throughout the Midwestern U.S. to manage the water table to avoid problems such as water and nitrogen stress caused by excess water. However, leaching of excess nitrogen into the drainage system can lead to environmental concerns. Drainage water recycling (DWR) is a drainage water management practice that was developed to meet crop production goals and address environmental concerns. The objective of this study was to compare the effects of three drainage water management practices on soil properties in corn production systems in Knox County, Missouri after seven years. Drainage water management treatments included no drainage (ND), drainage only (DO), and DWR. Soil samples were analyzed for a suite of standard soil properties, and a significant shift in soil clay content in the 40-60 cm soil depth layer was observed under the drainage treatments. Clay content increased 26% and 11% in DWR and DO treatments, respectively, compared with ND. In addition, accelerated soil organic matter losses were observed under DWR. In conclusion, continuous corn production under DWR affected multiple soil properties, and these changes have important implications for producers on floodplain soils that are balancing production goals with environmental outcomes.

Technical Abstract: Subsurface drainage is one of the most common water table management practices. Subirrigation through the subsurface drainage system using drainage water recycling (DWR) was developed to meet crop production goals and address environmental concerns. The objective of this study was to examine differences in soil properties after seven years of different subsurface drainage treatments in continuous corn production in Knox County, Missouri. Drainage water management treatments included no drainage (ND), drainage only (DO), and DWR. Soil samples were collected at 0-10 cm, 10-20 cm, 20-40 cm, and 40-60 cm soil depths periodically from 2015-2021 and analyzed for soil pH, cations, cation exchange capacity (CEC), nitrate-N, phosphorus, organic matter (OM), organic carbon (OC), bulk density, penetration resistance, and soil texture. A significant shift in soil texture from 2015 to 2021 was observed, with a 26% and 11% increase in clay content at the 40-60 cm soil depth in DWR and DO treatments, respectively, compared to ND. Accelerated soil OM and OC mineralization was observed in DWR, which may be due to soil acidification and increased soil moisture compared with DO and ND. This was further supported by increased CEC at deeper soil depths. In conclusion, continuous corn production under DWR affected soil texture and enhanced soil acidification, which in turn amplified mineralization of soil OM and OC. These changes in soil properties under DWR have important implications for production and environmental outcomes. More research is needed to evaluate the long-term effects of subirrigation practices on cropping systems.