Predicting effects of drainage water management in Iowa's subsurface drained landscapes

• Published in: Agricultural water management 2007-09, Vol.92 (3), p.162-170
• Main Authors: Singh, R., Helmers, M.J., Crumpton, W.G., Lemke, D.W.
• Format: Article
• Language: English
• Subjects: Agricultural and forest climatology and meteorology. Irrigation. Drainage; Agronomy. Soil science and plant productions; Biological and medical sciences; Controlled drainage; corn; crop production; drainage systems; drainage water; DRAINMOD; DRAINMOD model; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Hydrologic modeling; hydrologic models; Irrigation. Drainage; prediction; runoff; Shallow drainage; simulation models; subsurface drainage; systems analysis; water management; water stress; Zea mays
• ISSN: 0378-3774; 1873-2283
• DOI: 10.1016/j.agwat.2007.05.012

Long-term hydrologic simulations are presented predicting the effects of drainage water management on subsurface drainage, surface runoff and crop production in Iowa's subsurface drained landscapes. The deterministic hydrologic model, DRAINMOD was used to simulate Webster (fine-loamy, mixed, superactive, mesic) soil in a Continuous Corn rotation (WEBS_CC) with different drain depths from 0.75 to 1.20 m and drain spacing from 10 to 50 m in a combination of free and controlled drainage over a weather record of 60 (1945–2004) years. Shallow drainage is defined as drains installed at a drain depth of 0.75 m, and controlled drainage with a drain depth of 1.20 m restricts flow at the drain outlet to maintain a water table at 0.60 m below surface level during the winter (November–March) and summer (June–August) months. These drainage design and management modifications were evaluated against conventional drainage system installed at a drain depth of 1.20 m with free drainage at the drain outlet. The simulation results indicate the potential of a tradeoff between subsurface drainage and surface runoff as a pathway to remove excess water from the system. While a reduction of subsurface drainage may occur through the use of shallow and controlled drainage, these practices may increase surface runoff in Iowa's subsurface drained landscapes. The simulations also indicate that shallow and controlled drainage might increase the excess water stress on crop production, and thereby result in slightly lower relative yields. Field experiments are needed to examine the pathways of water movement, total water balance, and crop production under shallow and controlled drainage in Iowa's subsurface drained landscapes.