TY - JOUR T1 - Influence of drainage on soybean seedling health JF - Journal of Soil and Water Conservation SP - 266 LP - 271 DO - 10.2489/jswc.72.3.266 VL - 72 IS - 3 AU - G. Han AU - Y.R. Kandel AU - L.F.S. Leandro AU - M.J. Helmers AU - L.R. Schott AU - D.S. Mueller Y1 - 2017/05/01 UR - http://www.jswconline.org/content/72/3/266.abstract N2 - Subsurface tile drainage is a commonly used agricultural practice in Iowa croplands. Little is known about the effect of drainage on soybean (Glycine max) disease. Field and greenhouse studies were conducted to study the effect of drainage on seedling health. A field experiment was conducted at the Iowa State University research farm near Crawfordsville, Iowa, in 2012 and 2013. Four treatments were compared: conventional drainage (CvD, subsurface drains installed 1.2 m [3.9 ft] deep with 18 m [59 ft] spacing), shallow drainage (SD, 0.76 m [2.5 ft] deep with 12.2 m [40 ft] spacing), controlled drainage (CtD, 1.2 m [3.9 ft] deep and 18 m [59 ft] spacing with a water table control structure located at the outlet), and no drainage (ND, no artificial drainage). A greenhouse experiment was conducted three times to compare two soil sources (ND and CvD soil from the field experiment), two soybean cultivars (Ripley and Williams 82), and three watering intensities (low, moderate, and saturated). Plants were sampled at the second trifoliate stage to assess root rot severity, root dry weight, root size, and Fusarium spp. incidence in roots. In the field, root rot severity was significantly (p < 0.01) greater in the ND and SD drainage treatments than in the CvD treatment in 2013 but not in 2012. Fusarium spp. were isolated less frequently from roots grown in ND soil than all other drainage treatments, in both years. In the greenhouse study, watering intensity significantly affected root rot on Ripley, with more water causing more root rot (p < 0.01). Despite greater rot, roots showed increased root weight, root length, root diameter, and number of root tips with increasing soil water up to saturation for both varieties. Fusarium incidence decreased as water amount increased. In summary, fields with high moisture are more prone to root rot, but well-drained soil favors infection of soybean roots by Fusarium spp. ER -