Tile-Drainage of Bioenergy Cropping Systems.

Bioenergy systems have been proposed as a way to enhance United States energy security.  However, research of the impacts such systems have on quantity and quality of tile-drain effluent has been limited.  The objective of this study was to determine the effects of six lignocellulosic-feedstock production systems on tile-drain effluent loads and drainage dynamics.  Bioenergy cropping systems evaluated in this study consisted of mixed prairie (nitrogen-fertilized and unfertilized), continuous maize with 50 % stover removal (with and without cover crop), and maize-soybean rotation (each crop type grown each year).  The study site consists of twenty-four (27 x 61 m) individually tile-drained plots on Typic Endoaquoll and Aquic Hapludoll soils.  Bioenergy systems were replicated four times in a randomized complete block design.  The prairie systems had smaller drainage volumes than the annual row crop systems.  Less nitrate-nitrogen appeared in the prairie drainage than in the annual row crop drainage whereas no differences in phosphate loads were observed among systems.  Full results from 2009 through 2011 will be presented.