Bio-Char and Nitrogen Effects on Corn Grain Yield.

Bio-char is a by-product of pyrolysis of corn stover.  Its qualities vary according to reactor conditions during pyrolysis, but it contains phosphorus (P) and potassium (K).  The carbon (C) in bio-char is stable, so it can be applied to soils enlarging the C sink.  To find the effects of bio-char on crop production a field study was conducted in 2007 and 2008.  Treatments were arranged in a split-plot design.  The main plot treatments were bio-char at rates of 0, 4.5, 18 Mg ha^-1.  Sub-plot treatments were N-rates of 0, 56, 112, 224 kg ha^-1 as urea (46-0-0).  These treatments were applied to a continuous corn cropping system.  Soil samples were taken to measure ammonium-N and nitrate-N in the soil during the first eight weeks of the growing season and after harvest.  The potassium and phosphorus in the soil was also measured after harvest.  The nitrogen in the plant and grain was measured along with yield and plant biomass.  Yields increased from 4.5 to 5.9 Mg ha^-1 with the addition of N averaged across bio-char treatments.  In 2007 there was no difference in the yield with the addition of char.  Data from 2008 will be included.