Effects of Biosolids Type and Tillage On Carbon and Nitrogen Cycling In a Corn-Soybean Rotation.

Reduced tillage on biosolids-amended land reduces erosion and runoff and increases infiltration and soil moisture; however, little research has been conducted on the effects of no-tillage on crop response nitrogen availability and carbon sequestration where biosolids were applied. We conducted field studies to investigate the effects of lime-stabilized and anaerobically digested biosolids on crop yield, carbon sequestration, and nitrogen availability in a corn (Zea mays L.)-soybean (Glycine max L.) rotation under both conventional and no-tillage practices. Research was established on a Orangeburg loamy sand (Fine-loamy, kaolinitic, thermic Typic Kandiudults) soil in 2009 and on a mineral sands mine reclamation site, whose soil series prior to mining were Slagle (Fine-loamy, siliceous, subactive, thermic, Aquic Hapludults), Myatt (Fine-loamy, siliceous, active, thermic, Typic Endoaquults) and Roanoke (Fine, mixed, semiactive, thermic, Typic Endoaquults) in 2010.  Both biosolids treatments increased soil inorganic (plant-available) N immediately prior to the high N uptake period by corn, plant tissue N and P at silking, post-season corn stalk nitrate and soil total organic C and total N by the end of the 2009 growing season, but grain yield was not different from the 1.0x and 1.5 x agronomic fertilizer N rate. Post-season corn stalk nitrate was increased by both biosolids types under conventional tillage, but not under no-tillage. The no-tillage treatments increased post-harvest soil total organic C and total N. These results indicated that both biosolids types could maintain high concentration of plant available N and increase C amount under conventional tillage and no-tillage practices in the first growing season. We will also provide data for the 2010 season.