Location: Northwest Irrigation and Soils ResearchTitle: The effects of biochar and manure in silage corn Author
Submitted to: Progressive Forage Grower
Publication Type: Popular Publication
Publication Acceptance Date: 12/24/2014
Publication Date: 2/1/2015
Citation: Lentz, R.D., Ippolito, J.A., Spokas, K.A. 2015. The effects of biochar and manure in silage corn. Progressive Forage Grower. 16(2):26-29.
Technical Abstract: Amending soil with biochar may be a means of sequestering atmospheric CO2 and improving soil quality, but few multiyear field studies have examined the impacts of a one-time biochar application in an irrigated, calcareous soil. We fall-applied four treatments: dairy manure (18.7 tons/ac dry wt.); hardwood-derived biochar (10 tons/ac dry wt.); combined biochar and manure; and no amendments (control). We measured net N-mineralization using buried soil bags and soil greenhouse gas emissions (CO2, CH4, and N2O) from late spring to fall, corn silage yields, and crop N uptake each year. The influence of biochar and manure on silage yield changed with time after application in fall 2008. Biochar increased corn yields slightly (5%) in 2009, decreased yields by 14% in 2010, and had no effect in 2011. Conversely, manure had no affect on yields in 2009, but increased yields substantially in 2010 (33%) and again slightly in 2011 (7%). When compared with a class comprising all other treatments, biochar-only produced 33% less cumulative net N mineralization, 20% less CO2-C and 50% less N2O-N gas emissions, and increased the soil NH4:NO3 ratio 1.8-fold, indicating that biochar impaired nitrification and N immobilization processes. While the biochar-only treatment demonstrated a potential to increase corn yields and minimize CO2-C and N2O-N gas emissions in these calcareous soils, biochar also caused decreased corn yields under conditions in which NH4-N dominated the soil inorganic N pool. The combined biochar-manure treatment more effectively utilized the two soil amendments as it eliminated potential yield reductions caused by biochar and maximized manure net N mineralization potential.