Biomass Production and Nutrient Uptake of Corn Grown in Adequate and N-Limited Sandy Soil Amended with Biochar.

Use of inorganic nitrogen (N) fertilizer in corn production is energetically and economically expensive.  Additionally, fertilizer use efficiency is low due to N fertilizer leaching and volatilization, reducing the benefit of fertilization and posing environmental risks (ie. run-off and N₂O emissions).  Biochar has been shown to interact with N fertilizer, however, data is lacking on how plants respond to reduced N fertilization in the presence of biochar.  The first objective of this research was to understand how corn plants adapt to altered soil N availability in the presence of biochar. The second objective of this research was to determine if these adaptions allow for corn biomass production and nutrient uptake to be maintained at lowered N fertilizer application rates.

 

Corn was grown to tasseling in a greenhouse experiment, on a sandy rooting medium amended with 0, 10 and 20 Mg ha^-1 equivalent pine wood biochar.  N fertilizer, in the form of ammonium nitrate, was applied at 3 rates (90, 135 and 180 kg N ha^-1 equivalent) in factorial combination with biochar rates.  SPAD readings were taken weekly to assess plant N status over time.  Above- and below-ground biomass were recorded at tasseling. Soil samples and leaf tissue were analyzed for plant available N, P, K, Ca, Mg and nutrient uptake, respectively.  Detailed PCA results will be presented to highlight biochar relationships with N levels and measured variables.