Effect of peanut hull and pine chip biochar on soil nutrients, corn nutrient status and yield

Authors: GASKIN, J - University Of Georgia; SPEIR, A - University Of Georgia; LEE, R - University Of Georgia; HARRIS, K - University Of Georgia; MORRIS, L - University Of Georgia; DAS, K - University Of Georgia; Fisher, Dwight

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/2009
Publication Date: 3/1/2010
Citation: Gaskin, J., Speir, A.R., Lee, R.D., Harris, K., Morris, L., Das, K.C., Fisher, D.S. 2010. Effect of peanut hull and pine chip biochar on soil nutrients, corn nutrient status and yield. Agronomy Journal. 102:623-633.

Interpretive Summary: Fuel can be produced from biomass such as peanut hulls or pine chips. One method of producing fuel is to use extreme heat to covert the biomass to biofuel. The byproduct of the energy production is “biochar”. The biochar is somewhat like charcoal and gives the option of using this byproduct to add carbon and nutrients to the soil after producing energy. The typical soils of the southeastern United States have inherently low soil organic carbon and fertility. These soils may benefit from the addition of biochar from energy production. Our objectives were to evaluate the effect of peanut hull and pine chip biochars on soil nutrients and corn production in a typical sandy soil of the southeastern United States for two growing seasons. We conducted two experiments (one for each biochar source). Biochar was applied at approximately 0, 10, and 20 tons/acre and nitrogen fertilizer was applied at approximately 0 and 220 lbs/acre. Nitrogen in the peanut hull biochar (200 lb/acre at 10 tons/acre of peanut hulls) was not available to the plants. The peanut hull biochar increased potassium, calcium, and magnesium in the soil. The increase in available potassium was reflected in an increase in potassium in the corn plants in 2006 but not in 2007. Pine chip biochar increased soil acidity by the end of the study but had no effect on potassium or magnesium in the soil and little effect on nutrients in the corn tissue. Corn grain yields were depressed by the greatest rate of biochar in 2006 but this did not persist in 2007. Overall responses to biochar either positive or negative were smaller than expected based on previous work.

Technical Abstract: Pyrolysis is the process of anaerobic thermal conversion of biomass for energy production that may offer an option of returning carbon and nutrients to the soil while producing energy. The Ultisols in the southeastern United States have inherently low soil organic carbon and fertility. These soils may benefit from the addition of biochar from pyrolysis. Our objectives were to evaluate the effect of peanut hull and pine chip biochars on soil nutrients, corn (Zea mays L.) nutrient status and yield in a Kandiudult soil for two growing seasons. Two experiments (one for each biochar source) were conducted as completely randomized designs. Biochar was applied at 0, 11, and 22 Mg/ha and N fertilizer at 0 and 220 kg/ha. Nitrogen in the peanut hull biochar (209 kg/ha at 11 Mg/ha rate) was not available over 18 months. The peanut hull biochar linearly increased Mehlich I K, Ca, and Mg at 0-15 cm. The increase in available K was reflected in the corn tissue analysis at R1 in 2006, but not in 2007. Pine chip biochar decreased soil pH by the end of the study, but had no effect on Mehlich I K or Mg, and little effect on nutrients in the corn tissue. Grain yields at 22 Mg/ha in the N fertilized treatments were depressed in 2006, but this did not persist in 2007. Overall responses to biochar either positive or negative were smaller than expected based on previous studies.