Author(s)

Katy E. Brantley^*, Kristofor R. Brye, Mary C. Savin, David E. Longer

Department of Crop, Soil, and Environmental Sciences, University of Arkansas, Fayetteville, USA.

Biochar is a stable carbon substance produced by the pyrolysis of biomass and used as a soil amendment. Biochar application to soil has resulted in agronomic benefits, including improved water-holding capacity. However, limited studies exist quantifying different biochars’ roles in soil water retention, especially when the soil is drier than field capacity. The objective of this study was to investigate the effects of poultry litter and woodchip biochars, applied at various rates (i.e., 0, 5, and 10 Mg.ha-1 incorporated to a depth of 10 cm) to a loam soil, on the relationship between soil water potential and water content across a wide range of moisture conditions. Based on analysis of variance, the relationship between water potential and water content differed (P < 0.05) between biochar sources based on differing (P < 0.02) power-function coefficients, with poultry litter biochar having greater water retention capacity across a wide range of water potentials, but was unaffected by application rate. Based on regression analyses, application rate affected the relationship between water potential and water content for poultry litter biochar. Results indicate that biochar may not generally improve water retention at all water contents with one-time application rates. Additional experiments will be necessary to understand the impact on water retention of biochars produced from different feedstocks under varying pyrolysis conditions.

Biochar, Poultry Litter, Water Retention

Brantley, K. , Brye, K. , Savin, M. and Longer, D. (2015) Biochar Source and Application Rate Effects on Soil Water Retention Determined Using Wetting Curves. Open Journal of Soil Science, 5, 1-10. doi: 10.4236/ojss.2015.51001.