Gaskin

Best Management Practices for Wood Ash as a Soil Amendment
Prepared by Mark Risse, Extension Engineer, Updated by Julia Gaskin, Land Application Specialist 2002, Cooperative Extension Service,The University of Georgia College of Agricultural and Environmental Sciences

Wood was burned in the United States in the 1700s through the early 1900s to produce ash for chemical extraction. The ash was used mainly to produce potash for fertilizer and alkali for industry. As other potash production technologies became more economical, the value of wood ash as a raw material dropped.

Recently, ash has been considered a waste product instead of a resource, because few industries have taken advantage of its beneficial properties. Approximately 3 million tons of wood ash are produced annually in the United States. While approximately 80 percent of all ash is land applied in the Northeast United States, less than 10 percent is land applied in the Southeast. The other 90 percent in the Southeast is landfilled. Several alternative uses for wood ash have been developed. Land application is one of the best because nutrients taken from the land during harvest are recycled back to the land. In a survey of more than 80 Southeastern paper mills, 60 percent of the respondents reported interest in land application of wood ash. Figure 1 shows the distribution of wood ash in Georgia. It is apparent that wood ash has potential to be used as a lime substitute throughout Georgia.

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POTENTIAL FOR PYROLYSIS CHAR TO AFFECT SOIL MOISTURE AND NUTRIENT STATUS OF A LOAMY SAND SOIL
J.W. Gaskin, Adam Speir, L.M. Morris, Lee Ogden, Keith Harris, D. Lee, and K.C Das, Proceedings of the 2007 Georgia Water Resources Conference, held March 27–29, 2007, at the University of Georgia.

Abstract.

Pyrolysis of biomass for hydrogen fuel and bio-oil produces a char byproduct. There is evidence that land application of char may increase soil water holding capacity and the ability of the soil to retain nu-trients. Increases in these soil characteristics could be beneficial to plant growth as well as improving water quality. Chars produced under different conditions and from different feedstocks have different characteristics. Of the common feedstocks tested, peanut hull char con-tained higher nutrients and had a higher cation ex-change capacity than pine chip, pine bark, or hardwood chip chars. Preliminary moisture release curve data from a Tifton loamy sand indicated moisture holding capacity may be increased at very high rates of char addition. Soil moisture was periodically measured dur-ing the growing season in a field study of microplots amended with peanut hull and pine chip pellet char. Although the average soil water content of the plots amended at 22 Mg ha-1 was higher than the control, dif-ferences in volumetric water content were only signifi-cant on one date.

Characterization of Pyrolysis Char for Use as an Agricultural Soil Amendment
Keith Harris1, Julia Gaskin1, Leticia Sonon2, and K.C. Das1
1Dept. of Biol. & Ag. Eng., 2AESL, College of Ag & Env. Sci University of Georgia, Athens, GA

Introduction:
The Southeastern Coastal Plain in the United States is a major agricultural production area; however, soils are typically low in cation exchange capacity (CEC), nutrient content, and organic carbon content. For example, Tifton