|Hunt, Patrick - Former ARS Employee|
|Miller, Jarrod - Former ARS Employee|
|Cantrell, Keri - Former ARS Employee|
Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/22/2017
Publication Date: 1/25/2018
Citation: Ducey, T.F., Bauer, P.J., Sigua, G.C., Hunt, P.G., Miller, J.O., Cantrell, K.B. 2018. Manure-derived biochars for use as a phosphorus fertilizer in cotton production. Journal of Cotton Science. 21:259-264. Available: http://www.cotton.org/journal/2017-21/4/upload/JCS21-259.pdf
Interpretive Summary: For the fertilization of crops, manure can be an invaluable resource. Manure can be used as a fertilizer, however it often has excess phosphorus, that when land applied can find its way into the environment. This excess phosphorus is responsible for contaminating rivers and streams, and creating “dead zones” in large bodies of water. One way to protect against this excess phosphorus, is by application of manure based on phosphorus levels. This however often results in limited nitrogen application which can impact plant growth. Therefore, methods must be developed whereby “balanced” rates of nitrogen and phosphorus are applied at the same time. One way to achieve this balance is via pyrolysis, treating manure at high temperatures to create a biochar. This biochar contains concentrated phosphorus and other micronutrients, to which chemical nitrogen is then adding back into the product. Using this method, we created ten biochars, using five animal manures at two different pyrolysis temperatures. In a greenhouse experiment, we grew cotton plants in pots containing a regional soil amended with individual biochars or chemical phosphorus fertilizer. Results indicate that the biochar treatments performed as well as chemical phosphorus fertilizer, and provided enough for suitable growth of cotton plants without any toxic effects. These results indicate that when applied at standard P fertilization rates, manure-derived biochars perform equally to calcium phosphate fertilizer added at a similar rate.
Technical Abstract: Biochars made from animal manure feedstocks appear to be a potential P fertilizer source. Our objective was to assess five different manure-derived biochars, pyrolyzed at two different temperatures (350 and 700 °C), for their potential as a Phosphorus (P) fertilizer for cotton (Gossypium hirsutum L.). A greenhouse study was conducted using a Uchee sand soil. Biochar was applied at rates that provided 40 mg P kg-1 soil. Four rates of calcium phosphate (0, 20, 40, and 60 mg P kg-1 soil) were included in the study. Cotton plants were allowed to grow to 60 days post-emergence at which point leaves and stems were harvested for physical and chemical analysis. The experiment was conducted twice. Results demonstrate that biochar worked as a P fertilizer, and that feedstock choice combined with biochar processing temperature, accounted for a majority of the differences between the ten treatments tested. Further analysis indicated that, when applied at standard P fertilization rates, manure-derived biochars perform equally to calcium phosphate fertilizer added at a similar rate.