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ARS Home » Southeast Area » Florence, South Carolina » Coastal Plain Soil, Water and Plant Conservation Research » Research » Publications at this Location » Publication #287439
Title: Phosphorus fertilization of ryegrass with ten precisely prepared manure biochars

Author
item Hunt, Patrick
item Cantrell, Keri
item Bauer, Philip
item Miller, Jarrod

Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/2013
Publication Date: 12/20/2013
Citation: Hunt, P.G., Cantrell, K.B., Bauer, P.J., Miller, J.O. 2013. Phosphorus fertilization of ryegrass with ten precisely prepared manure biochars. Transactions of the ASABE. 56(6):1317-1324.

Interpretive Summary: Biochar is made by applying high temperature heat in an oxygen free environment to carbon containing materials such as wood. It has garnered great interest as a carbon sequestering soil amendment. Yet, biochars made from livestock manures need to be better understood in relation to their high nutrient contents. The objective of this investigation was to assess the plant availability and agronomic efficacy of the plant nutrient phosphorus contained in 10 precisely prepared and characterized manure-derived biochars. The experiment was in a greenhouse with ryegrass. The 10 manure biochars were created from dairy, swine, beef, turkey, and poultry manures. Each manure feedstock was converted into biochar at two temperatures (350°C and 700°C). The soil was a low phosphorus sandy soil typical of the Coastal Plain. The biochars were applied at normal fertilizer rates for phosphorus. They generally produced ryegrass yields similar to chemical fertilizer. The chicken 350°C biochar produced the highest ryegrass yield. The swine 350°C biochar produced the lowest ryegrass yield. Thus, for ryegrass growth, manure biochars can be used for their phosphorus supplying capacities. This can be important to manure management, crop fertilization, and conservation of global phosphorus resources.

Technical Abstract: Biochar has garnered great interest as a carbon (C) sequestering soil amendment. Yet, biochars made from livestock manures need to be better understood in relation to their high nutrient contents. Thus, the objective of this investigation was to assess the plant availability and agronomic efficacy of phosphorus (P) contained within chemical fertilization compared to the P contained in 10 precisely prepared and characterized manure-derived biochars. Two identical experiments were conducted using greenhouse grown ryegrass (Lolium multiflorum Lam.). The 10 manure biochars were created from dairy, swine, beef, turkey, and poultry manures. Each manure feedstock was converted into biochar at two temperatures (350°C and 700°C). The soil was a low phosphorus sand [Uchee series (Loamy, kaolinitic, thermic Arenic Kanhapludults)]. The biochar-amended treatments received P on a basis of 50 milligrams phosphate fertilizer per kilogram of soil. The biochar treatments were compared to chemically-fertilized treatments of 0 to 150 milligrams P per kilogram of soil. The biochars did not contain yield limiting levels of electrical conductivity, pH, zinc, or copper. Phosphorus in the manure-derived biochars was readily plant available. The biochars generally produced ryegrass yields similar to chemical fertilizer. The chicken 350°C biochar produced the highest ryegrass yield. The swine 350°C biochar produced the lowest ryegrass yield. For the biochar treatments, the ryegrass copper and zinc concentrations were within normal range, and they were not significantly different than the simple chemical fertilization treatments. Thus, for ryegrass growth, manure biochars can be used for their P-supplying capacities. This can be important to manure management, crop fertilization, and conservation of global phosphorus resources.