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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 #418867
Research Project: Innovative Manure Treatment Technologies and Enhanced Soil Health for Agricultural Systems of the Southeastern Coastal Plain

Location: Coastal Plain Soil, Water and Plant Conservation Research

Title: Enhancing the agronomic efficiency of calcium phosphate recovered from swine manure

Author
item Paye, Wooiklee
item Vanotti, Matias
item SZOGI, ARIEL - Retired ARS Employee
item HERRERO, RAUL - Miguel Hernandez University

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/29/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: Phosphorus can be extracted from animal manure as recovered calcium phosphate which can replace commercial triple supper phosphate in crop production. However, recovered calcium phosphate is less soluble in water than triple supper phosphate. This low-water solubility could make the recovered calcium phosphate less effective as a phosphorus fertilizer. This presentation demonstrates how to improve the solubility and effectiveness of recovered calcium phosphate by using different acidification methods. We dissolved the recovered calcium phosphate in five different solutions including deionized water, 1-N hydrochloric acid (HCl), 2.5-N HCl, recovered nitrogen solution (RNS) and 1-N HCl + RNS.We found that strongly acidic solutions like the 2.5-N HCl and 1-N HCl + RNS dissolved the recovered calcium phosphate better than the weaker acid solutions like the deionized water, 1-N HCl and RNS. In a greenhouse study, the calcium phosphate dissolved in 1-N HCl + RNS was used as a liquid N&P fertilizer blend, and its agronomic effective was compared to RN+RP (without acidification) and Urea + TSP fertilizers blends, using annual ryegrass as test crop. Ryegrass treated with P solubilized in 1-N HCl + RNS produced 8 – 37% more dry matter and had 40 – 70% greater P uptake than the RN + RP and Urea + TSP blends. This shows that acidifying the recovered calcium phosphate makes it more effective than on-acidified RN+ RP and the Urea + TSP blends

Technical Abstract: Phosphorus (P) in animal manure can be extracted, concentrated, and upcycled into a new recovered P (RP) material which can substitute commercial triple supper phosphate (TSP) in crop production. However, the low water-solubility of this new RP material could reduce its agronomic effectiveness. In this study, the solubility and agronomic efficiency of RP from swine manure was modified using acidification of the material. Phosphorus solubility was evaluated in five dissolving solutions: deionized (DI) water, 1-N hydrochloric acid (HCl), 2.5-N HCl, recovered nitrogen solution (RNS) (with 5% N as liquid NH4 solution and pH<1.5), and 1-N HCl + RNS. Results showed that increased acidity affected the recovered P solubility. DI water, RNS, 1-N HCl, 1-N HCl + RNS and 2.5-N HCl solubilized 14, 16, 16, 62 and 93.5% respectively, of total P in the RP material. In a greenhouse trial, the RP dissolved in 1-N HCl + RNS was used as a liquid NP fertilizer blend, and its agronomic efficiency was compared to RN+RP (without acidification) and Urea + TSP fertilizers blends, using annual ryegrass (Lolium multiflorum Lam) as test crop. Annual ryegrass treated with P solubilized in 1-N HCl + RNS produced 8 – 37% more dry matter and had 40 – 70% greater P uptake than the RN + RP and Urea + TSP blends. Our results demonstrate that acidification of the RP material leads to better solubilization of total P, making it more agronomically effective than the non-acidified RN+ RP and the Urea + TSP blends.