Phosphorus enriched modified-Douglas fir biochar as a soil amendment

Author

Beatrice Arwenyo, Mississippi State UniversityFollow

ORCID

https://orcid.org/0000-0002-7687-4084

Issuing Body

Mississippi State University

Advisor

Mlsna, Todd E.

Committee Member

Mlsna, Deb

Committee Member

Varco, Jac J.

Committee Member

Patrick , Amanda

Committee Member

Wipf , David O.

Date of Degree

5-13-2022

Document Type

Dissertation - Open Access

Major

Chemistry

Degree Name

Doctor of Philosophy (Ph.D)

College

College of Arts and Sciences

Department

Department of Chemistry

Abstract

Biochar application as a soil additive is gaining global acceptance. In this era of climate change, biochar use for improved soil productivity is not just a sustainable eco-friendly substitute to synthetic fertilizer, but a noble contributor to the fight against climate change. Although biochar has been accredited with some environmental and agricultural benefits, most studies concentrated on agricultural and biowaste products as feedstocks. This research was designed to explore P-enriched modified-Douglas fir biochar potential as a soil additive. Using corn as a test crop, greenhouse studies were performed on acidic sandy soil, comparing phosphorus enriched modified-Douglas fir biochar efficacy to a commercial synthetic triple superphosphate fertilizer and a control treatment. Incubation studies were also performed to evaluate the liming and heavy metal immobilization efficacies. Firstly, P-enriched modified-Douglas fir biochar’s ability to release plant soluble P was investigated. At various P enrichment concentration, soil plant availability P from P enriched modified-Douglas fir biochar treatments differed insignificantly from superphosphate fertilizer treatment. The direct correlations between both K and Mg recoveries with available soil P, suggested P enriched modified-Douglas fir biochar potential to supply multiple plant nutrients. Secondly, the influence of P uptake on plant growth and P use efficiency was examined. The greater agronomic P use efficiency obtained in P enriched modified-Douglas fir biochar (~32 kg kg^-1) than the triple supper phosphate fertilizer (~17 kg kg^-1) treatment confirmed P enriched modified-Douglas fir biochar potential as a multiple nutrient released soil additive. Thirdly, biochar-supported phosphate (BP) effectively reduced Pb²⁺ mobility in simulated contaminated soil. Pb²⁺reacted with phosphate from Ca₁₀(PO₄)₆(OH)₂ embedded in the biochar supported phosphate at pHPb₁₀(PO₄)₆(OH)₂. Finally, the amendment of acidic soils with modified P-enriched modified-biochar improved soil buffering capacity because of its enhanced ash contents, alkalinity, and surface functional groups. Spectroscopic methods were used to analyze biochar, soil, and plant materials extracts. Several other analytical methods including BET and thermogravimetric analyses were used to characterized biochar. These findings suggest that the use of phosphorus enriched modified-Douglas fir biochar in agricultural soil is a feasible relatively low-cost, effective, and environmentally sustainable soil management and P recycling strategy

Sponsorship

Fulbright Organization and US Department of State

Recommended Citation

Arwenyo, Beatrice, "Phosphorus enriched modified-Douglas fir biochar as a soil amendment" (2022). Theses and Dissertations. 5400.
https://scholarsjunction.msstate.edu/td/5400