Preservation and Deployment of Biofertilizers to Mitigate Soil Phosphorous Loss from Agricultural Systems

The world is approaching peak phosphorus within the next 20 years, which poses a severe threat to the food security of a rapidly growing global population. Phosphorus is the second most essential macronutrient for plants after nitrogen, and its scarcity results in stunted growth, poor root development, and reduced crop agricultural crop yields. While phosphorus is naturally present in the soil, it is often not available in sufficient quantities or in a form that plants can synthesize. The use of phosphate-rich fertilizers has compensated for the low levels of phosphorus in agricultural systems, however, up to 95% of these fertilizers become "fixed" in the soil, causing environmental damage and reducing soil fertility. It is critical to find sustainable ways to manage our depleting phosphorus resources and minimize the environmental impact of phosphate fertilizers. To address these challenges, this research introduces a framework that leverages silk-based biopolymer encapsulation to preserve and deliver phosphate solubilizing microorganisms to the soil on naturally occurring phosphate rocks. By enabling the revival of phosphate solubilizing bacteria and initiating the solubilization of adjacent phosphate rocks, this approach not only improves the accessibility of untapped phosphate resources for plant roots but also facilitates the continual solubilization of various forms of insoluble phosphate, including legacy phosphorus from past fertilizer applications. This research showed phosphate solubilizing bacteria encapsulated in the biopolymer-coated phosphate rock remained viable after 30 days of storage and demonstrated effective solubilization of its host phosphate rock in solution. The addition of the biopolymer-coated phosphate rocks to chickpea seedlings showed a significant increase in the phosphorous content in chickpea leaves compared to the addition of uncoated rocks. Additional investigations can be undertaken to evaluate the potential of this framework as a controlled-release fertilizer by varying coating parameters such as material processing, biopolymer concentrations, and fertilizer amounts. The results of this thesis provide a foundation for further exploration and development of natural phosphate biofertilizers, bringing us one step closer to a more sustainable and resilient future in agriculture.

Name thesis:degree_name

Master

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Mechanical Engineering

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2023

Author dc:creator

• Barghouti, Zeina

Advisor dc:contributor.advisor

• Varanasi, Kripa

Statement dc:rights

• In Copyright - Educational Use Permitted
• Copyright retained by author(s)

Licence dc:rights.uri

• https://rightsstatements.org/page/InC-EDU/1.0/

Handle dc:identifier.uri

https://hdl.handle.net/1721.1/151881

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/151881