The "Fertilizer Transparency Act of 2026" amends the Agricultural Marketing Act of 1946 to establish a comprehensive mandatory price reporting program for fertilizer. Its primary objective is to enhance market transparency by providing farmers and market participants with timely, accurate, and reliable information to facilitate more informed marketing decisions and promote competition within the fertilizer industry. Under this program, manufacturers and wholesalers of nitrogen, phosphorous, potassium, and fertilizer products will be required to report their weekly prices and quantities marketed to the Secretary of Agriculture. This reporting will categorize prices and quantities by domestic or foreign origin. Cooperatives and non-manufacturer retailers are exempt from mandatory reporting but can voluntarily submit their data. The Secretary of Agriculture is mandated to make this reported information publicly available at least weekly, both nationally and on a regional or statewide basis. Additionally, the bill establishes a Fertilizer Retail Survey program within the Agricultural Marketing Service to conduct weekly surveys of retail fertilizer prices and provide regional benchmarks. All collected data, including mandatory reports and retail survey results, will be summarized and made available on an easily accessible dashboard for farmers. Strict provisions are included to protect confidential business information and identities, ensuring that individual company data is aggregated before public disclosure and is exempt from Freedom of Information Act requests. The Secretary will also periodically review reporting requirements to ensure they remain relevant and accurate.