The purpose of this project is to assess nitrogen (N) fertilization rates for high-density plantings of different scion androotstock combinations in four commercial citrus growers. The overall approach is to 1) determine the appropriate N ratesneeded to support tree growth and productivity, 2) compare data obtained with existing UF/IFAS N recommendations, and3) revise best management practices (BMPs) for N application in young trees planted in high-density plantings affected byHuanglongbing (HLB). The Ph.D. student and Research Assistant dedicated to the project worked with the three growercollaborators participating in the project: IMG Citrus (Brian Randolph), Peace River Citrus (Larry Black Jr.), AgromilloraFlorida/ Lost Lake Groves (Clay Pedersen), Graves Brothers (David Howard), and performed the first applications of thefertilizers. Fertilizers were donated by Yara (Bill Easterwood) for the first year (20 tons or 40k lbs). Treatments were applied in all locations and the 2nd fertilization for the season was completed on 07/16/2021. The first tree size and leaf area index data collection was performed and analyzed as expected. After being informed by CRDF that the project will be prematurely concluded in December 2021, cooperating growers were informed that we will not proceed with further applications and data collections.