Research & Project Database

Fertilizer Research And Education Program

Research and Project Database

Since 1990, FREP has funded research on many of California’s important and environmentally sensitive cropping systems. This database aims to make the wealth of information contained in FREP research projects available, understandable, and convenient for growers to implement. See the Crop Fertilization Guidelines for tips on how to improve nutrient management, based on information gleaned from research.

Current Projects

The following is a list of FREP projects that are currently being conducted. Each title links to the project's approved proposal and scope of work. Summaries of many of these projects are featured in previous FREP Conference Proceedings.

Copies of interim and annual project reports are available by contacting FREP at (916) 900-5022 or

  • 2023 FREP-funded projects
  • Optimizing Potassium Fertilization Management in Almond and Pistachio Orchards
    Patrick Brown
  • Estimating Mineralization and Nitrogen Utilization from Banded Compost Applications in Drip Irrigated Sweetpotatoes and Processing Tomatoes
    Daniel Geisseler
  • Improving Nitrogen and Potassium Management in Almond Orchards with Hulls and Shells as a Soil Amendment and Offground Harvest
    Sat Darshan Khalsa
  • Nitrogen Movement Out of Root-Zones in Central Valley Irrigated Lands: A Multi-Scale Management, Monitoring, Modeling, and Outreach Project
    Isaya Kisekka
  • No-till planting of Rice to Conserve Water and Ensure the Sustainability of Rice Systems
    Bruce Linquist
  • Facilitating Grower Adoption of Cover Crop Nitrogen Scavenging to Minimize Residual Nitrogen Loss and Comply with the Irrigated Lands Water Quality Protection Program (Ag Order 4.0) on the Central Coast of CA
    Sacha Lozano
  • 2022 FREP-funded projects
  • Developing Tools and Information on Irrigation and Nitrogen Best Management Practices in California’s Low Desert Lettuce Production Systems (22-1312) Ali Montazar
  • The Role of Irrigation Management for Improving Nitrogen Use Efficiency for Broccoli Grown with Nitrate-Contaminated Irrigation Water (22-1454) Charlotte Decock
  • Development of Precision Yield Monitor for Almond and Pistachio (22-1455)
  • 2021 FREP-funded projects
  • Targeted Nitrogen and Irrigation Education in California’s Nitrate Impacted Regions (21-0502)
    Doug Parker
  • Nutrient Management and Irrigation Efficiency Outreach and Education for Latino and Southeast Asian Farmers (21-0573)
    Carmen Carrasco
  • Nitrogen Fertilizer and Irrigation Best Management Practices for the Low Desert Sudangrass Production Systems (21-0586)
    Oli Bachie
  • Optimizing Nitrogen Fertilizer Concentrations in Vegetable Transplant Production (21-0587)
    Lorence Oki
  • Quantify and Model Overlooked Pathways of Nitrogen Loss From Organic Inputs Across Contrasting Soil Types (21-0588)
    Timothy Bowles
  • Distributed Water and Fertilizer Delivery for Minimizing Nitrogen Losses by Leaching and Volatilization (21-0594)
    Teamrat A. Ghezzehei
  • 2020 FREP-funded projects
  • Assessment of Nitrogen Content of the Harvested Portion of Specialty Crops to Estimate Crop Nitrogen Removal and Improve Nitrogen Management in Crops (20-0250)
    Richard Smith and Michael Cahn
  • “Crop Nutrient Minute” Video Series (20-0877)
    Parry Klassen
  • Ventura County Nitrogen Management Training Program (20-0878)
    Jodi Switzer
  • Assessment of Harvested and Sequestered Nitrogen Content to Improve Nitrogen Management in Crops, Phase 2 (20-0879)
    Charlotte Gallock
  • Development of site-specific nitrogen fertilization recommendations for annual crops (20-0880)
    Daniel Geisseler
  • Enhancing Nitrogen and Water Use Efficiency in California Carrot Production Through Management Tools and Practices (20-0960)
    Aliasghar Montazar
  • Certification and Distance Learning for Fertigation (20-0961)
    Charles M. Burt
  • Outreach and revenue generation for sustaining CropManage irrigation and nutrient management decision support tool (20-0962)
    Michael Cahn
  • Nitrogen Response of Industrial Hemp Cultivars Grown for CBD, Essential Oils (20-0964)
    Robert Hutmacher
  • Techniques to minimize nitrate loss from the root zone during managed aquifer recharge (20-1019)
    Anthony Toby O’Geen
  • 2019 FREP-funded projects
  • Development of Nutrient Management Budget and Nutrient Demand Model for Nitrogen Management in Cherry
    Patrick Brown, Douglas Amaral and Pedro Lima
  • Irrigation and Nitrogen Management, Monitoring, and Assessment to Improve Nut Production while Minimizing Nitrate Leaching to Groundwater
    Thomas Harter, Patrick Brown and Isaya Kisekka
  • Developing a Nitrogen Mineralization Model for Organically Managed Vegetable Farms on the Central Coast
    Joji Muramoto, Richard Smith and Mike Cahn
  • Next Generation N Management Training for Certified Crop Advisors
    Doug Parker et al.
  • Immobilization of Nitrate in Winter-Fallow Vegetable Production Beds to Reduce Nitrate Leaching
    Richard Smith, Michael Cahn, Joji Muramoto and Daniel Geisseler
  • 2018 FREP-funded projects
  • Pima Cotton Nitrogen Management, Uptake, Removal - Impacts of Varieties, Subsurface Drip and Furrow Irrigation (18-0597)
    Robert Hutmacher
  • 2017 FREP-funded projects
  • Evaluation of Nitrogen Uptake and Applied Irrigation Water in Asian Vegetables; Bok Choy, Edible Chrysanthemums, Garlic Chives, Moringa and Lemongrass (17-0515)
    Aparna Gazula

Completed Projects

The following is a list of completed FREP projects. Each title links to a PDF of the project's final report. Summaries of many of these projects are available in the FREP Research Database andFREP Conference Proceedings. Some Project Leaders have published their results in academic journals. Reprints of the journal publications may be requested directly from the corresponding authors.