California Crop Fertilization Guidelines

UC Davis
A collaboration between CDFA, FREP and UC Davis

Additional Resources

The Fertilization guidelines can also be found on the UC Davis Nutrient Management website .

Management of Specific Crops

University of California - Vegetable Information and Resource Center (VRIC)

VRIC's mission is to foster appropriate research, collect and disseminate information relevant to consumers, growers and processors in the California vegetable industry and to continue its role as a leader and nationally-recognized source of research and information in support of the vegetable industry.

University of California Davis - Fruit & Nut Research & Information

The aim of the page is to aid the coordination and dissemination of University of California research-based information, accomplishments, and statewide research and extension activities related to fruit and nut crops.

University of California - Agronomy Research & Information Center

The site contains links to web pages with information about the management of specific crops as well as contact information of people associated with the Department of Plant Sciences at UC Davis.

University of California - California Rangelands

The site contains some information about rangeland in California. Currently little information about nutrient management is available.

University of California - Integrated Viticulture

On this website, users find publications, video seminars, and useful links on relevant topics from research by the University of California. The website is designed and maintained by the University of California Division of Agricultural and Natural Resources (ANR). The goal of the webpage is to increase accessibility to the work of UC researchers - including faculty, Cooperative Extension specialists, CE advisors, and staff - ensuring a beneficial and productive collaboration in research and extension to the public.

University of California Cooperative Extension Central Sierra - Grapevine Nutrition

A collection of links to sites and publications focusing on grapevine nutrition.

University of California - Nutrient Management for Vegetable, Fruit & Nut Crops

A collection of links to research reports about nutrient management. The information is searachable by crop and topic.

Site Specific Nutrient Management Models

Almond Nitrogen Calculator

Based on the research by Patrick Brown, UC Davis Department of Plant Sciences, the California Almond Board has developed a free, easy-to-use online tool that calculates nitrogen fertilizer needs throughout the season. The calculator takes into consideration yield estimates, leaf sampling results and nitrogen that comes from other sources.

Nitrogen and Potassium Prediction Model for Pistachio

This model calculates the N requirement for pistachio production based upon the yield history, current conditions and previous N applications. This model can be used to calculate both timing and rate of fertilizer application required to maintain optimum yield. Potassium fertilizer recommendations are based only upon the yield history and leaf K levels.


CropManage is an online database-driven tool that assists growers and farm managers in determining water and nitrogen fertilizer applications on a field-by-field basis. The software automates steps required to calculate crop water needs from CIMIS ET data, and estimates fertilizer N needs for lettuce using quick N test data and models of crop N uptake. The web application also helps growers track irrigation schedules and N fertilizer applications on multiple fields and allows users from the same farming operations to view and share data. The software was developed by UC Cooperative Extension specialists and is free to use.

Rice Phosphorus Fertilizer Budget and Application online calculator

This online application calculates the P balance of rice fields as the difference between the amount of fertilizer P applied and what is removed by the crop. The application provides guidelines on the need for P applications taking yield levels and soil P tests into account.

Nutrient Removal with Harvested Crops

Nitrogen concentrations in harvested plant parts. A literature overview for crops grown in California's Central Valley

The report is a literature overview of nitrogen concentrations found in harvested plant parts of crops. The report assesses the relevance of the data for the Central Valley and discusses the factors affecting nitrogen concentrations in harvested plant parts.

Crop Nutrient Removal Calculator

This tool, developed by the International Plant Nutrition Institute (IPNI), provides crop nutrient removal estimates for a broad, and continually expanding, list of field crops. Results are calculated based on user-selected yield goals and can be displayed in either metric or US/Imperial units. Compatible with all computer and mobile devices.

NRCS Crop Nutrient Tool

The tool calculates the approximate amount of nitrogen, phosphorus, and potassium that is removed by the harvest of agricultural crops.

Irrigation, Water Use

University of California Cooperative Extension - Irrigation Management

A collection of presentations and publications about irrigation management by Larry Schwankl, University of California Cooperative Extension specialist.

WATERIGHT by the Center for Irrigation Technology at California State University, Fresno

The WATERIGHT site was developed by the Center for Irrigation Technology at California State University, Fresno with significant support from the US Bureau of Reclamation. WATERIGHT is designed to be a multi-function, educational resource for irrigation water management. The site is designed for three audiences: homeowners, commercial turf growers, and agriculture.

California Irrigation Management Information System (CIMIS)

The California Irrigation Management Information System (CIMIS) is a program in the Office of Water Use Efficiency (OWUE), California Department of Water Resources (DWR) that manages a network of over 120 automated weather stations in the state of California. CIMIS was developed in 1982 by the California Department of Water Resource and the University of California at Davis to assist California's irrigators manage their water resources efficiently.

California Institute for Water Resources

The California Institute for Water Resources develops and supports water-related research, education, and outreach across the state and beyond. The institute brings together local, state, and federal communities to identify issues and sources of political and financial support for solutions-oriented water research and outreach.

National Agricultural Library - Water Management

Find information about methods to improve or protect soil. Topics include water conservation and water-saving irrigation techniques.

Fertilizer Material

Nutrient Source Specifics

Nutrient Source Specifics are one-page fact sheets highlighting various fertilizers and nutrient sources. Information about the production, agricultural use, management practices, and chemical properties of common fertilizer materials is included. Written by International Plant Nutrition Institute (IPNI) scientific staff, these items are primarily for educational use by a non-technical audience.

Manure Management

University of California - Manure Management for California Certified Crop Advisers

This site contains technical information on dairy manure nutrient management intended to help Certified Crop Advisers who are serving dairy farmers in the Central Valley of California. Maintained by Stuart Pettygrove, University of California Cooperative Extension specialist.

University of California Cooperative Extension - Manure Nutrient Management

The site contains the latest practical information and easy to use tools for manure nutrient management. The site is primarily authored by Marsha Campbell Mathews, University of California Cooperative Extension Agronomy Farm Advisor in Stanislaus County.

Cover Crops

University of California SAREP - Cover Crop Database

The cover crop database by the Sustainable Agriculture Research and Education Program (SAREP) at UC Davis contains descriptions of more than 40 different cover crop species. The information provided includes climate and soil requirements, management practices, uses and other topics.

Oregon State University - Organic Fertilizer and Cover Crop Calculator

This Oregon State University page provides information about cover crops and organic fertilizers, including a free calculator to compare the nutrient value and cost of cover crops, organic and synthetic fertilizers and compost.

Cover Crop Topic Room: Soil and Fertility Management

The Cover Crop Topic Room is an organized collection of educational materials developed out of decades of cover crop research funded by the Sustainable Agriculture Research & Education (SARE) grants and education program.

Managing Cover Crops Profitably

The book 'Managing Cover Crops Profitably' explores how and why cover crops work and provides all the information needed to build cover crops into any farming operation.

Site Specific Soil Information

SoilWeb: An Online Soil Survey Browser

Explore mapped soil survey areas using an interactive Google map and view detailed information about map units and their components. This app runs in your web browser and is compatible with desktop computers, tablets, and smartphones.

NRCS Web Soil Survey

Web Soil Survey (WSS) provides soil data and information produced by the National Cooperative Soil Survey. It is operated by the USDA Natural Resources Conservation Service (NRCS) and provides access to the largest natural resource information system in the world. NRCS has soil maps and data available online for more than 95 percent of the nation's counties and anticipates having 100 percent in the near future.

Nitrogen Cycle

The California Nitrogen Assessment

The California Nitrogen Assessment (CNA) is the first comprehensive account of nitrogen flows, practices, and policies for California, encompassing all nitrogen flows - not just those associated with agriculture - and their impacts on ecosystem services and human wellbeing.

Nitrogen Notes

This series of fact sheets, written by International Plant Nutrition Institute (IPNI) staff, covers the major nitrogen fertilizer transformations that occur in crop production.

Nitrate in Groundwater

Nitrate Groundwater Pollution Hazard Index

The Nitrate Groundwater Pollution Hazard Index was developed to provide information to farmers interested in voluntary management practices that reduce nitrogen contamination potential in groundwater. The index works with an overlay of soil, crop, and irrigation information. Based on these three components, an overall potential hazard number is assigned and management practices are suggested where necessary.

UCCE Groundwater Hydrology Program

The UCCE Groundwater Hydrology Program provides educational, scientific, and technical support on current and emerging groundwater resources and groundwater quality issues in rural areas of California.

California Water Boards

The State Water Board's mission is to preserve, enhance and restore the quality of California's water resources, and ensure their proper allocation and efficient use for the benefit of present and future generations.

Water Quality Coalitions

California Water Quality Coalitions

This site by the State Water Board contains a map and list of Water Quality Coalitions.

California Rice Commission

Sacramento Valley Water Quality Coalition

San Joaquin County & Delta Water Quality Coalition

Westside San Joaquin River Watershed Coalition

East San Joaquin Water Quality Coalition

Grassland Drainage Area Coalition

Westlands Water Quality Coalition

Southern San Joaquin Valley Management Practices Evaluation Program

The Southern San Joaquin Valley Management Practices Evaluation Program Committee includes the following seven irrigated agricultural water quality coalitions in California's central Valley, generally located between Fresno and Bakersfield: Buena Vista Coalition, Cawelo Water District Coalition, Kaweah Basin Water Quality Association, Kern River Watershed Coalition, Kings River Water Quality Coalition, Tule Basin Water Quality Coalition, West Side Water Quality Coalition.

Other Topics

California Agriculture

California Agriculture is a peer-reviewed journal reporting research, reviews and news from the University of California and its Agriculture and Natural Resources division. The authors are primarily, but not exclusively, faculty from the University of California. It is currently published quarterly.

Agricultural Sustainability Institute at UC Davis

The mission of the Agricultural Sustainability Institute (ASI) is to ensure access to healthy food and to promote the vitality of agriculture today and for future generations. This is done through integrative research, education, communication and early action on big, emerging issues. ASI provides a hub that links initiatives and education in sustainable agriculture and food systems across all divisions of the College of Agricultural and Environmental Sciences at UC Davis, across the University of California, and with other partners across the State of California.

U.S. Department of Agriculture

Find the latest news about US agriculture and links to all agencies and offices within USDA.

National Agricultural Library - Soil Management

Find information about methods to improve or protect soil. Topics include soil quality and testing, nutrient management, cover crops, compost, and conservation tillage.

International Plant Nutrition Institute

The International Plant Nutrition Institute (IPNI) is a not-for-profit, science-based organization dedicated to the responsible management of plant nutrition for the benefit of the human family. Companies that are basic producers of one or more of the major plant nutrients (nitrogen, phosphate, potash, and sulfur) for agricultural purposes are the members of IPNI. As a global organization, IPNI has initiatives addressing the world's growing need for food, fuel, fiber, and feed.