Other Resources

Crop-Specific Resources

Almond Early-Season Sampling and In-Season Nitrogen Application Maximizes Productivity, Minimizes Loss
University of California, Division of Agriculture and Natural Resources

This article focuses on the rates of nitrogen application to almonds.

Almond N Model
University of California and California State University

This program provides recommendations for making N and K fertilization decisions.

Best Management Practices for Nitrogen Fertilization of Grapevines
University of California Cooperative Extension

This PDF includes best management practices for N fertilization of grapevines.

Best Management Practices for Profitable Fertilization of Potatoes
University of California, Division of Agriculture and Natural Resources

This article discusses the fertilizer best management practices for potatoes.

Carrot Production in California
University of California, Division of Agriculture and Natural Resources

This 2008 article provides basic information for commercial growers of carrots.

Chile Pepper Production in California
University of California, Division of Agriculture and Natural Resources

This 2011 article provides basic information for commercial growers of chile peppers.

Common Dry Bean Production in California
University of California, Division of Agriculture and Natural Resources

This 2010 16-page publication provides basic information for commercial growers of dry beans.

Fertilization of Small Grains
University of California, Division of Agriculture and Natural Resources

This 11-page publication by is part of the Small Grain Production Manual and specifically talks about the fertilization of small grains.

Fertilizer Management in Strawberry Production
University of California, Division of Agriculture and Natural Resources

This 2011 blog post provides specific information about fertilizer management in strawberries.

Fertilizing Olive Trees
University of California Cooperative Extension, Sonoma County

This article discusses the specific fertilizer needs of olive trees.

Irrigated Pasture Nitrogen Management & Planning
UCRangelands – University of California

This application is a nitrogen management planning tool for irrigated pastures. Results can be used for the Nitrogen Management Plan Worksheet.

Nutrient Budget in Citrus Groves

California Department of Food and Agriculture, Fertilizer Research and Education Program

This FREP-funded project update covers the process of developing nutrient demand curves and an early season leaf sampling protocol for mandarin and orange groves.

Nitrogen Budgeting Worksheet for Walnuts
University of California, Division of Agriculture and Natural Resources

This worksheet provides a tool to estimate nitrogen fertilizer needs in walnuts.

Nitrogen Calculator for Processing Tomatoes
Geisseler Lab, University of California, Davis

This calculator was developed based on results from a 3-year study in commercial subsurface-drip irrigated fields in the Central Valley and a replicated field trial at UC Davis.

Nitrogen Fertilizer Management Tool for California Wheat
University of California, Agriculture and Natural Resources

This tool estimates grain yield and protein responses to in-season applications of N fertilizer. The tool combines site-specific weather and soil data with user-supplied, field-specific measurements & management information to produce real-time estimates of crop responses to added N fertilizer.

Nutrient Management
Almond Board of California, Almond Sustainability Program

This training module covers nutrient management checklists related to the source, amount, timing, and place of fertilization.

Nutrient Management for Vegetables, Fruit, and Nut Crops
University of California Division of Agriculture and Natural Resources

This site contains articles about more than 40 crops and 12 topics (including fertilizer management, fertilizer technology, and site-specific management), as well as several learning modules designed to provide in-depth training on specific topics relating to soil fertility and irrigation management of horticultural crops.

Nutrient Management Goals and Management Practices for Cool-Season Vegetables
University of California, Division of Agriculture and Natural Resources

This publication discusses management practices for the reduction of nutrient pollution in cool-season vegetables.

Nutrient Management in Cool-Season Vegetables
University of California, Division of Agriculture and Natural Resources

This article discusses efficient nutrient management practices.

Nitrogen Mineralization from Organic Amendments Calculator
Geisseler Lab, University of California, Davis

The calculations in this tool are based on an analysis of 113 datasets from the scientific literature. Nitrogen mineralization rates are adjusted based on soil temperature data from local CIMIS weather stations. Soil moisture is assumed to be optimal near field capacity.

Nitrogen Prediction Models for Almond and Pistachio
University of California Davis

These prediction models are based on research conducted through a 4-year, multi-state project with goals to optimize resource use in deciduous tree crops. The page provides a protocol for early-season leaf sampling and models to predict N and K status of the trees and in-season N budgeting based on leaf analyses.

Nitrogen Uptake and N Release Models
University of California Division of Agriculture and Natural Resources

This tool calculates nitrogen uptake for each irrigation interval for winter cereal forage, silage corn and triplecrop sudangrass.

Tailoring Fertilizer Rates for Diverse Nursery Crops
University of California, Division of Agriculture and Natural Resources

This article addresses the specific fertilizer needs of nursery crops.

Water and Nitrogen Management Workshop Presentations
Almond Board of California, Almond Sustainability Program

This site includes several workshop presentations related to water and nitrogen management for almonds throughout the state.

Evapotranspiration Variability Viewer

The Evapotranspiration Variability Viewer is another new tool to support irrigation management. Variability of crop and soil conditions within a given field must be understood and managed to achieve productivity and environmental performance goals. A good measure of crop condition and variability within a field, as affected by factors such as irrigation uniformity, is the actual evapotranspiration (ETa). The Evapotranspiration Variability Viewer maps field-level actual Evapotranspiration Distribution Uniformity (ETa DU) for an irrigation season (May to October) and for July (peak ETa). Using an online data portal provided through coalition websites, growers can zoom into their fields and view maps and quantitative charts of field variability. Contact your coalition for more information.

General Information Related to Nitrogen Management in California

Barriers to Adoption of Improved Nitrogen Management Practices
University of California Davis and California Dept. of Food & Agriculture

Rates of adoption of recommended nitrogen (N) management practices by crop type and management type, key barriers to adoption, and announcement of survey to be held Spring and Summer 2018.

California Nitrogen Assessment
University of California Sustainable Agriculture Research and Education Program

This site provides a big-picture view of California’s nitrogen system, including how nitrogen moves through the environment, affects human health, and can be effectively managed.

FREP Conference Proceedings By Year (1992 – 2016)
The Fertilizer Research and Education Program (FREP) is a division of the California Department of Food and Agriculture (CDFA)

These proceedings are compiled for the annual FREP Conferences and contain pioneering research from academia, industry, and agricultural consulting providing general and technical information, current research and data, and practical applications addressing statewide and regional management issues.

Irrigated Lands Regulatory Program (ILRP)
Central Valley Regional Water Quality Control Board

This site provides a general overview of the ILRP, including program background, grower requirements, new waste discharge requirements, water quality information, and grower outreach and enforcement. The site includes a “Frequently Asked Questions” fact sheet for growers, and the Waste Discharge Requirements General Order for the Tulare Lake Basin Area.

Nitrogen fertilizer use in California: Assessing the data, trends and a way forward
University of California, Davis

In this 2013 article, the authors assess existing knowledge on inorganic nitrogen fertilizer flows, and practice and policy in California agriculture. They examine how statistics are generated, identify sources of uncertainty, and compare and interpret data.

Nitrogen Sources and Loading to Groundwater
California Nitrate Project, University of California, Davis Center for Watershed Sciences

This 343-page report focusing on the Tulare Lake Basin and Salinas Valley Groundwater was prepared for the State Legislature by the State Water Resources Control Board in response to Senate Bill X2 1.

Resources for Growers: Irrigation and Nutrient Management Agency Resources, Services and Useful Information
Central Coast Regional Water Quality Control Board (RWQCB)

This 2014 article provides growers with information that will assist them in implementing irrigation and nutrient management practices, including agency resources, services and other useful information. Although developed by the Central Coast RWQCB, many of the materials are relevant to the San Joaquin Valley.

SoilWeb App (USDA-NRCS) Links
The University of California Soil Resource Lab utilizes USDA-NRCS SoilWeb

Five different SoilWeb product apps are available, used for accessing the USDA-NRCS detailed soil survey data. Apps include SoilWeb (using an interactive Google Map), SoilWeb Earth (shows mapped areas in 3-D display), SEE – Soil Series Extent Explorer, Soil Properties App, and Soil Agricultural Groundwater Banking Index.

Solution Center for Nutrient Management
A Project of the University of California Agriculture and Natural Resources, Sustainable Agriculture Research and Education Program (UC SAREP)

This resource was created to increase access to California agricultural nutrient management resources and serve as a platform for conversations on important nutrient management issues.

Irrigation Planning and Management

General Information

Irrigation Effects on N Availability
Michael Cahn, UC Cooperative Extension

This article provides information regarding the utilization of weather and soil-based approaches to achieve uniform distribution while minimizing deep percolation.

Advanced Pumping Efficiency Program
Fresno State Center for Irrigation Technology

This site offers online training modules related to managing water, pumping efficiency, pressure, and rate schedule.

California Institute for Water Resources Tools
University of California, Division of Agriculture and Natural Resources, California Institute for Water Resources

This site offers drought resources, the CropManage online irrigation scheduling, nitrate groundwater pollution hazard index, and Enviro-Gro (which provides growth simulations of agricultural crops).

Center for Irrigation Technology
Fresno State

This site offers special software packages designed to improve efficiency in large- and small-scale irrigation systems. On-site testing services and seminars on irrigation and pumps also are available.

Irrigation Management
California Ag Water Stewardship Initiative

This site provides an overview of irrigation management, and links to dozens of resources on soil moisture monitoring, irrigation scheduling, drip irrigation, and subsurface drip irrigation.

Irrigation Management
University of California Cooperative Extension

This site provides informational PowerPoint Presentations, and links to the University of California Drought Management and Microirrigation System Maintenance websites.

Irrigation Management and Agronomy
University of California Cooperative Extension, Kern County

This site provides information on irrigation management and agronomy, including links to many resources related to crop-specific evapotranspiration, irrigation scheduling, and salinity management.

Irrigation Training and Research Center
Cal Poly State University

This site contains a searchable database of more than 86 reports related to irrigation. Additional databases are available for irrigation evaluation data and evapotranspiration data. Multiple classes on irrigation and water management are offered online and in-person.

Irrigation Scheduling

California Irrigation Management Information System (CIMIS)
California Department of Water Resources (DWR)

Precipitation, reference evapotranspiration data, and other climate parameters are available to the public on this site. CIMIS, a program unit in the DWR Water Use and Efficiency Branch, manages a network of over 145 automated weather stations in California.

Crop Irrigation Strategies
University of California, Division of Agriculture and Natural Resources

This site includes individual crop deficit irrigation information for almonds, pistachios, stone fruit, walnuts, alfalfa, olives, winegrapes, corn, and processing tomatoes. For each crop, the site includes detailed information on irrigation management for crops under drought conditions, as well as a list of other resources.

Irrigation Scheduling
University of California, Division of Agriculture and Natural Resources

This site includes information related to evapotranspiration scheduling, soil moisture monitoring, and plant-based irrigation scheduling.

Irrigation Scheduler Mobile
AgWeatherNet – Washington State University

This website provides an irrigation scheduling tool that uses CIMIS climate data to produce charts related to daily and cumulative water use, crop coefficients, deep water loss, and water stress.

Kern County Weekly Evapotranspiration Report
University of California Cooperative Extension, Kern County

This site uses CIMIS data to calculate the previous and coming week ETc for almond, pistachio, citrus, grapes, alfalfa and cotton in Kern County. Users can subscribe to weekly e-mails.

WATERIGHT
Fresno State Center for Irrigation Technology

WATERIGHT is designed to be a multi-function, educational resource for irrigation water management. The site includes irrigation scheduling programming that helps users develop site-specific, seasonal irrigation schedules. WATERIGHT is connected to CIMIS.

Weather-Related Models and Services
University of California, Davis

This site includes programs developed to provide timely weather-related tree crop information specifically for California fruit and nut growers, researchers, and industry. Air temperatures collected from the CIMIS weather stations are used for model calculations.

Rangeland Irrigation

UC Rangelands’ Irrigated Pasture Nitrogen Management & Planning online application for determining nitrogen budgets on livestock grazed, irrigated pasture.
University of California, Rangelands

UC Rangelands provides this online nitrogen management planning tool for irrigated pastures that may be used by coalition members to assist in completing a Nitrogen Management Plan (NMP). Members with irrigated pasture that apply fertilizer are required to prepare an NMP – this tool does not replace the NMP, but will calculate some of the values required in the NMP for irrigated pasture.

Fertigation

Chemigation and Fertigation Basics for California
Irrigation and Training Research Center, Cal Poly State University

This article provides basic information about chemigation and fertigation in a question and answer format.

Fertigation
University of California, Davis

This article provides basic information about fertigation.

Nitrogen Planning and Management

California Fertilization Guidelines
California Department of Food and Agriculture in collaboration with University of California, Davis

This site includes fertilizer guidelines for 25 major crops describing nitrogen, phosphorus, potassium, and other important nutrient guidelines. Information on soil tests and leaf analysis is also provided.

Fertilizer Research and Education Program
California Department of Food and Agriculture

This site has information about crop fertilization, N management training, and relevant research summaries for over 130 projects. The research database is searchable by crop, county, and date range, and results are in the form of concise summaries with links to the full research report. FREP funds and facilitates research to advance the environmentally safe and agronomically sound use and handling of fertilizing materials.

Field-Specific Nitrogen Fertilization Adjustments
California Department of Food and Agriculture

This site provides an overview of the considerations needed to account for nitrogen from non-fertilizer sources, including residual soil nitrate, nitrate in irrigation water, and previous crop N credits. Information is also provided on leaching, volatilization, and denitrification losses.

Nutrient Management Solutions
University of California Sustainable Agriculture Research and Education Program

This website was created to increase access to California agricultural nutrient management resources and serve as a platform for conversations on important nutrient management issues.

SoilWeb Apps
UC Davis California Soil Resource Lab

This website offers multiple apps that access USDA-NCSS soil survey data (SSURGO) for most of the United States in a variety of interfaces.

4 Rs of Nutrient Management Training Material
Iowa State University, The Fertilizer Institute, the International Plant Nutrition Institute, and the USDA Natural Resources Conservation Service

This site includes 10 online training modules to provide information about basic components of soil fertility and nutrient best management practices.

4 Rs of Nutrient Management Pocket Field Guide
Iowa State University, The Fertilizer Institute, the International Plant Nutrition Institute, and the USDA Natural Resources Conservation Service

This site includes a 16-page pocket guide to the 4Rs of nutrient stewardship.

4Rs of Nutrient Stewardship Infographic
Iowa State University, The Fertilizer Institute, the International Plant Nutrition Institute, and the USDA Natural Resources Conservation Service

This 1-page infographic provides an overview of this approach for nutrient management.

A Guide to Collecting Soil Samples
Oregon State University Extension Service

This article provides information on collecting soil samples to assess the soil’s available nutrient-supplying capacity.

Toolkits
Agriculture Water Quality Alliance (AWQA)

This site provides a compilation of resources for use by Certified Crop Advisers, certified agronomists, and other irrigation and nutrient management professionals to assist in farming operations with water and nutrient equipment and scheduling. Three toolkits are available: Irrigation Systems and Scheduling; Irrigation Assessment; and Nutrient Management.
AWQA is a partnership of agriculture industry groups, resource conservation agencies, researchers, and environmental organizations working to ensure the health of Monterey Bay Sanctuary and its watersheds.

Details on the Nitrate Quick Test
University of California, Division of Agriculture and Natural Resources
(Salinas Valley Agriculture Blog)

This 2011 blog post provides information about obtaining representative soil samples in order to conduct the nitrate quick test analysis.

Estimating Plant-available Nitrogen Release from Cover Crops
Oregon State University Extension Service

This 2012 extension publication compares plant-available nitrogen from several cover crops.

Fertilizer Calculator Tool
University of Georgia Extension

This tool calculates how much fertilizer to apply. The user inputs expected yield and the type of fertilizer being used, and the calculator determines the agronomic amount to apply without the user having to do any additional calculations to convert fertilizer N to applied N.

Fertilizer Calculator Tool
Texas A & M AgriLife Extension

This tool is an agricultural fertilizer management calculator.

Manure as a Fertilizer
University of California Cooperative Extension, Tulare County

This 1997 document helps determine how much manure is needed. It includes tables for various manures and their estimated nitrogen, potassium, and phosphorus content.

Nitrate to Nitrogen Conversion and Estimating N Contribution from Irrigation Waters Containing Nitrate
University of California, Division of Agriculture and Natural Resources
(Salinas Valley Agriculture Blog)

This 2012 blog post provides information to calculate the conversion between nitrate (NO₃) and nitrate-nitrogen (NO₃-N).

Nitrogen Availability from High-Nitrogen-Containing Organic Fertilizers
University of California, Division of Agriculture and Natural Resources.

This 2006 article evaluates the rate of net nitrogen mineralization from four organic fertilizers.

Nitrogen Calculator for Central Valley Crops
Department of Land, Air, and Water Resources at the University of California, Davis.

The values calculated on this website are estimates based on literature data for N uptake.

Nitrogen Calculator for Processing Tomatoes
Geisseler Lab, University of California, Davis

This calculator was developed based on results from a 3-year study in commercial subsurface-drip irrigated fields in the Central Valley and a replicated field trial at UC Davis.

Nitrogen Fertilizer Management Tool for California Wheat
University of California, Agriculture and Natural Resources

Nitrogen Management and Water Quality Protection
University of California, Division of Agriculture and Natural Resources

This article discusses nitrogen management to improve water quality.

Nitrogen Management Training for CCAs
University of California, Division of Agriculture and Natural Resources

This site includes training materials and videos from 2014 and 2015 training sessions for Certified Crop Advisers related to N management for nitrogen management planning.

Nutrient Content of Crops Tool
USDA Natural Resources Conservation Service

This site is a tool for calculating the approximate amount of nitrogen, phosphorus, and potassium that is removed by the harvest of agricultural crops.

Nutrient Management for Vegetables, Fruit, and Nut Crops
University of California, Division of Agriculture and Natural Resources

This site is a compilation of information organized for more than 40 crops and 12 topics (including fertilizer management, fertilizer technology, and site-specific management). The site also has several learning modules designed to provide in-depth training on specific topics relating to soil fertility and irrigation management of horticultural crops.

Nitrogen Mineralization from Organic Amendments Calculator
Geisseler Lab, University of California, Davis

Nutrient Removal Calculator
International Plant Nutrition Institute

This calculator estimates removal of nitrogen, phosphorus, potassium, and sulfur for a broad list of field crops. Results are calculated based on user-selected yield goals, and can be displayed in either metric or US/Imperial units.

Research on nutrient and fertilizer management
University of California, Division of Agriculture and Natural Resources

The University of California Cooperative Extension and Agricultural Experiment Station researchers are working with growers with small and large acreage on fertilizer management, irrigation efficiency, and other farming practices to provide options for protecting groundwater. This site provides a summary of related research.

Soil Analysis
University of California, Division of Agriculture and Natural Resources

This 2016 article provides information about soil sample analysis.

Soil and Leaf Testing for Commercial Citrus Production
University of Florida Institute of Food and Agricultural Sciences Extension

This article provides information about quantifying nutrients in soils and trees to inform a fertilizer program.

Soil Sampling
University of California Cooperative Extension Small Farms Program

This site provides basic information about soil testing to analyze soil nutrients.

Soil Sampling in Orchards
California Department of Food and Agriculture in collaboration with University of California Davis

This article provides guidelines for soil sampling in orchards to optimize fertilization.

Solution Center for Nutrient Management
University of California, Division of Agriculture and Natural Resources

This site includes a nutrient management research database, focused summaries of nutrient management topics, case studies, discussion forums, and other important resources.

Tool Box
International Plant Nutrition Institute

This site includes a selection of calculators and tools that provide estimates for crop nutrient removal, response, trends in soil test results, yield loss from nutrient rate reductions, and more.