Nitrogen Calculator Optimizes N Use


Under the Irrigation Lands Regulatory Program (ILRP), Central Valley Water Quality Coalitions’ reporting requirements include farm evaluations, nitrogen summary reports, and a sediment and erosion plan. In high-vulnerability groundwater areas, growers are required to submit certified summary reports annually; in low-vulnerability areas, the report must be kept on-site and certification is not required.


It is important to comply with these requirements, as the Central Valley Regional Water Board is actively enforcing the program with heavy fines for growers who either have not signed up for a coalition or who have not submitted a Nitrogen Management Plan.


N Calculator

Almond Board of California (ABC) has created a tool, the Almond Nitrogen Calculator, that not only helps almond growers to manage nitrogen applications for efficient fertilizer use, but also generates a Nitrogen Management Plan as required by ILRP. The N Calculator:


  • Calculates fertilization rates based on newest UC nitrogen management research;
  • Employs the Four R’s of nutrient management (right source, right rate, right timing and right location);
  • Is based on almond crop demand and accounts for vegetative growth, as well;
  • Enables efficient fertilizer use;
  • Has a library of fertilizers in pull-down menus for easy rate calculations, based on data you put into the system;
  • Calculates nitrogen contributions from non-fertilizer sources, such as groundwater, compost and legume cover crops;
  • Recalculates fertilizer rates as April leaf sample data and/or better yield estimates become available during the season; and
  • Can clone the N budget from one orchard to another within and between years if orchards are similar.


This tool uses models developed by UC Davis plant scientist Dr. Patrick Brown and colleagues to predict how much nitrogen to apply and when to apply it to meet yield-based demand. To use this tool, growers enter their yield estimates pre- and post bloom, and then add early-season tissue-sampling results. “The Nitrogen Calculator is not only a powerful tool that calculates N requirements, but is also tied to regulatory compliance with, the ability to create the required Nitrogen Management Plan Worksheet under the ILRP,” said Franklin Dlott, product manager for SureHarvest, which developed and manages the calculator for Almond Board of California.


Responsive Model

“The model for the Almond Nitrogen Calculator is responsive, and you can revise your yield estimate as many times as you see fit between post bloom and final harvest,” Dlott continued. “The model that Patrick Brown came up with includes all of the elements that are required for reporting under the ILRP. It has estimated yield, fertilizer plan, actual yield, and accounts for nitrogen credits from irrigation water and other sources, so by hitting one button, growers can produce the Nitrogen Management Plan Worksheet required by coalitions.” SureHarvest works closely with the coalitions to be sure each coalition’s reporting requirements are met, added Dlott.


Mobile Friendly

A presentation on the Almond Nitrogen Calculator was given at The Almond Conference last December, according to Dlott. At this presentation, new features of the N Calculator were introduced. These include:


  • A mobile-friendly update that allows access with smartphones and tablets for on-the-go data entry, calculations and report generation; and
  • On-screen guides and a “take a tour” guide for first-time users, as well as pop-up guides for specific steps within the calculator.


Although already a popular tool among almond growers, “There has been an uptick in new users since The Almond Conference,” Dlott noted.


Robert Arnold, with Farmland Management Services, Shafter, has made good use of the N Calculator. In 2016, Arnold began using it for all properties he manages, which are in Tulare and Kern Counties, plus additional properties in Northern California.


“I played around with the calculator for a while until I could figure out how to make it work, and then I used it on all our almond properties, generating multiple Nitrogen Management Plans,” he said. The most important feature of the N Calculator, Arnold asserted, is that it generates nitrogen requirements so you don’t exceed them when making applications.


Saving, Cloning Data

Another benefit he found is that the Nitrogen Calculator saves information from year, to year and only revised information has to be input. Arnold also utilized the cloning feature, using data from one field for a similar field, making modifications as necessary. “Often, the soil is way different, and almost every time the water is different,” he cautioned. “You don’t want to assume too much — water coming from different wells may have different N content.”


SureHarvest maintains, where the Almond Board’s Nitrogen Calculator, Irrigation Calculator and Mapping Tool can be accessed. This is also where you will find modules to fill out under Almond Board of California’s California Almond Sustainability Program (CASP). CASP uses grower-submitted production information to demonstrate the sustainability1 of the California Almond industry to stakeholders — buyers, regulators and consumers — and helps growers find ways to improve efficiencies. For more on CASP, go to