California Fruit and Vegetable

Tag: Nitrogen Management

  • AI Tool to Help Farmers Measure Real-Time Crop Health from the Field

    Leaf Monitor, a new mobile tool backed by artificial intelligence and predictive modeling, could revolutionize how farmers monitor crops and make decisions by providing real-time nutrition and leaf trait information in the field.

    “Having this information is very valuable for the farmers,” said Alireza Pourreza, associate professor of Cooperative Extension and director of the Digital Agriculture Laboratory in the Department of Biological and Agricultural Engineering at the University of California, Davis. “In five seconds, they can have a sense of how much nutrition they have in a leaf.”

    Development of the AI model was funded by the U.S. Department of Agriculture’s National Institute of Food and Agriculture’s HiRes Vineyard Nutrition multistate project and its Animal and Plant Health Inspection Service, as well as the California Table Grape Commission.

    Maha Afifi, director of viticulture research at the California Table Grape Commission, said the tool could be a game changer for the table grape industry if it leads to faster decision-making about fertilizer use. The right amount typically leads to healthier vines that produce more grapes with optimal size, weight and color.

    “The evaluation of vine nutrient status is one of our top priorities,” Afifi said. “At the same time, exploring new technology tools like this project is a high priority for us because they will be important to the future of the table grape industry.”

    Field testing

    The Leaf Monitor tool uses a handheld spectrometer to measure leaf reflectance beyond the range of light visible to the human eye.

    Once a leaf is scanned, its spectral data is uploaded to a cloud-based machine learning system designed to predict leaf traits and nutrient content. This algorithm was developed and trained by the Digital Agriculture Laboratory over five years using a dataset of thousands of leaf samples collected from California’s specialty crops, primarily grapevines and almonds. The samples were chemically analyzed to determine nutrient levels and structural leaf traits, providing the data needed to build an accurate prediction model.

    “Nutrient deficiencies in plants often go unnoticed until late in the season, by which point the damage is already irreversible,” said graduate student Parastoo Farajpoor, who is running the project. “This is why early detection is essential. Spectrometry provides a rapid and reliable way to identify these deficiencies before visible symptoms appear.”

    After a recent demonstration, Bulleseye Farms Irrigation Manager Geoff Klein said the tool could help save money and improve yields. Bullseye grows walnuts, pistachios, tomatoes, corn, wheat, rice and sunflowers in Yolo and Solano counties.

    Tailored crop management

    Currently, farmers typically take leaf samples, dry them, grind them up and send the samples off to a lab for testing, which can take up to two weeks to return results. Bullseye samples leaf tissues about three times a year.

    “Right now, it doesn’t really make sense to go out and take tissues in every single corner just because it’s expensive,” Klein said. “It’d be really cool if I could just walk out there and test a couple of different places.”

    The Leaf Monitor tool helps farmers tailor management decisions to specific areas rather than an entire field. Calibrating fertilizer use to real-time data can prevent overuse and nitrogen runoff, a financial and environmental challenge that many growers face.

    “I feel like there’s a lot of times we do need to put less [fertilizer] on, where we end up putting more, because that’s what the nitrogen removal formula says,” Klein said. “But with this app we can use less because we know the actual conditions at the time. I think it opens a lot of doors in terms of getting data back in real time and also utilizing the level of control we have with the data.”

    The app can also aggregate the scans and map out spatial patterns over a large area.

    “What we know is every field has variability that is not necessarily visible to the farmer’s eye,” Pourreza said.

    The prototype Leaf Monitor tool is free and included in a set of tools that can be downloaded on the Digital Agriculture Laboratory website. A web-based version of the tool will follow while the team continues to feed new data into the algorithm to refine the predictions. On average, it achieves about 65% accuracy across all traits, with predictions for certain nutrients, such as nitrogen and phosphorus, performing better than the overall average. Users will need to pair it with a spectrometer.

    “We need to produce more food while using less resources so we need to have some kind of monitoring system to give us precise and accurate feedback on our management practice,” Pourreza said. “This technology is growing very fast.” — By Emily Dooley, UC Davis

  • New Tomato Plant that Tells you When to Fertilize

    An invention developed by two Cornell doctoral students that turns engineered tomato plants a vivid red when soil nitrogen levels are low has been named a finalist in the national Collegiate Inventors Competition.

    The RedAlert Living Sensors, created by Jacob Belding and Ava Forystek, is one of five finalists contending in the graduate student category of the competition, run by the National Inventors Hall of Fame.

    Developed through the National Science Foundation’s Center for Research on Programmable Plant Systems (CROPPS), the students’ genetically modified sensor plants could one day help gardeners, farmers and hydroponic growers assess if their plants need more nitrogen. When the sentinel plants turn red, growers may then target where and when to fertilize. Farmers currently apply up to 50% more nitrogen than needed, which has led to run-off that pollutes groundwater and lakes, where it promotes harmful algae blooms.

    Graduate students Ava Forystek (left) and Jacob Belding check tomato plants.

    The two students will present their invention in a “Shark Tank” style pitch to a panel of judges composed of some of the most influential inventors and invention experts in the country on Oct. 16 in Washington, D.C. The judges, including National Inventors Hall of Fame inductees and U.S. Patent and Trademark Office officials, will select two top teams and a people’s choice award, each of which will receive cash prizes and a form that fast-tracks patent acquisition. An undergraduate contest will also take place.

    Currently, one common method for detecting nitrogen deficiencies in plants assesses yellowing and wilting in leaves. By the time leaves turn yellow, the plant is already stressed from low nutrients.

    “We like to use the analogy of a dog that whines when it’s hungry,” said Forystek, who works in the lab of Neil Mattson, professor in the school of Integrative Plant Science Horticulture Section in the College of Agriculture and Life Sciences. “It would be kind of ridiculous to wait until you feel its ribs to feed it.”

    The RedAlert Living Sensors take advantage of a native pathway where the plant detects nitrogen around its roots and translates those signals to the rest of the plant. The tomato plants used in the project were genetically modified to express a red pigment when root zone nitrogen is low. Shades of redness also reflect varying gradients of available soil nitrogen.

    “We’re taking a signal from the roots where the plant first notices there’s not enough nitrogen in the soil and it translates that into visible pigment, so we can see on the plant that it is hungry for nitrogen, but it’s not already starving,” said Belding, a member of the lab of Abraham Stroock, the Gordon L. Dibble ’50 Professor in the Smith School of Chemical and Biomolecular Engineering in Cornell Engineering.

    Stroock and Mattson are team advisers, along with Margaret Frank, associate professor in the School of Integrative Plant Science, Plant Biology Section, in CALS, who first came up with the idea for the nitrogen-sensing plants.

    One day, farmers may be able to plant tomato sentinel seeds in their corn fields to monitor nitrogen levels; home gardeners might use them in their backyards; and hydroponic growers might employ them to ensure their systems’ plumbing is distributing the necessary nutrients.

    “It’s amazing to see this technology move from our research labs into the world where it can positively impact sustainable agriculture,” Frank said.

    In large field systems, tractors already equipped with cameras that read infrared and visible wavelengths could survey crop fields for interspersed sentinel plants, to inform farmers of nitrogen needs. The team is exploring the development of a smartphone app that would directly correlate sensor plant leaf colors to root zone nitrogen levels. In this way, small farmers could monitor their fields with their phones.

    “It’s kind of a democratization of these smart agriculture tools that have seen a lot of popularity in the past decade, but are mostly restricted to pretty sophisticated, expensive systems, with highly technically trained operators,” Belding said. “This could be a smart ag device that is affordable and can be easily used by even a home gardener.”

    Initial work on the project was done by Brandon Williams, M.S. ’23, Ph.D. ’25, a former member of Frank’s lab, and Yinan Wu, a former postdoctoral researcher in the lab of Sijin Li, assistant professor in the Smith School of Chemical and Biomolecular Engineering in Cornell Engineering. Forystek has helped Belding and other engineers work in the greenhouses and in better understanding challenges of field applications. — By Krishna Ramanujan, Cornell University

  • NEW NITROGEN MANAGEMENT RESOURCE AVAILABLE FOR CITRUS & AVOCADO

    To address nitrate pollution of groundwater, the Central Valley Regional Water Quality Control Board has initiated a regulatory program requiring growers to utilize nitrogen management practices that mitigate nitrate loading. Because nitrogen plays such a critical role in in the growth and development of avocado trees — and because it can be difficult to ensure trees are receiving the optimal amount of nitrogen — the University of California Department of Agriculture and Natural Resources has created the Nitrogen Management in Citrus and Avocado publication.

    This document is designed to optimize growers’ application of nitrogen while reducing nitrogen leaching by focusing on applying nitrogen at the right rate, at the right time with the right placement and from the right source (otherwise known as the four R’s of nutrient management). The guide provides specific examples for the rate of application based on the age, alternate bearing status and vegetative state of the tree and discusses the optimal spring/fall application periods. In addition, the document provides guidance on how to conduct leaf analysis and what optimal concentration percentages to look for.