Triticale, wheat farmers get help with new UC software

By Bob Johnson

Wheat and triticale growers may be able to take some of the guesswork out of midseason nitrogen applications aimed at reaching yield and protein goals for a particular field without paying for wasted fertilizer.

University of California researchers are releasing the software they have been using for years to do their soil and grain growth calculations.

"We have been using the Nitrogen Fertilizer Management Tool, and now you can use the beta version of the software," said Taylor Nelsen, assistant specialist in the University of California, Davis, grain cropping systems lab.

This software tool lets users establish a nitrogen-rich zone within the field to serve as a control and compare economically obtained soil and vegetative growth information from the rest of the field. Then they can quickly perform calculations to learn how much nitrogen to apply midseason to hit yield and protein targets.

The nitrogen tool lets a grower begin by choosing a spot anywhere in the state's grain-growing region. Next, the grower chooses the variety of common wheat, durum or triticale, the beginning and end of the growing period under examination and the irrigation levels.

The software can take this information and quickly calculate the amount of water and nitrogen already taken up by the crop and its growth stage. The findings can be adjusted if the crop is at a different growth stage.

Next, a grower enters the results of simple tests comparing a nitrogen-rich zone with the rest of the field.

A nitrogen-rich zone is a relatively small area fertilized well enough to ensure that nitrogen would not limit the crop.

In a trial, researchers applied 62 pounds of midseason nitrogen an acre as urea to a rich zone within a field of NS Swift 77 triticale planted last November.

"Once the zones are in the field, you can develop a sufficiency index," explained Nicholas Clark, a UC Cooperative Extension farm advisor for Fresno, Tulare and Kings counties, who conducted the triticale trial. "Reference zones can be established in small grains and used to make in-season nitrogen decisions."

With an area of the field established known to have enough nitrogen, a grower can compare the rest of the field in terms of soil nitrate, gauged by a quick test in the field, and differences in vegetative vigor as measured by cameras.

Unfortunately, one of the most economical and convenient tools for taking plant growth measurements is no longer on the market. "The GreenSeeker is not being manufactured anymore," said Mark Lundy, UCCE small grains specialist.

The GreenSeeker is a relatively inexpensive, hand-held device that lets farmers take readings of vegetative vigor as they walk through a field. The information previously obtained with this device is still available from satellite photography or from vegetative pictures taken by cameras mounted on drones.

Years of trials have been conducted to develop standards for the ratio of growth in the field compared to the nitrogen-rich zone measured by the camera that warrants a midseason fertilizer application. With comparisons of soil nitrate and plant growth in hand, a farmer can learn whether additional fertilizer—and how much—can help the field reach yield and quality goals.

In the triticale trial, both satellite photographs and GreenSeeker measurements showed the field had about 85% the canopy reflectance of the nitrogen-rich zone.

Timing of taking tests and entering results into the software matters because— as the crop grows— more information is available. But that information must come early enough to decide whether to fertilize.

"You want to take measurements in time to make a decision," Clark advised. "In the triticale trial, we flew in the recommended application of 90 pounds of nitrogen on the field except for an exclusion zone covered by a tarp for comparison."

The expected result of this recommended nitrogen was a yield increase of around 2,000 pounds an acre and a 2.3% increase in protein.

The point of the software is to make it easier for growers to apply enough nitrogen to grow an optimal crop without wasting money on fertilizer that eventually ends up in the groundwater.

The Nitrogen Fertilizer Management Tool is the latest UC software offered to help small-grains growers quickly make complex calculations to help make decisions about managing their crop.

The Nitrogen Management Tool and a video explaining how to use it are available at the University of California's Agronomy Research & Information Center Small Grains website.

Additional resources on the site include a nitrate quick test tool that translates the results of a color-coded strip test of soil nitrate into the amount of nitrogen that is available to the crop. In addition, there is a seeding rate calculator that lets a farmer enter a small grains variety and learn the number of pounds of seed needed to plant a healthy stand. Meanwhile, a weather tool lets a farmer access current and historical weather information for particular locations from a variety of public sources.

(Bob Johnson is a reporter in Monterey. He may be contacted at bjohn11135@gmail.com.)

Permission for use is granted, however, credit must be made to the California Farm Bureau Federation when reprinting this item.