Soil fertility insights in strawberries, forages published in latest Sabbe Series
June 1, 2026
By Mary Hightower
University of Arkansas Division of Agriculture
Fast Facts
- Find the latest edition of the Sabbe Series publication online
- Compilation includes soil studies in row crops, cover crops, specialty crops
(958 words)
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FAYETTEVILLE, Ark. — Farms were the biggest users of soil testing by the University of Arkansas Division of Agriculture, with samples representing more than a million acres, according to a summary in the latest edition of the Wayne E. Sabbe Arkansas Soil Fertility Studies.
The annual publication is a collection of soil fertility research done by scientists with the Arkansas Agricultural Experiment Station, the research arm of the Division of Agriculture, and with the Dale Bumpers College of Agricultural, Food and Life Sciences.
The publication also includes a summary of a year’s work at the division’s Marianna Soil Testing Lab. In 2024, the lab tested 158,592 client soil samples representing more than 1.14 million acres.
The publication is named for Wayne Sabbe, who retired from the department of crop, soil and environmental sciences in 1999. Sabbe edited the research collection from its inception in 1989, when it was called the Arkansas Soil Fertility Studies, until his retirement. It was named in his honor in 2001.
The compilation is now edited by Nathan Slaton, associate director of the experiment station and head of the soil testing program for the University of Arkansas Division of Agriculture.
Of the samples sent to the Soil Testing Lab in Marianna, 71 percent represented row crops, 21 percent represented hay and pasture, and 2 percent represented home gardens and lawns. Miscellaneous uses, such as ornamental plants, small fruit production, and playing fields — including golf courses and football fields — made up the remaining 6 percent.
Slaton said the tough farm economy is showing in a decline in the total number of soil samples sent for testing. From a record high of 201,896 client soil samples in 2023, 2025 saw only 127,693 samples.
“The decline in sample numbers is basically due to a decline in grid soil samples,” Slaton said.
Grid sampling is a process that gives farmers a more precise read on the field variability of soil chemical properties. Growers divide their fields into a grid with cells of 1-5 acres. A composite sample is drawn from each grid cell and tested. The results help farmers see the spectrum of soil nutrients across their farmland.
Clients submitted 117,644 grid soil samples in 2024 — a substantial decline from 2023 when 155,096 grid samples were submitted. In 2025, the lab analyzed only 74,953 grid samples.
While soil testing is provided to Arkansas residents free of charge, grid soil sampling is often handled by agricultural consultants, Slaton said. Many farmers have reduced or omitted agronomic services offered by consultants in an effort to reduce their crop production expenses.
In the last few years, farmers have been squeezed hard between low commodity prices and the increasing costs of fuel and fertilizer.
Free soil testing in Arkansas is supported by fertilizer tonnage fees. The Soil Test Review Board helps allocate these funds for research purposes and provides oversight to the soil testing program.
Strawberry fertility
The Sabbe collection also includes research results by Amanda McWhirt, associate professor and extension horticulture specialist, and Aaron Cato, associate professor and extension horticulture integrated pest management specialist, who studied nitrogen applications for the popular strawberry cultivar, ‘Ruby June.’
They found that spring nitrogen applications can improve yields in the form of more berries instead of larger berries.
“Ruby June has been a very important cultivar in the last five years and is very popular due to flavor,” she said.
Spring nitrogen is applied between March and May, typically before plastic is laid for berry growth.
Finding the right rates for nitrogen application in strawberries is critical because over-application can lead to soft or malformed fruit and excessive foliage that favors disease development.
The researchers examined nitrate levels in leaves and petioles, the stems of the leaves.
“Early spring petiole nitrate concentration is closely tied to spring yields. Recommended ranges for petiole nitrate and leaf tissue nitrogen ranges were established almost 30 years ago” for an older variety, McWhirt said. “With new varieties being widely grown, updated ranges are needed, particularly as we recognize the need to fertilize these cultivars at different levels.”
Preliminary results of the study were shared in 2024, and final results were shared at the Mid-America Strawberry Growers Association meeting the following year.
“Growers have actively increased the rate of spring-applied nitrogen for the strawberry cultivar 'Ruby June' and are using updated leaf tissue nutrient ranges to monitor their nitrogen fertility program in the spring for this cultivar,” McWhirt said.
Forage soil fertility
The authors of an article titled “Bermudagrass Forage Yield Response to Nitrogen Fertilization Under Rainfed and Irrigated Management” set out to compare bermudagrass forage yield and nutritive value in response to nitrogen fertilizer rate and application management, as well as to improve fertilizer recommendations for hay production.
The rainfed plots were located at the Milo J. Shult Agricultural Research and Extension Center in Fayetteville and the Livestock and Forestry Research Station near Batesville. The center pivot-irrigated plots were on farmer cooperator land near Marmaduke in Greene County, and near Mayflower in Faulkner County.
2025, a year where drought dominated the last half, was the first year of a three-year study.
“Early study responses indicate that the season's total production of irrigated hybrid bermudagrass may benefit from nitrogen application rates greater than those recommended in rainfed conditions,” said Bronc Finch, extension soil fertility and forage nutrient management specialist.
Drought impaired some of the research locations dependent on rain and did “not provide insight for recommendations in the first year,” Finch said. “Results from the irrigated sites and previous research support the application of nitrogen for maximizing bermudagrass forage yield.”
“Future results may indicate additional beneficial responses by nutritive values such as crude protein,” he said.
Results of the studies will be published in future research reports and extension fact sheets.
To learn more about ag and food research in Arkansas, visit aaes.uada.edu. Follow the Arkansas Agricultural Experiment Station on LinkedIn and sign up for our monthly newsletter, the Arkansas Agricultural Research Report. To learn more about the Division of Agriculture, visit uada.edu. To learn about extension programs in Arkansas, contact your local Cooperative Extension Service agent or visit uaex.uada.edu.
About the Division of Agriculture
The University of Arkansas Division of Agriculture’s mission is to strengthen agriculture, communities, and families by connecting trusted research to the adoption of best practices. Through the Agricultural Experiment Station and the Cooperative Extension Service, the Division of Agriculture conducts research and extension work within the nation’s historic land grant education system.
The Division of Agriculture is one of 22 entities within the University of Arkansas System. It has offices in all 75 counties in Arkansas and faculty on three system campuses.
Pursuant to 7 CFR § 15.3, the University of Arkansas Division of Agriculture offers all its Extension and Research programs and services (including employment) without regard to race, color, sex, national origin, religion, age, disability, marital or veteran status, genetic information, sexual preference, pregnancy or any other legally protected status, and is an equal opportunity institution.
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Media Contact:
Nick Kordsmeier
nkordsme@uada.edu