In a recent study, Chinese researchers found that citrus seedlings clearly prefer nitrate over ammonium as a nitrogen source. The researchers — Hao Xu, Wenlang Hu, Kaiyuan Du, Yan Dong, Qingru Fan, Zengrong Huang, Lin-Tong Yang, Li-Song Chen and Jiuxin Guo — are with the Fujan Agriculture and Forestry University. In their study, the researchers compared two citrus cultivars (C. reticulata …
Organic Fertilizer Substitution Improves Citrus Quality
A recently published Chinese study found that long-term substitution of chemical fertilizers with organic fertilizers can improve the quality of citrus fruits. The authors found that 50% organic nitrogen substitution is the appropriate proportion for promotion in Newhall navel orange production. The study is titled “Organic fertilizer substitution synergistically improves the fruit-soil-bacteria system in Newhall navel orange under long-term management.” …
Emerging Trends in Nutrient Rate Studies
By Davie Kadyampakeni, Noor Basar, Alisheikh Atta, Muhammad Shahid, Shahid Iqbal and Alan Wright Citrus trees in Florida impacted by HLB have limited nutrient uptake largely due to limited root mass, compromised physiology and extremely sandy soil. The state’s current nutrient management guidelines were developed based on data prior to the spread of HLB, when trees had dense canopies and …
A Review of Enhanced Efficiency Fertilizers
A newly published article in the Journal of Plant Nutrition and Soil Science explains how enhanced efficiency fertilizers (EEFs) can help maximize yields while reducing farmers’ chances of hurting their pocketbooks or the planet. EEFs include controlled-release fertilizers (CRFs) and slow-release fertilizers (SRFs). Hardeep Singh, a University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) assistant professor of cropping …
Senators Call for Freeze on H-2A Wage Rate
Sixteen U.S. senators recently introduced a bill to revert the H-2A program’s adverse effect wage rate (AEWR) to the December 2023 rate through the end of the 2025 growing season. Two of the senators who introduced the Supporting Farm Operations Act of 2024 are from citrus-producing states — Rick Scott of Florida and John Cornyn of Texas. A majority of …
Critical Minerals Bill Seeks to Secure Fertilizer Supplies
Four members of Congress have introduced a bill to include phosphate and potash on the final List of Critical Minerals of the U.S. Department of the Interior. The U.S. representatives are Kat Cammack of Florida, Barry Moore of Alabama, Elissa Slotkin of Michigan and Jimmy Panetta of California. “A nation that cannot feed itself is not secure,” Cammack said. “Without …
Nutrient Application Rates Bill Signed Into Law
Florida Citrus Mutual Executive Vice President/CEO Mathew Joyner announced that Gov. Ron DeSantis signed SB 1000, the Nutrient Application Rates bill. Joyner called SB 1000 “a critical piece of legislation.” See the full text of the new law here. The law takes effect July 1. “Sponsored by Senator Ben Albritton and Representative Lawrence McClure, the bill had previously passed both …
Consequences of Skyrocketing Fertilizer Prices
By Ariel Singerman and Stephen H. Futch Chemical input prices have increased significantly over the last year. In particular, the price of fertilizer has roughly doubled during the last 12 months, as denoted by Figure 1. Figure 1. Producer Price Index of Nitrogenous Fertilizer Manufacturing Source: Federal Reserve Bank of St. Louis Supply and demand factors help explain such an …
Fertilizer Price Spike Highest Since Great Recession
During January’s Southeast Regional Fruit & Vegetable Conference in Savannah, Georgia, Daniel Tregeagle, an Extension economist with North Carolina State University, gave a presentation on economic and regulatory trends impacting citrus and specialty crop growers. MODEST MARKET GROWTHThe biggest blip on the proverbial economic radar has been COVID-19 and its continuing effects. Tregeagle noted these impacts mostly will be transient, …
Making Sense of Biologicals – Biofertilizers: Improving Nutrition in Citrus Trees
Citrus greening disease appears to be a problem for the foreseeable future for Florida growers. But what if growers could improve nutrition so trees could better cope with the disease? Scientists at Douglas Plant Health believe biofertilizers have that capability. “Think about it from a human health standpoint,” says Marcus Jones, vice president of research and development at Douglas Plant …
Making Sense of Biologicals: Biofertilizers Designed to Make Roots ‘Happy’
“If mama ain’t happy, ain’t nobody happy.” That same mindset can also be applied to agriculture. If the roots of a plant are not happy, the top of the plant won’t be happy either. Anything else will prove to be futile, believes Mark Egan. Egan, an agronomist at Douglas Plant Health, says biofertilizers are a management tactic that growers can …
Grower Sees Steady Production Without Chemical Fertilizer
By Owen “Sonny” Conner The two greatest challenges of the last 20 years, for me as a citrus grower, have been HLB and foreign competition depressing prices. Citrus growers had never faced a disease threat even approaching the devastating effects HLB has had on the industry. It was the industry killer we all feared would one day raise its ugly …
Avoid Salt-Out of Liquid Fertilizers
By Ajia Paolillo The use of liquid fertilizers in citrus production has increased over the years. Liquid fertilizers offer the grower a way of applying frequent doses of fertilizer to trees to optimize nutrient efficiency. Now that the winter months are here with cooler weather and some cold nights, growers may face the issue of liquid fertilizer salting-out in the …
Nutrition: Get the Rate Right
Davie Kadyampakeni emphasized the importance of the four Rs of good nutrition of HLB-affected orange trees, with a heavy focus on the “right rate” of nutrient use. The other three Rs are right time, right placement and right source of nutrient applications. Kadyampakeni, a University of Florida Institute of Food and Agricultural Sciences researcher, discussed nutrition at this year’s virtual …
TCP Might Help Trees Tolerate HLB
Laboratory tests of tricalcium phosphate (TCP) indicate it has potential use as a fertilizer that might help citrus growers cope with HLB, says Laura Waldo, a University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) laboratory manager. “The hope is that it can help a tree by inducing root hair development and thereby allowing the tree to uptake nutrients …
Strategies for Stronger Roots
Citrus growers discuss production practices to improve root health. By Tacy Callies What began as an experiment in Ben Krupski’s 10-acre grove in Howey-in-the-Hills, Florida, is now a common practice he uses as production manager for Lennon Grove Service. Four years ago, Krupski started testing the use of compost in his small leased block of Hamlin trees. In the first …
Grower Discusses HLB Management Strategies
Jim Snively, vice president of grove operations at Southern Gardens Citrus, discusses his company’s management of HLB and the psyllids that spread it. He summarizes a presentation he made at the International Citrus Business Conference in March. “By reducing stress, the trees can deal with disease much better,” Snively says. “We’re doing this through continuous-type feeding or frequent feeding with …
Tools for Integrated Management of Citrus Psyllids and Leafminers
By Jawwad A. Qureshi, Philip A. Stansly and Lukasz L. Stelinski Pest management has always been important for citrus production in Florida. It has become even more critical following invasion of the Asian citrus psyllid (ACP) and citrus leafminer (CLM), due to their association with huanglongbing (HLB or citrus greening) and canker diseases, respectively. ACP and CLM develop and reproduce …
Pruning and Controlled-Release Fertilizer to Rehabilitate HLB Trees
By Tripti Vashisth and Troy Gainey Pruning is one of the oldest horticultural practices that changes the form and growth of a tree. The pruning process 1) adjusts tree shape and the ratio of framework to fruit-bearing shell of the canopy, 2) alters the shoot/root ratio and 3) changes the carbohydrate (food storage) status of the tree. Under Florida weather …
Controlled-Release Fertilizer Boosts Health of HLB Trees (Part 2)
By Pete Spyke, Joby Sherrod and Jude Grosser Part 1 of this article, published in the April 2017 issue of Citrus Industry magazine, provided some background information on controlled-release fertilizer (CRF) along with a discussion of practical applications in citrus production. This article, part 2, includes summaries of observations from several case studies in which CRF has been applied for …




























