Hemp Fertilization: Current Knowledge, Gaps and Efforts in Florida: A 2020 Report

Hemp (Cannabis sativa) cultivation in Florida. Credits: Luis Monserrate, graduate student, UF/IFAS Agronomy Department

Hemp is an annual herbaceous plant that may be grown for fiber, seed, or flowers. Starting in April 2020, the Florida Department of Agriculture and Consumer Services began accepting applications for cultivation of hemp in Florida, with the potential for building a $20-$30 billion industry in the state. The statewide UF/IFAS Industrial Hemp Pilot Project is researching aspects of agronomic production for hemp cultivation. While a few other state soil testing laboratories provide soil tests and nutrient recommendations based on research and experience, at this time no Florida-specific data on nutrient requirements and fertilization are available. This new 5-page article, written by Rao Mylavarapu, Zachary Brym, Luis Monserrate, and Michael J. Mulvaney and published by the UF/IFAS Department of Soil and Water Sciences, provides a summary of published and personal communications from different states on hemp fertilization.

Soil Sampling Procedures

Placing a soil sample into a bag. Photo taken 07-15-19.

To achieve optimal grove nutrition, citrus growers must test grove soil before beginning any fertilization program. Standard procedures for sampling, preparing, and analyzing soil should be followed for meaningful interpretations of the test results and accurate recommendations. This new two-page fact sheet, published by the UF/IFAS Department of Soil and Water Sciences, provides illustrated soil sampling procedures and tables to aid in basic interpretation of lab results. Written by Davie Kadyampakeni, Kelly Morgan, Arnold Schumann, and Rhuanito S. Ferrarezi.

UF/IFAS Standardized Nutrient Recommendations for Vegetable Crop Production in Florida

Soil testing is a scientific tool for effective nutrient management that provides an estimate or an index of the available nutrient-supplying capacity of the soil. This 9-page publication presents the fertilization recommendations for vegetable crops based on soil tests performed by the IFAS Extension Soil Testing Laboratory (ESTL). Written by Rao Mylavarapu, George Hochmuth, and Guodong Liu and published by the UF/IFAS Department of Soil and Water Sciences, December 2017.

Soil Testing and Interpretation for Florida Turfgrasses

John Cisar, a professor of Environmental Horticulture at the University of Florida's Fort Lauderdale Research and Education Center, is studying how turfgrass and other landscape plants can help prevent nitrogen from leaching through the soil into groundwater, Wednesday - Aug. 13, 2003. He said three years of research have shown that turfgrass is most effective in reducing nitrogen leaching and should be used in Florida landscapes. Other plants require more time to become established and slow nitrogen leaching through the soil.
Most people agree that healthy, well-maintained turfgrass is a thing of beauty. The successful growth of turfgrass is aided by having knowledge of a few basic facts concerning the nutritional requirements of turfgrasses and the properties of fertilizer and liming materials. This four-page document will help the reader understand how soil testing may be used to more efficiently manage nutrient applications for Florida turfgrasses. Written by T.W. Shaddox and J.B. Sartain and published by the UF/IFAS Department of Soil and Water Sciences, October 2017.

Parameters for Site-Specific Soil Phosphorus Loss Modeling from Soil Test Data

Bags of soil samples at the UF/IFAS soil testing lab  Photo Credits:  UF/IFAS Photo by Marisol Amador
This four-page fact sheet is part of a series titled Soil Phosphorus Storage Capacity (SPSC) for Phosphorus Risk Assessment and Management. This series is intended for use by those who are interested in management practices and policies that minimize the risk of phosphorus loss from soils. Written by Biswanath Dari, Vimala D. Nair, and Willie G. Harris and published by the Department of Soil and Water Sciences.

Determination of Carbonate Concentrations in Calcareous Soils with Common Vinegar Test

Qiang Zhu

When raising crops on calcareous soils, growers need to know how much calcium carbonate is in the soil before they can employ any management practices. Growers can test the level of carbonate in their soils using store-bought vinegar and other household supplies. This 3-page fact sheet explains the chemistry behind the vinegar test and instructions for performing the test and interpreting the results. Written by Qiang Zhu, Monica Ozores-Hampton, and Yuncong Li, and published by the UF Department of Horticultural Sciences, June 2015.

Fertilizer Recommendation Philosophies

Figure 2. Incorporating fertilizer for an experiment on fertilizer rate and source for tomato.Farmers receive varying fertilizer recommendations depending on which lab they consult because labs employ different chemical methods and procedures to analyze the samples and subscribe to different fertilizer recommendation philosophies. This 4-page fact sheet explains the main soil-test philosophies, their basis, and their applications, and explains why the Sufficiency Level of Available Nutrient philosophy (SLAN), also called the Crop Nutrient Requirement (CNR), is most likely to be the best to govern fertilizer recommendations in Florida today. Written by George Hochmuth, Rao Mylavarapu, and Ed Hanlon, and published by the UF Department of Soil and Water Science, October 2014. (Photo by George Hochmuth, UF/IFAS)

Soil Testing for Plant-Available Nutrients: What Is It and Why Do We Use It?

Figure 1. Scheme illustrating random soil sampling on a commercial agricultural farm or a landscapeFarmers need soil-testing procedures to assess soils for potential plant-available nutrients. Soil testing is the foremost best management practice (BMP). It helps farmers achieve profitable crops while protecting the environment from excessive fertilization and nutrient losses. This 5-page fact sheet describes the important steps required to test soil for potential plant-available nutrients. Written by George Hochmuth, Rao Mylavarapu, and Ed Hanlon, and published by the UF Department of Soil and Water Science, October 2014.

Developing a Soil Test Extractant: The Correlation and Calibration Processes

Soil Sampling.An understanding of soil testing is an important part of preventing excess fertilizer applications that can potentially impact the environment and ensuring commercially viable yields and aesthetic, healthy landscapes. This 4-page fact sheet describes the process UF/IFAS soil scientists used to develop a predictive and/or diagnostic soil test that can be depended on by commercial agricultural and horticultural producers as well as homeowners and can provide accurate nutrient recommendations or diagnose nutrient imbalances for crops or plants. Written by George Hochmuth, Rao Mylavarapu, and Ed Hanlon, and published by the UF Department of Soil and Water Science, October 2014.

Soil and Plant Tissue Testing

Soil Sampling.  Soil testing is the best tool for monitoring soil fertility levels and providing baseline information for cost-effective fertilization programs. But a major limitation is that it typically accounts for the plant-available nutrient pool present in the surface soil layer. Because of the extensive root system in some plants, plant analysis is a complement to the soil test to better assess the overall nutrient status of a perennial forage system, while revealing imbalances among nutrients that may affect crop production. This 4-page fact sheet was written by Maria L. Silveira, and published by the UF Department of Soil and Water Science, June 2014.

Extraction of Soil Nutrients Using Mehlich-3 Reagent for Acid-Mineral Soils of Florida

Figure 4. Correlation between M1 and M3 extraction methods for soil MgSoil testing is a multistep process starting with the collection of a sample that adequately represents the area or field to be tested. Due to wide-ranging soil conditions across Florida and the United States, multiple soil test methods exist. During the 1970s, Florida along with several other southeastern US states adopted Mehlich-1 (M1) as the official extractant for acidic soils. The UF/IFAS Plant Nutrient Oversight Committee approved the change from M1 to M3 in 2010. Based on observations of the interpretations, the technical committee revised the M3 interpretation in March 2014. The new interpretations have been correlated with the M1 interpretations, as closely and realistically as possible, so the actual nutrient recommendations are not changed. This 7-page fact sheet was written by Rao Mylavarapu, Tom Obreza, Kelly Morgan, George Hochmuth, Vimala Nair, and Alan Wright, and published by the UF Department of Soil and Water Science, May 2014.

Comparison of Soil Test Extractants for Available Soil Phosphorus in High pH Sandy Soils of South Florida

Soil Sampling.This document addresses the selection of soil nutrient extractants in high pH soils and discusses their relationship to both nutrition and fertilizer management. This document’s objective is to describe the impact of selected soil extractants on nutrient management and their ability to determine soil phosphorus availability. The target audience for this series dealing with citrus nutrition includes Certified Crop Advisers; citrus, vegetable, and sugarcane producers; fertilizer dealers; and other parties interested in crop fertilization practices. This 4-page fact sheet was written by Kelly T. Morgan and Kamal Mahmoud, and published by the UF Department of Soil and Water Science, December 2014.

SL322/SS534 Preplant Soil Assessment for New Residential Landscapes in Florida

SL322, a 5-page illustrated fact sheet by Amy L. Shober and Christine Wiese, advocates performing an assessment of soil conditions before landscape installation, and outlines the issues that may be identified through such an assessment. Includes references. Published by the UF Department of Soil and Water Science, June 2010.

SL285/SS498 Measuring Organic Matter in Everglades Wetlands and the Everglades Agricultural Area

SL-285, a 5-page illustrated fact sheet by Alan L. Wright and Edward A. Hanlon, recommends for growers, managers and researchers the new and simple Loss-On-Ignition (LOI) test for determining the organic matter content of soils. Includes references. Published by the UF Department of Soil and Water Sciences, April 2009.

SL281/SS494 Soil Sampling and testing for the Home Landscape or Vegetable Garden

SL-281, a 6-page illustrated fact sheet by Amy L. Shober, and Rao S. Mylavarapu, provides information for homeowners about taking a soil sample and submit it for testing and how to understand the soil test report. Published by the UF Department of Soil and Water Science, March 2009.

SL-181/SS317 Soil and Tissue Testing and Interpretation for Florida Turfgrasses

Revisd! SL-181, an 8-page fact sheet by J.B. Sartain, provides essential basic facts about the nutritional requirements of turfgrasses, the properties of fertilizer and liming materials, and how to use them to maintain sufficient nutrient levels through soil and tissue analysis. Published by the UF Department of Soil and Water Science, October 2008.