Miami-Dade County is the primary production region for fresh-market bush snapbeans with 57% or 18,696 acres of the Florida bean acreage. Production costs vary from $16.53 to $21.87 per 30 lb. bushel or $4,046 to $4,711 per acre.... more
Miami-Dade County is the primary production region for fresh-market bush snapbeans with 57% or 18,696 acres of the Florida bean acreage. Production costs vary from $16.53 to $21.87 per 30 lb. bushel or $4,046 to $4,711 per acre. Acceptable yields range from 185 to over 300 bushels per acre. Snapbeans produced in Miami-Dade County are sold nationwide for the fresh market starting just before Thanksgiving and continuing through the winter and spring months. This revised 9-page fact sheet was written by S. Zhang, D. Seal, M. Ozores-Hampton, M. Lamberts, Y. Li, W. Klassen, and T. Olczyk, specifically for growers in Miami-Dade County as a supplement to The Vegetable Production Handbook for Florida (SP170). Published by the UF Department of Horticultural Sciences, July 2014.
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SL289, a 4-page illustrated fact sheet by Daniel L. Irick, Yuncong Li, and Alan L. Wright, describe the regulatory nature of wetland delineation and classification for landowners, wetland and soil scientists, and the general public.... more
SL289, a 4-page illustrated fact sheet by Daniel L. Irick, Yuncong Li, and Alan L. Wright, describe the regulatory nature of wetland delineation and classification for landowners, wetland and soil scientists, and the general public. Includes references. Published by the UF Department of Soil and Water Science, May 2009. SL 289/SS502: Wetland Delineation: An Overview of Regulations and Methods (ufl.edu)
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Revised! TR001, a 6-page illustrated fact sheet by Kati W. Migliaccio and Yuncong Li, describes why irrigation is needed in south Florida, and the advantages and disadvantages of various tools available for determining an optimum... more
Revised! TR001, a 6-page illustrated fact sheet by Kati W. Migliaccio and Yuncong Li, describes why irrigation is needed in south Florida, and the advantages and disadvantages of various tools available for determining an optimum irrigation schedule. Includes references. Published by the UF Department of Agricultural and Biological Engineering, January 2009. TR001/TR001: Irrigation Scheduling for Tropical Fruit Groves in South Florida (ufl.edu)
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Bald cypress has been retreating in the estuary ecosystem of the Loxahatchee River Watershed in southeastern Florida because of the negative impacts of anthropogenic activities. Seed germination of bald cypress is an important means to... more
Bald cypress has been retreating in the estuary ecosystem of the Loxahatchee River Watershed in southeastern Florida because of the negative impacts of anthropogenic activities. Seed germination of bald cypress is an important means to increase the arbor population in the vegetation community and accelerate restoration of the wetland ecosystem. The objective of this research was to find an effective method to enhance seed germination of bald cypress, an ecologically and economically important tree species. Bald cypress seeds were hand collected under mature bald cypress trees in southeastern Florida, and kept under refrigeration at 4 o C prior to the commencement of the study. The seeds were chemically treated in either 1% NaOH, 95% ethyl alcohol, 0.03 to 0.3% H 2 O 2 , or 1% HCl, or mechanically cut into two halves, or heated on a burner for 3.0 s. After treatment, all of the seeds were sown in Park's seed-starting trays with 72 Cells with Pro Mix BX growth medium. The results...
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Wang, Q., Y. Li, Z. Handoo, and W. Klassen. 2007. Influence of cover crops on populations of soil nematodes. Nematropica 37:79-92. A pot experiment was carried out in south Florida to elucidate suppressive or antagonistic effects of... more
Wang, Q., Y. Li, Z. Handoo, and W. Klassen. 2007. Influence of cover crops on populations of soil nematodes. Nematropica 37:79-92. A pot experiment was carried out in south Florida to elucidate suppressive or antagonistic effects of several cover crops grown in rotation on soil nematode populations. The crops were two marigolds, Tagetes patula L. Dwarf Double French Mix (MDF), and Tagetes patula L. 'Lemon Drop' (MLD), Indian mustard (IM) [Brassica juncea (L.) Czern.], radish (RD) [Raphanus sativus L.], sunn hemp (SH) [Crotalaria juncea L., Tropic Sun], velvetbean (VB) [Mucuna deeringiana (Bort.) Merr.], a Meloidogyne-susceptible cowpea (CP) [Vigna unguiculata (L.) Walp, Purple Knuckle Hull], and okra (OK) [Abelmoschus esculentus (L.), Clemson Spineless 80]. Eight rotation schemes each with 3 rotations were carried out from June, 2002 to December, 2003. Those schemes were MDF-RD-MDF, MLD-CPMLD, IM-VB-IM, RD-MDF-RD, SH-OK-SH, VB-IM-VB, CP-MLD-CP, and OK-SH-OK. The results show...
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At early stages of establishment of tropical plantation crops, inclusion of legume cover crops could reduce soil degradation due to erosion and nutrient leaching. As understory plants these cover crops receive limited irradiance and can... more
At early stages of establishment of tropical plantation crops, inclusion of legume cover crops could reduce soil degradation due to erosion and nutrient leaching. As understory plants these cover crops receive limited irradiance and can be subjected to elevated CO2 at ground level. A glasshouse experiment was undertaken to assess the effects of ambient (450 µmol mol−1) and elevated (700 µmol mol−1) levels of [CO2] on growth, physiological changes and nutrient uptake of six perennial legume cover crops (Perennial Peanut, Ea-Ea, Mucuna, Pigeon pea, Lab lab, Cowpea) under low levels of photosynthetic photon flux density (PPFD; 100, 200, and 400 µmol m−2 s−1). Overall, total and root dry biomass, total root length, specific leaf area, and relative growth rates were significantly influenced by levels of [CO2] and PPFD and cover crop species. With few exceptions, all the cover crops showed significant effects of [CO2], PPFD, and species on net photosynthesis (PN) and its components, such ...
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Parthenium hysterophorus L. is a member of the Asteraceae and is indigenous to Mexico, and Central and South America. It is a widely distributed invasive weed in India, Australia, Taiwan, Ethiopia, and in 23 states in the U.S. In Florida,... more
Parthenium hysterophorus L. is a member of the Asteraceae and is indigenous to Mexico, and Central and South America. It is a widely distributed invasive weed in India, Australia, Taiwan, Ethiopia, and in 23 states in the U.S. In Florida, parthenium is found in 24 of the state’s 67 counties. Parthenium invades urban and disturbed areas as well as the vegetable fields and fruit groves throughout southern Miami–Dade County. Roundup PowerMax®, Rely® and Chateau® alone and Rely®plus Chateau® applied in several combinations were investigated in a field trial for their efficacy in controlling parthenium under south Florida grove conditions. Treatments were laid out in a completely randomized design with three replications of each treatment. Parthenium plant population was assessed by counting green live plants within a 361-inch2 grid 1 day prior and 10 times at 15-day intervals after post herbicide application. Data were analyzed as repeated measures analysis using Student’s t-test (alpha...
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Understanding and Applying Chelated Fertilizers Effectively Based on Soil pH (HS1208) Plant nutrients are one of the environmental factors essential for crop growth and development. Nutrient management is crucial for optimal productivity... more
Understanding and Applying Chelated Fertilizers Effectively Based on Soil pH (HS1208) Plant nutrients are one of the environmental factors essential for crop growth and development. Nutrient management is crucial for optimal productivity in commercial crop production. Those nutrients in concentrations of ≤ 100 parts per million (ppm) in plant tissues are described as micronutrients and include iron (Fe), zinc (Zn), manganese (Mn), copper (Cu), boron (B), chlorine (Cl), molybdenum (Mo), and nickel (Ni). Micronutrients such as Fe, Mn, Zn, and Cu are easily oxidized or precipitated in soil, and their utilization is, therefore, not very efficient. Chelated fertilizers have been developed to increase micronutrient utilization efficiency. This 5-page fact sheet provides an overview of chelated fertilizers and considerations for their use to county Extension faculty, growers, and students who are interested in commercial crop production. Written by Guodong Liu, Edward Hanlon, and Yuncong L...
ABE-369, a 5-page fact sheet by Kati W. Migliaccio, Edward Evans, Jonathan H. Crane, Bruce Schaffer, Yuncong Li, and Rafael Muñoz -Carpena, presents the results of a survey designed to assess changing views of ornamental plant producers... more
ABE-369, a 5-page fact sheet by Kati W. Migliaccio, Edward Evans, Jonathan H. Crane, Bruce Schaffer, Yuncong Li, and Rafael Muñoz -Carpena, presents the results of a survey designed to assess changing views of ornamental plant producers in Miami-Dade County regarding water quantity and quality management practices. Published by the UF Department of Agricultural and Biological Engineering, July 2006.
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The objective of the in-service training for extension personnel with responsibilities in agriculture, horticulture and natural resources was to introduce field concepts and applications related to environmental evaluation of surface... more
The objective of the in-service training for extension personnel with responsibilities in agriculture, horticulture and natural resources was to introduce field concepts and applications related to environmental evaluation of surface water and groundwater. Training focused on advanced technology of water chemistry and hydrology related to water sampling and monitoring techniques, instrumentation, water quality data analysis and evaluation, and reporting. The training was a combination of lectures, hands-on laboratory activities, and field tours. Several water quality monitoring programs in south Florida were presented. Various water sampling methods were demonstrated. Participants measured water quality using quick testing kits and sophisticated instruments.
This document is ABE 361, from the Department of Agricultural and Biological Engineering, UF/IFAS Extension. First published March 2006.
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ABE-381, a 5-page illustrated fact sheet by Kati W. Migliaccio and Yuncong Li, summarizes US water quality legislative history, Florida water quality legislation, and water quality criteria development. Includes references. Published by... more
ABE-381, a 5-page illustrated fact sheet by Kati W. Migliaccio and Yuncong Li, summarizes US water quality legislative history, Florida water quality legislation, and water quality criteria development. Includes references. Published by the UF Department of Agricultural and Biological Engineering, December 2007. ABE 381/AE431: Evolution of Water Quality Regulations in the United States and Florida (ufl.edu)
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The addition of agricultural by-products to mineral soils has the potential to improve crop production. This study aimed to determine the effects of the readily available sugarcane (Saccharum officinarum) milling by-product bagasse as a... more
The addition of agricultural by-products to mineral soils has the potential to improve crop production. This study aimed to determine the effects of the readily available sugarcane (Saccharum officinarum) milling by-product bagasse as a soil amendment on yields of sugarcane grown on a sandy Entisol of South Florida. The field trial was conducted on a commercial sugarcane farm for three annual crop cycles (plant cane and two ratoons). Four treatments including 5 cm bagasse (85 ton ha−1); 10 cm bagasse (170 ton ha−1); 10 cm bagasse (170 ton ha−1) plus 336 kg ha−1 ammonium nitrate; and a control (without bagasse and ammonium nitrate) were evaluated. Results indicate that one single application of bagasse increased sugarcane biomass and sugar yield by approximately 23% in the plant cane year. A higher application rate of bagasse (10 cm of bagasse) was recommended since it had a longer effect on increasing sugarcane biomass and sugar yield. Bagasse application enhanced silicon (Si) suppl...
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Calcareous soils are those that have free calcium carbonate (CaCO3) and have pH values in the range of 7.0 to 8.3. If they are managed properly, calcareous soils can be used to grow any crop. Before employing any management practices, it... more
Calcareous soils are those that have free calcium carbonate (CaCO3) and have pH values in the range of 7.0 to 8.3. If they are managed properly, calcareous soils can be used to grow any crop. Before employing any management practices, it is important to know how much carbonate exists in the soil. Soil carbonate is usually quantified by acid dissolution followed by the volumetric analysis of the released carbon dioxide (CO2). In geological sciences, a simple acid test consists of placing a drop of dilute hydrochloric acid on a rock or mineral and observing if there are CO2 bubbles released; the bubbles indicate the presence of carbonate minerals. The household test below uses vinegar and other simple instruments to estimate soil carbonate concentration. Minor revision with an added author.
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Cost-effective zero valent iron (ZVI)-based bimetallic particles are a novel and promising technology for contaminant removal. The objective of this study was to evaluate the effectiveness of CCl4 removal from aqueous solution using... more
Cost-effective zero valent iron (ZVI)-based bimetallic particles are a novel and promising technology for contaminant removal. The objective of this study was to evaluate the effectiveness of CCl4 removal from aqueous solution using microscale Ag/Fe bimetallic particles which were prepared by depositing Ag on millimeter-scale sponge ZVI particles. Kinetics of CCl4 degradation, the effect of Ag loading, the Ag/Fe dosage, initial solution pH, and humic acid on degradation efficiency were investigated. Ag deposited on ZVI promoted the CCl4 degradation efficiency and rate. The CCl4 degradation resulted from the indirect catalytic reduction of absorbed atomic hydrogen and the direct reduction on the ZVI surface. The CCl4 degradation by Ag/Fe particles was divided into slow reaction stage and accelerated reaction stage, and both stages were in accordance with the pseudo-first-order reaction kinetics. The degradation rate of CCl4 in the accelerated reaction stage was 2.29–5.57-fold faster ...
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This document synthesizes information about the warm season cover crop sunn hemp. The question-and-answer format addresses frequently asked questions for growers with answers that summarize the growing body of sunn hemp research. The... more
This document synthesizes information about the warm season cover crop sunn hemp. The question-and-answer format addresses frequently asked questions for growers with answers that summarize the growing body of sunn hemp research. The information is provided so that growers in Florida can learn about up-to-date cultivation and management options for sunn hemp as well as better understand its practical uses. This document is a follow-up to the following: Wang, Qingren, Yuncong Li, Waldemar Klassen, and Edward Hanlon. 2015. “Sunn Hemp : A Promising Cover Crop in Florida”. EDIS 2015 (7), 4. https://doi.org/10.32473/edis-tr003-2015. Wang, K., and Robert McSorley. 2004. “Management of Nematodes and Soil Fertility With Sunn Hemp Cover Crop”. EDIS 2004 (18). https://journals.flvc.org/edis/article/view/114109.
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In the early stages of the establishment of plantation crops such as cacao, perennial legume cover crops provide vegetative cover to reduce soil and nutrient loss by erosion. Light intensity at cover crop canopy levels greatly influences... more
In the early stages of the establishment of plantation crops such as cacao, perennial legume cover crops provide vegetative cover to reduce soil and nutrient loss by erosion. Light intensity at cover crop canopy levels greatly influences their adaptability and optimum growth. As tree crops mature, understory cover crops suffer from inadequate light intensity. A greenhouse experiment was undertaken with nine perennial legume cover crop species (Calopo, Ea-Ea, Jack Bean, Lab-Lab, Mucuna ana, Mucuna preta, Cowpea, Black Pigeon Pea and Mixed Pigeon Pea) to assess the effects of three photosynthetic photon flux densities (PPFDs, µmol m−2 s−1) 180 (inadequate light), 450 (moderate light) and 900 (adequate light) on growth, physiological and nutrient uptake parameters. PPFD had highly significant effects on leaf, shoot and root growth parameters and increasing the light intensity from 180 to 900 µmol m−2 s−1 increased all growth parameters with the exception of specific leaf area. In all t...
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This study investigated the spatial variability of soil organic carbon (SOC), total nitrogen (TN), soil microbial biomass carbon (SMBC) and soil microbial biomass nitrogen (SMBN) in Hongqipao reservoir dominated by different vegetation... more
This study investigated the spatial variability of soil organic carbon (SOC), total nitrogen (TN), soil microbial biomass carbon (SMBC) and soil microbial biomass nitrogen (SMBN) in Hongqipao reservoir dominated by different vegetation types and the possible relationships with other soil properties. Top 0–50cm soil samples were collected in sites dominated by different vegetation types within the reservoir littoral zone. There was high spatial variability for SOC, TN, SMBC and SMBN in the Hongqipao reservoir. In addition, the SOC, TN, SMBC and SMBN contents decreased with increasing soil depth. This could be attributed by the fact that when plants detritus decompose, most of their organic matter is mineralized and a new soil layer which contains a greater amount of organic carbon is formed at the top. According to Pearson's correlation values and redundancy analysis (RDA) results, SOC was significantly and positively correlated with TN likely because the vegetation organic matte...
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Potatoes are an important crop in the United States, and Florida is ranked the 7th producer nationwide for potato production. In Florida, potatoes are mainly planted on sandy soils with low nutrient- and water-holding capacities. Nitrogen... more
Potatoes are an important crop in the United States, and Florida is ranked the 7th producer nationwide for potato production. In Florida, potatoes are mainly planted on sandy soils with low nutrient- and water-holding capacities. Nitrogen is the most limiting nutrient in these soils. Adopting efficient fertilization methods such as fertigation is imperative for minimizing leaching and improving use efficiency of nitrogen. This new 12-page article provides step-by-step guidelines for fertigation practices for commercial potato production. Written by Xiangju Fu, Guodong Liu, Lincoln Zotarelli, Steven Sargent, Kati Migliaccio, and Yuncong Li, and published by the UF/IFAS Horticultural Sciences Department.https://edis.ifas.ufl.edu/hs1361
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The commercial blueberry industry in Florida has expanded significantly in both acreage and value in the past several years. The southern highbush blueberry (SHB, Vaccinium corymbosum L. interspecific hybrid) is the major blueberry type... more
The commercial blueberry industry in Florida has expanded significantly in both acreage and value in the past several years. The southern highbush blueberry (SHB, Vaccinium corymbosum L. interspecific hybrid) is the major blueberry type grown in Florida. The nitrogen (N) demand of young SHB differs from the northern highbush blueberry (NHB, V. corymbosum L.) and from mature blueberry plants. The objective of this study was to optimize fertigated N rates for the growth and yield of young SHB plants. One-year-old ‘Emerald’ and ‘Farthing’ plants were fertilized with 32N-0P-0K through drip irrigation at annual rates of 0, 42, 84, 168, and 336 kg N ha−1. Soil nitrate levels at multiple depths were measured along with leaf nutrient concentration, percent canopy ground cover, fruit yield and fruit quality. The results indicated that N rates had no significant effect on leaf nutrient concentrations. Greater N rates advanced bloom and harvest, increased percentage of ground cover (an indicat...
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Biochar, a low-cost porous carbonaceous adsorbent, has low adsorption capacity for anion contaminants. The objective of this study was to improve biochar’s ability to adsorb phosphorus (P) through polyethyleneimine (PEI) modification to... more
Biochar, a low-cost porous carbonaceous adsorbent, has low adsorption capacity for anion contaminants. The objective of this study was to improve biochar’s ability to adsorb phosphorus (P) through polyethyleneimine (PEI) modification to form an amine-functionalized biochar. Biochars prepared by pyrolysis of bamboo biomass, before and after PEI modification, were characterized using the Fourier transformed infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), elemental analysis, and batch sorption experiments. The effects of pH, coexisting anions, and ionic strength on P adsorption by PEI-modified biochar were also investigated. Results indicated that PEI was successfully grafted onto biochar which resulted an increase in surface amine group and in P adsorption. The peak of P adsorption occurred at pH of three and adsorption of P was decreased with increasing of ionic strength and when coexisting ions, such as HCO 3 − , SO 4 2− , NO 3 − , and Cl − , were coexisted. The electrostatic interaction between P and surface functional groups of PEI-modified biochar served as the primary mechanism controlling the adsorption process. These results indicate that chemically functionalized biochar with amine groups can enhance P adsorption.
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Compost is the product resulting from the controlled biological decomposition of organic material that has been sanitized through the generation of heat and processed to further reduce pathogens as defined by the U.S. Environmental... more
Compost is the product resulting from the controlled biological decomposition of organic material that has been sanitized through the generation of heat and processed to further reduce pathogens as defined by the U.S. Environmental Protection Agency and stabilized to the point that the compost is beneficial to plant growth. Organic materials used for composting in Florida are mainly yard wastes (trash) and food wastes. More than 5.7 million tons of composts could be produced from yard trash and food waste in the state. Animal manure and biosolids (treated sludge) can also be composted, but are not discussed in this article. “Other wastes” as discussed herein [food processing wastes, coal ash, wood ash, drinking water treatment residuals (WTRs), and phosphogypsum] are by-products of leading Florida industries and are available in large quantities for reuse. About 5 million tons of food processing waste [citrus (Citrus spp.) and vegetables alone], 1.85 million tons of coal ash (from 2...
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Excessive bicarbonate concentrations and high irrigation water pH affect the growth and appearance of nursery plants in southern Florida. A greenhouse experiment consisting of five nitrogen (N) rates of urea or nitric acid was conducted... more
Excessive bicarbonate concentrations and high irrigation water pH affect the growth and appearance of nursery plants in southern Florida. A greenhouse experiment consisting of five nitrogen (N) rates of urea or nitric acid was conducted to evaluate the influence of N sources and rates in irrigation water on bicarbonate concentrations, medium pH, and growth and appearance of anthurium (Anthurium andraeanum Lind.) plants. Pot medium pH, dry weight, plant appearance and N uptake by plants were significantly affected by N rates in irrigation water amended with either liquid urea or nitric acid, but the differences between the two N sources were not significant. The optimum growth and the best appearance of anthurium were achieved when N was added to irrigation well water as either urea or nitric acid at a rate of 20 mg·L-1 (ppm) and an electrical conductivity in a range of 0.36 to 0.42 dS·m-1 Nitrogen rates at 80 and 120 mg·L-1 induced adverse plant growth because of the greater salinit...
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A simple foaming method was applied to fabricate urea formaldehyde (UF) microspheres with cross-linked porous structures for environmental remediation of heavy metals. The specific surface area and average pore radius of the resultant... more
A simple foaming method was applied to fabricate urea formaldehyde (UF) microspheres with cross-linked porous structures for environmental remediation of heavy metals. The specific surface area and average pore radius of the resultant foamed UF microspheres were 11-29 m2/g and 11-25 nm, respectively, which increased with the increasing molar ratio of formaldehyde to urea. All the foamed UF microspheres showed good removal of heavy metals ions (Pb(II), Cu(II), and Cd(II)) in both single- and mixed-metal solutions. Further investigations of Pb(II) adsorption on a selected UF microspheres showed fast kinetics and relatively high adsorption capacity (21.5 mg/g), which can be attributed to the mesoporous structure and abundance of oxygen surface functional groups of the microspheres. Both experimental and model results showed that chelation or complexation interactions between Pb(II) and the surface functional groups were responsible to the strong adsorption of the heavy metal ions on the microspheres. Hydrochloric acid (0.05 M) successfully desorbed Pb(II) from the post-adsorption microspheres for multiple times and the regenerated microspheres showed high Pb(II) removal rates (>96%) in five adsorption-desorption cycles. With many promising advantages, foamed UF microspheres show great potential as a wastewater treatment agent for heavy metal removal.
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Controlled-release fertilizers (CRFs) are an effective approach in providing essential nutrients for plant growth while minimizing the loss of nutrients in water and air, reducing contamination risks. However, commercial CRFs often... more
Controlled-release fertilizers (CRFs) are an effective approach in providing essential nutrients for plant growth while minimizing the loss of nutrients in water and air, reducing contamination risks. However, commercial CRFs often release nutrients either too quickly or slowly due to the properties of their coating materials (polymer or sulfur). In this work, a novel CRF technology was developed using chitosan (CS) and graphene oxide (GO) nanocomposites as coating materials. CS and GO solutions were applied at varying ratios in preparing different nanocomposites. CS and GO formed homogeneous nanocomposite films through their interactions with each other. Fertilizer beads were successfully encapsulated by the CS-GO films using the simple dipping method. Resulting CRFs showed controlled-release behaviors, with nutrient release lasting for about a week. Although additional investigations are required for further evaluation and optimization, this method presents a promising concept for an alternative fertilizer-coating technology.
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A pot experiment with summer cover crops and soil amendments was conducted in two consecutive years to elucidate the effects of these cover crops and soil amendments on `Clemson Spineless 80' okra (Abelmoschus esculentus) yields and... more
A pot experiment with summer cover crops and soil amendments was conducted in two consecutive years to elucidate the effects of these cover crops and soil amendments on `Clemson Spineless 80' okra (Abelmoschus esculentus) yields and biomass production, and the uptake and distribution of soil nutrients and trace elements. The cover crops were sunn hemp (Crotalaria juncea), cowpea (Vigna unguiculata), velvetbean (Mucuna deeringiana), and sorghum sudangrass (Sorghum bicolor × S. bicolor var. sudanense) with fallow as the control. The organic soil amendments were biosolids (sediment from wastewater plants), N-Viro Soil (a mixture of biosolids and coal ash, coal ash (a combustion by-product from power plants), co-compost (a mixture of 3 biosolids: 7 yard waste), and yard waste compost (mainly from leaves and branches of trees and shrubs, and grass clippings) with a soil-incorporated cover crop as the control. As a subsequent vegetable crop, okra was grown after the cover crops, alone...
Research Interests: Biology, Power Plant, Sorghum, Environmental Effect, Nutrient Uptake, and 15 moreFly Ash, Soil Fertility, ORGANIC SOIL, Field Study, Biomass production, Fallow, Cover Crops, Trace element, Soil Nutrients, Crop Yield, Coal Fly Ash, Soil Amendment, Cover Crop, Horticultural production, and Sorghum bicolor
Rapid and accurate diagnosis of plant nutrient deficiency is critical for growers to use fertilizer economically and to minimize environmental concern. The objective of this study was to evaluate the use of leaf chlorophyll meter... more
Rapid and accurate diagnosis of plant nutrient deficiency is critical for growers to use fertilizer economically and to minimize environmental concern. The objective of this study was to evaluate the use of leaf chlorophyll meter (SPAD-502) to predict nitrogen status and yield response of grapefruit trees. The study includes two irrigation treatments, three fertilizer sources, and four fertilizer rates. No significant differences in SPAD readings and leaf N were found between two irrigation treatments. Correlations between SPAD readings and leaf N were higher for the spring flush (r = 0.61) than that for summer flush (r = 0.49). There were poor relations between SPAD meter readings and the extractable chlorophyll content in the spring flush on a dry-weight basis (r = 0.25). Higher correlations between SPAD meter readings and N rates or fruit yields than between leaf N concentrations and N rates or fruit yield.
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Cover crops have become an integral part of vegetable production practices in south Florida for weed control and retaining nutrients during the heavy summer rains. A wide variety of plants are used as cover crops in south Florida.... more
Cover crops have become an integral part of vegetable production practices in south Florida for weed control and retaining nutrients during the heavy summer rains. A wide variety of plants are used as cover crops in south Florida. Obviously, legumes contribute more nitrogen by fixing N compared to nonlegumes such as sorghum sudan grass, which is a common cover crop in this area. We have evaluated 10 cover crops, where six were legumes in 1997. In 1998, four cover crops (sunnhemp, sorghum sudan, sesbania, and aeschynomene) were evaluated. The sunnhemp (Crotalaria juncea L.) stands out from other tested cover crops for 2 years. Sunnhemp produced 8960 to 11,400 kg dry weight/ha and fixed up to 285 kg N/ha. The evaluation of effects of sunnhemp and other cover crops on the following tomato growth and yield are still in progress and will be discussed.
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The objective of this study was to evaluate the role of chloride (Cl-) and other anions in soil water on the incidence and severity of Rio Grande Gummosis (RGG) in grapefruit (Citrus paradisi MacFadyen) trees. White `Marsh' grapefruit... more
The objective of this study was to evaluate the role of chloride (Cl-) and other anions in soil water on the incidence and severity of Rio Grande Gummosis (RGG) in grapefruit (Citrus paradisi MacFadyen) trees. White `Marsh' grapefruit trees on sour orange (C. aurantium Lush.) rootstock were grown on two-row raised beds. Due to differential rates of K application (as KCl), the trees received various rates of Cl- ranging from 0 to 156 kg·ha-1 per year. Soil water was sampled using suction lysimeters at 120- and 180-cm depths. The severity of RGG was evaluated 18 months following the application of various rates of KCl. The concentration of Cl- in soil water samples varied from 16.2 to 617 mg·L-1, with mean concentrations across all treatments of 160.7 and 188.4 mg·L-1 for 120- and 180-cm depth water samples, respectively. The concentrations of Cl- and other anions (\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsm...
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Cover crops are used for weed control and to retain nutrients during the heavy summer rains and have become an integral part of vegetable production practices in south Florida. Moreover the use of cover crops will continue to increase as... more
Cover crops are used for weed control and to retain nutrients during the heavy summer rains and have become an integral part of vegetable production practices in south Florida. Moreover the use of cover crops will continue to increase as farmers seek to improve soil quality and reduce chemical inputs. A wide variety of plants are used as cover crops in south Florida. Obviously legumes contribute more nitrogen by fixing N compared to nonlegumes such as sorghum–Sudan grass, which is a common cover crop in this area. We have evaluated 10 cover crops, and five of them are legumes. The sunn hemp, Crotalaria juncea L, stands out from other tested cover crops. Sunn hemp produced 8960 kg dry weight per ha and fixed up to 336 kg N/ha. We have strongly recommended sunn hemp as a cover crop for vegetables and tropical fruits in south Florida. A large field demonstration will be conducted in a grower's field in the summer rainy season of 1998.
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Using herbs for medicinal purposes, ornamentals, and landscape plantings has increased significantly. Propagating from seeds is considered the most-efficient method of producing medicinal plants for commercial production. Among the herb... more
Using herbs for medicinal purposes, ornamentals, and landscape plantings has increased significantly. Propagating from seeds is considered the most-efficient method of producing medicinal plants for commercial production. Among the herb seeds the purple coneflower (Echinacea angustifolia) was found difficult to germinate. Laboratory studies were conducted to: 1) determine optimum temperature from a temperature range 15 to 30 °C for seed germination; 2) determine effects of 5 10, 20, and 30 days of stratification at 5 and 10 °C in darkness on germination; and 3) determine effects of priming in the dark for 1, 3, 6, and 9 days with 0.1 M KNO3 and biostimulants at optimum temperature to enhance early emergence and final germination. Germination was enhanced from 45% in untreated seeds to 81% in seeds treated with either 50 ppm GA4/7 or 100 ppm ethephon at 24 °C. Final germination was 81% under daylight conditions when seeds were stratified in dark at 10 °C for 30 days over nonstratifie...
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Mulching in vegetable cultivation has been widely used to conserve water and improve yield. Field experiments with four treatments, including yard waste compost combined with plastic mulches in raised beds for winter fresh market bell... more
Mulching in vegetable cultivation has been widely used to conserve water and improve yield. Field experiments with four treatments, including yard waste compost combined with plastic mulches in raised beds for winter fresh market bell peppers (Capsicum annuum L.), were conducted at two experimental sites [Pine Island Farm (PIF) and Tropical Research and Education Center (TREC)] in Miami-Dade county for two different years each. The treatments were: 1) control (PM): plastic mulch alone; 2) MC33: fumigation of the soil with a mixture of methyl bromide and chloropicrin and covered with plastic mulch; 3) herbicide/OM: organic mulch sprayed with herbicides (S-metolachlor and napropamide) without plastic mulch; and 4) PM/OM: organic mulch covered by plastic mulch. The treatment of PM/OM at both experimental sites in 2 years each increased the total marketable yields of bell pepper by 1.5- to 3.2-fold, total extra large fruit yields by 2.0- to 5.7-fold, and total large fruit yields by 1.4-...
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Intensive rainfall during summer causes substantial nutrient leaching in a subtropical region, where most vegetable lands lay fallow during this period. Also, an excessive amount of irrigation water supplied during the winter vegetable... more
Intensive rainfall during summer causes substantial nutrient leaching in a subtropical region, where most vegetable lands lay fallow during this period. Also, an excessive amount of irrigation water supplied during the winter vegetable growing season leads to soil nutrient loss, which greatly impacts vegetable yields, especially in soils that possess a low capacity to retain soil water and nutrients. A 2-year field experiment was carried out to evaluate the effects of various summer cover crops and irrigation rates on tomato yields and quality, and on soil fertility in a subtropical region of Florida. The cover crops were sunn hemp [Crotalaria juncea (L.) `Tropic Sun'], cowpea [Vigna unguiculata (L.) Walp, `Iron Clay'], velvetbean [Mucuna deeringiana (Bort.) Merr.], and sorghum sudangrass [Sorghum bicolor × S. bicolor var. sudanense (Piper) Stapf.], with a weed-free fallow as a control. The cover crops were planted during late Spring 2001 and 2002, incorporated into the soil...
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Florida, like other states, is developing BMPs for specific commodities. Vegetables are in a statewide document that includes field crops. Vegetable advisory committee members from the counties in southern Florida were concerned that the... more
Florida, like other states, is developing BMPs for specific commodities. Vegetables are in a statewide document that includes field crops. Vegetable advisory committee members from the counties in southern Florida were concerned that the existing document was too broad in its scope and that many practices did not apply to production on sandy or calcareous soils. Based on grower comments, extension agents organized grower meetings to address these issues. The first meeting was a presentation by the Florida Department of Agriculture and Consumer Services (FDACS) Office of Agricultural Water Policy. The second meeting in Miami–Dade was a hands-on session, where growers and industry were divided into three areas—nutrition, pesticides, and water quality. Each group was facilitated by a faculty member or the NRCS conservationist. Other counties used newsletters and other methods to receive grower feedback. Participant comments were compiled and forwarded to FDACS, where they are being inc...
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Consumer demand for fresh market organic produce combined with the increasing market share of ready-to-eat products indicates the potential for expansion of an organic culinary herb market. Barriers to organic herb greenhouse production... more
Consumer demand for fresh market organic produce combined with the increasing market share of ready-to-eat products indicates the potential for expansion of an organic culinary herb market. Barriers to organic herb greenhouse production are high as a result of lack of available technical information and the low number of producers experienced in this area. There is a critical need for information and technologies to improve the management of organic soil and fertilizer amendments to optimize crop yields and quality, manage production costs, and minimize the risk from groundwater nitrogen (N) contamination. Because of limited information specific to organic culinary herb production, literature on organic vegetable transplants and conventional basil (Ocimum basilicum) production was also considered in this review. Managing N for organic crops is problematic as a result of the challenge of synchronizing mineralization from organic fertilizer sources with crop N demand. A combination of...
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A low-volume/high frequency (LVHF) soil moisture-based drip irrigation system was tested on a shallow sandy soil at a commercial tomato (Lycopersicon esculentum) farm in southern Florida. Six LVHF irrigation treatments were compared with... more
A low-volume/high frequency (LVHF) soil moisture-based drip irrigation system was tested on a shallow sandy soil at a commercial tomato (Lycopersicon esculentum) farm in southern Florida. Six LVHF irrigation treatments were compared with the standard commercial practice on the farm (control), where a portable pump was used for manual drip irrigation twice each week. In the six LVHF treatments the system was continuously pressurized by means of an electrical pump and a pressure tank, and controlled by an irrigation timer set to irrigate a maximum of five times per day with the irrigation time (i.e., volume) set according to historical evapotranspiration (ET) demands in the area. Two treatments were based on timer schedules, one to supply 100% of the maximum recommended crop water needs in the area based on historical ET (ET-100%), and the other to supply 150% of those needs (ET-150%). The other four treatments were created by interfacing two types of soil moisture sensors (switching ...
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The review of effects of excessive soil water on performance of various vegetable crops and selected field crops indicates that in areas where temporary flooding hazards are expected during the growing season, crops can be selected on... more
The review of effects of excessive soil water on performance of various vegetable crops and selected field crops indicates that in areas where temporary flooding hazards are expected during the growing season, crops can be selected on their relative ability to tolerate excessive moisture. Field crops are generally less sensitive than vegetable crops in terms of yield. In addition to the choice of crop species, planting dates could be shifted when possible by delaying dates of sowing or planting to avoid probable periods of flooding during the sensitive growth stages. In most instances, crops are more sensitive at their early developmental phase than at the later stages in terms of yield. Soil management practices like ridging and furrowing or making raised beds before planting is recommended. In addition, amelioration with foliar application of chemicals like nutrients, growth hormones and fungicides is also recommended to overcome nutritional deficiencies, hormonal imbalances and d...
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The objective of this study was to evaluate the use of a leaf chlorophyll meter (SPAD-502) to predict nitrogen status and yield response of grapefruit trees. The study included two irrigation treatments, three sources, and four rates of... more
The objective of this study was to evaluate the use of a leaf chlorophyll meter (SPAD-502) to predict nitrogen status and yield response of grapefruit trees. The study included two irrigation treatments, three sources, and four rates of fertilizer [dry soluble granular fertilizer broadcast or through fertigation with N rates either 50, 100, 150 lb/acre/yr (56, 112, or 168 kg.ha-1.yr-1)], and controlled-release fertilizer with N rates either 25, 50, 100 lb/acre. Irrigation treatments did not affect SPAD readings and leaf N concentrations. Correlations between SPAD readings and leaf N were greater for the spring flush (r2 = 0.61) than for the summer flush (r2 = 0.49). High correlations of SPAD meter readings with either fruit yields or leaf N suggests that SPAD meter reading is an acceptable index of N status and fruit production of the trees. SPAD readings can be made rapidly without destructive sampling of the leaves. This study demonstrates that the SPAD meter can be used to evalua...
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Source quantification of heavy metals in farmland is essential for developing and implementing restoration strategies. We used various data analyses to identify and quantify sources of arsenic, cadmium, chromium, copper, mercury, nickel,... more
Source quantification of heavy metals in farmland is essential for developing and implementing restoration strategies. We used various data analyses to identify and quantify sources of arsenic, cadmium, chromium, copper, mercury, nickel, lead, and zinc in vegetable-growing soils. A new method of collaborative assessment, combining soil environmental quality and agricultural product safety, showed that approximately 5.20% of cultivation systems were multi-contaminated by heavy metals. The nonlinear relationship between pollution sources and the comprehensive contamination situation was established, deriving from a fitted bivariate model. The model revealed that anthropogenic sources and natural origins accounted for 65.8-86.0 and 34.2-14.0% of the comprehensive pollution, respectively. These results suggested that both human activities and natural factors contributed to the decline of local soil quality and the influence of the former was more substantial than that of the latter.
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This study aimed to construct objective and accurate geographical discriminant models for tea leaves based on multielement concentrations in combination with chemometrics tools. Forty mineral elements in 87 tea samples from three growing... more
This study aimed to construct objective and accurate geographical discriminant models for tea leaves based on multielement concentrations in combination with chemometrics tools. Forty mineral elements in 87 tea samples from three growing regions in Guizhou Province (China), namely Meitan and Fenggang (MTFG), Anshun (AS) and Leishan (LS) were analyzed. Chemometrics evaluations were conducted using a one-way analysis of variance (ANOVA), principal component analysis (PCA), linear discriminant analysis (LDA), and orthogonal partial least squares discriminant analysis (OPLS-DA). The results showed that the concentrations of the 28 elements were significantly different among the three regions ( < 0.05). The correct classification rates for the 87 tea samples were 98.9% for LDA and 100% for OPLS-DA. The variable importance in the projection (VIP) values ranged between 1.01⁻1.73 for 11 elements (Sb, Pb, K, As, S, Bi, U, P, Ca, Na, and Cr), which can be used as important indicators for g...
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For 46 years (1957-2002), irrigation with wastewater has increased the amount of heavy metal and organic contaminants in soils and altered bacterial communities in Shenyang, northeastern China. There has been characterization of the... more
For 46 years (1957-2002), irrigation with wastewater has increased the amount of heavy metal and organic contaminants in soils and altered bacterial communities in Shenyang, northeastern China. There has been characterization of the different heavy metal and petroleum contaminants in two types of land uses (cornfields and paddy fields). The Nemerow composite indices of heavy metal contaminants have been higher in cornfields (1.17-4.73) than those in paddy fields (0.57-1.64). Molecular-based techniques and biochemical-based techniques were used to analyze soil microbial diversity in our study. The metabolic activity of soil microbe communities was higher in paddy sites than that in cornfields. Organic pollutants such as saturated and polycyclic aromatic hydrocarbons have significantly affected soil bacterial compositions. Heavy metals differed in how they disturbed the microbial communities. Arsenic (As) and lead (Pb) shifted the community composition and decreased microbial diversit...
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In this work, lignite, a low-grade coal, was modified using the solid-phase activation method with the aid of a Pd/CeO nanoparticle catalyst to improve its pore structure and nutrient absorption. Results indicate that the adsorption... more
In this work, lignite, a low-grade coal, was modified using the solid-phase activation method with the aid of a Pd/CeO nanoparticle catalyst to improve its pore structure and nutrient absorption. Results indicate that the adsorption ability of the activated lignite to NO, NH, HPO, and K was significantly higher than that of raw lignite. The activated lignite was successfully combined with the polymeric slow-release fertilizer, which exhibits typical slow-release behavior, to prepare the super large granular activated lignite slow-release fertilizer (SAF). In addition to the slow-release ability, the SAF showed excellent water-retention capabilities. Soil column leaching experiments further confirmed the slow-release characteristics of the SAF with fertilizer nutrient loss greatly reduced in comparison to traditional and slow-release fertilizers. Furthermore, field tests of the SAF in an orchard showed that the novel SAF was better than other tested fertilizers in improve the growth of young apple trees. Findings from this study suggest that the newly developed SAF has great potential to be used in apple cultivation and production systems in the future.
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Florida produces the most vegetables in the United States during the winter season with favorable weather conditions. However, vegetables grown on calcareous soils in Florida have no potassium (K) fertilizer recommendation. The objective... more
Florida produces the most vegetables in the United States during the winter season with favorable weather conditions. However, vegetables grown on calcareous soils in Florida have no potassium (K) fertilizer recommendation. The objective of this study was to evaluate the effects of K rates on leaf tissue K concentration (LTKC), plant biomass, fruit yield, and postharvest quality of tomatoes (Solanum lycopersicum L.) grown on a calcareous soil. The experiment was conducted during the winter seasons of 2014 and 2015 in Homestead, FL. Potassium fertilizers were applied at rates of 0, 56, 93, 149, 186, and 223 kg·ha−1 of K and divided into preplant dry fertilizer and fertigation during the season. No deficiency of LTKC was found at 30 days after transplanting (DAT) in both years. Potassium rates lower than 149 kg·ha−1 resulted in deficient LTKC at 95 DAT in 2014. No significant responses to K rates were observed in plant (leaf, stem, and root combined) dry weight biomass at all the samp...