Tomato Production In Florida Research Articles

RETRACTED: Biocontrol of Fusarium wilt in tomato by Trichoderma spp

Tomato is the most economically important vegetable crop in Florida where produces the most fresh-market tomatoes in the United States. Fusarium wilt, caused by Fusarium oxysporum f. sp. lycopersici (FOL), is an important disease in tomato production in Florida, particularly due to lacking effective chemicals for soil treatment. Biological control is an alternative approach in the management of plant diseases, including those caused by soilborne pathogens. In this study, we evaluated two Trichoderma strains (T. atroviride T11 and T. asperellum T25) on their effects against FOL in vitro and in planta. T. asperellum T25 and its cultural filtrate showed inhibitory effects against mycelial growth of FOL in vitro and significantly reduced disease severity of Fusarium wilt in tomato in the greenhouse when T25 was mixed into soil at seeding. Although the mechanisms for biocontrol are still under investigation, results from this study indicate that T25 has great potential in the management of Fusarium wilt in tomato production.

Application of biostimulants to improve tomato yield in Florida

Biostimulants are shown to increase crop production. This study was conducted to investigate the effects of individual biostimulants on tomato ('Phoenix') growth and yield. Six different biostimulants: CP₁, CP₂, BS, CP₂+BS, Competitor, and Water (control) were foliar applied at three different stages: pre-blooming, fruit setting, and color changing. The concentration of calcium (Ca), potassium (K), magnesium (Mg), and phosphorus (P) in leaves and roots were also determined. The results showed that plants treated with biostimulants had greater concentrations of Ca, K, Mg, and P compared to those treated with water only. Competitor and CP₂+BS significantly increased yield, plant height, and stem diameter by 76% and 41%, 42% and 34%, and 29% and 24%. Likewise, leaf greenness, photosynthetic rate (PN), relative water content (RWC), nitrate level in petiole sap, and fruit quality (citric acid, malic acid, tartaric acid, soluble solid concentration, and fruit firmness) were also improved by Competitor. In addition, enzymatic activities of nitrate reductase (NR) and nitrite reductase (NiR) were significantly increased by biostimulants compared to the control. Statistically, Competitor and CP₂+BS showed the greatest augmentation in plant height, stem diameter, leaf greenness, PN, RWC, nitrate level in petiole sap, and fruit yield and quality. Similarly, Competitor-treated plants also increased NR, NiR, leaf Ca, leaf K, leaf Mg, and leaf P by 34%, 70%, 22%, 26%, 27%, and 45%, respectively. Based on the findings of this study, application of Competitor or CP₂+BS showed promising results and may be used as a BMP tool for tomato production in Florida.

Optimizing Tomato Growth and Productivity Using Nitrogen and Irrigation Application Timing

Soil nutrients and water management practices according to the concept of 4R nutrient stewardship (right rate, right timing, right placement, and right source) can have significant benefits on crop productivity and reduce the negative effects of agricultural practices on the environment. Therefore, this present study evaluated the effects of nitrogen (N) application timing under different irrigation regimes on open-field, fresh-market tomato production in Florida. In this study, 2 N application timings applied at 25% pre-plant with 75% fertigation (BM), and 0 pre-plant with 100% fertigation (NB), were evaluated. The two N application methods were evaluates using three irrigation regimes: full irrigation (FI, 100% ETc), deficit irrigation (DI, 66% ETc), and regulated deficit irrigation (RDI, 66% ETc during the first 4 weeks after transplanting and 100% ETc afterward). The results showed that BM treatment significantly improved early-season tomato growth compared to NB treatment. The results also indicated that under RDI and DI irrigation conditions, tomato root length was lowest (average value of 13%) within the first 15 cm compared to 40% within 15–30 cm and 47% at 30–40 cm soil depths. Similar to plant growth, BM treatment significantly increased tomato yield (average valued 56.00 Mg ha−1) compared to the NB (average value 40.23 Mg ha−1). The application of DI throughout the growing season reduced tomato yield; however, there were no differences in yield under the RDI and FI irrigation regimes. Therefore, based on the results from this study, it can be concluded that, under Florida growing conditions, pre-plant N application is essential for tomato growth and productivity. Additionally, irrigation application using the RDI method could be successfully adopted in Florida tomato production for improved water savings without any negative effects on tomato growth and productivity.

Technology, Policy, and Market Adaptation Mechanisms for Sustainable Fresh Produce Industry: The Case of Tomato Production in Florida, USA

Tomato (Solanum lycopersicum L.) is an important vegetable crop in Florida, a state located in the south-eastern region of the United States. The state is the second largest producer of tomatoes in the country and contributes to almost 90% of the domestic winter tomato supplies. However, tomato farmers in Florida have come under increasing pressure due to climate changes, foreign imports, and rising production costs. The purpose of this paper is to analyze whether Florida tomato growers will continue to sustain their production given the seasonal and geographic production advantage, yet against various internal and external threats emerging throughout the fresh produce supply chain. We developed our study on a multi-disciplinary conceptual model of network (supply chain) relationship and primary and secondary data gathered from various stakeholders and the literature. We found that Florida farmers have done remarkably well by adapting to warming temperatures and changing consumer expectations about environmental sustainability and responsible labor practices. However, foreign competition, labor shortage, the rising costs of inputs, extreme weather events (hurricanes), and pests and diseases due to humid climate continue to affect the sustainability of the Florida tomato production. Our paper suggests various farm-, market-, and institution-level adaptation mechanisms for preventing the regional production advantage of the Florida tomato industry from eroding. Newer immigration laws are necessary for easing the labor situation. In order to have a level playing field with respect to the use of protected agriculture technology such as in Mexico and Canada, U.S. farmers in general and Florida farmers in particular need government support. Florida farmers need to diversify their fresh produce market strategies, finding new product streams. There is also a need for reforming the product certification landscape, which some growers find cumbersome and cost prohibitive. Growers may gain from being better able to convey to consumers the information regarding their effort put into environmental sustainability, workers welfare, and safe food.

Assessing Changes and Associations in the Xanthomonas perforans Population Across Florida Commercial Tomato Fields Via a Statewide Survey.

Before 1991, Xanthomonas euvesicatoria was the causal agent of bacterial spot of tomato in Florida but was quickly replaced by X. perforans. The X. perforans population has changed in genotype and phenotype despite lack of a clear selection pressure. To determine the current Xanthomonas population in Florida, we collected 585 Xanthomonas strains from 70 tomato fields, representing 22 farms across eight counties, in the Florida tomato production region. Strains were isolated from 23 cultivars across eight seed producers and were associated with eight transplant facilities during the fall 2017 season. Our collection was phenotypically and genotypically characterized. Only X. perforans was identified, and all strains except one (99.8%) were tolerant to copper sulfate and 25% of strains were resistant to streptomycin sulfate. Most of the strains (99.3%) that were resistant to streptomycin sulfate were sequence type 1. The X. perforans population consisted of tomato races 3 (8%) and 4 (92%) and all three previously reported sequence types, ranging from 22 to 46% frequency. Approximately half of all strains, none of which were sequence type 2, produced bacteriocins against X. euvesicatoria. Effector profiles were highly variable among strains, which could impact the strains' host range. The effector xopJ4, which was previously thought to be conserved in X. perforans tomato pathogens, was absent in 19 strains. Nonmetric multidimensional scaling and network analyses show how strains and strain traits were associated with production system variables, including anonymized farms and transplant facilities. These analyses show that the composition of the Florida X. perforans population is diverse and complex.

Tomato Brown Rugose Fruit Virus (ToBRFV): A Potential Threat for Tomato Production in Florida

Tobamoviruses are mechanically transmitted plant viruses that cause severe economic damage to vegetable and ornamental crops in Florida and worldwide. While certain tomato cultivars have genetic resistance to the most common tobamoviruses, no commercial tomato cultivars are resistant to tomato brown rugose fruit virus (ToBRFV), a recently described tobamovirus that also infects pepper and eggplant. It is currently unknown how ToBRFV may affect tomato production in Florida. This new 5-page publication of the UF/IFAS Plant Pathology Department describes symptoms of the virus, how it is different from other tobamoviruses, and how it is transmitted, as well as what to do if you think you have ToBRFV in your field. Written by Ozgur Batuman, Salih Yilmaz, Pamela Roberts, Eugene McAvoy, Samuel Hutton, Kishore Dey, and Scott Adkins.https://edis.ifas.ufl.edu/pp360

Tomato Growth, Yield, and Root Development, Soil Nitrogen and Water Distribution as Affected by Nitrogen and Irrigation Rates on a Florida Sandy Soil

Effective nutrient and irrigation management practices are critical for optimum growth and yield in open-field fresh-market tomato production. Although nutrient and irrigation management practices have been well-studied for tomato production in Florida, more studies of the current highly efficient production systems would be considered essential. Therefore, a two-season (Fall 2016 and Spring 2017) study was conducted in Immokalee, FL, to evaluate the effects of the nitrogen (N) rates under different irrigation regimes and to determine the optimum N requirement for open-field fresh-market tomato production. To evaluate productivity, the study investigated the effects of N rates and irrigation regimes on plant and root growth, yield, and production efficiency of fresh-market tomato. The study demonstrated that deficit irrigation (DI) targeting 66% daily evapotranspiration (ET) replacement significantly increased tomato root growth compared with full irrigation (FI) at 100% ET. Similarly, DI application increased tomato growth early in the season compared with FI. Therefore, irrigation applications may be adjusted downward from FI, especially early during a wet season, thereby potentially improving irrigation water use efficiency (iWUE) and reducing leaching potential of Florida sandy soils. However, total marketable yield significantly increased under FI compared with DI. This suggests that although DI may increase early plant growth, the application of DI throughout the season may result in yield reduction. Although N application rates had no significant effects on biomass production, tomato marketable yield with an application rate of 134 kg·ha−1 N was significantly lower compared with other N application rates (179, 224, and 269 kg·ha−1). It was also observed that there were no significant yield benefits with N application rates higher than 179 kg·ha−1. During the fall, iWUE was higher under DI (33.57 kg·m−3) than under FI (25.57 kg·m−3); however, iWUE was similar for both irrigation treatments during spring (FI = 14.04 kg·m−3; DI = 15.29 kg·m−3). The N recovery (REC-N) rate was highest with 134 kg·ha−1 N; however, REC-N was similar with 179, 224, and 269 kg·ha−1 N rates during both fall and spring. Therefore, these study results could suggest that DI could be beneficial to tomato production only when applied during early growth stages, but not throughout the growing season. Both yield and efficiency results indicated that the optimum N requirement for open-field fresh-market tomato production in Florida may not exceed 179 kg·ha−1 N.

Tomato Production in Florida Using Fertigation Technology

Tomato is in high demand because of its taste and health benefits. In Florida, tomato is the number one vegetable crop in terms of both acreage and value. Because of its high value and wide acreage, it is important for tomato production to be efficient in its water and nutrient use, which may be improved through fertigation practices. Therefore, the objective of this new 7-page article is to disseminate research-based methods of tomato production utilizing fertigation to enhance yield and nutrient use efficiency. Written by Mary Dixon and Guodong Liu, and published by the UF/IFAS Horticultural Sciences Department.https://edis.ifas.ufl.edu/hs1392

Management of bacterial spot of tomato caused by copper-resistant Xanthomonas perforans using a small molecule compound carvacrol

Bacterial spot of tomato (BST), caused by Xanthomonas perforans, is one of the most serious diseases in fresh market tomato production in Florida, and currently available management measures are largely ineffective or insufficient. Using small molecule compounds has been shown to be promising in management of BST. Carvacrol is a plant-derived small molecule, which is effective against many human and plant pathogens. In this study, we evaluated the efficacy of carvacrol for control of BST in vitro, in the greenhouse and in field trials. In the laboratory, X. perforans strain used in this study was able to grow on nutrient agar (NA) amended with CuSO4 at 400 mg L−1, which proved that this X. perforans strain was copper resistant. Our results also showed that the minimum inhibitory concentration (MIC) of carvacrol was 32 mg L−1 and its minimum bactericidal concentration (MBC) was 64 mg L−1. Carvacrol increased the sensitivity of the copper-resistant X. perforans strain to copper. In the leaf disc assay, carvacrol combined with copper reduced recovery of X. perforans from tomato leaf discs. Seed priming with carvacrol at 32 mg L−1 was found to be effective in promoting seed germination and seedling vigor of tomato. In greenhouse assays, carvacrol foliar applied alone or in combination with copper significantly (P < 0.05) reduced BST severity. Moreover, carvacrol at 32 mg L−1 combined with copper at 76.8 mg L−1 was most effective in reducing BST severity, which was significantly greater than either treatment alone and also greater than copper at 153.6 mg L−1. In field trials during 2018 and 2019, control efficacy of carvacrol at 32 mg L−1 was significantly greater than copper. Results from this study indicate that carvacrol significantly reduces BST severity and enhances the efficacy of copper against copper resistant X. perforans. There is potential for the small molecule compound carvacrol to be integrated into BST management programs for copper resistant X. perforans and provide a more environmentally sustainable approach for controlling BST.

Dissipation of fomesafen in fumigated, anaerobic soil disinfestation-treated, and organic-amended soil in Florida tomato production systems.

Fumigated, anaerobic soil disinfestation-treated (ASD), and organic-amended soil management strategies have been investigated as potential methyl bromide (MBr) alternatives for controlling diseases, nematodes, and weeds in soil. Nutsedge and broadleaf weed control using fomesafen has been reported to be comparable to MBr in normal cropping systems. There is no information on the fate of fomesafen used in combination with alternative practices. In this study, the fate of fomesafen in these alternative systems was measured byliquid chromatography-tandem mass spectrometry (LC/MS-MS) following extraction using a modifiedQuick Easy Cheap Effective Safe (QuEChERS) method. The reported half-life (DT50 ) values for fomesafen in the top 15 cm of soil were from 62.9 to 107.3 days. The DT50 values in organic-amended soil were higher than in ASD-treated soil in the top 15 cm. For all treatments, reductions in concentrations were positively correlated with lower redox potentials and organic matter content. Some leaching of fomesafen into the 16-30 cm zone was observed in all treatments. The DT50 values in this study were generally higher than those reported in previous studies performed at different locations. Due to increased losses of the herbicide and subsequent reduction in weed control, fomesafen is likely not to be suitable for effective weed control in systems using ASD techniques employing composted poultry litter and molasses. Integration of fomesafen using composted yard waste 1 (CYW1) and Soil Symphony Amendment (SSA) may result in acceptable weed control. Given that the soil was very sandy and the pH was higher than the pKa, fomesafen might leach deeper than 30 cm, particularly with the use of chemical soil fumigants (CSFs). © 2019 Society of Chemical Industry.

Economics of fumigation in tomato production: the impact of methyl bromide phase-out on the Florida tomato industry

The Florida tomato industry is facing challenges of increased production costs and decreased yields resulting from the methyl bromide (MBr) phase-out under the Montreal Protocol for environmental concerns. MBr and several accepted alternative soil fumigant systems are analyzed in this study from an economic perspective. This article focuses on identifying optimal fumigant systems by analyzing the cost effectiveness and economic risk associated with MBr and several other commercially available soil fumigant systems using data collected from scientific field trials. The results obtained show that a 67:33 formulation of MBr: chloropicrin is the most cost-effective treatment, and no alternative fumigant systems investigated can substitute MBr cost-effectively in Florida tomato production. The analysis indicated that switching from MBr (67:33) to the new industry standard PicChlor 60 approximately resulted in a loss of $3,569 per acre in gross revenue and $1,656 per acre in profit using market prices in the 2013/14 season. Higher market prices would further increase the loss.

Chapter 41: Tomato Production in Florida

This document is HS739, Horticultural Sciences Department, UF/IFAS Extension. Published November 2006. HS739/CV137: Chapter 18. Tomato Production (ufl.edu)

Evaluation of a small molecule compound 3-indolylacetonitrile for control of bacterial spot on tomato

Bacterial spot, caused by Xanthomonas perforans, is one of the major diseases in fresh market tomato production in Florida. It is reported that X. perforans has developed resistance to copper, an element of major bactericides used for management of this disease in Florida and worldwide. Continuous efforts are necessary for providing the tomato industry with new effective approaches to managing this important disease. A small molecule 3-indolylacetonitrile (IAN) that can inhibit biofilm formation has been reported to be effective against many medical bacterial pathogens. In this study, we evaluated the efficacy of IAN in planta for the control of bacterial leaf spot on tomato, the effectiveness of IAN when applied at different times from pathogen inoculation, how IAN efficacy compared to a copper bactericide (Kocide 3000), and if IAN could be applied as a tank mixture with copper bactericide. In vitro testing in liquid media was also completed to further investigate observations made in planta. Our results showed that IAN was effective in reducing disease severity of bacterial leaf spot on tomato between 0.5 and 1.0 mg/ml. However, phytotoxicity to tomato plants occurred when the concentration was higher than 1.0 mg/ml. IAN significantly (P < 0.05) reduced the disease when it was foliar applied during the period from 3 days prior to inoculation to 1 day after inoculation. When IAN was applied in combination with a copper bactericide Kocide 3000, additive effect was observed in reducing both disease severity and bacterial growth, compared to either IAN or copper alone, for both copper-sensitive and copper-resistant X. perforans strains. Results from this study indicated that IAN significantly reduced bacterial leaf spot on tomato and enhanced the efficacy of copper against X. perforans. Specifically, IAN significantly improved the control of bacterial leaf spot caused by a copper-resistant X. perforans strain.

Evaluating anaerobic soil disinfestation and other biological soil management strategies for open-field tomato production in Florida

AbstractIn the search for alternative practices to chemical soil fumigation (CSF), anaerobic soil disinfestation (ASD) has proven to be a promising tool for soil-borne pest management and crop production improvement. The ASD treatment with composted poultry litter (CPL) and molasses (M, a labile carbon source) was identified as an effective approach for a biologically based soil disinfestation system in tomato (Solanum lycopersicum L.) production in Florida. However, environmental and food-safety concerns are associated with animal manure-based amendments, which led to the exploration of composted yard waste (CYW) as a potential substitute for CPL in ASD application. In this study, field trials were conducted in Citra and Immokalee, FL to examine the effects of ASD using CYW, CPL and M compared with a commercially available microbial amendment system on root-knot nematodes, weeds, fruit yield and quality of fresh-market tomato. Treatments included (1) ASD with CPL (11 Mg ha−1) and M (6.9 m3 ha−1) (ASD0.5), (2) ASD with CYW (26.9 Mg ha−1) and M (CYW1 + M), (3) ASD with CYW (13.5 Mg ha−1) and M (CYW0.5 + M), (4) Soil Symphony Amendment (SSA), (5) CYW (26.9 Mg ha−1) alone (CYW1) and (6) a combination of CYW1 + SSA, in comparison with (7) untreated control and (8) CSF (Pic-Clor 60 at 224 kg ha−1). Cumulative soil anaerobiosis was greater in ASD0.5 compared with all the other treatments. The root-knot nematode gall index ratings on the tomato crop were significantly lower in CSF, ASD0.5, CYW1 + M and CYW0.5 + M than untreated control in Citra. Although CYW1 and SSA alone had a moderately suppressive effect on weed coverage and root-knot nematodes, their positive impact on crop performance was limited when used alone. ASD0.5, CYW1 + M and CSF had significantly higher marketable and total fruit yields than untreated control in both locations, while all treatments showed promising results in the Immokalee trial in comparison with untreated control. In general, few differences in major fruit quality attributes were found. Although using CYW in ASD was not as effective as CPL in creating soil anaerobic conditions, the enhanced crop performance in CYW1 + M and CYW0.5 + M suggests the potential of using CYW as an alternative source of organic amendment in combination with M to achieve benefits similar to those obtained with CPL-based ASD.

Impacts of anaerobic soil disinfestation and chemical fumigation on soil microbial communities in field tomato production system

Anaerobic soil disinfestation (ASD), a potential alternative to pre-plant chemical fumigation for controlling soilborne pathogens, has been demonstrated in several agricultural production systems. The effect of ASD on the soil microbial community is considered one of the major factors responsible for pathogen suppression. However, rather limited information is available regarding the response of the soil microbial community to ASD throughout the cropping season, particularly in sandy soils. A field experiment was conducted to optimize the ASD technique for tomato production in Florida, utilizing two rates of molasses and composted poultry litter (CPL), and a pre-emergent herbicide application. The pre-plant soil treatments included ASD with 6.9 m3 ha−1 of molasses and 11 Mg ha−1 of CPL (ASD0.5), ASD with 13.9 m3 ha−1 of molasses and 22 Mg ha−1 of CPL (ASD1.0), and chemical soil fumigation control (CSF). The herbicide treatments included with and without halosulfuron application. Soil microbial community composition was monitored using phospholipid fatty acid (PLFA) analysis during the fall 2015 tomato production season. Halosulfuron application did not result in changes in the soil microbial community during the season. CSF led to significantly lower levels of bulk soil total microbial biomass, Gram negative bacteria, Gram positive bacteria and actinomycetes, compared to the ASD treatments. However, the rhizosphere effect of plants under CSF alleviated the microbial suppression and stimulated the growth of Gram negative bacteria and protozoa to reach similar levels to that of rhizosphere soils under the ASD treatments. Compared to 0 day after transplanting (DAT), Gram positive bacteria in bulk soils under the three pre-plant soil treatments significantly decreased while the fungi:bacteria ratio in bulk soils under CSF significantly increased at 36 DAT, and then remained stable throughout the season. Despite the similar microbial composition in bulk and rhizosphere soils between the two ASD treatments, the dynamic changes of some biomarker groups in bulk soils during 0–99 DAT showed distinct patterns particularly for total microbial biomass, Gram negative bacteria, actinomycetes, and fungi. Compared to 0 DAT, bulk soil microbial community composition shifted after 36 DAT under all soil treatments and remained stable until the end of the season. The changes in soil microbial community composition over time were related to changes in soil nutrient availability.

Detection of multi-tomato leaf diseases (late blight, target and bacterial spots) in different stages by using a spectral-based sensor

Several diseases have threatened tomato production in Florida, resulting in large losses, especially in fresh markets. In this study, a high-resolution portable spectral sensor was used to investigate the feasibility of detecting multi-diseased tomato leaves in different stages, including early or asymptomatic stages. One healthy leaf and three diseased tomato leaves (late blight, target and bacterial spots) were defined into four stages (healthy, asymptomatic, early stage and late stage) and collected from a field. Fifty-seven spectral vegetation indices (SVIs) were calculated in accordance with methods published in previous studies and established in this study. Principal component analysis was conducted to evaluate SVIs. Results revealed six principal components (PCs) whose eigenvalues were greater than 1. SVIs with weight coefficients ranking from 1 to 30 in each selected PC were applied to a K-nearest neighbour for classification. Amongst the examined leaves, the healthy ones had the highest accuracy (100%) and the lowest error rate (0) because of their uniform tissues. Late stage leaves could be distinguished more easily than the two other disease categories caused by similar symptoms on the multi-diseased leaves. Further work may incorporate the proposed technique into an image system that can be operated to monitor multi-diseased tomato plants in fields.

A Novel Phylogroup of Pseudomonas cichorii Identified Following an Unusual Disease Outbreak on Tomato.

Recently, in Central Florida tomato production fields, tomato foliage and fruit were observed with symptoms similar to bacterial speck. Fluorescent pseudomonads were consistently isolated and the strains were characterized by standard LOPAT tests, pathogenicity tests, and genetic characterization using 16S ribosomal RNA (rRNA) sequences and multilocus sequence analysis (MLSA) of conserved housekeeping genes. LOPAT test results indicated that the strains were likely Pseudomonas cichorii. These strains were pathogenic on tomato and were also pathogenic on lettuce, the host for the type strain of P. cichorii. Likewise, strains of P. cichorii isolated in Florida since the early 1980s from hosts other than tomato, along with the type strain, were also pathogenic on tomato. Genetic characterization using 16S rRNA and MLSA confirmed that the strains were most closely related to P. cichorii but varied significantly from the type strain. The Florida P. cichorii strains formed a separate phylogenetic group along with P. cichorii strains isolated from tomato in Tanzania. These strains were different from the previously described morphotypes and genomovars of P. cichorii. Our results indicate the presence of a genetically distinct group of multihost pathogenic P. cichorii strains that have been present in Florida since at least the early 1980s.

Good, the Bad, and the Ugly: What the Future Could Hold for Bs2 Tomatoes

Bs2 tomatoes are transgenic tomatoes that have been engineered to contain the Bs2 gene from pepper. As such, they are considered a genetically modified (GM) food, or a genetically modified organism (GMO). Numerous trials conducted by University of Florida researchers have shown the benefits of these cultivars for bacterial spot disease management, and growers and industry members recognize the potential for Bs2 tomatoes to make Florida tomato production more sustainable. This 4-page fact sheet discusses the benefits that might be realized by the adoption of Bs2 tomato varieties, and the challenges standing in the way of their commercial production. Written by S. F. Hutton, J. W. Scott, J. B. Jones, R. E. Stall, G. E. Vallad, B. J. Staskawicz, and D. M. Horvath , and published by the UF Department of Horticultural Sciences, April 2015. HS1259/HS1259: The Good, the Bad, and the Ugly: What the Future Could Hold for Bs2 Tomatoes (ufl.edu)

Prediction of Controlled-release Fertilizer Nitrogen Release Using the Pouch Field and Accelerated Temperature-controlled Incubation Methods in Sand Soils

Controlled-release fertilizers (CRFs), a vegetable production best management practice in Florida, are soluble fertilizers (SFs) coated with a polymer, resin, or a hybrid of polymer coating sulfur-coated urea. In 1994, a Controlled Release Fertilizer Taskforce developed an accelerated temperature-controlled incubation method (ATCIM) to predict column-incubated CRF nitrogen (N) release for regulatory purposes. Determination of CRF field N release uses a field method such as a pouch field study, which requires multiple samples and high costs for laboratory N analysis. If the ATCIM may be used to predict CRF N release in the field, then vegetables growers will have a faster and lower-cost method to determine N release compared with the pouch field method. Therefore, the objective of this study was to evaluate the correlation of the ATCIM and the pouch field method as a predictor of N release from CRFs in tomato production in Florida. In 2011 and 2013, 12 and 14 CRFs, respectively, were incubated in pouches placed in polyethylene mulched raised beds in Immokalee, FL, and extracted in the ATCIM during 2013. The ATCIM CRF results were used individually and grouped by release duration to create predicted N release curves in a two-step correlation process. The two-step processes predicted the percentage N release of individual CRF with R2 of 0.95 to 0.99 and 0.61 to 0.99 and CRFs grouped by release duration with R2 of –0.64 to 0.99 and –0.38 to 0.95 in 2011 and 2013, respectively. Modeling CRF N release grouped by release duration would not be recommended for CRF 180-d release (DR), because coating technologies behaviors differ in response to high fall soil temperature in polyethylene mulched beds. However, with further model calibration, grouping CRFs of 90 to 140 DR to simulate the CRF N release profile may allow the ATCIM to predict CRF N release without performing the pouch field method, which currently negated the usefulness of the ATCIM in a tomato production system.

Factors Affecting the Choice of Irrigation Systems for Florida Tomato Production

Several economic factors should be considered in selecting an agricultural irrigation system. This 7-page fact sheet compares two widely used irrigation systems for tomato production: seepage and sub-surface drip irrigation. Written by Jenna Rogers, Tatiana Borisova, Jeffrey Ullman, Kelly Morgan, Lincoln Zotarelli, and Kelly Grogan, and published by the UF Department of Food and Resource Economics, October 2014. (UF/IFAS Photo: Tyler Jones)