About

Loren Fisher is the Philip Morris Professor and the Assistant Director at NC State Research Stations and Field Labs within the Department of Crop and Soil Sciences at NC State University. His research focuses on flue-cured tobacco, including its yield, quality, nutrient concentration, and response to various management practices. Fisher has contributed to understanding the implications of crop management techniques such as harvest timing, nitrogen application, and application methods of organic poultry feather meal on tobacco production. His work also explores the effects of herbicide retention and sublethal herbicide rates on tobacco, as well as the influence of genetics and harvest timing on postharvest measurements. Fisher's research aims to improve tobacco crop management and production efficiency, and he has published extensively in reputable agronomy and crop science journals.

Research topics

• Agronomy
• Biology
• Biochemistry
• Chemistry
• Horticulture
• Animal science
• Chromatography
• Toxicology

Selected publications

• Flue‐cured tobacco and Cl rates: Implications on yield, quality, and nutrient concentration

  Agronomy Journal · 2022 · 9 citations

  Senior authorCorresponding
  • Chemistry
  • Horticulture
  • Agronomy

  Abstract The increase in flue‐cured tobacco ( Nicotiana tabacum L.) yields in recent decades due to genetic improvements of new cultivars and management technologies may increase the plant demand for Cl, and the increased dry mass may dilute Cl concentration, thereby reducing negative effects. This study evaluated the effect of increasing doses of Cl on tobacco production, quality, and chemical composition of leaves, in four growing environments located at research stations where flue‐cured tobacco is produced in North Carolina. The treatments consisted of 11 rates of Cl (0, 11, 22, 34, 45, 56, 67, 78, 90, 101, and 112 kg ha −1 ) in each growing environment, with four replications in a randomized complete block design. The yield and visual quality, total alkaloids, and reducing sugars concentrations of cured leaf were determined. In addition, the concentration of selected nutrients (N, P, K, Ca, Mg, S, and Cl) and nitrate (NO 3 − ) in tobacco leaves was measured in five different periods. Rates of Cl up to 112 kg ha −1 did not reduce the productivity or quality of flue‐cured tobacco in any environment. The Cl rate required to reach the threshold of 1.0% Cl content in cured leaf was site‐specific, being surpassed even in the control treatment at one location, or with Cl rates higher than 34 and 90 kg ha −1 in two environments. In one environment, the Cl rates increased tobacco yield, probably due the direct effect of Cl as a nutrient. Although the increasing Cl rates increased the reducing sugars concentration, visual quality was not attenuated.

  PublisherDOI

• Flue‐cured tobacco holding‐ability is affected by harvest timing

  Crop Forage & Turfgrass Management · 2021-01-01 · 3 citations

  articleOpen accessSenior author

  Abstract The propensity for flue‐cured tobacco ( Nicotiana tabacum L.) leaves to retain or improve their visual quality and value over an extended period of time is referred to as “holding‐ability.” General holding‐ability models that are specific to popular cultivars are not available to commercial farmers. Research was conducted at five locations from 2009 to 2014 to determine the effect of flue‐cured tobacco cultivar and upper‐stalk harvest timing to cured leaf yield, visual quality, price per pound, and economic value per acre. Two commercial cultivars, ‘K326’ and ‘NC196’, were evaluated within each location, with upper‐stalk leaf harvest schedule as follows: 7 d under‐ripe (Day 0), 3 d over‐ripe (Day 10), 13 d over‐ripe (Day 20), 23 d over‐ripe (Day 30), and 33 d over‐ripe (Day 40). The measured parameters were not influenced by cultivar selection, thus indicating that K326 and NC196 are likely to have similar ripening patterns and holding‐ability when produced under the same growing conditions. Quadratic responses for harvest timing were significant for cured leaf measurements. Yield and visual quality were greatest at Days 17 and 20, respectively. Cured leaf price continued to increase until Day 25, although maximum economic value per acre was obtained at Days 20 and 21 (US$3,041 acre –1 ). Increases in yield, quality, and value from Day 0 through 20 suggest that a 2‐wk delay in the harvest of upper‐stalk leaves may prove to be financially advantageous to farmers.

  PublisherDOI

• Flue‐cured tobacco response to sublethal rates of glufosinate

  Crop Forage & Turfgrass Management · 2021-11-13 · 1 citations

  articleOpen access

  Abstract Glufosinate is a broad‐spectrum, contact herbicide that is currently applied to genetically engineered row crops that tolerate exposure to the compound. Flue‐cured tobacco ( Nicotiana tabacum L.) is susceptible to glufosinate, yet it is commonly grown in close proximity to tolerant crops in North Carolina. The impact of glufosinate drift on flue‐cured tobacco is not known. Research was conducted in North Carolina to test the effects of sublethal rates of glufosinate (0.270, 0.135, 0.067, 0.034, 0.017 lb a.i. acre –1 ) on flue‐cured tobacco injury, yield, visual quality, financial value, and leaf chemistry. Simulated drift was imposed approximately 5 wk after transplanting. Visual injury increased with exposure rate and ranged from 15 to 83% and from 10 to 83% 1 and 2 wk after treatment, respectively. Cured leaf yield was reduced by 45% at the highest sublethal exposure rate and exhibited a linear decline of 47 lb acre –1 for every 0.01 lb glufosinate acre –1 . Visual quality and per acre financial value were not affected by glufosinate, most likely due to the loss of necrotic tissue and late‐season plant growth compensation. Residues of glufosinate in green and cured leaves were likewise not detected. Producers and commercial applicators should exercise caution when applying glufosinate around flue‐cured tobacco because of the injury and yield loss that can result from physical spray drift, as well as the inability to sell tobacco that has been exposed to a pesticide that is not labeled for application.

  PublisherOA PDFDOI

• Evaluations of <i>S</i>‐Metolachlor in flue‐cured tobacco weed management programs

  Agronomy Journal · 2021-12-13 · 2 citations

  articleOpen access

  Abstract Effective weed control is critical to growth and development of flue‐cured tobacco; however, current herbicide options are limited in commercial production. Field experiments were conducted from 2017 to 2018 to evaluate S ‐metolachlor for use in flue‐cured tobacco weed management programs. Treatments included 10 herbicide programs: pretransplanted incorporated (PTI) applications of S ‐metolachlor (1.07 kg a.i. ha –1 ) alone or in various combinations with sulfentrazone (0.18 kg a.i. ha –1 ), clomazone (0.84 kg a.i. ha –1 ), and pendimethalin (0.79 kg a.i. ha –1 ). S ‐metolachlor and pendimethalin were also applied posttransplanting directed to row middles (POST‐DIR) following PTI applications of sulfentrazone + clomazone. A single posttransplanting over‐the‐top (POST‐OT) application of S ‐metolachlor and a non‐treated control were included for comparison. The inclusion of S ‐metolachlor in PTI herbicide programs did not improve weed control beyond the combination of sulfentrazone + clomazone. However, weed control after final harvest was improved by 8%, when S ‐metolachlor was applied POST‐DIR. S ‐metolachlor applied POST‐OT caused injury to tobacco plants (12%), although symptoms were transient with less than 2% visual injury 6 wk after transplanting. Due to increased weed control through harvest and the low injury potential, our results suggest that POST‐DIR applications of S ‐metolachlor are the best fit for flue‐cured tobacco production when used in conjunction with recommended PTI herbicide programs.

  PublisherDOI

• Genetics influence postharvest measurements of flue‐cured tobacco more than nitrogen application rate

  Agronomy Journal · 2020-12-21 · 3 citations

  articleOpen accessSenior author

  Abstract Regulations under consideration by the U.S. Food and Drug Administration and the World Health Organization propose that nicotine concentration in tobacco ( Nicotiana tabacum L.) should be lowered to non‐addictive levels (0.3 to 0.5 mg g −1 ). The proposed standards are 90 to 95% lower than the nicotine concentration typically documented in commercially available cultivars. Research was conducted in six environments to evaluate two cultivars with normal alkaloid levels (K326 and NC95) and four genotypes with low alkaloid levels (DH16A, DH22A, DH32, and LAFC53). Each cultivar and genotype was paired with three N application rates: 70, 85, and 100% of the recommended rate. As N application declined, so too did cured leaf yield and nicotine, anabasine, and anatabine concentration in K326 and NC95. These factors were generally not affected by N application in the low alkaloid genotypes. In contrast, LAFC53 consistently produced the lowest cured leaf quality, value, and reducing sugar concentration when compared to all other cultivars. This observation demonstrates that K326 isolines are agronomically superior to LAFC53. Despite reductions in nicotine, the lowest documented concentration was still 10‐fold greater than the proposed minimum (LAFC53). Nitrogen did not influence the measured parameters as much as genetics; therefore, additional research that involves other agronomic practices is warranted. In addition, further genetic manipulation will be required to meet the standards proposed by regulatory groups.

  PublisherDOI

• Flue-cured tobacco tolerance to <i>S</i>-metolachlor

  Weed Technology · 2020-06-30 · 1 citations

  article

  Abstract Currently, there are seven herbicides labeled for U.S. tobacco production; however, additional modes of action are greatly needed in order to reduce the risk of herbicide resistance. Field experiments were conducted at five locations during the 2017 and 2018 growing seasons to evaluate flue-cured tobacco tolerance to S -metolachlor applied pretransplanting incorporated (PTI) and pretransplanting (PRETR) at 1.07 (1×) and 2.14 (2×) kg ai ha −1 . Severe injury was observed 6 wk after transplanting at the Whiteville environment in 2017 when S -metolachlor was applied PTI. End-of-season plant heights from PTI treatments at Whiteville were likewise reduced by 9% to 29% compared with nontreated controls, although cured leaf yield and value were reduced only when S -metolachlor was applied PTI at the 2× rate. Severe growth reduction was also observed at the Kinston location in 2018 where S -metolachlor was applied at the 2× rate. End-of-season plant heights were reduced 11% (PTI, 2×) and 20% (PRETR, 2×) compared with nontreated control plants. Cured leaf yield was reduced in Kinston when S -metolachlor was applied PRETR at the 2× rate; however, treatments did not impact cured leaf quality or value. Visual injury and reductions in stalk height, yield, quality, and value were not observed at the other three locations. Ultimately, it appears that injury potential from S -metolachlor is promoted by coarse soil texture and high early-season precipitation close to transplanting, both of which were documented at the Whiteville and Kinston locations. To reduce plant injury and the negative impacts to leaf yield and value, application rates lower than 1.07 kg ha −1 may be required in these scenarios.

  PublisherDOI

• Impacts of lower‐leaf removal timing, number, and nitrogen application to flue‐cured tobacco

  Crop Forage & Turfgrass Management · 2020-01-01

  articleOpen access

  Abstract The removal and exclusion of lower‐stalk tobacco ( Nicotiana tobacum L.) from harvest continues to be encouraged by industry. Very little information addresses the timing aspect of leaf removal, specifically when it occurs near floral initiation. Research was conducted in 2016 and 2017 to evaluate each possible treatment combination of two lower‐leaf removal programs (0 and 8 leaves/plant), three removal timings (2 wk before topping, at topping, and 2 wk after topping), and two N application rates (0 and 10 lb/ac). Soil plant analysis development (SPAD) measurements consistently revealed a lighter leaf color in treatments consisting of leaf removal 2 wk before topping, regardless of N application rate. Foliar cured leaf samples from upper‐stalk positions also contained less total N when eight leaves (2.25%) were removed relative to zero leaves (2.32%). These results indicate that subsequent N fertilizer application did not supply N as efficiently as remobilization from lower, older leaves. In the 8‐leaf removal program, both cured leaf yield and value declined by 27% relative to the 0‐leaf program. Despite significant losses in yield and value, the 8‐leaf program completely eliminated lug grades of tobacco. Leaf removal timing and N application rate did not affect yield, quality, value, or grade distribution. Our results suggest that there is no agronomic or cost to removing lower leaves 2 wk before or after topping; however, commercial farmers may find this information to be of use from a time management perspective, should they decide to implement this practice.

  PublisherOA PDFDOI

• Nitrogen Fertilizer Programs for Organic Flue-Cured Tobacco (Nicotiana Tabacum L.) Seedling Production

  Tobacco Science · 2020-01-01 · 1 citations

  articleOpen accessSenior author

  Certified organic flue-cured tobacco ( Nicotiana tabacum L.) production has experienced significant expansion in the United States. Despite this expansion, there is very little information available that outlines organic nitrogen (N) programs for seedling production. To develop grower recommendations, research was conducted to evaluate the effects of a Peruvian seabird guano (SG), sodium nitrate (SN), or a combination of the two (SN_SG) in a float system on float water chemistry and seedling vigor. A conventional treatment (Conv; SQM Ultrasol Premium) was included for comparison. A greenhouse study was conducted twice between June 2016 and January 2017. Nitrogen fertilizer treatments were applied to tobacco float system water twice during the germination and growth of tobacco transplants. Float system water was collected every 5 days and analyzed for N forms, pH, dissolved oxygen, and bicarbonate. At the end of each experiment, transplant dimensions were measured and percent of usable plants collected. Float water bicarbonate concentration was &lt;1 meq L −1 in treatments absent of SG for the duration of the study, but were in excess of 12 meq L −1 25 days after seeding (DAS) when SG was the exclusive N source. Despite high ammonium and bicarbonate concentrations with SG, neither factor negatively impacted seedling growth. Both SG and SN_SG produced as many usable plants as Conv; however, seedling height and diameter tended to be lower in SG compared to the other two treatments. No usable transplants were produced when SN was the sole fertility source, likely because of lack of nutrients other than N. Furthermore, many of the organic fertility products require biological activity to mineralize organic N to a plant-available form. This activity can have potentially detrimental outcomes on float system solution pH, dissolved oxygen, and bicarbonate levels.

  PublisherOA PDFDOI

• Implications of chloride application rate and nitrogen fertilizer source to flue‐cured tobacco

  Agronomy Journal · 2020 · 10 citations

  • Chemistry
  • Animal science
  • Agronomy

  Abstract Chloride assimilation by flue‐cured tobacco ( Nicotiana tabacum L.) can negatively impact leaf development and quality when tissue concentration exceeds 1%. The influences of Cl − application rate and N fertilizer sources have not been fully described in field research utilizing reduced‐cost or custom‐blend fertility programs that are common in modern times. Research was conducted to test the interaction of four Cl − application rates (0, 34, 67, and 101 kg ha −1 ) and four N fertilizer sources {calcium nitrate, Ca(NO 3 ) 2 ; ammonium nitrate, NH 4 NO 3 ; liquid urea‐ammonium nitrate [UAN], and ammonium sulfate, (NH 4 ) 2 SO 4 } on the growth and development of flue‐cured tobacco. The impact of N source was minimal in green leaf tissue; however, (NH 4 ) 2 SO 4 reduced cured leaf quality relative to other N sources. Two weeks after fertilizer application, Cl − rates ≥34 kg ha −1 reduced foliar total N and NO 3 − measurements by 0.12−0.42% and 789−1348 mg kg −1 , respectively. Leaf NO 3 − concentration was also reduced by Cl − application at the layby growth stage, while P, K, and Mg increased following Cl − application in late‐season measurements. After curing, total N and alkaloids were reduced by an average of 0.17 and 0.23%, respectively, while reducing sugars were increased by 1.67% where Cl − was applied. Chloride concentration exceeded 1% in application rates ≥34 kg ha −1 in early‐season and post‐curing measurements, although toxicity symptoms were not observed nor were yield, quality, or value affected. Farmers should adhere to the current recommendation of ≤34 kg Cl − ha −1 to ensure that cigarette manufacturers receive tobacco that is usable in products.

  PublisherOA PDFDOI

• Evaluation of dicamba retention in spray tanks and its impact on flue-cured tobacco

  Weed Technology · 2020 · 6 citations

  • Toxicology
  • Chemistry
  • Animal science

  Abstract In recent years, there has been increased use of dicamba due to the introduction of dicamba-resistant cotton and soybean in the United States. Therefore, there is a potential increase in off-target movement of dicamba and injury to sensitive crops. Flue-cured tobacco is extremely sensitive to auxin herbicides, particularly dicamba. In addition to yield loss, residue from drift or equipment contamination can have severe repercussions for the marketability of the crop. Studies were conducted in 2016, 2017, and 2018 in North Carolina to evaluate spray-tank cleanout efficiency of dicamba using various cleaning procedures. No difference in dicamba recovery was observed regardless of dicamba formulation and cleaning agent. Dicamba residue decreased with the number of rinses. There was no difference in dicamba residue recovered from the third rinse compared with residue from the tank after being refilled for subsequent tank use. Recovery ranged from 2% to 19% of the original concentration rate among the three rinses. Field studies were also conducted in 2018 to evaluate flue-cured tobacco response to reduced rates of dicamba ranging, from 1/5 to 1/10,000 of a labeled rate. Injury and yield reductions varied by environment and application timing. When exposed to 1/500 of a labeled rate at 7 and 11 wk after transplanting, tobacco injury ranged from 39% to 53% and 10% to 16% 24 days after application, respectively. The maximum yield reduction was 62%, with a 55% reduction in value when exposed to 112 g ha −1 of dicamba. Correlations showed significant relationships between crop injury assessment and yield and value reductions, with Pearson values ranging from 0.24 to 0.63. These data can provide guidance to growers and stakeholders and emphasize the need for diligent stewardship when using dicamba technology.

  PublisherDOI

Frequent coauthors

• David L. Jordan

  31 shared

• Matthew C. Vann

  North Carolina State University

  26 shared

• William D. Smith

  Carleton University

  23 shared

• Randy Wells

  North Carolina State University

  15 shared

• John W. Wilcut

  9 shared

• Keith L. Edmisten

  North Carolina State University

  8 shared

• Alexander M. Stewart

  St. Lawrence University

  5 shared

• Peter M. Eure

  University of Georgia

  5 shared