An increasing demand for organic crops in the US represents a considerable opportunity for organic, as well as conventional growers interested in exploring the transition to organic production. Renewed interest in organic farming has resulted in a need for research involving organic fertilizers. Limited research has been conducted on organic vegetable production with previous research conducted primarily outside the Deep South US. Field studies were conducted at the Louisiana State University (LSU) AgCenter Burden Center to investigate the effect of three levels of pre-plant organic NPK fertilizer (8-5-5, Nature Safe) combined with a sidedress application of organic NPK fertilizer (13-0-0, Nature Safe), compared to fish emulsion (5-2-2, Agro-K) or no fertilizer control treatments on the growth and yield of Red LaSoda potatoes. Plant height, width, leaf area, and above and below ground biomass (dry weights) were determined 3 times (once a month) and marketable yield was evaluated at harvest for the fall 2006 and spring 2007 growing seasons. Plots were harvested 3 months after planting according to USDA guidelines. There were no differences in marketable yield due to fertilizer treatment for the fall growing season, but there were differences for the spring growing season. In the spring study, the recommended rate of nitrogen (100 lbs. N/A) had adequate yields, the double rate (400 lbs. N/A) had lowest yields and the fish emulsion (66 lbs. N/A) had the highest yields. The results of the study suggest that organic potato production in Louisiana is profitable. If compared, commercial organic fertilizer is more expensive than conventional fertilizer, as are labor costs, but due to price premiums ($20/50 lb. sack of conventional fresh market potatoes and $35/50 lb. sack of organic fresh market potatoes, as of 2007), the organic production systems had potentially 2 to 3 times higher gross and net benefits when compared to a conventional production system. In this study, the use of fish emulsion as the sole fertilizer was one of the most costly but profitable production systems, as yields and gross and net benefits were highest. Fish emulsion may have a beneficial association with plant growth regulators.

Poinsettias are the number one flowering potted plant in the U.S. and it is the most popular Christmas plant sold. Miniature roses have become an increasingly important flowering potted plant. However, growers must overcome production problems to produce a quality finished plant and avoid disease incidence. Supplemental calcium has been proven to increase the amount of good quality flowers and increase disease resistance. Silicon can increase plant growth and crop quality and decrease disease pressures. Two experiments were conducted on miniature rose cultivars Sonya and Alto. The objective of experiment 1 was to determine the effects of preharvest application of calcium nitrate [Ca (NO3)2], Foli-Cal® (chelated Ca), chelate, Maniplex-Traffic® (chelated Si) or Sil-Matrix® (potassium silicate) applied as a spray or a drench on growth and development. Spray application of Foli-Cal® increased plant growth as indicated by a greater dry weight compared to all other treatment applications. Drench application of Foli-Cal® increased finished quality as indicated by greater flowering, height, width, leaf area, and dry weight. The objective of experiment 2 was to determine the efficacy of weekly spray applications of biofungicides Sil-Matrix (potassium silicate), Fosphite® (phosphoric acid), Kaligreen® (potassium bicarbonate), and Manniplex Traffic® (chelated Si) on powdery mildew on miniature roses compared to a standard fungicide Heritage® (azoxystrobin). Miniature roses treated with Kaligreen®, Heritage® alternated with Foshpite®, or Heritage® alternated with Kaligreen® were not as susceptible to powdery mildew. For the second study of powdery mildew, Kaligreen® gave the best control of powdery mildew for cultivar Sonja but treatments for Alto showed no significance.

Sweetpotato [Ipomoea batatas (L.) Lam.] is an important provider of nutrition in developing countries. High productivity in the form of starch and beta carotene richness underlies its potential. A sweetpotato with adequate levels of iron and zinc would greatly aid efforts to reduce dietary deficiencies of iron and zinc. The objective of this work is to document the physiological accumulation of iron and zinc in sweetpotato during development and the mechanisms responsible for iron uptake. Six varieties (IPS 163, Beauregard,Koto-puki, Pung-mi, Duanyanghon, and Xushu 18) were compared to understand iron and zinc accumulation during development. Results showed that micronutrient content in developing roots varied minimally during storage root development (13-16 weeks after planting). Varieties tend to accumulate these micronutrients similarly throughout development. These results suggest that varieties can be assayed for iron and zinc concentration anytime roots are of sufficient size for analysis. Hydroponic studies were conducted to determine how high and low iron concentration genotypes respond to the absence of iron in nutrient solution. Variables included iron reductase, pH, and root mass development. Results from the nutrient solution study showed that the pH of nutrient solution increased. A low pH environment facilitates the transition from an unavailable form of Fe (III) to an available form Fe (II). Sweetpotato may respond differentially than other species. Iron reductase activity differed among varieties. High iron accumulating Pata de Oso showed reduced iron reductase activity in plants grown in an iron deficient environment. In contrast, Pung-mi, a low iron accumulating variety, significantly increased iron reductase activity when grown in an iron deficient environment. These results suggest that high iron accumulating varieties did not increase iron reductase activity. Varieties poor in iron accumulation either did not vary or seemed to increase iron reductase activity in an iron deficient environment. A greater root mass is also a means by which plants can uptake greater amounts of iron. High iron concentration varieties had the lowest root mass in comparison to low concentration varieties. When Fe-sufficient and Fe-deficient treatments were compared, only Pung-mi showed a significantly smaller root mass when grown in an Fe-deficient environment.

Hot pepper and hot sauce production and consumption in the United States are on the rise. The demands of consumers need to be met by high-quality products in an increasingly competitive market. Increasingly knowledgeable and discerning consumers notice any problems in hot sauce, and problems with appearance are often the first noticed. A well-known and successful hot sauce company has found an occasional problem with discoloration in their flagship product. Small dark specks have been found in the sauce, and the company in question is interested in elucidating their makeup and cause. This is of especially pertinent scientific interest because the specks themselves may be products of lipid oxidation, a constant concern in any food products containing lipids of any kind. In hot sauce in particular, one of its most important components is capsaicin, a lipid-like molecule that imparts its characteristic pungency. Capsaicin is also an antioxidant, and peppers and hot sauce are also high in carotenoids, another antioxidant. Antioxidants are becoming increasingly interesting to the public and to scientists because of their purported health benefits. In this study, centrifugation was used in an attempt to separate out the specks in the hot sauce, and to compare it to oils found in normal hot sauce. Samples were taken to perform microbiological tests to see if the specks were microbiological colonies. It was shown that they were not. Light microscopy and scanning electron microscopy were used to view samples and to compare them to known pepper parts visually. They were found to resemble microscopic pieces of pepper skin. Finally, pepper mash was made by grinding pepper samples with varying amounts of salt and, in some treatments, adding oxygen. The peppers were grown in two different locations and all samples were made in duplicate. This was an attempt to re-create a black oil that is sometimes found on the top of barrels of mash in commercial production and which may be the cause of the specks in question. A single sample was found to produce the dark oil, although its appearance was apparently random with regard to treatment.

Ozone (O3), one of the most powerful oxidants known, is phytotoxic at high levels in the troposphere, or ground-level. Effects of acute ozone exposure for two consecutive days was examined on Bermudagrass (Cynodon dactylon), centipedegrass (Eremochloa ophiuroides), zoysiagrass (Zoysia japonica), St. Augustinegrass (Stenotaphrum secundatum), Liriope muscari Big Blue, Liriope muscari Aztec, and Ophiopogon japonicus. Zoysiagrass, St. Augustinegrass, Liriope muscari Big Blue were used in the second study based on the differential responses found in the study. Ozone induced severe visual damage to St. Augustinegrass with symptoms appearing as chlorotic streaks. St. Augustinegrass and Liriope muscari had a significant reduction in the maximum quantum yield of PSII electron transport as measured by Fv:Fm ratio, which would indicate no correlation between the visual injury and Fv:Fm. Zoysiagrass and centipedegrass proved to be tolerant to ozone. The objectives of the second study were to evaluate: 1) response to ozone due to cutting; 2) the use of the SPAD-502 chlorophyll meter as an objective measure of ozone-induced injury; 3) xanthophyll cycle involvement in dissipating light energy due to increased oxidative stress; 4) the relationship of chlorophyll fluorescence coefficients, chlorophyll content, and xanthophyll cycle in the regulation and protection of photosynthesis. Cutting had no significance on any of the parameters in this study. Centipedegrass with significantly more â-carotene and a quicker engagement of the xanthophylls cycle than the other species in this study was tolerant to increased ozone. This suggests that closing the stomata to exclude ozone is important but does not repair or detoxify the ozone and/or reactive oxygen species that have already entered the leaf. Visual injury differences in the ozone sensitive St. Augustinegrass may be due to the large thin leaves. Liriope with thick fibrous leaves is sensitive to increased ozone but lacked visual injury.

Torpedograss (Panicum repens L. Beauv.) is a common weed problem along the Gulf Coast in highly managed turf. Non-selective herbicides are currently used to control torpedograss within centipedegrass [Eremochloa ophiuroides (Munro) Hack.] and St. Augustinegrass [Stenotaphrum secundatam (Walt.) Kuntze], but turfgrass injury can be extensive. Research was conducted to evaluate torpedograss and centipedegrass response to the application of the selective, post-emergence herbicides quinclorac, sethoxydim, and clethodim. Quinclorac applied at 0.42 kg ai ha-1 three times 4 wks apart reduced torpedograss to 25% coverage (55% of control) 10 weeks after initial treatment (WAIT), but re-establishment was rapid and by 16 WAIT coverage was greater than that of the control. Centipedegrass injury to quinclorac was 46% 6 WAIT. Sethoxydim or clethodim applied at rates of 0.32 kg ha-1 or 0.30 kg ha-1, three times at 4 wk intervals reduced torpedograss coverage 79% and 84% from control 10 WAIT. Centipedegrass injury at 10 WAIT was 4% for sethoxydim and 13% for clethodim. Torpedograss treated with sethoxydim and clethodim was able to re-establish, and by 16 WAIT, groundcover was 25% and 26% compared to 59% for the control. Effects of N fertility and mowing height to reduce torpedograss infestation in centipedegrass and St. Augustinegrass were also examined. Nitrogen and mowing treatments were categorized as low, recommended and high according to each turfgrass species. For St. Augustinegrass, N fertility regimen were 0 kg N ha-1 month-1, 50 kg N ha-1 month-1, and 100 kg N ha-1 month-1and mowing heights were 2.54 cm, 6.35 cm, and 10.16 cm. Centipedegrass N fertility regimen were and 0 kg N ha-1 month-1, 12.5 kg N ha-1 month-1, or 25 kg N ha-1 month-1 with mowing heights of 2.54 cm, 5.08 cm, or 7.62 cm. Torpedograss spread increased in both turfgrasses under all N and mowing regimen. The highest mowing height accelerated torpedograss spread. Control of torpedograss in St. Augustinegrass and centipedegrass using cultural management practices proved unsuccessful. Some success in controlling torpedograss was attained with use of sethoxydim and clethodim in centipedegrass. Prevention by use of un-infested soils and application of non-selective herbicides during turfgrass establishment should be employed.

Chemical manufactures are often associated with a negative publicity due to chemical spills that can cause human health problems and environmental pollution. Innovative methods such as phytoremediation in lieu of traditional remediation methods are being researched to determine environmentally friendly options for remediation. Phytoremediation was studied as an alternative remediation method for removal of chemicals in a contaminated groundwater plume in Louisiana. The main constituents of concern in the plume were cumene and 4-cumylphenol. Two pilot phytotoxicity studies were funded to determine an optimum tree species for removal and control of the constituents of concern. A greenhouse and hydroponic system were constructed to test Taxodium distichum, Salix nigra, Juniperus virginiana, Pinus glabra, Populus deltoids, and Quercus nigra for their phytoremediation capabilities. Both phytotoxicity pilot studies covered a nine month growing period. Trees in the first study were subjected to six water treatments from three of the contaminated groundwater plume monitoring wells. Treatments included undiluted well water containing the constituents of concern; well water containing high salinity levels (above 2.0mS); and several dilutions of each. Three water treatments were tested in the second pilot study, high, low, and deionized water. The high and low water treatments were based on historically recorded high levels of contamination in the plume water. Trees were evaluated monthly for possible health affects of the constituents of concern. Monthly height, trunk diameter, and foliage visual ratings were taken. Initial and final tissue (root and shoot) and soil samples were collected and analyzed for the potential presence and concentrations of the constituents of concern in the tissue and potting media. Monthly water input and discharge samples were collected and analyzed for the constituents of concern. Results from the pilot studies indicated that both the Salix nigra and Taxodium distichum species were acceptable phytoremediation choices. However, Taxodium distichum was selected for the full scale planting over the groundwater plume because it was tolerant of the contaminated water treatments and salinity levels present in the groundwater. Additionally, Taxodium distichum was a low maintenance tree with a conical form that complied with security restrictions at the chemical facility.

High temperature and drought stress are two of the greatest impediments to bedding plant growth and development. The objective of this study was to develop a rapid and effective protocol for screening Petunia x hybrida for basal heat or drought tolerance. A practical growth system for measuring seedling growth, or seedling growth sensitivity test (SGST), was first established. Based on this protocol, radicle growth rate was chosen over hypocotyl growth as the most reliable and accurate measurement for the SGST. Nineteen petunia cultivars from three plant classes (floribunda, grandiflora, or spreading) were previously evaluated, where cultivars within the same plant class and series were grouped as either best or worst for overall landscape performance, and then subjected to the SGST. Seeds were germinated in Petri dishes at 26°C for 4 days and then subjected to 5-h heat shock at a temperature of 40°C or 6 d drought stress at an osmotic potential of -0.8MPa achieved with PEG 6000 to determine heat or drought tolerance, respectively. The results indicated heat or drought stress significantly affected the relative radicle growth rate of seedlings. However, the imposed stress did not affect all cultivars similarly. While Avalanche Lilac and Dreams Burgundy Picotee had the greatest radicle growth rate, they were considered as more heat susceptible cultivars due to a significant reduction in radicle growth rate under heat stress. Avalanche Lilac was also regarded as the most drought sensitive cultivar. The results from this study indicate that the SGST may be used to determine heat or drought tolerance, but further research should be conducted to determine greenhouse and landscape performance under heat or drought stress.

Heat stress is one of the greatest challenges affecting growth and development of bedding plants during greenhouse production and in the landscape. Inducing an acquired stress tolerance during production may greatly improve postproduction marketability and survival in the landscape when exposed to heat stress. Few researches have investigated the morphological effects of bedding plants during heat shock or enduring heat stress preconditioning in the greenhouse and subsequent landscape performance. The present objectives were to quantify morphological and physiological responses to heat stress and use this information to develop a greenhouse protocol for inducing acquired thermotolerance for improved landscape survivability using Petunia x hybrida. Preliminary studies revealed petunia Dreams Midnight grown at 35/25 or 40/30ºC caused desirable traits such as compact growth for improved landscape performance but also decreased flowering during production resulting in poor marketable quality. Heat shock at 35 or 40ºC for 2 h every 7 d did not significantly effect petunia growth and development. Determination of optimum heat shock temperature and duration for development of acquired thermotolerance revealed that heat shock every 3 d or enduring heat stress was most effective at 45ºC. However, the critical duration or frequency of exposure necessary for promotion of a heat tolerant marketable plant at 45ºC was not fully elucidated within the treatments investigated. Chlorophyll fluorescence (maximum quantum efficiency of PSII - Fv/Fm) was measured in young and mature leaves to investigate stress response and photosynthetic performance of petunia pre and post acquired thermotolerance test. Fv/Fm ratios indicated the heat shock or enduring heat stress treatments did not cause permanent damage to photosynthetic apparatus. Nineteen previously evaluated petunia cultivars from three plant classes were heat shocked at 45ºC for 4 h every 3 d during greenhouse production followed by landscape evaluation. Greenhouse and field results indicated the heat shock treatment did not significantly promote heat tolerance compared to control. The critical temperatures used in this study were effective for promoting heat tolerance in petunia, but specific durations or frequency of exposure at 45ºC should be further investigated in order to define an effective acquired thermotolerance protocol to improve landscape survivability.

Fertilizer applications to newly constructed levee embankments during soft armor establishment may pose an increased threat to water quality. Potential nutrient and sediment loading can impact human and aquatic organisms that rely on water resources. The objectives of this study were to 1) determine the effect of grass coverage on surface runoff 2) evaluate bermudagrass establishment between water-soluble and insoluble N sources and 3) quantify nutrient and sediment losses from surface runoff during grass establishment. In 2008, fertilizer treatments consisted of sulfur-coated urea (SCU) or urea applied at 50 kg ha-1 to runoff collection trays installed on a 30% sloped levee embankments planted with common bermudagrass (Cynodon dactylon L.). Simulated rainfall was applied at 96 mm h-1 14, 28, 42, 56 and 70 days after seeding (DAS). In 2009, ammonium nitrate (NH4-NO3) and urea-formaldehyde (UF) were applied at 100 kg ha-1. Simulated rainfall was applied for 30 minutes after the onset of continuous runoff every 14 days during bermudagrass establishment. Runoff collected from storm and simulated precipitation events was analyzed for volume, NO3-N, NH4-N, total dissolved phosphorus (TDP), and total phosphorus (TP). Other measurements included time until runoff, sediment loss, percent vegetative groundcover, and soil volumetric water content. Nitrogen applications accelerated bermudagrass growth compared to unfertilized controls for both years of the study. In 2008 and 2009, nutrient losses from initial precipitation events were 40% to 87% greater from fertilized bermudagrass than unfertilized controls. Sediment, volume, time until runoff, and nutrient losses declined as bermudagrass coverage increased, but fertilized bermudagrass did not decrease total sediment losses and runoff volumes compared to unfertilized controls for either year. In 2008, total N losses were similar between fertilizer sources (SCU and Urea) with the greatest losses of 5 mg L-1 during initial rainfall events following application. In 2009, total N losses from unfertilized grass and UF-fertilized grass were 0.49 kg ha-1 while losses from NH4-NO3 fertilized grass were 1.73 kg ha-1. Water-soluble N sources and SCU resulted in the highest N losses. Application of the slow-release N fertilizer, UF, accelerated bermudagrass establishment and limited N losses.