bluuebunny/crossref_metadata_2025 huggingface dataset:
122 Minimizing Fertilizer Input for Nitrate Management and Optimum Growth of Ilex verticillata L.
Authors: Schultz T.L. , Schuch U.K.
Published: February 2019

Nitrate nitrogen is becoming a major pollutant in much of our nation's water supply. High levels of nitrate runoff are commonly found to occur from intense agricultural areas such as container nurseries. The objective of this study was to investigate combinations of liquid fertilizer (LF) plus controlled-release fertilizer (CRF) that would both minimize nitrate runoff and provide nutrient levels for optimum growth of Ilex verticillata L. The experiment was established in 1998 at the Iowa State Univ. Horticulture Research Station, Ames. Six fertilizer treatments were arranged in a randomized block design with eight replications. Treatment combinations of liquid fertilizer (LF) and controlled-release fertilizer (CRF) were [LF (mg/L)/CRF (g)]: 90/0, 90/8.5, 90/17, 180/0, 180/8.5, 180/17 (Peter's Excel 21-5-20 and Osmocote 18-6-12, 9-month release, respectively). Analysis of nitrate leaching showed that in 12 out of 16 weeks, the 180 mg/L LF treatments resulted in twice the amount of nitrate leached compared to the 90 mg/L LF. In 3 out of 16 weeks, treatments containing 0 g CRF leached significantly less nitrate than those containing 17 g CRF. None of the treatments produced a difference in total dry weight or caliper of Ilex verticlillata L. This data suggests that plant growth remains similar over a range of fertilizer input and higher rates of applied LF result in higher nitrate leaching.
129 High Nitrate Fertilizers Control Shoot Growth through Low Phosphate Stress
Authors: Song Cheon-Young , Huang Jin-Sheng , Nelson Paul V.
Published: February 2019

The greenhouse industry successfully uses high NO3 fertilizers to produce plants with short, compact shoots. It is commonly assumed that NO3 results in compactness while NH4 or urea stimulate large shoot growth. However, high NO3 fertilizers contain little or no phosphate. Four sets of treatments were applied to five species of bedding plant plug seedlings in two experiments to differentiate the effects of N source vs. phosphate supply on growth. Seedlings were established on 20-4.4--16.6 fertilizer until 10 days into stage 3, when the following treatments began. Set 1: phosphate-P was held at 22 mg/L and total N at 100 mg/L with NH4 comprising 40%, 13%, 7%, or 0% of total N, the remaining being NO3. Differences in shoot size did not occur as a consequence of the shift in NH4:NO3 ratio. Set 2: N was supplied at a concentration of 100 mg/L from 40% NH4 plus 60% NO3 while PO4-P was varied over the series of concentrations of 21.9, 6.6, 3.3, and 0 mg/L. Set 3: the same as Set 2 except that N was supplied entirely as NO3. Height and weight of shoots in Sets 2 and 3 were positively related to PO4 supply. Set 4: three commercial fertilizers containing 0 PO4-P and 8, 13, or 20% of N in the NH4 form. Compact shoots developed in these treatments. When 22 mg phosphate-P/L was added to one of these fertilizers, compactness was reversed. Shoot suppression by high NO3 fertilizers was concluded to be a function of low phosphate and not N form.
131 Effect of Blended Composts and N Rates on Growth Performance of Potted Poinsettia
Authors: Ku Catherine S.M. , Bouwkamp John C.
Published: February 2019

Growth performance of potted `Peterstar Pink', `Top White', `Red Sails', and `Red Success' were evaluated in eight substrates and three fertilization rates. The substrates included Sunshine Mix 1 and Pro Gro 300S as control, and compost blends at 33%, 50%, and 67% of final substrate volumes mixed with peat and perlite (1:1). The blends included 2:1, 1:1, or 1:2 ratio of polymer dewatered biosolids (PDB):poultry litter (PL) and PDB: yard wastes (YW). Fertilization was applied twice weekly at 75, 100, and 150 mg/L N from 19N--2.2P-16.6K. Plants grown in Sunshine Mix 1 performed better than those grown in Pro Gro 300S. The growth parameters measured improved as the N rates increased for both controls. Plant diameter, grade, and dry weight of plants grown in 150 mg/L N treatment were usually similar to those in 100 mg/L N and were not 11% more than those at the lowest N treatment. The 1 PDB: 1 PL blend at the high N treatment produced premium-quality plants, and all remaining PDB:PL treatments produced good quality plants. The PDB:YW blends that received 100 and 150 mg/L N produced premium quality plants. The PDB:YW blends at the low N treatment produced slightly better quality plants than those grown in PDB:PL at the 75 mg/L N and were similar in quality as those grown in Sunshine Mix 1 at the 150 mg/L N treatment.
133 Agronomic and Economic Evaluation of Seven Organic Nitrogen Fertilizers Applied to Bell Peppers
Authors: Gaskell Mark
Published: February 2019

Organic vegetable production acreage is expanding in California, but little research-based information is available to guide growers. Several new organic fertilizer materials are available but little data exists on efficient use of these materials. During 1998, the following materials: compost (C), pelleted chicken manure (PCM), fish meal (FM), liquid fish (LF), liquid soybean meal (LSM), feather meal (FTM), and seabird guano (SG) were evaluated. Each material was applied at treatment rates of 0, 60, 120, and 180 kg nitrogen (N)/ha to transplanted, sprinkler irrigated bell peppers. The materials were applied as 30N pre-transplant (PRE) and 30N at 20 days post-transplant (POST) for the 60N treatment; 60N PRE and 30N at 20 days POST and 30N at 40 days POST for the 120N treatment; and 60N PRE, 30N at 20 days POST, 45N at 40 days POST, and 45N at 70 days POST for the 180N treatment. Weekly soil nitrate nitrogen (SSN) over 16 weeks POST and fresh pepper yield was determined for all treatments. Weekly SSN varied from lows of 4 mg·kg-1 in 0N-treated plots to over 80 mg·kg-1 in FTM 180N-treated plots. Highest SSN was observed in FTM-, SG-, LSM-, LF-, and FM-treated plots at 180N and peaks in SSN lagged fertilizer application 3 to 4 weeks. Total pepper yield was not as markedly affected as early yield and size. Highest early yield and largest sizes were observed in FTM 180N-treated plots. Compost treated plots at 180N produced highest economic return per fertilizer dollar.
136 Limitations to the Use of Poultry Litter as a Fertilizer for Vegetables
Authors: Roberts Warren , Duthie Jim , Edelson Jonathan , Shrefler Jim
Published: February 2019

Poultry litter is readily available in eastern Oklahoma. Poultry litter contains most of the essential elements for plant growth, and has long been used as a fertilizer for various crops. The ratio of N-P-K is about 1-1-1. In some areas, litter has been used excessively, and buildups of certain nutrients have occurred. There are concerns that a buildup of phosphorus (P) will lead to excessive amounts of P in water systems, which will affect water quality. There are also concerns that nitrogen (N) will leach or run off into water systems and also lower the water quality. Oklahoma has enacted legislation that will control how much litter can be applied to a given field, and regulations are being set in place to monitor and control the applications of litter. Studies have been conducted at the Lane Agricultural Center in southeastern Oklahoma over the past 6 years to determine vegetable production and soil nutrient changes when different litter application strategies are followed. In general, poultry litter has produced yields of cucumbers, collards, and corn that are equal to or greater than yields of the same crops fertilized with conventional synthetic fertilizers. Buildups of certain nutrients, particularly P, are occurring. At this time, the buildups are considered beneficial. The highest rate of litter application has resulted in levels of soil P that are about half the maximum amount allowed under present legislation.
146 The Master Gardener Program in Wisconsin
Authors: Harrison Helen C.
Published: February 2019

The Master Gardener Program in the state of Wisconsin is growing rapidly and has been in existence since the late 1970s. There are several aspects of our program(s) that make us unique. First, we are one of the very few states to service all counties within the state, not just our heavily metropolitan areas. Second, we have two major program types along with some unique county programming. We have the basic Master Gardener Program, which covers the major aspects of horticulture—this gives the learner 36 h of training with an expectation of 36 h of volunteer work in return. We now offer the general program in districts (extension has six clusters of counties in Wisconsin)—such that the counties within a district (usually around 16) will have the chance to offer the course at least once every 3 years. That is because the general course is offered once a week (3 h in the evening) for 12 weeks; and thus the basic course is offer spring and fall. If some of the counties within a particular district do not choose to participate, then other counties around the state can take part. Most of the 12 programs are high quality 2-h video productions followed by a 1-h ETN program, which is like a big conference call—everyone has an interactive session with the specialist who developed the video. The specialized program is a series of four 36-h (six 6-h days) training over a 4-year period, which covers flowers, fruit, vegetables, and turf, along with trees and shrubs. This program is offered in our four largest metropolitan areas and is still done all by live lecture. Finally, we require update training for our MGs if they want to continue to be members in good standing (wallet-size cards are issued). This involves 10 h of specified educational opportunities and 10 volunteer hours per year. We also have a day-long educational conference each spring as well as cooperating with Iowa and Minnesota to offer a 2-1/2 day workshop on the alternating years of the international conference. This is hands-on training, held usually the end of June, and rotates among the three states. We now have a stong MG association which has nonprofit status and is an integral partner with us here at the university. Not only do MGs receive members in good standing cards annually, they also receive certificates for 150, 250, 500, 750, and 1000 h of service as well as a 10-year certificate.
157 Estimation of Environmental Impact of Two Cropping Systems Using PLANETOR
Authors: Kalo A. , Hoepner P.H. , Sterrett S.B. , Diem J.F.
Published: February 2019

Long-term goals of reducing environmental impacts associated with agricultural activities must include economic sustainability as well as production feasibility. This study compared the potential economic and environmental impact of two specific cropping systems [wheat/soybeans (w/s) vs. selected vegetable crops with wheat/soybeans (veg/w/s)]. Profitability of w/s was lower than the veg/w/s system but demanded a smaller, less extensive resource base of labor and machinery with fewer conflicts in resource utilization rates. The PLANETOR computer program (Univ. of Minnesota) was used to analyze the potential negative environmental effects of growing a particular crop mix within these two systems. Although some of the vegetable crops exceeded the targeted soil loss tolerance value (T-value) of 3 t/ha, the weighted average of the veg/w/s system was below the target T-value for soil erosion. Analyses suggest that the profits from vegetables in the veg/w/s production more than offset the negative impacts on soil erosion and the veg/w/s system would be more economically feasible than w/s. Potential impact of pesticide leaching and runoff from vegetable production as calculated by PLANETOR was less than that from w/s. Specific cultural practices, including soil/tissue testing to manage nutrient applications, could reduce nitrogen/phosphorus movement. The veg/w/s system may offer the necessary profit margins to allow adoption of more environmentally friendly production alternative.
167 Promoting the Value of Community Service by Involving Students in Landscape Improvement Projects
Authors: McGann Martin R. , Stearns Dan T. , Kuhns Larry J.
Published: February 2019

In discussions among industry representatives, faculty, and graduates of the department of horticulture at Penn State community service was identified as an important attribute of successful landscape contracting companies. To foster a sense of community service responsibility among students, service projects were integrated into three horticulture courses. Fifty-four students in a planting design course worked with township officials to develop a planting plan for a new park located 10 miles from campus. Students planted 120 trees, which were obtained from a nursery operated by the Pennsylvania Dept. of Corrections. Eighty-eight students in two classes, landscape planning and issues in landscape contracting, volunteered to work on a farm being developed as an environmental education center. Work included mechanical and chemical control of invasive species and planting of natives. In discussions following these projects, students expressed personal satisfaction and a willingness to participate in future community service projects.
179 Control of Clubroot on Chinese Mustard and Cauliflower using Meadowfoam (Limnanthes alba) Seedmeal or Screenings
Authors: Deuel Wes , Svenson Sven
Published: February 2019

Seedmeal (MSM) and screenings (MS) of meadowfoam (Limnanthes alba H.) were evaluated for their influence on the development of clubroot caused by Plasmodiophora brassicae in potted seedlings. Treatments included MSM at 0%, 5%, 10%, and 20% (by vol.); MSM at 10% (by vol.) plus an 8 oz. application of 3% H2O2 per pot; and MS at 10% (by vol.) pre-sowing incorporation into potting media (Sunshine Mix #1) with a 10% (by vol.) clay-loam soil known to be infested with P. brassicae resting spores. One-hundred percent Sunshine mix #1 was used as a control medium. Following media preparation, seeds of Chinese mustard (Brassica chinensis) and cauliflower (Brassica oleracea var. botrytis `Snowball Y Improved') were sown every 7 days for 4 weeks. Symptoms of P. brassicae infection (clubbing or rotting of roots) occurred in 70% to 90% of all plants grown in pots with media containing infested soil and no MSM or MS, with disease severity ranging from <25% to >50% of root systems clubbed or rotted. Chinese mustard seedlings had more clubbing compared to cauliflower seedlings. All plants grown in media containing MSM or MS showed no clubbing or rotting. Plants grown in 20% MSM or 10% MSM plus a 3% H2O2 had symptoms of phytotoxicity. Plants grown in 10% MSM or 10% MS were taller compared to controls. Although plants grown in MSM and MS showed no clubroot symptoms, asymptotic presence of pathogen has not been excluded.
190 Growing Highbush Blueberry in Coal Ash-Compost Mixtures
Authors: Zimmerman Richard H.
Published: February 2019

Highbush blueberry is adapted to well-drained sandy soils containing some organic matter, but these are often unavailable in many areas where blueberry production is desired. I tested the concept of using freely available by-products to produce an artificial medium for growing blueberries. In June 1997, 1-year-old tissue-cultured plants of `Bluecrop' and `Sierra' blueberry were planted into 15-L plastic pots filled with soil or soilless medium in a total of 10 treatments. Soils used were Berryland sand (alone) and Manor clay loam (alone or amended with 25% or 50% compost mix 1); soilless media were composed of coal ash amended with 25% municipal biosolid compost (B), 25% leaf compost (L), 25% or 50% compost mix 1 (1 B: 1 L),\ or 25% or 50% compost mix 2 (1 compost mix 1: 1 acid peatmoss). pH of all mixes containing compost was adjusted to ≈4.5 with sulfur. After the first year, plants of both cultivars in Berryland sand had significantly more shoot growth than in any other treatment except for Manor clay loam. The least growth was produced by plants growing in Manor clay loam amended with compost mix 1 and in coal ash amended with unblended compost (B or L). After the second year, plants in the best treatments were 90 to 100 cm tall. More shoot growth was produced by plants in Berryland sand and in coal ash amended with 25% or 50% of compost mix 1, followed by plants in coal ash amended with 50% compost mix 2 or 25% compost B; plants in Manor clay loam, whether or not amended with compost, had the least growth. In 1998, 95% of the plants flowered and most set fruit, but differences among treatments were not significant. `Sierra' plants produced more growth than those of `Bluecrop' in all treatments.
197 Rate of Flower Formation in Primula malacoides Varied with Photoperiod and Temperature Conditions
Authors: Karlsson Meriam , Werner Jeffrey
Published: February 2019

Primula malacoides (`Prima Red') was grown at 16 or 20 °C and 8- or 16-hr daylength. Irradiance was adjusted to 10 mol/m2 per day. Germination took place at 16 °C and seedlings were transplanted 28 d from seeding into 10-cm (800 mL) containers. Growing conditions until treatment 58 d from seeding were 16 °C and long days. Flower buds first appeared 80 d from seeding at 16 °C and after 100 d at 20 °C independent of daylength. Less time was required for the development of flower buds at 16-compared to 8-h daylength. Fastest flowering (110 days) was observed at 16 °C and long days. Short days at 16 °C delayed flowering 5 to 6 days. At 20 °C, open flowers were recorded 120 d from seeding with long days and 138 days with short days. In addition, groups of 10 plants within each temperature were moved weekly from one day length to the other and allowed to flower. The rate of flowering gradually increased with increasing exposure to long days while increasing durations of short days delayed flowering.
198 Daylength and Temperature Affect Rate of Flowering in Primula obconica
Authors: Karlsson Meriam , Werner Jeffrey
Published: February 2019

Primula obconica (`Libre Light Salmon') was grown from transplant at 16 or 20 °C in combination with 8- or 16-h daylength. Irradiance was adjusted to 10 mol/'m2 per day. Germination took place at 20 °C and seedlings were transplanted into 10-cm (800-mL) containers. Growing conditions until treatment 58 days from seeding were 20 °C and 16-h daylength. Rate of flower bud formation was independent of photoperiod at 16 °C requiring 88-93 days from seeding. A similar rate was observed at 20 °C and 16-h daylength. However, short days (SD) delayed flower bud appearance with 10-15 d at 20 °C. Open flowers were first recorded 110 days from seeding at 20 °C and long days (LD). At 16 °C, 12 more days were required for flower development at LD and 22 days at SD. Open flowers did not develop by termination 145 days from seeding at SD and 20 °C. Treatments within each temperature were included where plants were moved weekly to the alternate photoperiod and allowed to flower. There was no significant difference in flower bud appearance among plants exposed to 16 °C or LD at 20 °C. Flower bud formation progressively slowed at increasing duration beyond 4 weeks of SD and 20 °C. Any duration of LD at 20 °C resulted in similar flowering time while more than 1 week at SD slowed or prevented flower appearance. At 16 °C, more than 6 weeks of exposure to SD delayed, while LD hastened flowering.
200 Photoperiod Influences Growth and Flowering of Seven Tropical Perennial Species
Authors: Schoellhorn Richard K. , Compton A.J.
Published: February 2019

Floricultural crops without the benefits of extensive breeding or selection often pose problems for commercial cutting and finished plant producers. The objective of this work was to determine the effects, if any, of daylength control on the growth and flowering of the following genera; Barleria cristata, Angelonia angustifolia `Pandiana', Stachytarpheta mutabilis var. violacea, Streptosolen jamesonii, Mandevilla sanderi, Dichorisandra thyrsiflora, and Pseuderanthemum laxiflorum. Daylength of 8, 10, 12, or 14 h was imposed for 20 weeks, with cuttings harvested from plants every 4 weeks. At 20 weeks, plants were evaluated for degree of flowering and plant size. Photoperiod had a significant interaction with genera grown. Compared to plants grown under 14-h daylength; flowering and growth were reduced in Stachytarpheta and Angelonia at 8- and 10-h daylength. Flowering was increased, but overall growth reduced in Pseuderanthemum, Mandevilla, Barleria, and Dichorisandra as daylength decreased. Flowering of Streptosolen was not evident under any photoperiod. Vegetative growth was greatest with 14 h daylength for all genera tested, but only increased flower number of Stachytarpheta. Production temperatures of 20 °C night and 30 °C day were maintained throughout the study, the experiment was conducted in the summer production seasons of 1997 and 1998.
203 Selection Strategies for Selecting Alternative Cut Flowers for Greenhouse Production
Authors: Crowell Andrea , Newman Steven E.
Published: February 2019

The cut-flower industry is continually searching for unique products to introduce to the floral industry. Our objective was to select potential species for trial as new greenhouse-grown alternative cut flowers. Hardy perennials from the Rock/Alpine Garden at the Denver Botanical Garden served as the selection pool. Plants in this collection were fitting due to their durability in Colorado conditions and their rugged unique beauty. Several trial cuts of potential species were taken, and the flowers were evaluated for flower size, stem length, stem strength, foliage, vase life, usefulness, and general aesthetic quality. Next, an informal survey of growers, retailers, researchers, and consumers was taken to determine which flowers had already been seen on the market and which flowers would be potentially successful in the trade. After assimilating the information, the following six species were selected for trial future greenhouse production: Anthyllis vulneraria, Dianthus giganteus, Diascia integerrima, Echium lusitanium, Heuchera sanguinea `Bressingham Hybrids', and Trollius yunnanensis.
205 Interactive Greenhouse Simulation (GHSIM) Translated from Quattro Pro to Microsoft Excel for Flexibility and Portability
Authors: Hopper Douglas A.
Published: February 2019

Improvements to computer software and advancing technology made it necessary to convert the computer greenhouse simulation model, GHSIM, to a new application for operation across a greater number of platforms. Originally, economics and internal organization compatibility led to use of spreadsheet Quattro Pro. Standard features were relative and absolute references, multiple pages for topic organization, random event generation, and graphing of calculated trends. However, Quattro Pro contained many convenient features, yet proprietory, which were not readily converted: certain formats for graphing trends, recursive formulas, cross page referencing, buttons, macros for dynamic time execution, and floating toolbars that actually changed between old and newer versions (v.5.0 vs. v.7.0). Translation from Quattro Pro v.5.0 to Microsoft Excel 97 produced tedious page by page (worksheet) conversions, loss of buttons and macros, distorted/unreadable graphs, nonexistent toolbars, and, most troubling, obscure problems with recursive execution causing Excel to crash amid nondescript error messages and a core dump. All these were eventually resolved; current efforts seek to reach other platforms, including MacIntosh and the Internet.
210 Water Uptake in Film-coated shrunken-2 Sweet Corn (Zea mays)
Authors: Wilson Tina , Geneve Robert , Rowell Brent
Published: February 2019

One possible influence film-coating may have on seeds is modifying water uptake and electrolyte leaking during imibibition. Film-coating is a seed treatment that can improve sweet corn germination, especially under cold soil conditions. Two shrunken-2 sweet corn varieties (`Even Sweeter' and `Sugar Bowl') were treated with a polymer film-coating and evaluated for water uptake patterns during imibibition. `Even Sweeter' is a low-vigor sweet corn, while `Sugar Bowl' is a high-vigor variety. Standard germination tests were performed according to AOSA rules and suggest film-coated seeds germinated at a slower rate than untreated seeds. After 4 days of imibibition, `Sugar Bowl' film-coated seeds had 5% germination, while untreated seeds had ≈20% germination. However, after 7 days, film-coated seeds had 94% germination with untreated seeds at 80% germination. Results were similar for `Even Sweeter'. Bulk electrical conductivity readings were taken over 24 h to determine the amount of electrolyte leakage during imibibition. Low-vigor `Even Sweeter' had 92% higher overall leakage than high-vigor `Sugar Bowl'. Additional conductivity readings were taken for both seed lots every 2 h for 12 h. Film-treated seeds leaked 15% less than untreated seeds for `Sugar Bowl'. However, `Even Sweeter' film-coated seeds actually leaked 17% more than the untreated seeds. In both cases, 70% of electrolyte leakage occurred within the first 12 h of imibibition. An imibibition curve was established for the two seed lots comparing untreated and film-coated seeds. During the first 6 h of water uptake, film-treated seeds weighed ≈50% more than the untreated seeds for both `Even Sweeter' and `Sugar Bowl'. Pathways for water uptake as influenced by film-coating shrunken-2 seeds will also be presented.
228 Effect of Ethylene Inhibitors on Postharvest Peach Quality
Authors: Parker Michael L. , Blankenship Sylvia M.
Published: February 2019

A problem facing the peach industry is the ability to harvest field-ripened peaches and get them to market without significant softening or damage. However, getting mature peaches into marketing channels before significant softening occurs is a challenge. Our objectives were to evaluate two growth regulators to determine the effect on fruit quality and softening at harvest and after 1, 2, or 3 weeks in cold storage and to evaluate the effect on harvest date. The two products evaluated in this study were ReTain (aminoethoxyvinylglycine (AVG)—Abbott Labs) and EthylBloc (1-methylcyclopropene (MCP)—Biotechnologies for Horticulture). ReTain is a growth regulator that inhibits ethylene production and is used in commercial apple production to delay harvest. EthylBloc is applied as a gas and attaches to ethylene receptor sites which inhibits ethylene effects. A trial with preharvest foliar applications of ReTain and postharvest gassing with EthylBloc was initiated in July 1998 on `Contender' peaches. ReTain applications were made at 3-day intervals beginning 19 days before first harvest at the rate of 50 g a.i./acre. Applications 3 days before harvest resulted in increased flesh firmness at harvest and decreased ethylene evolution, which continued for up to 3 weeks in cold storage. Fruit were also gassed with 1 μl•L-1 (1ppm) EthylBloc in the laboratory the day following harvest for 24 h. Fruit treated with ReTain and EthylBloc had twice the flesh firmness of peaches that were not treated after 1 week in storage. ReTain applied 3 days before harvest delayed maturity. Further evaluation will be conducted in 1999.
232 Determination of Cucurbitaceous Seedling Quality and Leaves Orientation for Robotic Grafting by Machine Vision
Authors: Mganilwa Z. , Nagata M. , Wang H. , Cao Q.
Published: February 2019

Based on seedling properties and stage of growth for cucurbitaceous and solanaceous vegetables, separate robots are being marketed for each. Full automatic grafting robots are used for solanaceous vegetables like tomato and egg-plant employing ordinary splice method by making a diagonal cut through the hypocotyl of both the scion and the rootstock. However, cutting one piece of cotyledon diagonally from the rootstock does grafting of cucurbitaceous vegetables like cucumber, melon, and pumpkin. This method had the advantage of easy recovery and high survival rate of seedlings. Only semi-automatic robots are marketed for this kind of plants because a fixed cotyledon orientation is required for grafting operation. Both the scion and the rootstock are loaded manually to their corresponding feeding devices. To replace the manual loading operation, this study proposed a neural network based automatic seedling loading system. The system automatically estimates the quality and determines the cotyledon orientation of seedling for guiding the loading device of the grafting robot. As a first step toward solution, we report the development of a model for seedling quality estimation and orientation detection using image processing and neural network techniques. The model has a learning ability and can judge seedlings according to the training patterns. A seedling leaves feature extraction model of 10 characteristics was proposed and a three-layer neural network was constructed. The experimental results indicate that the seedling leaves orientation was accurately detected with an average error of 3 degrees within 360 degrees of freedom and the machine vision system could properly classify seedlings into three classes (A-good, B-fair, and C-bad) according to the training pattern.
234 Holding Tomato Transplants beyond Planned Transplant Date
Authors: Maynard Elizabeth T.
Published: February 2019

In a wet spring, transplants must often be held beyond the planned transplant date. The plants become overgrown, making mechanical transplanting difficult. We compared several ways of holding `Mountain Spring' tomato (Lycopersicon esculentum L.) transplants. Transplants were 1) planted outside on planned transplant date in late May (NH), 2) held outside for 2 weeks (HOF), 3) held outside for 2 weeks and not fertilized during that period (HONF), and 4) held in the greenhouse for 2 weeks (HGF). Throughout transplant production, half of the transplants in each holding treatment were fertilized with 100 ppm N and half with 25 ppm N from 20N-4.4P-17K or 15N-2.2P-12.3K. HONF reduced plant height 1.7 to 1.5 cm compared to HOF or HGF. Plants grown with 25 ppm N were 5 to 6.4 cm shorter than plants grown with 100 ppm N and showed symptoms of nutrient deficiency. On average, holding treatments reduced marketable yield 20% to 23% and early yield 31% to 37%, compared to NH. HOF and HGF produced similar marketable yield, early yield, and fruit size. HONF decreased early yield in 1997 and decreased marketable yield in 1998, compared to HOF. The differences between holding treatments were usually greater with 100 ppm N. Plants grown at 25 ppm N produced lower marketable and early yields and larger fruit than 100 ppm N. The best method for holding transplants among those tried here is to put them outdoors and continue fertilizing as during transplant production.
243 Vegetative Growth of Malus domestica sp. Enhanced with the Use of the Mycorrhizal Fungus Glomus intraradices
Authors: Mantha S. , Desilets H. , Rioux J.-A. , Gagne S. , Parent S. , Moutoglis P.
Published: February 2019

Two experiments with Malus domestica sp. were planted in 1997 at the Laval Univ. experimental farm located south of the St. Lawrence river near Quebec City. These experiments examined the association of the mycorrhizal fungus Glomus intraradices with Malus domestica sp. The first experiment compared the vegetative growth of `McIntosh' apple trees on M.106 rootstock in presence or absence of a commercial inoculum of G. intraradices (Premier Tech, Riviere-du-Loup, Quebec) under three levels of phosphorus fertilization (P) to the soil (0%, 50%, and 100% of the usual recommandation for this crop). After two seasons, all the treatments had better growth than the control (0% P without G. intraradices). The best treatment was achieved with 100% of the P associated with mycorrhizal inoculation. The second experiment compared the vegetative growth of three apple rootstocks Bud.9, M.26, and M.106, inoculated with G. intraradices under the same three P levels as the preceding experiment. Uninoculated rootstocks receiving the usual phosphorus fertilization served as control. Two roostocks, M.26 and M.106, increased growth with G. intraradices, while the third one, Bud.9, did not respond to the presence of mycorrhizal fungus.
249 Shading Effects on Vegetative Growth and Fruiting of Coffee
Authors: Liu Guofan , Kobayashi Kent D.
Published: February 2019

A shade experiment for pruned coffee trees was conducted on Maui, Hawaii, in 1996. Nine-year-old `Guadalupe' trees were stumped at 70 cm above the ground, and three main verticals were allowed to remain on the main trunk. Each stumped tree was randomly selected and covered with shade cloth. The shade cloths were 30%, 50%, and 70% shade, and each shade structure had a length × width × height of 1.5 × 1.5 × 2.5 m. Data were collected in 1997. In general, the basal diameters of the verticals were similar in all treatments, as were the lengths of the verticals. The total number of laterals in the full-light treatment was slightly more than that of the other treatments. The numbers of flowering laterals were similar in all treatments. The numbers of fruit per tree in the full light, 30%, 50%, and 70% shade treatments were 1876, 3434, 2399, and 403, respectively. Fruit per flowering node was the best index relating to yield. Fruit per node was highest under 30% shade, followed by full light and 70% shade. At the beginning, fruit ripened faster in the full light treatment than in the other treatments, but at the end of September, fruit in 70% shade ripened slower than the other treatments. Therefore, after stumping, coffee trees grew best under 30% shade. For coffee, pruning under the field condition, stumping every other row of trees may be a satisfactory way to obtain the best yield in the future.
250 Using Leaf Area Devices (LADS) to Estimate Total Leaf Area of Coffee Plants
Authors: Liu Guofan , Kobayashi Kent D.
Published: February 2019

It is difficult to estimate the total leaf area of coffee plants with accuracy due to the large number of leaves and the high leaf density of the plant canopy. In 1996, on Maui, Hawaii, 98 leaves of various sizes were randomly collected for each of five cultivars of Coffea arabica L. The cultivars used were `Guadalupe', `Guatemalan', `Mokka', `Red Catuai', and `Yellow Caturra'. Leaf length, width, and area were measured. Seventy-five leaves were used to develop leaf area models, and the remaining leaves were used to test the accuracy of the models using a 1:1 line. We then developed leaf area devices (LADs), which were made of sheet plastic and shaped to resemble coffee leaves. There were three groups of areas in the leaf area devices, based on leaf sizes. Total leaf area (TLA) contained three components. Each component related to the mean leaf area (k) and the number of leaves (n) in that group. The model for the total leaf area was: TLA = k1n1 + k2n2 + k3n3, where k is a constant in each group. The estimation errors for the different cultivars ranged from 5.6% to 12.3% for 1-year-old plants (four cultivars) and from 1.9% to 7.8% for mature plants (five cultivars). By using the LADs and counting the number of leaves, we can obtain the total leaf area for coffee plants in the field.
257 Evaluation of in situ N Mineralization of Composted Organic Wastes Applied to Sandy Soil
Authors: Ozores-Hampton Monica , Obreza Thomas A.
Published: February 2019

In 1997, 24.7 million t of solid waste were produced in Florida (about 4.3 kg per person per day). If all biodegradable material was composted, 12.4 million t of compost would be produced annually. If this compost was used as a soil amendment in fruit and vegetable production, knowledge of its N mineralization rate would be important to determine the application rate. We measured the field N mineralization of four commercial Florida composts mixed with sandy soil (dry weight rate): Jacksonville (yard trimming compost, 127 t•ha-1), Sumter (municipal solid waste compost, 67 t•ha-1), and Nocatee and Palm Beach (yard trimming and biosolids composts, 63 and 56 t•ha-1). The control treatment was unamended soil. Open-top, 20-cm long PVC columns were filled with soil/compost mixtures and fitted at the bottom with a trap containing cation and anion exchange resin to capture leaching NO3 and NH4-N. The columns were buried in the soil at ground level and incubated in situ for 45 and 90 days in the spring. The resin was extracted with 1 N KCl and the mass of NO3-N and NH4-N adsorbed was determined. A similar procedure measured the NO3-N and NH4-N left in the soil/compost mixture. After 90 days in the field, net N immobilization was observed with Nocatee (-4.3%), Sumter (-3.0%), and Jacksonville (-1.3%) composts, while N mineralized (6.4%) from Palm Beach compost. Where N immobilization occurred, composts had initial C: N greater than 20: 1 and N concentration <1.6%. Mineralization occurred where compost had C: N ratio lower than 20: 1 and N concentration greater than 1.6%.
264 Identification and Characterization of Overwintering Methods for Container-grown Herbaceous Perennials
Authors: Iles Jeffery K.
Published: February 2019

A survey was conducted to identify and characterize the effectiveness of overwintering methods used to protect container-grown herbaceous perennials in USDA hardiness zones 3 through 8. Survey questionnaires were sent by first-class mail on 20 Aug. 1996 to 634 firms involved in growing and/or selling container-grown herbaceous perennials identified from the Perennial Plant Association Membership Directory. Completed questionnaires were received from 293 individuals (46.2% response rate) in 38 states, the District of Columbia, and six Canadian provinces. Survey participants reported using several overwintering methods: structureless systems (71.0%), polyhouses (52.9%), polyhouses with inflated double polyethylene covers (30.7%), and low-profile polyhuts (12.3%). Over three-fourths of the respondents (78.8%) said their winter protection methods resulted in minimal to no plant loss (0-10%). Only 53 respondents (18.1%) reported losses >10%. The most frequently cited reason for plant loss across all hardiness zones was excessive moisture inside the overwintering environment (50.2%). Equal percentages (33.4%) indicated low temperatures and damage from animals as the next most likely factors responsible for plant loss. Respondents identified, in descending order, Iris, Delphinium, Lavandula, Papaver, and Lupinus as the five genera most difficult to overwinter.
267 Phytotoxic Effect of Pine Bark Mulch in Landscape Beds
Authors: Mirabello R.A. , Einert A.E. , Klingaman G.L.
Published: February 2019

The use of shredded bark, wood chips, and other organic mulches to conserve water and moderate soil temperatures is a common practice in landscape maintenance. Four mulch materials (cottonseed hulls, cypress pulp, pine bark, and pine straw) were examined to determine effects on plant growth and soil conditions in annual flower beds during a 1-year rotation of warm season to cool season annuals. Inhibited plant growth was observed in pine bark treatments at the conclusion of the growing season for both plantings. Effects on soil conditions were insignificant over the year-long study in pine bark treatments. To further investigate potential phytotoxic effects of pine bark and other mulch used in the initial study, a seed bioassay was performed to determine the influence of mulch extracts in solution on germination and primary root elongation.
274 Effects of Supplemental Calcium on Plant Growth, Ion Accumulation in Roots and Transports to Shoots of Brassica rapa L.
Authors: Kwon T.R. , Harris P.J.C. , Bourne W.F.
Published: February 2019

The effects of supplemental Ca on salinity tolerance were tested using a Brassica rapa L. landrace, `Sani', which is salt-sensitive. Plants were grown in a continuous aerated hydroponic system with 0.25-strength Hoagland solutions containing 125 mM NaCl plus 0, 2.5, 5.0 or 10 mM CaCl 2. The effects of Ca treatment were significant in reducing Na accumulation in roots, Na+ transport from roots to shoots and in enhancing K and Ca accumulation and transport. The Ca addition also enhanced the selectivities of both K and Ca over Na of accumulation at roots and of transport to shoots. However, supplemental Ca did not alleviate the growth reduction caused by the NaCl salinity. These results suggest that the growth inhibition of salt-treated B. rapa `Sani' is mainly caused by factors other than Na, K, and Ca contents in plants.
276 Effects of Water Stress on Super Oxide Dismutase (SOD) and Water Content of Tomato Cultivars at Different Plant Ages
Authors: Rahman S.M. Lutfor , Nawata Eiji , Sakuratani Tetsuo
Published: February 2019

Effects of water stress at different plant ages on SOD activities were studied in two tomato cultivars. Water stress treatment decreased the leaf water potential in all stages, but reduction of leaf water potential was more rapid and pronounced in KF than TM at all DSLs (days of seedlings). After withdrawal of water stress treatment, stressed plants of TM increased leaf water potential to the values of control level in all DSLs, but in KF, leaf water potential of stressed plants were much lower than that of control plants. Effects of water stress on relative water content (RWC) of leaves at 20 DSL showed a similar tendency to that on leaf water potential. The SOD activities in both cultivars showed significant increase by water stress treatment at all DSLs, but the increase of SOD by water stress was larger in TM than in KF. This tendency was observed at all DSLs. The results may indicate that SOD activities play an important role in drought tolerance of tomato at various plant ages and suggest a possible use of SOD activities as a criterion for tomato drought tolerance.
279 Influence of NaCl on Seed Germination of Selected Cool-season Turfgrass Species
Authors: Kang Hoon , Lee Chiwon W.
Published: February 2019

The influence of increasing levels (0.0%, 0.05%, 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1.2%, 1.6%, and 2.0%) of NaCl on the germination of Kentucky bluegrass (Poa pratensis), annual ryegrass (Lolium multiflorum), perennial ryegrass (Lolium perenne), creeping bentgrass (Agrostis palustris), tall fescue (Festuca arundinacea), and crested wheatgrass (Agropyron cristatum) was investigated. Kentucky bluegrass, creeping bentgrass, and crested wheatgrass had a 50% reduction in germination at 0.2%, 0.6%, and 0.6% NaCl, respectively, compared to the control and completely lost germination at 0.6%, 1.2%, and 1.6% NaCl, respectively. Seed germination in both annual ryegrass and perennial ryegrass was only 50% of the control at 1.2% NaCl and completely inhibited at 2.0% NaCl. Tall fescue, red fescue, and creeping red fescue showed a 50% reduction in germination at NaCl concentrations of 1.2%, 1.2%, and 0.8%, respectively, while showing a complete inhibition of germination at 2.0%, 2.0%, and 1.6% NaCl, respectively.
284 Towards Efficient Nutrient Management in Recirculating Hydroponic Culture
Authors: Bugbee Bruce
Published: February 2019

There is an increasing need to recirculate and reuse nutrient solutions to reduce environmental and economic costs. However, one of the weakest points in hydroponics is the lack of information on managing the nutrient solution. Many growers and research scientists dump out nutrient solutions and refill at weekly intervals. Some authors have recommended measuring the concentrations of individual nutrients in solution as a key to nutrient control and maintenance. Dumping and replacing solution is unnecessary. Monitoring ions in solution is unnecessary; in fact the rapid depletion of some nutrients often causes people to add toxic amounts of nutrients to the solution. Monitoring ions in solution is interesting, but it is not the key to effective maintenance. During the past 18 years, we have managed nutrients in closed hydroponic systems according to the principle of “mass balance,” which means that the mass of nutrients is either in solution or in the plants. We add nutrients to the solution depending on what we want the plant to take up. Plants quickly remove their daily ration of some nutrients while other nutrients accumulate in the solution. This means that the concentrations of nitrogen, phosphorous, and potassium can be at low levels in the solution (<0.1 mM) because these nutrients are in the plant where we want them. Maintaining a high concentrations of some nutrients in the solution (especially P, K, and Mn) can result in excessive uptake that can lead to nutrient imbalances.
289 Ammonium Ion Uptake by Feeder and Extension Roots of MM106 Apple Rootstock
Authors: Dong Shufu , Cheng Lailiang , Fuchigami L.H.
Published: February 2019

New roots of Malus domestica Borkh MM106 apple rootstock were divided into two categories, 1) feeder roots and 2) extension roots based on morphology and their ability to take up NH4+, were studied. The roots were harvested in August from 1-year-old potted plants growing under natural conditions in Corvallis, Ore. Extension roots were thicker and longer than feeder roots. Average diameter and length were 0.89 and 45.29 mm for extension roots and 0.27 and 5.36 mm for feeder roots. Root special length (cm/g FW) and surface area (cm2/g FW) were 11.94 and 33.17 for extension roots and 108.97 and 93.38 for feeder roots. Maximum uptake rate, Imax, Km, and root absorption power, α (α = Imax•1/Km), for NH4+ absorption were 6.875, 0.721, and 9.48 for extension roots and 4.32, 0.276, and 15.63 for feeder roots. Feeder roots had stronger affinity to NH4+ (low Km) and higher NH4+ absorption power (high α value) than extension roots. The feeder roots were better able to uptake NH4+ at lower external solution concentrations than extension roots according to the nutrient depletion curve, which indicates feeder roots being more efficient than extension roots in nutrient absorption when NH4+ availability was low.
292 Nitrate Uptake and Root Morphology of Kentucky Bluegrass
Authors: Sullivan W. Michael , Jiang Zhongchun , Hull Richard J. , Sawyer Carl D.
Published: February 2019

Intraspecific variation in nitrate absorption by turfgrasses has been studied, but differences in turfgrass root morphology, which may contribute to observed variation, have not been ascertained. This information may benefit breeding programs aimed at improving the ability of turfgrasses to absorb nitrate from low fertility soils. This study quantified root morphological traits of Kentucky bluegrass (Poa pratensis L.) cultivars and their nitrate uptake rates (NUR). Tiller-generated plants were grown in silica sand, mowed weekly, and watered daily with half-strength modified Hoagland's nutrient solution containing 1 mM nitrate. When 5 months old, plants were excavated, and roots washed to remove sand. The plants were then transferred to 120-mL black bottles. After nitrate depletion of the nutrient solution was monitored for 8 consecutive days, the underground portion of each plant was separated into three parts: 1) adventitious roots, 2) fibrous roots, and 3) rhizomes. Measurements of total root length, total surface area, and average diameter were made by a scanning and image analysis system. NURs were calculated from nitrate depletion data and expressed as micromoles per plant per hour. Correlation analyses were performed on these morphological traits and NUR by the Minitab program. NUR was significantly and positively correlated with the total biomass, length, and area of the three underground parts. This was attributable mainly to fibrous roots as indicated by significant and positive correlations between NUR and the total biomass, length, area, and average diameter of fibrous roots. NUR was also positively correlated with the total biomass, length, and area of adventitious roots but negatively correlated with total biomass, area, and average diameter of rhizomes.