Search Results

You are looking at 31 - 40 of 41 items for

  • Author or Editor: John A. Biernbaum x
Clear All Modify Search

The rhizon soil solution sampler (RSSS) currently is being used for in situ extraction of the soil solution for nutrient analysis of mineral soils used to produce field-grown crops. In this study, laboratory and greenhouse experiments were conducted to test the effectiveness of the RSSS for in situ solution extraction from soilless container root media and to compare an RSSS extraction method for measuring root-medium pH, electrical conductivity (EC), and NO3-N and K concentrations with that measured with the saturated media extract (SME) method. A near 1:1 correlation was found between the pH, EC, and NO3-N and K concentrations measured in the extracted solution of the RSSS and SME method in media without plants and in media from ten species grown using three water-soluble fertilizer concentrations applied by subirrigation. More testing is needed with the RSSS, perhaps using composite samples form several pots for analysis. The RSSS shows promise for nutrient extraction in container-grown crops because it is fast, nondestructive, simple, economical, and has minimal effect on the nutritional status of the medium in the pot.

Full access

Abstract

Triacontanol (TRIA), a 30-carbon primary alcohol, was shown to be a more effective plant growth stimulator when formulated as a colloidal dispersion than as a suspension in chloroform and Tween 20 or acetone naphthaleneacetic acid (NAA), and CaCl2. TRIA applied at rates of 0.1 and 1.0 μg/liter consistently increased the dry weight of maize (Zea mays L.) shoots and rice (Oryza sativa L.) seedlings in short-term greenhouse and growth chamber experiments. This application rate is 1000-fold lower than optimum levels applied with other formulations. A 99.45% pure sample of TRIA stimulated maize growth 2 times more than a sample containing 96.40% TRIA at a concentration of 0.5 μg/liter. Neither dispersion pH nor water hardness altered activity of TRIA formulated as a colloidal dispersion. It may be practical to apply TRIA with a controlled-droplet applicator in volumes of water as low as 8–11 liters/ha. The most important environmental factors evaluated for their effect on crop response to TRIA were time of day and temperature prior to spraying. In growth chamber studies, foliar application of TRIA 3 to 7 hours into the photoperiod resulted in twice the growth increase as applications made 11 hours into the photoperiod. In the greenhouse, with supplemental high intensity lamps, sprays were about twice as effective applied 11 hours (5 pm) as 3 hours (9 am) into the photoperiod. There was a positive correlation between the temperature of the growth chamber environment one hour before spraying and the response to TRIA; however, temperature of the environment for one hour after spray application had no effect on TRIA activity.

Open Access

Two identical surveys were conducted with separate samples to determine consumer perceptions of the quality of five edible flower species. Participants were either members of a class that reviewed the history and uses of edible flowers at an annual, 1-day event (Garden Days) or Michigan Master Gardeners who attended a similar class. Participants were shown a randomized series of projected photographic slides of five edible flower species and asked to indicate whether they found the flower quality acceptable. The slides depicted a range of ratings of mechanical damage, insect damage, or flower senescence on a Likert reference scale (1 through 5) developed by the researchers. A flower rated 5 was flawless, while a flower rated 1 had substantial damage. Nearly one-half of all participants had eaten edible flowers before the study, and 57% to 59% had grown them for their own consumption, indicating many individuals had previous experience. Both samples rated flower quality equally and found pansy (Viola ×wittrockiana `Accord Banner Clear Mixture'), tuberous begonia (Begonia ×tuberhybrida `Ornament Pink'), and viola (Viola tricolor `Helen Mount') acceptable from stage 5 to 3. Both groups found the nasturtium (Tropaeolum majus `Jewel Mix') flowers acceptable at only rating 5. Garden Days participants rated borage (Borago officinalis) acceptable from ratings 5 to 3, while the Master Gardeners rated their acceptability from only 5 to 4. Participants also rated flower color (yellow, orange, and blue) as equally acceptable.

Full access

A small suction lysimeter tube (SLT) was used to extract media solution samples for twelve pot plant species in peat-based media subirrigated with 50, 100, or 200 mg · liter-1 N and K2O. Media samples from different pots were also tested using the saturated media extract (SME) procedure. Sample solution pH, EC, NO3 --N and K+ were measured with Cardy flat electrode meters. Averaged over crops, solution pH was similar for SLT and SME (after extraction) at each N concentration. The mean (12 crops × 3 reps at each N level) SME and SLT solution EC and K+ concentrations were similar for samples collected from the 50 and 100 mg · liter-1 N treatments. NO3 --N values were lower with the SLT than SME method at 50 mg·liter-1 N. SLT levels for EC, NO3 --N, and K+ were 27, 39, and 24% higher than SME values for samples collected from the 200 mg·liter-1 N treatments. Sample variation between replicates and between methods for the single pot samples was unacceptable. More testing is needed with SME and SLT samples from the same pot and composite samples from several pots, but SLT sampling is fast, nondestructive, simple, and economical at $6-7 per tube.

Free access

Two surveys were conducted to determine characteristics important in containerized edible flowers that could be sold in retail outlets. Self-selected participants at Bloomfest at Cobo Hall, Detroit, were assigned to one group that rated the importance of attributes such as color of pansy (Viola ×wittrockiana Gams. `Accord Banner Clear Mixture'), color combinations, container size, and price. Participants assigned to a second group rated color, color combinations, and container size. Flower color was allocated the most points in the purchasing decision (63% for the first group and 95% for the second), with a mixture of all three colors (blue, yellow, and orange) being the most desirable. Responses were subjected to Cluster Analysis (SPSS Inc., Chicago), which resulted in the formation of three distinct groups. The groups were labeled “Likely Buyer” (those who had eaten and purchased edible flowers before and rated characteristics of edible flowers favorably); “Unlikely Consumer” (those who had eaten edible flowers before and had rated characteristics of edible flowers unfavorably); and “Persuadable Garnishers” (those who had not eaten edible flowers before, but were very likely to purchase edible flowers for a meal's garnish).

Free access

Two surveys were conducted to assess consumer and professional chefs' perceptions of three edible-flower species. Our objectives were to determine opinions, preferences, and uses of Viola tricolor L. `Helen Mount' (viola), Borago officinalis L. (borage), and Tropaeolum majus L. `Jewel Mix' (nasturtium). Flowers were grown using certifiable organic methods and chosen to reflect a variety of flower tastes, textures, and appearances. We quantified three attributes (taste, fragrance, and visual appeal) with a total of seven semantic, differential scales adapted from a scaling authority. The attributes were rated as: visual—“appealing”, “desirable,” and “very interested in tasting”; fragrance—“appealing” and “pleasant”; and taste—“tasty” and “desirable”. Garden Day participants were self-selected to evaluate and taste flowers from a consumer perspective. When asked to rate the three species on visual appeal and desire, no less than 76% of consumers awarded all flowers an acceptable rating. We found similar results when consumers answered questions regarding the taste of two of the three species. Results from this study support our hypothesis that customers would rate edible flower attributes highly and would be likely to purchase and serve the three species tested. Members of the Michigan Chefs de Cuisine Association participated in a similar survey. At least 66% of these chefs rated the three visual attributes and two fragrance attributes of viola and nasturtium acceptable. Chefs' ratings of the fragrance of borage as “appealing” and “pleasant” were higher than those of consumers, but the ratings were still low, 21% and 25%, respectively. Unlike consumers, chefs' ratings of the taste of viola as “appealing” and “desirable” were low (29% and 36%, respectively). We found some minor differences in ratings when groups were compared, using demographic variables as a basis for segmentation, indicating a homogenous marketing strategy may be employed.

Free access

Do consumers prefer certain combinations of edible-flower species and colors over other assortments? Two hundred and sixteen people were self-selected for a survey at a Michigan flower show to rate 15 photographs of edible flowers arranged in 0.24-L, clear, plastic containers. Each container had either an individual species or combinations of Viola tricolor L. `Helen Mount' (viola), Borago officinalis L. (borage), and Tropaeolum majus L. `Jewel Mix' and `Tip Top Apricot' (nasturtium). To determine what color(s) of nasturtium participants would prefer, containers held either orange and crimson, peach and cream, or a combination of all four flower colors. Participants rated photographs using a semantic differential on a 7-point Likert scale (7 being the highest rating) based on their likelihood to purchase each container of edible flowers to serve to family and friends in a meal. Participants were asked an additional 21 questions regarding their attitudes about edible flowers, gardening habits, dining habits, and several demographic questions. Responses were subjected to conjoint analysis (SPSS Inc., Chicago). The addition of other species to nasturtium (viola, borage, viola, and borage) had a greater relative importance (53%) than the color of the nasturtium (47%). A mixture of all four nasturtium colors (peach, cream, orange, and crimson) was awarded the highest utility (0.091). Peach and cream nasturtiums or containers that did not contain any nasturtium flowers at all were least preferred (-0.070 and -0.083 utilities, respectively). Mean ratings that participants assigned to containers of edible flowers supported these utilities. The container assigned the highest mean rating included nasturtiums of all four colors, yet 66% were unlikely to purchase any container with 10% insect damage. Differences in preferences were noted using selected demographic characteristics such as age, gender, and income.

Free access

A series of experiments was conducted to quantify the rate of nutrient loss from a container medium in a 15-cm-wide (1.3-liter) pot with a container capacity (CC) of 0.7 liter/pot under mist propagation and to determine the effectiveness of reapplying fertilizer to medium at 90% of CC with either top watering or subirrigation. Reducing the volume of water applied per day decreased the rate of nutrient leaching. Based on CC leached (CCL), the rate of nutrient loss was similar for all treatments. Differences in the rate of macronutrient removal from the media were measured, but, by 2 CCL, the concentration of all nutrients tested was below acceptable levels for the saturated media extract. With top watering, reapplying water-soluble fertilizer (WSF) at volumes under 0.2 liter/pot did not affect the nutrient concentration in the lower half of the pot at WSF concentrations up to 86 mol N/m3. Applying up to 0.8 liter/pot did increase nutrient concentrations in the lower half of the pot, but the media nutrient concentrations were lower than that of the applied WSF concentration. Applying WSF with subirrigation was limited by the moisture content of the media prior to the irrigation.

Free access

The measurement of evaporation and transpiration from container-grown crops is labor intensive and expensive if measurements are made by periodic weighing of the plants with electronic scales. Thin-beam load cells (LCL-816G, Omega Engineering) measured with a datalogger provides a method of making continuous mass measurements over time. Four load cells were tested to determine the feasibility for use in greenhouse studies. The sensors were calibrated to an electronic scale at a range of air temperatures. The electrical signal (μV) was a linear function of mass from 0 to 816 g. The change in mass per change in electrical signal (i.e. the slope) was the same for all four load cells (1.26 g ·μV-1), however the absolute electrical signal (the intercept) was unique for each sensor (-246 to + 101 g). The effect of temperature on sensor output was unique for each sensor in terms of both the magnitude and direction of change. A two-point calibration of mass performed at a range of temperatures is required to properly use thin-beam load cells to continuously measure evapotranspiration of container-grown crops.

Free access

Relatively low-cost season extension structures have the potential to contribute to farm economic viability in temperate climates by providing a means to continue sales beyond the limits of outdoor-only field production. These structures, commonly called hoophouses, high tunnels, passive solar greenhouses, or unheated greenhouses, allow for the extension of heat-tolerant (warm season) crops on both ends of the production time frame and at winter harvesting of cold-tolerant (cool season) crops. In this study, results are presented from a multiyear investigation into the economic impacts of year-round production and harvesting, with a focus on profitability of the structure and crop production as a whole. The results of case studies from nine Michigan farms reveal a very broad range of outcomes across farms in construction time, labor allocation and returns, and gross and net revenue. The economic implications of farmer use, including projected investment payback time, are discussed.

Full access