Nutrition of Floricultural Crops: How Far Have We Come?

According to Seeley (1979), even though the Society for Horticultural Science was formed in 1903, it wasn\u27t until the 1930s that research papers on the subject of floriculture were published in our journal. There were, however, numerous college and university bulletins about floricultural crops which included fertilizer studies (for example, Blake, 1915). Despite the sluggish start, in the last 25 years, in the American Society of Horticultural Science\u27s three journals (Journal of the American Society for Horticultural Science, HortScience, and HortTechnology) alone, there have been over 240 publications relating to the nutrition of floricultural crops. Journal such as Scientia Horticulturae, Journal of Plant Nutrition, Agrochemica, Journal of Environmental Horticulture as well as others also publish papers on this topic.Thus, the focus of this article will be on research published in ASHS journals. Even with this narrowed focus, only a sampling of the research that has occurred can be mentioned here. Floriculture in its broadest sense involves growth and development physiology, culture, management and postharvest physiology of cut flowers, potted flowering and foliage plants, cacti and carnivorous plants, bedding plants and herbaceous perennials including forbs and geophytes. Adequate elemental content of these plants is critical at all growth stages to ensure a marketable product

Annual Statice in Nebraska

Annual statice can be successfully grown, harvested, and preserved under Nebraska\u27s climatic conditions. Start plants from seed nine weeks before they are field or garden planted. The earlier in the season that planting occurs, the greater the yield. Apply fertilizer before and after planting. Herbicides are recommended to eliminate hand weeding and allow maximum yield. Flowers should be harvested when all florets are fully open and can be used fresh, or dry stored at 2C (36F). Statice can also be preserved by drying or soaking fresh cut stems in 1:2 or 1:3 glycerine to water solution for 48 hours and then microwaving for 1 minute at 34C (97F) (medium high setting)

Management and Modeling of Winter-time Basil Cultivars Grown with a Cap MAT System

Basil (Ocimum basilicum) is a high value crop, currently grown in the field and greenhouses in Nebraska. Winter-time, greenhouse studies were conducted during 2015 and 2016, focusing on cultivars of basil grown on a Cap MAT II® system with various levels of fertilizer application. The goal was to select high value cultivars that could be grown in Nebraska greenhouses. The studies used water content, electrical conductivity, photosynthetically active radiation (PAR), and relative humidity, air and soil media temperature sensors. Greenhouse systems can be very complex, even though controlled by mechanical heating and cooling. Uncertain or ambiguous environmental and plant growth factors can occur, where growers need to plan, adapt, and react appropriately. Plant harvest weights and electronic sensor data was recorded over time and used for training and internally validating fuzzy logic inference and classification models. Studies showed that GENFIS2 ‘subtractive clustering’ of data, prior to ANFIS training, resulted in good correlations for predicted growth (R2 \u3e 0.85), with small numbers of effective rules and membership functions. Cross-validation and internal validation studies also showed good correlations (R2 \u3e 0.85). Decisions on basil cultivar selection and forecasting as to how quickly a basil crop will reach marketable size will help growers to know when to harvest, for optimal yield and predictable quantity of essential oils. If one can predict reliably how much essential oil will be produced, then the methods and resultant products can be proposed for USP or FDA approval. Currently, most plant medicinal and herbal oils and other supplements vary too widely in composition for approval. The use of fuzzy set theory could be a useful mathematical tool for plant and horticultural production studies

Management and Modeling of Winter-time Basil Cultivars Grown with a Cap MAT System

Basil (Ocimum basilicum) is a high value crop, currently grown in the field and greenhouses in Nebraska. Winter-time, greenhouse studies were conducted during 2015 and 2016, focusing on cultivars of basil grown on a Cap MAT II® system with various levels of fertilizer application. The goal was to select high value cultivars that could be grown in Nebraska greenhouses. The studies used water content, electrical conductivity, photosynthetically active radiation (PAR), and relative humidity, air and soil media temperature sensors. Greenhouse systems can be very complex, even though controlled by mechanical heating and cooling. Uncertain or ambiguous environmental and plant growth factors can occur, where growers need to plan, adapt, and react appropriately. Plant harvest weights and electronic sensor data was recorded over time and used for training and internally validating fuzzy logic inference and classification models. Studies showed that GENFIS2 ‘subtractive clustering’ of data, prior to ANFIS training, resulted in good correlations for predicted growth (R2 \u3e 0.85), with small numbers of effective rules and membership functions. Cross-validation and internal validation studies also showed good correlations (R2 \u3e 0.85). Decisions on basil cultivar selection and forecasting as to how quickly a basil crop will reach marketable size will help growers to know when to harvest, for optimal yield and predictable quantity of essential oils. If one can predict reliably how much essential oil will be produced, then the methods and resultant products can be proposed for USP or FDA approval. Currently, most plant medicinal and herbal oils and other supplements vary too widely in composition for approval. The use of fuzzy set theory could be a useful mathematical tool for plant and horticultural production studies

Dynamic Classification of Moisture Stress Using Canopy and Leaf Temperature Responses to a Step Changes of Incident Radiation

Environmental conditions affect plant productivity and understanding how plants respond to drought stress can be measured in different ways. This study focused on measuring leaf response time to induced water stress. Leaf response time to a step increase and step decrease in radiation was computed for four species of well-watered and water-stressed plants in a controlled environment. The canopy temperature was measured with an infrared thermometer and a thermal imaging camera. Thermal images were analyzed to determine the average temperature of a selected single, unobstructed leaf at the top of the canopy. Both the canopy response time and the single leaf response time were computed for this study. The response times to a step change of radiation for well-watered plants were generally longer than the response times of water stressed plants. These results show that response time may be used as an indicator of plant water stress

Incorporating Chokeberry (Aronia) into a Home Landscape

Chokeberry (Aronia) is an ornamental plant that has found use in the home landscape, providing colorful displays and annually producing berries for the enjoyment of the homeowner and wildlife alike. With careful placement, this durable plant needs minimal care and has few pest problems. It is gaining attention for its timeless beauty

Dynamic Classification of Moisture Stress Using Canopy and Leaf Temperature Responses to a Step Changes of Incident Radiation

Environmental conditions affect plant productivity and understanding how plants respond to drought stress can be measured in different ways. This study focused on measuring leaf response time to induced water stress. Leaf response time to a step increase and step decrease in radiation was computed for four species of well-watered and water-stressed plants in a controlled environment. The canopy temperature was measured with an infrared thermometer and a thermal imaging camera. Thermal images were analyzed to determine the average temperature of a selected single, unobstructed leaf at the top of the canopy. Both the canopy response time and the single leaf response time were computed for this study. The response times to a step change of radiation for well-watered plants were generally longer than the response times of water stressed plants. These results show that response time may be used as an indicator of plant water stress

Evaluation of Soilless Media Sensors for Managing Winter-time Greenhouse Strawberry Production using a CapMat System

It is important for a greenhouse strawberry grower to know that their capillary mat (CapMat™) fertigation system is working correctly and that plants are receiving the correct amounts of water and fertilizer. Pots with soilless mix are not expected to hold more than 70% water on a volumetric basis. Pots with less than 40% water content continuously are not supplied enough water and nutrients to the plants. Typically, pots located near the manifold distribution system get a little more water than those at the other locations, but water use will really vary according to the factors listed above as well as environmental parameters, but should not vary more than 20%. Fertigation is based on the drip tape distribution system, the media density of individual pots, and the spatial energy distribution within the greenhouse. To understand how these factors interact, pot moisture, media temperature, and electrical conductivity were spot checked with a relatively new commercial sensor and also monitored continuously along with greenhouse temperature, humidity, and photosynthetically active radiation (PAR) using a data logger system. We found that the variance in pot medium moisture and fertilizer was as expected as were fluctuations in air and mix temperatures. Calibrated commercial electrical conductivity and soil moisture sensors for measuring pot moisture and/or electric conductivity were reliable. Having this data may be a key to determining why plants in the UNL greenhouse produced more marketable fruit than plants in the commercial house

Storage and breakdown of starch aid \u3cem\u3eP. parviflorus\u3c/em\u3e in leaf re-greening after nitrogen deficiency

Plectranthus parviflorus, common Swedish ivy does not lose leaves when it is deprived of nitrogen. Instead this plant retains its yellow leaves and upon reintroduction of nitrogen will re-green and start to grow. In two experiments, rooted cuttings of common Swedish ivy were grown with (150 ppm N) and without nitrogen for 3 weeks. After some plants were sampled the others were either switched or kept at 0 or 150 ppm N and allowed to grow for another 3 weeks. After another sampling, plants were again switched or kept at 0 or 150 ppm N for a final 3 weeks. At each harvest, leaves were tested for starch, sampled for microscopy and then dried and weighed for soluble carbohydrate extraction. Data collected indicates that yellow leaves store and breakdown starch into soluble carbohydrates (specifically reducing sugars) in order to keep leaves from senescing. When nitrogen is re-supplied to these plants, leaves re-green and the plant continues to grow. We propose that common Swedish ivy’s ability to store and breakdown starch aids in the process of leaf re-greening

Foliar Micronutrient Application for High-Yield Maize

Nebraska soils are generally micronutrient sufficient. However, critical levels for current yields have not been validated. From 2013 to 2015, 26 on-farm paired comparison strip-trials were conducted across Nebraska to test the effect of foliar-applied micronutrients on maize (Zea mays L.) yield and foliar nutrient concentrations. Treatments were applied from V6 to V14 at sites with 10.9 to 16.4 Mg ha−1 yield. Soils ranged from silty clays to fine sands. Soil micronutrient availability and tissue concentrations were all above critical levels for deficiency. Significant grain yield increases were few. Micronutrient concentrations for leaf growth that occurred after foliar applications were increased 4 to 9 mg Zn kg−1 at 5 of 17 sites with application of 87 to 119 g Zn ha−1, 12 to 16 mg kg−1 Mn at 2 of 17 sites with application of 87 to 89 g Mn ha−1, and an average of 8.1 mg kg−1 Fe across 10 sites showing signs of Fe deficiency with application of 123 g foliar Fe ha-1. Foliar B concentration was not affected by B application. Increases in nutrient concentrations were not related to grain yield responses except for Mn (r = 0.54). The mean, significant grain yield response to 123 g foliar Fe ha−1 was 0.4 Mg ha−1 for the 10 sites with Fe deficiency symptoms. On average, maize yield response to foliar Fe application can be profitable if Fe deficiency symptoms are observed. Response to other foliar micronutrient applications is not likely to be profitable without solid evidence of a nutrient deficiency