A gradient concept was initiated and evaluated at the Gulf Coast Research and Education Center, Bradenton, during the 1960s as the nutritional component in a full-bed mulch system of production. Commercial tomato yields in Florida more than doubled with the shift to the gradient-mulch system. Conventionally, nutrients move to the root in the water by mass flow and thus are a function of water requirement. With the soil as the buffer component, nutrient input may or may not be synchronized with root removal. Movement with the gradient is by diffusion and the nutrient/water input is synchronized with rate of removal by the root. The limited buffer potential of the soil is replaced by the gradient with an unlimited buffer potential. Production in the field or a container has a maximum potential with the gradient procedure but can become limited in the field and a failure in the container with conventional procedure. The gradient requires minimal soil (a framework for the gradient) uses minimal water, creates minimal pollution, requires minimal management and provides a nutritional stability that has an unlimited productivity potential. The N–K banded on the soil bed surface in conjunction with a continuing water supply are the basic parameters of the gradient concept.
Colorado State Univ. recently underwent the development of a new all university core curriculum. All faculty were encouraged to submit proposals for new courses or revised courses, which would be reviewed for inclusion under specified categories. Basic Horticulture was redesigned te emphasize the scientific method, the understanding between science and society, and the use of handson and inquiry-based instruction in the laboratory. Horticultural Science is now an applied science course that includes the use of hypothesis formulation, experimentation, observation, data collection, summation and presentation in scientific format of reports of at least three laboratory exercises, as well as extensive general observation and presentation in both written and oral format. It teaches science in the context of everyday interaction with the environment in which the student lives, the interior and exterior plants that surrounds the student at CSU, and the controversies as well as the health aspects that surround the production of foods derived from plants that require intensive cultivation. Examples of such issues include sustainability, the organic movement, genetically modified organisms, ground water pollution form overfertilization, and water usage for landscaping and golf courses in a water short region. A review of the revisions as noted above and the use of technology in teaching the course will be presented.
C. Siobhan Dunets and Youbin Zheng
Phosphorus (P) pollution from greenhouse wastewater is currently a major issue. A treatment method that can efficiently remove P concentrations ([P]) that fluctuate between greenhouse systems and throughout the year is required. An ideal method would also recover nutrients in a reuseable form. A combined precipitation/flocculation process incorporating addition of lime and a biodegradable flocculant (guar gum, cationic starch, or chitosan) was investigated for providing optimized P removal and recovery. Effectiveness of this process was evaluated in simulated wastewater of low and high alkalinity, as well as real greenhouse wastewater. Precipitation via lime addition reduced total P to below 1 mg·L−1 in low-alkalinity simulated wastewater, but high alkalinity slightly inhibited separation. This inhibition was overcome by flocculation via guar gum or cationic starch addition, which improved separation efficiency and reduced separation time, although chitosan was ineffective as a flocculant. The precipitation/flocculation method was found to be effective for treating real greenhouse wastewater, although effectiveness varied with variation in wastewater composition. Recovered precipitate contained 57.4 g·kg−1 P as well as high levels of Ca, Mg, K, Fe, and Zn. This study demonstrates a P separation process incorporating lime and biodegradable flocculants could provide a means of reducing P in greenhouse wastewater below a 1 mg·L−1 regulatory limit in a settling time of less than 30 minutes, while simultaneously recovering P and other nutrients in a form that could be reused as fertilizer. An evaluation of viability of full-scale application of this technology is now warranted.
John D. Lea-Cox*
Environmental and human safety regulations are now an inevitable part of horticultural crop production. For most businesses, worker training and the subsequent collection and administration of data required for reporting purposes is often regarded as an economic burden. There are few systematic models that firstly provide an ecompassing approach to this business requirement, but more importantly which provide resources that simplify and perhaps automate the reporting of data to any significant degree. A good environmental management system (EMS) should provide a framework to systematically plan, control, measure and improve an organization's environmental performance and assessment. Significant environmental improvements (and cost savings) can be achieved by assessing and improving management and production processes, but only if the data are collected and analyzed quickly and easily. Many times, growers do not realize the relationship between their improved environmental performance and other key EMS benefits, such as reduced liability, better credit ratings, enhanced employee performance, improved customer relations, marketing advantages together with improved regulatory compliance. The International organization for Standardization (ISO) 14001 series is the most widely accepted international standard for EMS. Growers in most states in the US are required to document their use of pesticides and other agrochemicals that can impact human health, and in some states are also required to to document and monitor their applications of water and nutrients, in an effort to environmental pollution. This paper will illustrate the key elements of environmental management systems and how this can be integrated into production management using process management software.
Jayesh Samtani, Gary Kling*, and David Williams
Conventional herbicide applications to container-grown landscape plants, often requires multiple spray applications of herbicides in a growing season and presents problems such as non-uniform application, leaching, run-off, environmental pollution, worker exposure and phytotoxicity to the landscape plants. The use of an organic herbicide carrier could help reduce some of the problems associated with spray applications. Landscape-leaf waste pellets were evaluated as a preemergent herbicide carrier for container-grown landscape plants. Isoxaben, prodiamine and pendimethalin were applied to Chrysanthemum × grandiflorum `Lisa', Euonymus fortunei `Coloratus' and Spiraea japonica `Neon Flash', at rates of 1.12, 2.25, and 2.25 kg·ha-1 active ingredient, respectively, with either water or landscape leaf waste pellets as a carrier. Portulaca oleracea, Senecio vulgaris, and Setaria faberi were seeded following treatment application. Visual ratings on efficacy and photoxicity to landscape plants, and shoot fresh and dry biomass were determined for both weeds and crop plants. Landscape leaf pellets served as an effective carrier for application of prodiamine and pendimethalin and combinations of these herbicides with isoxaben in controlling weeds. Leaf waste pellets as a carrier produced equivalent weed control and phytotoxicity ratings to conventional spray application of these herbicides, on both Chrysanthemum and Euonymus. The pellets did not make a consistently effective carrier for the application of isoxaben alone. Application of herbicides on leaf pellets could result in more uniform herbicide applications, minimize loss of herbicides to the environment and reduce the risk of herbicide contact with nursery workers.
N.S. Khoury, E.J. Holcomb, J.W. White, and M. Rand
Recycled subirrigation systems are a possible solution to grower concerns over water use, ground water pollution, and regulations concerning these. The objectives of this experiment were to examine the differences between top- and subirrigated plants, with different fertilizer regimes and with mulches.
Six treatments of `Crimson Fire' and `Victoria' CVI geraniums were grown in 11 cm. pots. Treatments were: top irrigation, 100% N supplied with 20-10-20 soluble fertilizer; subirrigation, 100% N supplied with 20-10-20 soluble fertilizer; subirrigation, N supplied in equal portions of 20-10-20 soluble fertilizer and CRF, gel mulch; subirrigation, N supplied with CRF, gel mulch; subirrigation, N supplied in equal portions of 20-10-20 soluble fertilizer and CRF, wool mulch; subirrigation, all N supplied with CRF, wool mulch.
`Crimson Fire': fresh weight was not significantly different between top- and subirrigation; fresh weight at the same fertilizer level was not significantly different with either a gel or a rockwool mulch; all CRF resulted in the lowest fresh weights. `Victoria': top irrigated fresh weight was significantly higher compared to subirrigated. Gel mulched plants resulted in significantly lower fresh weights than wool mulched plants. All CRF resulted in the lowest fresh weights.
Joseph H. Connell
Improving almond orchard management by integrating cultural practices, pest and disease controls, and vegetation management has been a goal of Univ. of California research and extension efforts for more than 25 years. Alternative cultural practices related to orchard floor management, fertilizer applications, and pest and disease control are currently important components of the almond production system. Nontillage, with or without a seeded cover crop, has improved potassium uptake and reduced pest problems. In-season fertilizer applications reduced the potential for nitrate pollution of groundwater. Minimizing dust, early harvest, and destruction of overwintering refugia are all cultural practices that reduce crop damage caused by pests. New methods of pest and disease monitoring using pheromone traps, egg traps, or a better understanding of disease life cycles have reduced unnecessary chemical applications. Degree-day phenology models have improved the timing of needed sprays. Expanded use of selective spray materials, such as narrow-range oils and Bacillus thuringiensis, reduce impacts on non-target species while natural predators and parasites are encouraged. Augmentative releases of beneficial insects are currently being evaluated as an additional alternative to in-season spraying. Cultivar and rootstock choices for new plantings present alternatives that can help avoid pests or diseases. Planting pattern affects productivity and is another factor to consider when evaluating alternative production practices for almond as new orchards are established.
Renee Keydoszius and Mary Haque
During the fall semester of 2003, a Clemson University introductory landscape design class collaborated with South Carolina Botanical Gardens staff and coordinators of Sprouting Wings, an after school gardening program for at risk children, to design an exploratory Children's Garden within the Botanical Gardens. Project methodology included site selection, research, site analysis, conceptual diagrams, preliminary designs, and full color renderings of final designs. Students periodically presented their progress on the project to the clients in order to receive feedback and advice. One of the thirteen themed gardens designed is the Wonders of Water Garden. Project goals were to create a center for environmental education addressing current issues in water quality such as pollution from industries and runoff, erosion, stream degradation, and sedimentation resulting from land clearing and development. Visitors will be able to observe and learn about various environmental factors affecting native plant and animal life. The garden will help to teach environmental stewardship and understanding of general aquatic ecology. An observation deck, serpentine bridge through a bog garden, and a bridge crossing a waterfall stream will allow close observation of native aquatic plant and animal life. The Wonders of Water Garden design includes the bog garden and carnivorous garden that border two pools connected by a stream of small waterfalls which may be used to create awareness of current water quality issues and serve as a model to teach visitors the importance of water and aquatic plants in the environment.
Jesús Valencia and Donald M. May
An irrigation water study was conducted in the West side of Fresno County to evaluate the impact of recycled drainage water nitrogen and salinity content in the growth of direct seeded processing tomatoes to reduce nitrate-ground water pollution. Four canal water treatments (0.4 dS/m) received 0, 67.5, 101.2, and 168.7 kg of nitrogen per hectare and four saline water treatments (7.01 dS/m) received 0, 33.7, 67.5 and 135.0 kg nitrogen per hectare. All treatments were established with fresh canal water, and at first flower half of treatments were switched to saline water. The nitrogen content of water had an average of 283 ppm N-NO3 for the canal water and the drainage water contained 4489 ppm N-NO3. There was no significant yield differences between the irrigation methods and the two N-fertilizer sources applied to the tomatoes. However, drainage water produced a significant increase in fruit soluble solids (5.05 Av.) in comparison to canal water and synthetic fertilizer (4.3 Av.). The overall fruit quality and maturity was better in the drainage water treatments than it was in the fresh canal water with synthetic N-applied treatments.
C. M. Geraldson
The purpose of this study was to evaluate the commerical feasibility of a containerized gradient concept with relevance to water requirement, pollution potential, and production efficiency. Basic components included one-half cu ft of media/plant with 2 plants/rigid plastic container. Phosphorous, liming material and micronutrients were mixed in the media and the N-K was banded on the surface at both ends of the container which was protected by a plastic cover. Intermittent micro-irrigation was used to maintain either a lateral or vertical nutrient/moisture gradient. Variations in the media, the size and shape of the container, and the frequency and time of water applications were included in the evaluations. In the spring of 1991, 65 gallons of water was utilized to produce 22.9 lbs of marketable tomatoes/plant. Leaching was insignificant and the water required on an acre basis was projected as 4.8 acre inches with a 2000 plant population. The results indicate that the containerized gradient concept is potentially feasible as a sustainable production system.