Thomas C. Weiler
Wen-fei L. Uva and Thomas C. Weiler
Adopting technology to achieve environmental stewardship is a high priority among greenhouse industry members. Zero runoff crop production systems can protect surface and ground water and use water, fertilizer, and labor resources more efficiently. However, scarce capital and fear of new technology are impediments to change. Our objectives were to characterize decision making and profitability related to zero runoff systems. Managers of 80 greenhouse operations with zero runoff systems in 26 states participated in a survey designed to gather information on the costs–benefits of adoption and production changes and issues related to zero runoff systems for greenhouse operations. The survey results revealed that some adjustments of production practices were essential when adopting zero runoff systems. It also appeared that greenhouse operators believe they are achieving the intended outcomes and efficiencies from their investment. Size of the operation appeared to be closely linked to the growers' willingness to adopt this new technology. Important reasons for making the decision of adopting zero runoff systems were to improve quality of productions, cut production costs, increase production efficiency, and respond to public concern for the environment. Two thirds of the operators surveyed found that special employee training in the operation of zero runoff systems was required. Most employers found in-house training was adequate for their needs. Operators verified that a significant learning curve slows implementation of zero runoff production Adjustments of cultural practices coupled with good production management were keys to growing zero runoff successfully.
Richard R. Iversen and Thomas C. Weiler
A renewed interest in perennial garden plants occurred during the 1980s. The need for more information on how to force the plants for flower-show exhibition prompted this research. Experiments were designed that combined the effects of cold storage, daylength, and greenhouse temperature on the development of perennials. The six species and cultivars studied were categorized by the interaction of cold and daylength on their growth and flowering strategy.
Dawn M. Alleman and Thomas C. Weiler
Four experiments were conducted over 2 years focusing on water and fertilizer delivery methods with emphasis on minimal resource use. Poinsettia `Freedom', `Celebrate 2'. `Peppermint Pink', `Angelika White', `Lilo' and `Angelika Marble' and geranium `Kim', `Aurora', Ritz', and `Melody' cuttings were grown in 6 inch pots with peat-lite mix and were harvested at marketable size. Nitrogen efficiency was compared by replicating each irrigation treatment with soluble fertilizer (SF) and controlled release fertilizer (CRF). Crops grown with SF were started at 225ppm N for several weeks, then finished at 125ppm N after monitored EC had dropped below 1000μS. CRF treatments were potted up with 1.6 total grams of N available to the plant and irrigated throughout production with tap water. Irrigation treatments included: drip tube leaching, drip tube, ebb & flow, trough. trough lined with capillary mat, trough lined with plastic-covered capillary mat, flats of capillary mat, flats with plastic-covered capillary mat. Daily irrigation volumes were recorded. Weekly data collection included EC, pH, nitrate nitrogen. and ammonium nitrogen. Harvest data included plant dry weight, and total nutrient analyses of plants and substrate. Water efficiency was significantly improved in recirculating systems and with capillary mat systems. No significance was noticed in dry weight or final nutrient analyses across treatments. Significance existed in water quality throughout crop production.
Wen-fei L. Uva, Thomas C. Weiler, and Robert A. Milligan
Zero runoff subirrigation (ZRS) technology is a promising method of managing fertilizer and pesticide inputs while improving production efficiency. However, high capital investment costs and inadequate technical information available to growers are major impediments to initiating the change. This study quantifies costs and returns associated with adopting ZRS systems and compares the profitability of four alternative ZRS systems (ebb-and-flow benches, Dutch movable trays, flood floors, and trough benches) for greenhouse operations in the northeastern and north central United States. The capital investment analysis showed that the Dutch movable tray system was most profitable for small potted plant production, and the flood floor system was most profitable for large potted plant and bedding crop flat production. Sensitivity analysis showed that changes in cost variables generally did not affect the profitability rankings of the alternative ZRS investment projects. Nonetheless, the flood floor system gained slight advantages when the product price increased, and the Dutch movable tray system gained advantages as the hourly labor cost increased.
Wen-fei L. Uva, Thomas C. Weiler, Robert A. Milligan, and Wen-fei L. Uva
Adoption of technology to achieve environmental stewardship and remain competitive is a high priority for greenhouse businesses. Zero runoff subirrigation (ZRS) technology offers great promise to manage fertilizer inputs while improving production efficiency. This study applied economic engineering methodology to quantify costs and returns associated with adopting ZRS systems and compare profitability of producing crops using alternative ZRS systems for greenhouse operations in the northeastern and north central United States. The production models showed that using ZRS systems to grow greenhouse crops can be profitable if growers select a system best suitable for their crop choices. Among the four ZRS systems studied (ebb-and-flow rolling benches, Dutch movable trays, flood floors and trough benches), the Dutch movable tray system returned the highest profit per square foot week (SFW) greenhouse area for small potted plant production ($0.244/SFW), and the flood floor system returned the highest profit when producing large potted plants ($0.002/SFW) and bedding crop flats ($0.086/SFW). The trough bench system was least profitable had the lowest profit for the two applicable crop categories—small potted plants ($0.183/SFW) and large potted plants (–$0.006/SFW). Sensitivity analysis showed that changes of cost variables generally did not affect the profitability rankings for alternative ZRS systems. Except for labor costs, as the hourly wage increased, the Dutch movable tray system gained advantages for small potted plant and large potted plant production. Among selected costs variables, changes in labor costs and tax rate had the highest impact on the profitability of small potted plant production, and changes in labor costs and initial investment costs had the highest impact on the profitability of large potted plant and bedding crop flat production.
Wen-fei L. Uva, Thomas C. Weiler, Louis D. Albright, and Douglas A. Haith
Although zero runoff subirrigation (ZRS) technology has great promise to manage fertilizer inputs while improving production efficiency in greenhouse operations, high initial investment costs and inadequate technical background are major impediments for initiating the change. In a world of uncertainty, greenhouse operators face the challenge of making an optimal investment decision to satisfy environmental compliance expectations and meet the companies' financial goals. Using Monte Carlo simulation, cost risk was analyzed to compare the relative risks of investing in alternative ZRS systems for greenhouse crop production. An investment model was defined for greenhouse production with alternative ZRS systems. Each cost variable was allowed to vary based on a probability distribution. Random numbers were generated to determine parameters for the probability distributions for the uncertain variables. The simulation process was repeated 300 times for each production model. Simulation results showed that among the four ZRS systems studied (ebb-and-flow benches, Dutch movable trays, flood floors, and trough benches), the Dutch movable tray system returned the highest average profit for small potted plant production and the flood floor system returned the highest average profit for large potted plant and bedding crop flat production. Risk of the production models were compared by the variability of simulation results. The Dutch movable tray system is the least risky for small potted plant production, and the flood floor system is the least risky for large potted plant and bedding crop flat production. Despite its low initial costs of adoption, the trough bench system was least competitive as a ZRS technology for a greenhouse operation because of the relative low profitability and high risk of production due to volatile profitability.