Improved quality and water use by scheduling irrigation for greenhouse production of Rosa hybrida L.
Date
1992
Authors
Woerner, Steven E., author
Hopper, Douglas A., advisor
Moore, Frank D., III, committee member
Smith, D. D., committee member
Journal Title
Journal ISSN
Volume Title
Abstract
Ground water contamination from greenhouse and nursery operations is a cause for concern owners, neighbors and governmental agencies alike. In fact, the state of Colorado has passed legislation that will directly effect greenhouse growers: these growers may eventually be mandated to control their waste water pollution. One way to reduce the amount of waste water produced while maintaining product quality is to schedule irrigation, rather than manually irrigating and overwatering. Four irrigation scheduling techniques for greenhouse production of three cultivars of hybrid tea rose, Rosa hybrida L., were examined for their effect on bloom quality and production over time. The irrigation scheduling techniques developed for use in this study included: a time clock based method; an accumulated radiation based method; an accumulated vapor pressure deficit (VPD) based method; and a combination method, which used an accumulated combination of VPD and radiation. Results from the study indicate that the time clock method had poorer quality roses in three quality measurements: length, fresh weight, and dry weight. The other three treatments did not differ in a discernable pattern for their effect on the quality measurements. We hypothesize that the time clock method, while putting on as much or more water, was not able to apply water at the right time. Other researchers have shown that the timing of irrigations is critical, and we believe that because the other techniques were based on environmental parameters directly involved in plant processes (photosynthesis, translocation of mass flow solutes, etc.), they were able to respond more appropriately to the water needs of the plants. The treatment effect on numbers of blooms produced was highly variable, and the statistical analysis indicated that the variability within treatments was too great to allow for appropriate analysis. The methods did differ significantly on the amount of water that they applied to benches, as the VPD method supplied as much as 60% less water during the Valentine's Day harvest period, and as much as 80% less water during the Mother's Day harvest, without reductions in quality. This was mainly due to the selection of the trigger values, and future research could focus on increasing those trigger values and reducing the amount of water applied to benches. Implementation of these irrigation scheduling techniques may not be prohibitively expensive, as growers could use current sensors and computer facilities to accomplish these methods. Growers should look at return on investment when considering using these methods, and they should consider factors such as labor savings, flower quality and production efficiency improvements, and reduced cost for both water and fertilizer.
Description
Covers not scanned.
Rights Access
Subject
Greenhouse management
Irrigation scheduling