An increasing number of greenhouse growers are producing food crops using various types of recirculating solution culture. With nationwide trends toward local, sustainable, and/or organic food production (e.g., Dimitri and Greene, 2012), the greenhouse industry is shifting away from solely producing herbaceous ornamental crops and integrating or replacing these crops with vegetables and herbs. For this reason, hydroponics and other systems using recirculated nutrient solution have become an increasingly important topic for many greenhouse production courses.
Nutrient management in hydroponic production systems is more intensive than a typical production scenario because the grower must more closely manage all macro- and micronutrients for the crop. Additionally, because hydroponic nutrient solutions are unbuffered (i.e., compared with soils), pH can change dramatically over a 24-h period based on what nitrogen forms are supplied and levels of microbial activity in the solution. With these challenges in mind, the incorporation of a module where crops are produced in recirculating solution provides a means to put the knowledge students have gained from previous plant science courses to practice and hone plant nutrient management skills.
In an academic environment, the focus of a course is frequently on the recognition and recall of information presented by the instructor (Krathwohl, 2002). However, the understanding and use of knowledge is often considered a more important objective. In his revision of Bloom’s taxonomy, Krathwohl (2002) stated that higher cognitive processes, such as evaluating and creating, are often considered the more important and long-lasting fruits of education. Cannon and Feinstein (2005) furthered this idea as they divided Bloom’s taxonomy into different levels. They proposed that lower levels involved more knowledge and content-related objectives, whereas higher levels delved into more cognitive skills and processes. These authors further discussed one of the strong arguments for experiential learning is that it places students in real situations where they must not only call on lower-level concepts, but also engage in higher levels of learning as they “analyze what is going on in the game or exercise, synthesize solutions to address the situation, and evaluate their relative merits” (Cannon and Feinstein, 2005).
Kolb (1984) addressed experiential learning theory as a “holistic integrative perspective on learning that combines experience, perception, cognition, and behavior.” Kolb further proposed an experiential learning model where students engage in a concrete experience, reflective observation, abstract conceptualization, and active experimentation. This holistic perspective of teaching has been practiced in many horticulture scenarios. One such instance was the hands-on integration of sustainable design through the construction of an exhibit at a trade show for landscape architecture and horticulture students at Temple University (Lamba and Chapman, 2010); another was the installation of a residential irrigation system in an undergraduate landscape irrigation course (Lavis and Brannon, 2010). Scenarios such as these provide students with real-world experiences as well as foster an environment where the learning model proposed by Kolb can be put into practice.
The idea of establishing an experiential learning module involving recirculating solution culture stems from a desire to incorporate these higher levels of learning into a typical greenhouse management course. Additionally, by incorporating these systems into the course, students would become familiar with these production systems while also gaining an increased understanding of the pros and cons involved with them. With plants produced in hydroponics being rapidly responsive to management decisions, hands-on experience provides the students with the opportunity to evaluate and address firsthand critical nutrient management concepts, such as the role of nitrogen form in pH changes.
Our hypothesis was that by integrating a hands-on, 6-week module involving hydroponics and recirculating solution culture into the HORT 570 Greenhouse Operations Management laboratory at Kansas State University, multiple facets of student learning would be improved. Specifically, we wanted to discern if this added class experience would 1) improve student confidence and understanding of not only recirculating solution culture systems but also general crop nutrient management; and 2) improve higher-order thinking skills of applying, analyzing, and evaluating information (Krathwohl, 2002). With these goals in mind, the objectives of this study were to 1) measure change in student confidence to manage crops produced in recirculating solution culture from participation in the experiential module; 2) determine whether the module improved student mastery of general plant nutrient management content not specific to hydroponic production; and 3) assess the module impact on LOL vs. HOL.
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