Abstract:

Sophomore biochemistry undergraduates were introduced to the study of plant-microbiome interactions and their benefits for plant fitness and ecosystem functioning by taking Microbiology and Plant Physiology. Nutrient recycling and bioremediation are two key issues students are expected to understand. Nonetheless, by the end of the course some questions always remain. In addition to whether or not they have truly understood the scientific issues involved, there is a need to see how this science has contributed to their education by providing knowledge that can be practiced in their daily life. The latter constitutes a challenge as, for example, in our society, the importance of recycling home leftovers is a theoretically well-known, recommended practice. Nonetheless, survey results show that older people are better recyclers while a great percentage of adolescents do not do any kitchen leftover recycling at all.

When sophomores in an active learning activity were asked to encourage people and especially adolescents to become pro-active recyclers, they chose home worm composting and the effects of vermicompost on plant growth as an experimental experience to actively engage middle school students in the benefits of food waste recycling.

The activities were prepared in advance to their presentation in the annual science fair “Ciència per a tothom 2019” organized by the University of the Balearic Islands. The experimental design took into consideration the potential questions people might have on this issue, with the resulting final flow of three activities that were developed in response to three questions, on the basis of which the students could not only acquire concepts but also observe possible applications and consequences:
Q.1. What should we do with kitchen leftovers? The potential solution of vermicasts was given, a rich organic fertilizer obtained by using composting earthworms elaborated by a vermicomposter.
Q.2. What does compost do to our garden soil? Why is not soil enough for plant growth? To visualize the effect of adding compost to the soil, plants were grown in transparent 50 ml tubes filled up with soil and increasing compost concentrations. The effect of compost on the bioavailability of essential plant growth nutrients and their importance on the microbiome was demonstrated.
Q.3. What about the potentially toxic elements that can sometimes be found in the soil? Non-inoculated or inoculated plants with different bacteria previously isolated from the soil were used to explain the key role of plants and their associated microbiome in barring the entrance of toxic elements into the food chain.

The outcomes of these activities to access what visitors did learn was quantified by using a wheel of fortune to apply multiple response questions by chance, where the winners got a jelly worm as a reward for their participation!

Keywords:

Active and experimental learning, informal learning, nutrient recycling, home leftovers recycling, minimizing food waste, sustainable development, bioremediation.