O controle da invasora aguapé (Eichhornia crassipes) em ações de educação ambiental

Abstract

The present study was conducted with knowledge that all biomes have been suffering alterations due to anthropic action, which coexist with a lack in formation of conscience in formal and informal environmental education contexts. In the last two centuries alone, two great wars, policies centered on the use of fossil fuels, and the demographic explosion alongside epidemics and extreme social inequalities greatly impacted civilizations. Industrial products, polluting effluents, and deficiencies in public sanitation are some of the factors that have been increasing the levels of nitrogen (N) and phosphorus (P) in the already scarce world reserves of fresh water. Another problem are waters rich in nitrogen and phosphorus in tropical and subtropical zones: the ideal environment for Eichhornia crassipes, popularly known as water hyacinth, a species that is native to the Brazilian Amazon. Its beautiful flowering was marketed to all continents on the planet, except for Antarctica. This plant has been known for centuries by the indigenous South American people as aguapey. A decade ago, it became a matter of concern to the world, when it was considered the worst invasive pest in the Iberian Peninsula, requiring strict European legislation. It has two reproduction modes and there are no considerable predators, thus no natural control. It favors the proliferation of mosquitoes and disease dissemination. On top of that, its dense vegetation pulls the oxygen from springs with all forms of life existing in its surroundings, in addition to preventing the beneficial effects of sunlight reaching the liquid. The damage caused by this species impairs navigation, fishing, tourism, the operation of hydroelectric turbines, as well as all human initiatives involving the multiple uses of water. The control of this invader is a priority and it is an urgency to incentive immediate “eco-engagement” of children and young people to the cause, which are also vectors of information for the elderly, something of great importance. Knowledge about the use of herbicides, great bee killers, must be expanded. The application of glyphosates to combat this macrophyte is encouraged through unethical advertising (banned in several countries) aimed at agribusiness and rural areas, which only serves to disperse carcinogenic chemicals in nature and does not prevent new repopulations in the case of the species Eichhornia crassipes. We observed that the vast areas of predominance of the plant on the planet are the same floodplains proper to the extensive rice (Oryza sativa L) agricultural production. The popular rice husk, resulting from the rice monoculture, can even fertilize the soil if incinerated, but it contaminates the air and, if released into nature, it will pollute the ground. In the present study, we tried to put into practice a small-scale experiment, which we understand is replicable in larger scopes given the abundant offer of rice husks and water hyacinth in the environment. We expected to obtain a better composting when joining these different biomasses. Thus, we can suppress the two undesirable substances and their effects by associating them in decomposition, transforming their aggregate into a stable substrate and a natural fertilizer. The aim is to obtain a product rich in nutrients P and N and dozens of micronutrients well assimilated to the soil and agricultural crops. In the following paper, we seek to demonstrate how to achieve these goals in the most sustainable way possible. To do so, and to show it to students, we promoted informal environmental education practices on composting, with occasional systematized procedures in which the reutilization of materials and energy saving were prioritized. The results come from the comparative evaluations between two composts; while, in the didactic-quantitative aspect, we applied a questionnaire that demonstrates the success in instigating the curiosity and the investment of the students of the Physical Education Course and the Sports Center of the Universidade Federal de Santa Maria (CEFD/UFSM) in the research theme. At the conclusion of this study, we bring instructions that guide the aforementioned environmental education activities, which were demonstrated to be feasible and were carried out by only one individual. They were able to move and motivate the students as healthy and sustainable practices, as are the water hyacinth collection games, the Plogging of this plant, and the vegetable garden workshops using humus obtained from it: all instruments already available to UFSM’s Environmental Education practices.