Vai um cafezinho? Potenciais efeitos da adição de borra de café como fertilizante na germinação e desenvolvimento de Handroanthus chrysotrichus (Mart. Ex.) Mattos (Bignoniaceae)

Abstract

Emerging contaminants, such as caffeine, persist in aquatic environments, soils, and air, exhibiting resistance to conventional wastewater treatment methods. Present in coffee, tea, and pharmaceuticals, caffeine may be toxic to both plant and animal organisms. The global increase in coffee consumption and the improper disposal of by-products, such as spent coffee grounds (SCG), contribute to the introduction of this compound into the environment. Rich in organic compounds and nutrients, SCG is used as a fertilizer, potentially altering the soil's physicochemical properties and affecting plant growth. This study evaluated the effects of SCG and caffeine on the germination and development of Handroanthus chrysotrichus (Mart. ex.) Mattos, a native species of the Atlantic Forest. Four treatments were applied: CAF (SCG), DCAF (decaffeinated SCG), NPK (commercial fertilizer), and C (control), in 48 pots with 288 seeds, monitored for 240 days. Parameters analyzed included germination percentage, mean germination time, germination speed index, and seedling establishment percentage. In terms of germination, C, CAF, and DCAF showed similar performance, whereas NPK yielded lower values. The presence of caffeine in the CAF treatment was associated with signs of stress and reduced initial growth. The results indicate that SCG exerts a dual effect: providing nutrients, but caffeine may cause phytotoxic effects, compromising early development. The use of SCG as an agricultural input requires careful assessment to minimize risks and maximize environmental benefits.