Combined Reuse of Paint Industry and Cattle Slaughterhouse Effluents for the Fertigation of Mombaça Grass

Abstract This study aimed to evaluate the effects of the combined application of effluents from the paint industry and cattle slaughterhouses on the fertigation of Mombaça grass ( Panicum maximum cv. Mombaça). The experiment was conducted in pots with 12 plants using a completely randomized design in a 5 × 2 factorial arrangement, with five sampling times (0, 2, 4, 6, and 8 months) and evaluated under two conditions: with and without application of the combined effluent at a 1:1 ratio. Fertigation promoted a significant increase in Mombaça grass productivity, reaching an average of 18.28 t/ha of dry matter. Greater extraction of nitrogen, calcium, phosphorus, potassium, and magnesium was observed over 12 months, even with continuous plant extraction. An increase in potential cation exchange capacity was also observed, indicating improved soil fertility. In contrast, there was a decreasing trend in pH. The effective cation exchange capacity (ECCe) remained stable, revealing a dynamic balance between nutrient input and absorption. The data demonstrate the agronomic potential of reusing these effluents as a sustainable alternative for fertigation yet highlight the importance of long-term studies to assess potential environmental risks and contaminant accumulation. This study contributes to the integration of liquid-waste management and sustainable agricultural practices.