POTENCIAL AGRONÔMICO DO RESÍDUO DE Tenebrio molitor EM ALFACE-CRESPA (Lactuca sativa var. crispa)

Abstract

The cultivation of curly lettuce (Lactuca sativa var. crispa) is widespread in Brazil, with vegetable production expanding to commercial scales. Organic fertilization in lettuce farming, predominantly using manure and poultry litter, is a common practice. The growing demand for efficient, cost-effective, and nutrient-rich organic inputs highlights the need for viable alternatives. Tenebrio molitor production, relevant in the feeding of birds and fish, generates waste with potential as an organic fertilizer, though still underexplored in agriculture. This experiment, conducted in Morrinhos, Goiás, aimed to evaluate the cultivation of curly lettuce using organic compost. Four treatments were tested: T1 (0.0), T2 (2.5), T3 (5.0), and T4 (7.5 t ha⁻¹), with six replicates, in a randomized block design. The plots measured 2.5 m², and the residue was incorporated to a depth of 10 cm using an adjusted rotary hoe. Variables such as fresh head weight, total chlorophyll index, organic matter content, potassium, phosphorus, and soil pH were evaluated. The experiment was carried out in two distinct cycles, with three soil sampling periods during each cycle. The 7.5 t ha⁻¹ dose resulted in the highest total chlorophyll index recorded (21.78). The highest potassium level (320.06 mg dm⁻³) was also observed at the 7.5 t ha⁻¹ dose. Phosphorus content was significant in the second cycle, reaching 102.8 mg dm⁻³. Meanwhile, the pH remained above 6 in both cultivation cycles. Organic matter levels exceeded 3%, indicating the interaction of the compost with the soil. The highest fresh head weight was recorded in the first cycle, at 281.83 g. These results confirm the agronomic potential of Tenebrio molitor residue as an organic fertilizer in curly lettuce production.