biostimulant, efficiency, nutrition, Theobroma
Objective: To evaluate the effect of the application of biostimulant doses on the development, absorption, and use efficiency of nitrogen, phosphorus, and potassium by cacao seedlings.
Design/Methodology/Approach: Five doses of Enerplant® (0, 1, 2, 3, and 4 mL ha-1) were applied to cacao seedlings grown under a saran mesh. The study was carried out using a completely randomized design. The foliar area received a monthly application of the biostimulant. In order to determine the nutrient absorption, 3 plants per treatment were divided into leaves, stems, and roots; they were subsequently dried for 72 h at 65 °C. Finally, they were ground, packaged, labeled, and sent to the laboratory, where the macronutrients of each component were analyzed.
Results: The cacao seedlings had a positive response to the biostimulant application. In average, the results of our two-year study were: 1 mL ha-1 doses of Enerplant® significantly increased height (24%), dry mass (30%), quality index (58%), and foliar area (56%) of the cacao seedlings. Doses higher than 1- and 2-mL ha-1 decreased plant growth. The nutrient absorption by cacao in the nursery stage followed the following pattern: K > N > P.
Findings/Conclusions: The efficiency of nutrient use —regardless of the Enerplant® dose applied— was higher for P, followed by N and, finally, K. Applying 2 mL ha-1 doses of the biostimulant guaranteed the highest absorption and use efficiency values of macronutrients by cacao seedlings.