Respostas fisiológicas da cana-de-açúcar ao uso de pó rocha no sulco de plantio convencional

Abstract

The application of reminalizers, such as rock dust, is a promising strategy to improve soil fertility and crop performance. This study analyzed sugarcane ratoon crop, focusing on physiological variables, such as water use efficiency and internal CO₂ concentration. The influence of reminalizer doses on nutrient uptake and photosynthesis can impact productivity. Understanding these effects is crucial for sustainable agricultural practices under water stress conditions. Thus, the objective of this work was to study the physiological behavior of sugarcane in response to the use of rock dust in the juice bottom in conventional planting. The experiment was started on July 29, 2023, with a randomized block design, including five reminalizer treatments (0, 1, 2, 3, and 4 t ha⁻¹) and four replicates, totaling 20 plots of 30 m². The remineralizer "Vulcano Agrominerais", derived from granulitic rocks, was applied to the bottom of the furrows prepared in a Argissolo Vermelho-Amarelo Distrófico. The variables analyzed included photosynthesis rate, internal CO₂ concentration, transpiration, stomatal conductance, instantaneous water use efficiency, and instantaneous carboxylation efficiency. The planting of the sugarcane variety CTC 14 was carried out manually, with measurements of gas exchange using a portable analyzer and total chlorophyll evaluated with a chlorophyll meter at different plant heights. The data were analyzed by analysis of variance, and the means were compared by the Tukey test, using the Sisvar® software. The application of remineralizers in ratoon sugarcane positively impacted the physiological variables analyzed, with emphasis on the instantaneous water use efficiency, which presented significantly higher values in the treatment with 1 t ha⁻¹. Internal CO₂ concentration and stomatal conductance were balanced between treatments, suggesting adequate nutritional management. The results indicate that reminalizers can promote better growth conditions, reflecting on photosynthesis and plant productivity. This evidence highlights the importance of further research on the use of reminalizers, aiming at optimizing water and nutrient use. Thus, sustainable agricultural practices are essential to increase productivity, especially in contexts of water stress. The implementation of these strategies can significantly contribute to crop resilience in adverse environments.