Produção de soja sob aplicação de lithotamnium

Abstract

Soybean (Glycine max L.) cultivation is directly and indirectly linked to human nutrition and renewable energy generation, making it important to adopt agricultural practices to maximize plant production. Among these practices, the use of biofertilizers based on seaweed, amino acids, humic substances, and nutrients has become increasingly common. The objective of this work was to study the results of an experiment with soybeans with different doses of the Lithothamnium sp. based mineral fertilizer Lithotop, for the purpose of analyzing leaf diagnosis, biometry and development, severity of leaf diseases (Septoria glycines), thousand-grain weight, productivity, and pre- and post-harvest soil. The trial was conducted in the city of Nova Ponte - MG. Sowing took place on November 24, 2023, and harvesting on April 6, 2024, totaling 124 days of cycle. The experimental design was DBC with five replicates and five treatments: T1 (dose 0 kg ha-1), T2 (dose 10 kg ha-1), T3 (dose 15 kg ha-1), T4 (dose 20 kg ha-1) and T5 (dose 25 kg ha-1). There was no difference in leaf diagnosis by the test for most treatments, except for sulfur, zinc, boron and iron; however, these differences were not so marked, which does not make clear the possible influences of the treatments on the nutritional status of the plants. Regarding biometry, there was no significant difference between the treatments and the control for plant height, number of nodes and fresh mass; there was a statistical difference only for dry mass of the aerial part of the plants. Regarding nodulation at 49 days after planting (DAP), it was found that there was only a significant difference between treatments 3 and 5 in relation to the number of nodules. In the second biometric evaluation of the plants, at 110 DAP, there was no significant difference in any of the variables analyzed between the treatments and the control. Regarding the evaluation made to quantify the severity of leaf diseases, the symptoms found were typical of Septoria glycines, restricted to the lower third of the plants, therefore predominant in older leaves. Regarding the weight of a thousand grains, only the control had a lower value than the other treatments. For productivity, there were no statistical differences between the doses evaluated. In the data obtained for nodulation and productivity, the dose of 20 kg ha-1 demonstrated the best relative performance among the treatments. However, it is recommended to carry out complementary studies to analyze and validate the consistency in different edaphoclimatic conditions.