Aspectos morfofisiológicos de girassol em função de diferentes doses de terra diatomácea

Abstract

Sunflower (Helianthus annus L.) is an oleaginous plant cultivated all over the world and of great importance for its many uses. In Brazil, this species is not considered one of the main agricultural crops by producers, being more cultivated in the off-season of agricultural commodities, soy and corn. This reality can be changed, since the sunflower has gained prominence, mainly with regard to the use of its oil as biofuel. However, to make this crop more economical and interesting for producers, research must be conducted with a focus on increasing its economic efficiency, that is, increasing productivity with cost reduction. It is within this context that research is inserted that seeks to evaluate the use and concentration of fertilizers and minerals to be applied to crops. Among the existing fertilizers, Diatomaceous Earth (TD) is still little studied as a fertilizer. What is known about it is that it has been widely used in sprays to control pests and diseases in some crops. TD is rich in silicon, a mineral that is not essential for plants, but which, when present in its tissues, brings many benefits to cultures. Based on the above, the objective of this work was to evaluate the morphological characteristics in the vegetative and reproductive, and physiological gains in sunflower plants observed at different concentrations of DT. The study was carried out between June and August 2022, in a greenhouse belonging to the agrometeorological station of the Federal University of Ceará. Six concentrations (0; 3.0; 6.0; 9.0; 12.0 and 15.0 g Kg-1 of substrates) of DT whose composition is 90% SiO2 (BioMarkan®) were evaluated. Each experimental unit consists of a container with a volume of 20 liters, filled with 14 kg of organic compost. Seeds of the Multissol cultivar (BRSEEDS®) were used, and seven seeds were sown per container. The experimental arrangement was in a completely randomized design, with 12 repetitions, totaling 72 experimental units. It was verified that the only variable that presented a significant difference between the treatments was the capitulum diameter, being this morphological parameter directly related to the productivity. It is concluded that, possibly, the low solubility combined with the concentrations of Diatomaceous Earth used in research, were not enough to influence most of the morphological and physiological aspects evaluated in sunflower plants.