Promoção do crescimento de cafeeiros por Aspergillus niger sob diferentes formas de adubação fosfatada

Abstract

P is a very important nutrient for plants, as it is essential for carrying out major processes, such as cell energy transfer, respiration, photosynthesis, structure of nucleic acids, phosphoproteins, phospholipids, among others. Brazilian soils, mainly in the Cerrado region, present limitations to agricultural production because they are acidic and have low natural fertility, especially in relation to phosphorus. A natural and sustainable alternative to making this nutrient available to plants are phosphorus solubilizing microorganisms. In addition to making nutrients viable, fungi such as Aspergillus niger have the ability to produce phytohormones and thus promote plant growth. The objective of this work is to evaluate the ability of the fungus A. niger to promote the growth of coffee trees under different forms of phosphate fertilizer. The following variables were evaluated: plant height, crown diameter, stem diameter, branch length, number of nodes and number of branches. The experimental design was in randomized blocks, in a 3x5 factorial scheme. Three forms of inoculation: non-inoculated (Ni); inoculated seedling (80 to 90 days after sowing) and post-planting inoculation. The second factor was composed of phosphate fertilizers, with four sources of phosphorus: Natural Phosphate, (FN); Triple Superphosphate (TSP); Natural Phosphate + Triple Superphosphate (FN+TSP), Thermophosphate (TP) and without P (SF). The application of phosphate fertilizers was transparent, in the planting furrow, in November 2020. Of the treatments inoculated with the fungus Aspergillus niger, the one inoculated in the seedling proved to be more viable than the one inoculated after planting. Among the phosphorus sources used, the mixture of natural phosphate + triple superphosphate guaranteed higher growth rates, in four variables out of six evaluated, namely: stem diameter, crown diameter, plant height and number of nodes facing north.