Inoculação micorrízica e doses de fósforo no crescimento inicial da erva-mate

Abstract

Yerba mate is the main non-timber forest product in the southern region of Brazil. Arbuscular mycorrhizal fungi (AMF) can improve phosphorus (P) uptake efficiency in plants, but little is known about its effects on yerba mate. The objective was to evaluate the effects of AMF and P doses on the initial growth, dry matter production, and phosphorus nutrition in yerba mate. The experiment was conducted in the seedling production nursery of the Forest School in Irati-PR, Brazil. The experimental design was randomized blocks with four replicates in a 2x7 factorial scheme, with two mycorrhizal inoculation treatments and seven P-dose treatments added to the soil. At 90, 210, and 320 days after transplanting (DAT), growth evaluations were performed, including measurements of shoot height and stem diameter. Plants were harvested, and dry weights of roots, stem, and leaves were obtained. Subsequently, the amount of accumulated P in these plant parts was estimated after determining the P content in the dry matter. Phosphorus fertilization in moderate doses increased the growth and dry matter production of yerba mate. The amount of accumulated P in yerba mate shoot and roots increased with the increment of P doses in the soil. Arbuscular mycorrhizal fungi promoted greater initial growth of yerba mate in P-deficient soil and increased biomass production of roots and shoot, as well as the amount of accumulated P in the shoot. This demonstrates the feasibility of using AMF-based inoculants to improve the development and P uptake by yerba mate in nutrient-poor soils.