EFEITOS DE DOSES DE POTÁSSIO SOBRE Pratylenchus brachyurus EM SOJA

Abstract

The nematode of the root lesions has caused high and increasing damage to soybeans. The pathogenicity of Pratylenchus brachyurus is influenced by the nutrition of the host plant, and K has been attributed to the beneficial effect on plant health. Thus, the objective was to evaluate the effect of potassium on populations of P. brachyurus in soybean. The experiment was conducted in the greenhouse, with 1.8-liter pots and clayey soil, with low K content, previously autoclaved. Infestation with 400 nematodes / pot was performed nine days after planting. The experimental design was completely randomized (DIC), composed of four treatments, T0 (control, without application of K2O), T1 (recommended dose of K2O - 130 kg / ha), T2 (half of the recommended dose of K2O - 65 kg / ha), T3 (twice the recommended K2O dose - 260 kg / ha), and nine repetitions. Potassium fertilization was carried out in the form of KCl, meeting the recommendations of the MT Foundation (2017). The doses were applied and incorporated into the soil at pre-planting. The cultivar NS7227RR was used and 53 days after the infestation the fresh and dry mass of the aerial part and number of females / 10g of root were evaluated. There was no significant difference between K doses for morphometric data. All K doses evaluated reduced the population of P. brachyurus. Thus, it is concluded that potassium fertilization interferes by reducing the population of P. brachyurus. However, further studies are needed to improve the issue of potassium fertilization in the control of the P. brachyurus nematode.