Efeito da irrigação na distribuição espacial de nematoides endoparasitas em áreas de tabuleiro cultivados com cana-de-açúcar

Abstract

Sugarcane is one of the most important crop in Northeastern Brazil and the plant-parasitic nematodes, one of the most important threat for the crop productivity. The high temperature in the dray sand soils of the costal tables cultivated with sugarcane has increased the losses. Considering that the nematode spatial distribution in soil is associated to the soil water content, structure and management, this study aimed to evaluate the effect of irrigation on spatial distribution of Meloidogyne spp. and Pratylenchus spp., the main plant-parasitic nematodes, in a costal table cultivated with sugarcane. Experiments were carried out in two areas, irrigated and non irrigated, and soil samples were collected before planting and at 4, 9 and 14 months after, on a 12.5 × 12.5-m grid, with 36 points per area, at 0-25 cm depth. Descriptive statistics and geostatistics were used to characterize the nematode spatial dependence and prepare kriging maps. Based on semi variance, most data fitted to spherical model. In general, spatial dependence was high and weak, with ranges higher than 3 m. Sugarcane irrigation on the table area drove to a more uniform distribution of Pratylenchus sp. in soil, in contrast to the non irrigated area, in which the nematode population presented more aggregated.