Composição da nematofauna e qualidade do solo em cultivo irrigado de goiabeira no semiárido

Abstract

The Brazilian semiarid is characterized by low rainfall and high evapotranspiration. The native vegetation is Caatinga, with strong familiar agriculture and recurrent anthropic actions. Guava is one of the most important crops in semiarid, but it is highly damaged by plat-parasitic nematodes. Due to broad distribution and wide diversity, nematodes are good indicators of soil quality, and can be used as a tool for the plant-parasitic nematodes management. This work evaluated the structure and composition of nematode community in a guava orchard under agroecological system, in the sertão (hintexlands) of the state of Pernambuco in the Northeast Brazil, irrigated in the dry season through subsurface drip and without irrigation in the wet season. Soil quality was assessed through ecological indices of nematodes. Soil samples were collected from 74 points randomly distributed among guava plants in the wet (no irrigation) and dry (with irrigation) seasons. The plant-parasitic nematodes were dominant in both seasons, standing out Meloidogyne, and within the free living the bacterivorous Cephalobus, Rhabditis and Acrobeles and the omnivorous Dorylaimus and Eudorylaimus. Based on the faunal profile, the area was classified as enriched, in maturation. Soil humidity and temperature affected nematode community activities. Despite of no irrigation, soil humidity was more even in wet season ensuring increased homogeneity in soil food web. In dry season the irrigation was not enough to keep number of specimens and trophic structure of nematode community.