ABSTRACT Dry rot of yam (Dioscorea spp.) caused by Scutellonema bradys and Pratylenchus spp. has restricted yam production in Brazil. Plant-based products can be useful reducing nematode damages. The objectives of this study were to evaluate the nematostatic and nematicidal in vitro activities of pyroligneous extracts from Cocos nucifera, Syagrus cearensis, S. coronata, and Wodetia bifurcata palms against S. bradys and to evaluate the effect of C. nucifera pyroligneous extract in the treatment of yam tubers infected by S. bradys and Pratylenchus sp. under greenhouse conditions. The pyroligneous extracts obtained at pyrolysis temperatures of 400, 500, 600, and 700 ºC, and at different concentrations, were tested for nematode immobility and mortality in Kline slides. Cocos nucifera pyroligneous extract obtained at 400 °C and 1% concentration was tested on yam tubers, under different immersion periods. Six months after yam planting the nematode populations were evaluated. All pyroligneous extracts inhibited the mobility and caused mortality to S. bradys, however 100% inhibition of both variables was achieved at concentrations varying from 0.75 to 2%, depending on the pyrolysis temperatures. The reproduction factor was reduced in 43% by treating infected yam tubers with pyroligneous extract from C. nucifera.

RESUMO Neossolos Regolíticos no Agreste Meridional de Pernambuco são utilizados para diversas atividades agrícolas, com destaque para a produção de feijão. Há uma variação expressiva na produção dessa cultura, possivelmente associada à presença de lamelas, que conferem comportamento hídrico distinto entre esses solos. Objetivou-se analisar as características macromorfológicas, micromorfológicas e físicas de Neossolos Regolíticos localizados no Agreste Meridional de Pernambuco, com a finalidade de se entender o comportamento hídrico desses solos. Foram coletados e analisados dois perfis de solos localizados nos municípios de Paranatama (P1 - sem lamela) e de São João (P2 - com lamela). Os resultados mostraram que nos atributos morfológicos (cor, textura, estrutura e consistência) não foram observadas diferenças expressivas entre os dois perfis de solos; os atributos físicos (teor de argila, macroporosidade, microporosidade, capacidade de campo e ponto de murcha permanente) apresentaram diferença significativa entre os horizontes dos perfis estudados; a micromorfologia indicou que a maior retenção de água no P2 é consequência da presença de zonas com empacotamento mais denso de seus componentes (empacotamento aglomerático) e expressividade das pontes de argila; e sugere-se adoção do termo “lamélico” pelo atual Sistema Brasileiro de Classificação de Solos (em 4º nível categórico) para diferenciação dos perfis estudados.

ABSTRACT Regosols in the Agreste Meridional region of Pernambuco, Brazil, are used for various agricultural activities, and prominent among them is production of common bean. An expressive variation is perceived in common bean crop yield, possibly associated with the presence of lamellae, which make for distinct water fluxes among these soils. The objective was to analyze the macro- and micromorphological, and physical characteristics of the Regosols located in the Agreste Meridional region of Pernambuco to understand the water fluxes in these soils. Two soil profiles, located in the municipalities of Paranatama (P1 - absence of lamellae) and São João (P2 - presence of lamellae) were collected and analyzed. In the morphological properties (color, texture, structure, and consistency) no significant differences between the two soil profiles were observed; the physical properties (clay content, macro- and microporosity, field capacity, and wilting point) exhibited significant differences among the horizons of the profiles studied; micromorphology indicates that greater water retention in P2 is a consequence of the presence of areas with denser packing of their components (agglomerative packing), and expressiveness of clay bridges; and we suggest adoption of the term “lamellic” within the current Brazilian System of Soil Classification (in the 4th categorical level) for differentiation of the soil profiles studied.