No abstract

With an area of 6,200 km2, the Gilbués badlands region in the Brazilian drylands is the largest desertification site in the Country. It is located upstream the Boa Esperança Hydroelectric Power Plant and is contiguous to an important Brazilian agricultural area. However, primary quantitative data on erosive processes are scarce or nonexistent. We analyzed on‐site data (2018–2019) concerning small‐scale (hillslope and micro basin) processes: inter‐rill gross erosion, vegetation coverage factor, sediment yield, and sediment delivery ratio. We measured gross erosion in four hillslopes using metal pins; rainfall erosivity using an automatic meteorological station; soil erodibility; and siltation of five check‐dams that control micro basins (101–103 m2) by means of an unmanned aerial vehicle. Gross erosion (102 Mg ha−1 yr−1; 7.5 mm yr−1) is up to 100‐fold the regional mean value and up to 45‐times the tolerable soil‐loss reference value (0.17 mm yr−1), showing that degradation still evolves. Sparse small vegetation directly exposes two thirds of the soil, with a high vegetation factor (0.90). The sediment delivery ratio of the micro basins is 0.88, compatible with low (12%) sediment‐deposition pattern at this scale. The Maner delivery‐ratio model mimicked field observation, which indicates that relief is the key element influencing sediment deposition there. The check‐dam effectiveness considerably decreased after the first decade of operation due to high siltation rates. Although the Gilbués badland occupies only 5% of the basin upstream of the power plant, it contributes 32% of the sediment load to reservoir and dam. This shows the relevance of the badland restoration for the regional sustainability of water and energy supply.

RESUMO Devido à importância das moscas-das-frutas como pragas da fruticultura, este trabalho teve como objetivos caracterizar as populações das moscas-das-frutas em pomares comerciais de goiaba na região do Cariri, Estado do Ceará, por meio de índices faunísticos e estudar a flutuação populacional dessas moscas ao longo do ano. Para isso, foram instaladas armadilhas McPhail nos Municípios de Barbalha, Crato e Juazeiro do Norte. As armadilhas foram examinadas semanalmente e as moscas capturadas foram triadas, conservadas em álcool a 70% e identificadas. Constatou-se que Anastrepha zenildae (Wiedemann), A. sororcula Zucchi, A. fraterculus (Wiedemann), A. obliqua (Macquart) e Ceratitis capitata (Wiedemann) foram as moscas-das-frutas associadas à goiaba. Dessas, A. zenildae. A. sororcula e A. obliqua foram dominantes e constantes na região estudada, enquanto que A. fraterculus e C. capitata foram não-dominantes, mas também constantes. A. zenildae ocorreu em quase todos os meses do ano, exceto em outubro e dezembro de 2008, nos três pomares de goiaba do Cariri e com picos populacionais nos meses mais chuvosos e com temperaturas amenas.

The allelopathy is a process for which products of the secondary metabolism, as terpenes phenolic, of a certain vegetal intervene significantly, generally of antagonistic form, in the development of other species of plants. The objective of this work was to chemically characterize the essential oil of Lippia sidoides Cham. growing in the Cariri cearense region, Brazil, and evaluate the allelopathyc effect of this oil on the germination of lettuce (Lactuca sativa L.), arugula (Eruca sativa Mill.), and cauliflower (Brassica oleracea L.), in pre-plantation application. The monoterpene thymol (84.90%) has been identified as the principal constituent in the essential oil. The experiment was done in randomized complete block, in 4 × 3 factorial; being used four essential oil combinations applied in three different species in pre-plantation applications. Emergence velocity index (EVI), germination percentage and mean time to germination (MTG), had been analyzed through daily counting carried out until the 14 th day after sowing. Through qualitative analysis performed by gas chromatography coupled with mass spectrometry (GC/MS) were identified seven chemical constituents representing 97.82% of essential oil of L. sidoides, being that the constituent present in greater concentration in oil was the thymol (84.90%). Could be verified the occurrence of the negative allelopathyc effect of lettuce crop, because its present low EVI and greater MTG, for the other vegetable species there were no allelopathic effect.