Dades de plantes al·lòctones per a l’est de la península Ibèrica

Con las observaciones de los últimos años en el este de la península ibérica (concretamente en Cataluña, País Valenciano y la provincia de Teruel), se aportan un conjunto de datos corológicos de 41 plantas alóctonas naturalizadas u ocasionales. Cabe destacar Annona cherimola y Manihot grahamii que se citan por primera vez en la flora ibérica; Echinopsis pachanoi y Hydrocotyle verticillata para Cataluña; Solandra maxima en el País Valenciano. Se tiene que excluir Opuntia pestifer de la flora valenciana, ya que se confirma que las citas anteriores corresponden a Opuntia aurantiaca. Además, se aportan nuevas localidades de Acacia karroo, Cylindropuntia kleiniae, Euphorbia tirucalli, Leucaena leucocephala, Lophocereus marginatus, Nicandra physalodes, Pelargonium inquinans, Physalis peruviana, Podranea ricasoliana, Sedum pachyphyllum, Senna corymbosa, Tradescantia pallida y Tradescantia sillamontana, táxones interesantes y poco conocidos en la flora alóctona del este ibérico. [ca] Amb les observacions dels darrers anys fetes a l’est de la península Ibèrica (concretament a Catalunya, País Valencià i la província de Terol), s’aporten un conjunt de dades corològiques de 41 plantes al·lòctones naturalitzades o ocasionals. Cal destacar Annona cherimola i Manihot grahamii que es citen per primera vegada a la flora ibèrica; Echinopsis pachanoi i Hydrocotyle verticillata per a Catalunya; Solandra maxima per al País Valencià. Cal excloure Opuntia pestifer de la flora valenciana, ja que es confirma que les cites anteriors corresponen a Opuntia aurantiaca. A més a més, s’aporten noves localitats de Acacia karroo, Cylindropuntia kleiniae, Euphorbia tirucalli, Leucaena leucocephala, Lophocereus marginatus, Nicandra physalodes, Pelargonium inquinans, Physalis peruviana, Podranea ricasoliana, Sedum pachyphyllum, Senna corymbosa, Tradescantia pallida i Tradescantia sillamontana, tàxons interessants i poc coneguts a la flora al·lòctona de l’est ibèric.

Ervas daninha em pastagens: uma abordagem fitossociológica nas áreas do Ceará

The aim of this study was to study the phytosociology of weed species in areas of pasture cultivated with Brachiaria decumbens and Cynodon sp. (Tifton 85), in Ceará State, Brazil. The square inventory methodology was used in order to assess the weed community. Weed samples were quantified and classified by family, genus and species, using books and classification keys. The classification and quantification data of species allowed to calculate the following phytosociological variables: frequency (F), relative frequency (Fr), density (D), relative density (Dr), absolute dominance (DoA), relative dominance (DoR), importance value index (IVI), and similarity index (IS). The Amaranthaceae family was the one with the greatest intensity of species in both areas, represented mainly by Alternanthera tenera colla and Amaranthus viridis. In the area cultivated with B. decumbens, Cyperus rotundus presented higher results for frequency, density and abundance. In the Tifton 85 area, Nicandra physalodes presented higher values of density and abundance. The similarity of weed populations in pasture areas was 42.11%, with four species common to both areas.

ACCUMULATION POTENTIAL AND NUTRIENT CYCLING OF APPLE OF PERU (Nicandra physalodes)

ABSTRACT Weed residues can influence nutrient cycling in agroecosystems. Quantifying this potential nutrient source may influence weed control and fertilisation practices. Nicandra physalodes (L.) Gaertn. is a weed with a short life cycle and a great ability to accumulate dry matter. Field observations suggest that N. physaloides residues are easily decomposed in soil. The objective of this study was to evaluate the effect of increasing of N, P and K doses on the growth of N. physalodes, as well as the nutrient content, chemical characteristics and C/N ratio of the weed. A randomised block design, arranged in split-plot with three replications, was utilised. The main plots were given four doses of NPK (Dose 1 - 0, 0.3 and 17.2 mg dm-3; Dose 2 - 30, 450.3 and 75.4 mg dm-3; Dose 3 - 60, 900.3 and 133.4 mg dm-3; and Dose 4 - 120, 1800.3 and 249.68 mg dm-3), and the subplots were harvested at ten time points after emergence (26, 33, 40, 47, 54, 61, 76, 91, 106 and 121 days). Higher dry matter production and N, P and K content were observed in plants grown on higher levels of fertiliser. The increase of N, P and K levels in the soil resulted in greater total accumulation of these macronutrients. The highest macronutrient contents were K and N. The treatments did not affect neutral detergent fibre (NDF), acid detergent fibre (ADF) and C/N ratio of plant. N. physalodes had low C/N ratio, low NDF and ADF levels, and great nutrient accumulation, suggesting that this plant is quickly decomposed, providing a rapid cycling of nutrients.