Produção orgânica de rabanete em plantio direto sobre cobertura morta e viva.

O objetivo deste trabalho foi avaliar o uso de plantas espontâneas e cobertura viva de amendoim forrageiro(Arachis pintoi), associado à aplicação de composto orgânico na produção orgânica do rabanete em plantio direto. O experimento foi instalado na Universidade Federal do Acre, em Rio Branco-AC, de 15/06 a 14/07/2007. O delineamento experimental utilizado foi em blocos casualizados com parcelas subdivididas 4x3, em quatro repetições. As parcelas corresponderam ao sistema de plantio direto com cobertura viva de amendoim forrageiro, cobertura viva de planta espontânea, cobertura morta de planta espontânea e sistema de plantio em canteiro com solo descoberto. As subparcelas foram compostas pelas doses de composto orgânico de 5, 10 e 15 t ha-1 (base seca). O plantio direto na palha de plantas espontâneas teve desempenho semelhante ao preparo convencional do solo, ambos superiores ao plantio sobre as coberturas vivas. A produtividade do rabanete cv. Cometo, não foi afetada pelas doses crescentes de composto orgânico, podendo aplicar-se apenas 5 t ha-1, enquanto em preparo convencional do solo, o aumento da produtividade ultrapassa o plantio direto na palha apenas na dose maior de composto (15 t ha-1)

Plant communities as a tool in temporary ponds conservation in SW Portugal

Pond conservationTemporary ponds are seasonal wetlands annually subjected to extreme and unstable ecological conditions, neither truly aquatic nor truly terrestrial. This habitat and its flora have been poorly studied and documented because of the ephemeral character of the flora, the changeable annual weather that has a great effect on the small, herbaceous taxa and the declining abundance of temporary ponds. The objectives of this study are: (a) to define plant community diversity in terms of floristic composition of ephemeral wetlands in SW Portugal, (b) to identify temporary pond types according to their vegetation composition and (c) to identify those ponds that configure the European community priority habitat (3170* – Mediterranean temporary ponds). Vegetation sampling was conducted in 29 ponds, identifying 168 species grouped among 15 plant communities. Soil texture, pH, organic C and N content were measured, but only N and percent of clay appear to be related with the distribution of each community type. The results showed that ephemeral wetlands could be classified into four type: vernal pools, marshlands, deep ponds and disturbed wetlands. Vernal pools correspond to the Mediterranean temporary ponds (3170*), protected as priority habitat under the EU Habitats Directive. Submersed Isoetes species (Isoetes setaceum and Isoetes velatum) represents, together with Eryngium corniculatum, the indicator species for vernal pools. We identify also indicator plant communities of this priority habitat, namely I. setaceum and E. corniculatum– Baldellia ranunculoides plant communities. In this region, the conservation of temporary ponds has so far been compatible with traditional agricultural activities, but today these ponds are endangered by the intensification of agriculture and the loss of traditional land use practices and by the development of touris

The phenology of winter rye in Poland: an analysis of long-term experimental data

The study of the phenology of crops, although quite popular, has limitations, mainly because of frequent changes to crop varieties and management practices. Here, we present data on the phenology and yield of winter rye in western Poland collected between 1957 and 2012 from a long-term field experiment. Data were examined for trends through time and compared to climatological factors using regression analysis. Both annual air temperature and precipitation increased during the study period, equivalent to 2 °C and 186 mm, respectively, over the 52-year period for which met data were available. We detected significant delays in sowing date and recently in emergence, but significant advances were apparent in full flowering date equivalent to 4 days/decade. Yield and plant density experienced a step like change in 1986; yield increasing by ca. 70 % and plant density increasing by ca. 50 %, almost coinciding with a similar change in annual mean temperature, but most likely caused by a changed seed rate and use of herbicides. Future climate change is expected to have a greater impact on this crop, but farmers may be able to adapt to these changes by modifying water regimes, using new machinery and sowing new rye varieties

Badania chromatograficzne kwasow humusowych

Humic acids were isolated from A, horizon of soil. Paper electrophoresis and ion exchange chromatography were used for the separation of humic acids. Several substances from humic acids were separated using paper electrophoresis and DEAE Sepharose CL-6B. Molecular weight of humic acids was calculated. The optimalization of gel filtration process of humic acids has been worked out. The parameters of filtration (gels, eluents) of humic acids were determined

Określenie poziomu antocyjanów w truskawkach metodą spektroskopii różnicowej – jak uzyskać prawdziwe wyniki?

The aim of the research was to analyse the weaknesses of the pH differential method for strawberry anthocyanin determination. The work is based on practical experiments with 12 strawberry cultivars and on analysis of published papers. We used following molar absorption coefficients ( ƹ values): 26900 and 29600 M⁻¹ cm⁻¹ for cyanidin 3 glycoside (C3g) and 15600, 22400, 27300 and 36000 M⁻¹ cm⁻¹ for pelargonidin 3 glycoside (P3g). In order to show how the calculated value of total anthocyanins depends on the predominant anthocyanin used for the calculations, we compared the results of spectroscopic and chromatographic analysis. Present research demonstrated that different ƹ values may influence the results of total anthocyanins even more than cultivar properties. The most frequently used ƹ values 26900 M⁻¹ cm⁻¹ and 29600 M⁻¹ cm⁻¹ gave underestimated values. C3g was present in minor amounts in all cultivars. Conclusively, P3g with the ƹ = 15600 M⁻¹ cm⁻¹ should be used for ensuring most precise estimation of total anthocyanin content in strawberries.Celem niniejszego badania była analiza słabości metody różnicowego pH dla ustalenia antocyjanów w truskawkach. Praca powstała na podstawie doświadczeń na 12 odmianach truskawek oraz na podstawie analizy opublikowanych opracowań. Użyto następujących współczynników absorpcji molowej (wartości ƹ): 26900 i 29600 M⁻¹cm⁻¹ dla cyjanidyno 3-glukozydu (C3g) oraz 15600, 22400, 27300 i 36000 M⁻¹cm⁻¹ dla 3-glukozydu pelargonidyny (P3g). Aby wykazał, w jaki sposób wyliczona całkowita wartość antocyjanów zależy od dominujących antocyjanów, porównano wyniki analizy spektroskopowej i chromatograficznej. W niniejszym badaniu wykazano, że różne wartości ƹ mogą wpływać na wyniki całkowitych antocyjanów nawet bardziej niż cechy odmiany. Najczęściej stosowane wartości ƹ 26900 M⁻¹cm⁻¹ oraz 29600 M⁻¹cm⁻¹ dały wartości zaniżone. C3g był obecny w niewielkich ilościach we wszystkich odmianach. Podsumowując, można stwierdzić, że P3g o wartości ƹ = 15600 M⁻¹cm⁻¹ należy stosować, aby zapewnić najbardziej precyzyjne oszacowanie całkowitej zawartości antocyjanów w truskawkach