Performance of cultivars of crisp mini-lettuce with respect to ground cover and spacing, in three planting times

The planting of lettuce in greenhouses, as well as covering beds with a polyethylene sheet, is a viable technology, promoting improvements in microclimatic conditions of the environment. In view of the little information on mini-lettuce, the aim of this work was to evaluate the performance of three cultivars of crisp minilettuce ('Green Frizzly', 'Red Frizzly no. 1' and 'Red Frizzly no. 2') with and without ground cover, under different spacings (20 × 15 cm and 20 × 20 cm), in three planting times (1: November 16, 2004; 2: December 17, 2004; and 3: January 20, 2005). The study was conducted in a greenhouse at UNESP-FCAV, Jaboticabal-SP. The experiments were carried out using a randomized block design, following a 3 × 2 × 2 factorial scheme with 12 treatments and three repetitions. The characteristics evaluated were plant height (cm), head diameter (cm), fresh weight (g) and number of leaves per plant. Planting time 3 was shown to be favorable for all the characteristics analyzed. 'Red Frizzly no. 2' was found to be the most suited to planting time 1, and for planting times 2 and 3, this cultivar did not differ from 'Red Frizzly no. 1'. The factor ground cover was not found to affect the characteristics evaluated, and therefore, cultivation without ground cover is recommended. The spacing 20 × 15 cm was shown to be favorable, resulting in cultivation with the highest populations, thereby increasing productivity. Based on the results obtained and for the conditions in which the experiment was conducted, it can be concluded that: planting time 3 (January 20, 2005) was the most favorable; the cultivars 'Red Frizzly no. 2' and 'Red Frizzly no. 1' are adapted to all the planting times; and cultivation without ground cover using a spacing of 20 × 15 cm was the most suitable.

Jamaica: Economic policy and economic performance in the 1972-1980 period: an interpretation

Includes bibliography

Description and interpretation of Cenozoic vertebrate ichnofossils in Rio Grande do Sul State, Brazil

In the neighborhood of the city of Boqueirão do Leão (State of Rio Grande do Sul, Brazil) a set of three big-sized tunnels has been found. One of the tunnels is only partially filled with sand and accessible along its entire length. It is horizontal, slightly sinuous, 36 m long, up to 4.2 m wide and up to 2.0 m high. The surface morphology of the walls is composed of anthropogenic marks, speleothems, black incrustations and traces like digging scratches and smoothed surfaces. The 2nd tunnel has its entrance blocked by sand and sandstone cobbles, but the end of the tunnel is only partially clogged and therefore accessible. This accessible portion is 12 m long, 3 m wide and 1.5 m high. The 3rd tunnel is completely filled and collapsed and is nowadays only indicated by concave roof features at its end. The general features of the tunnel system and the analysis of the surface morphology of the walls of the accessible portions permit to conclude that the tunnels were produced by ground sloths of the Cenozoic South American megafauna. The size of the tunnels suggests that its excavation was gradually carried out by successive generations of sloth herds, and not by a single individual animal. The primary function of the tunnels probably was not protection from predators, which had easy access to structures of this size, but to shelter during a drier climate. However, it is not yet possible to relate the tunnels to a specific ground sloth genus, a task that depends on the discovery of better-preserved tunnel systems. © 2013 by the Sociedade Brasileira de Paleontologia.

The no-tillage system and cover crops-Alternatives to increase upland rice yields

Upland rice (Oryza sativa L.) cultivation has been increasing in importance in Asia while water availability for irrigation has been decreasing because of rapid growth in industry and urban centers. Therefore, the development of technologies that increase upland rice yields under aerobic conditions, thereby saving water, would be an effective strategy to avoid a decrease in global rice grain production. The use of the no-tillage system (NTS) and cover crops that maintain soil moisture would prove advantageous in the move toward sustainable agriculture. However, upland rice develops better in plowed soil, and it has been reported that this crop does not perform well under the NTS. Therefore, the aim of this study was to investigate the effect of cover crops on upland rice grain yield and yield components sowed in a NTS. A field experiment was conducted during two growing seasons (2008-2009 and 2009-2010), and treatments consisted of growing rice under five cover crops in a NTS and two control treatments under the conventional tillage system (plowing once and disking twice). Treatments were carried out in a randomized block design with three replications. Our findings are as follows: On average, Brachiaria brizantha (12.32Mgha-1), Brachiaria ruziziensis (11.08Mgha-1) and Panicum maximum (11.62Mgha-1) had outstanding biomass production; however, these grasses provided the worst upland rice yields (2.30, 2.04, and 2.67Mgha-1, respectively) and are not recommended as cover crops before upland rice. Millet and fallow exhibited the fastest straw degradation (half-lives of 52 and 54 days, respectively), and millet exhibited the fastest nitrogen release (N half-life of 28 days). The use of a NTS was promising when millet was used as a cover crop; this allowed the highest upland rice yield (3.94Mgha-1) and did not statistically differ from plowed fallow (3.52Mgha-1). © 2012 Elsevier B.V.

Cover crops and no-till effects on physical fractions of soil organic matter

Physical fractions (free light fraction, intra-aggregate light fraction and heavy fraction) of soil organic matter (SOM) are good indicators of soil quality for sustainable land use. The objective of this study was to evaluate the effect of cover crops on total organic carbon (TOC) and physical fractions of soil organic matter in soil under a no-tillage system (NTS) and a conventional tillage system (CTS, one plowing and two disking). A three-year field experiment was carried out as a cover crop-rice (Oryza sativa)-cover crop-rice rotation. Treatments included cover crops (Panicum maximum, Brachiaria ruziziensis, Brachiaria brizantha, and pearl millet (Pennisetum glaucum), fallow, till or no till. The SOM was physically fractionated in free light fraction (FLF), intra-aggregates light fraction (IALF) and heavy fraction (HF). The levels of C in whole soil were also evaluated, as well as C in the light fractions (FLF+IALF) and in the HF. Results indicated that concentrations of C in the FLF and IALF in surface soils (0-0.05m) were much higher (10.8 and 1.95gkg-1, respectively) than that in the 0.05-0.1m soil depth (7.68 and 1.54gkg-1, respectively) and in the 0.1-0.2m soil depth (4.98 and 1.24gkg-1, respectively). The NTS resulted in higher levels of FLF (12.2gkg-1) and IALF (2.19gkg-1) than with CTS (1.37-7.30gkg-1). Millet had the highest C (19.5gkg-1) and N (1.1gkg-1) concentrations in soil. There was an accumulation of TOC and total N in the surface soil with cover crops, and concentrations of TOC were higher in the HF (79.0%) than in the light fractions (21.0%). Although SOM changed little during the two years of this experiment, the various C fractions were significantly affected by the tillage treatments. We conclude that SOM physical fractionation allowed seeing significant differences caused by the soil management in the organic matter dynamics in a short period of time. © 2013 Elsevier B.V.

Consumer interpretation of ready to drink orange juice and nectar labelling

The aim of this study was to evaluate consumers' use and interpretation of ready to drink orange juice and nectar label information and its influence on the purchase decision. One hundred and sixty-seven consumers of ready to drink orange juice and nectar were interviewed. The labels were analysed to evaluate their conformance to Brazilian legislation. The manufacturing and shelf life date were the information most often checked, followed by health related issues. Brand, price and flavour were the most important factors for purchase decision. Brand and flavour showed significant association with consumer age. For most interviewed, 'nectar', 'whole' and 'natural' or '100% natural' were not well understood; they were not in accordance with the Brazilian legislation. 'Nectar', 'whole' and 'natural' or '100% natural' received a positive interpretation, whereas 'reconstituted juice' was considered a negative expression. Nevertheless, none of the labels completely conformed to the specific nutritional labelling legislation. © 2013 Institute of Food Science and Technology.

Interpretation of searches for supersymmetry with simplified models

The results of searches for supersymmetry by the CMS experiment are interpreted in the framework of simplified models. The results are based on data corresponding to an integrated luminosity of 4.73 to 4.98 fb-1. The data were collected at the LHC in proton-proton collisions at a center-of-mass energy of 7 TeV. This paper describes the method of interpretation and provides upper limits on the product of the production cross section and branching fraction as a function of new particle masses for a number of simplified models. These limits and the corresponding experimental acceptance calculations can be used to constrain other theoretical models and to compare different supersymmetry-inspired analyses. © 2013 CERN.

Cover crop termination timing on rice crop production in a no-till system

Measuring shikimic acid accumulation in response to glyphosate applications can be a rapid and accurate way to quantify and predict glyphosate-induced damage to sensitive plants. The objective of this paper was to evaluate the effect of cover crop termination timing by glyphosate application on rice (Oryza sativa L.) yield in a no-till system. A factorial experiment, arranged in a split-plot design, was conducted for 2 yr. Treatments consisted of cover crops (main plots) and timed herbicide applications (subplots) to these cover crops (30, 20, 10, and 0 d before rice planting). There was a decrease in rice yield from 2866 kg ha-1 to 2322 kg ha-1 when the herbicide was applied closer to the rice planting day. Glyphosate application on cover crops increased shikimate concentrations in rice seedlings cultivated under palisade grass (Brachiaria brizantha), signal grass (B. ruziziensis), guinea grass (Panicum maximum), and weedy fallow (spontaneous vegetation) but not under millet (Pennisetum glaucum), which behaved similarly to the control (clean fallow, no glyphosate application). Glyphosate applications in the timing intervals used were associated with stress in the rice plants, and this association increased if cover crops took longer to completely dry and if higher amounts of biomass were produced. Millet, as a cover crop, allowed the highest seedling dry matter for upland rice and the highest rice yield. Our results suggest that using millet as a cover crop, with glyphosate application far from upland rice planting day (10 d or more), was the best option for upland rice under a no-tillage system. © Crop Science Society of America.

The practical interpretation and application of the polluter pays principle

Revisa brevemente la teoría que hay detrás de las dos interpretaciones del principio contaminador-pagador, para comentar las implicaciones de éstas en la política ambiental, y considerar en qué medida este principio es aplicado en la práctica.

Novas formas de pensar/dizer, dizer/pensar: a imagem como linguagem mediadora da experiência do formador de professores

Pós-graduação em Artes - IA

Caracterização do uso do solo e das áreas de preservação permanente, visando a adequação ambiental

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação da informação sobre políticas públicas nos portais de governo na internet das regiões administrativas do Estado de São Paulo

Pós-graduação em Comunicação - FAAC

Cadernos íntimos diários publicados: um estudo das práticas da escrita de diários, no âmbito das práticas sociais disseminadas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)