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Mossoro, Brazil

The Universidade Federal Rural do Semi-Árido is a university located in the city of Mossoró in the State of Rio Grande do Norte in Brazil. Wikipedia.

The information of wetting soil volume under drip irrigation has great importance in design and management of surface drip irrigation for delivering required amount of water to the plant. This study aimed to describe the wetted soil volume for five mathematic models by water applied on soil surface from drip emitter. For that, six experiments were installed in different soils (Entisol, Ultisol, Inceptisol, Psamment, Oxisol, Fluvent) with the objective of evaluating models which can estimate wetted soil volume in function of emitter discharged and time of water application. It was concluded that except for the model proposed by NARDA & CHAWLA, the other models estimated satisfactorily the wetted soil volume for the superficial drip irrigation. The wetted soil volume for the same combinations of emitter discharged and water application time, were larger for Ultisol and smaller for Fluvent and excepting Ultisol and Fluvent, the wetted soil volume can be estimated for a single equation in function of emitter discharged and time of water application. Source

Goncalves A.A.,Federal Rural University of the Semiarid Region | Gagnon G.A.,Dalhousie University
Ozone: Science and Engineering | Year: 2011

In recirculating aquaculture systems (RAS), particulates (including feces, uneaten feed, bacteria, and algae) can cause several problems, in that they may harbor pathogens, can physically irritate the fish, and upon decomposition, release ammonia and consume oxygen. Mechanical filters, foam fractionators, and other engineered devices are used to remove particles quickly from aquaculture systems, in order to improve fish health and decrease the load on biofilters and oxygenators. Ozone is used in RAS as a disinfectant, to remove organic carbon, and also to remove turbidity, algae, color, odor and taste. Ozone can effectively inactivate a range of bacterial, viral, fungal and protozoan fish pathogens. But the effectiveness of ozone treatment depends on ozone concentration, length of ozone exposure (contact time), pathogen loads and levels of organic matter. In spite of ozone is a very effective oxidizing agent, higher ozone concentrations are a risk to cultured fish stocks causing gross tissue damage and stock mortalities, and also are a risk to bacterial films on the biofilter. © 2011 International Ozone Association. Source

Da Silva R.G.,UFERSA | Maia A.S.C.,Sao Paulo State University | de Macedo Costa L.L.,Federal Rural University of the Semiarid Region
International Journal of Biometeorology | Year: 2015

This paper presents a new thermal stress index for dairy cows in inter-tropical regions, with special mention to the semi-arid ones. Holstein cows were measured for rectal temperature (TR), respiratory rate (FR) and rates of heat exchange by convection (C), radiation (R), skin surface evaporation (ES) and respiratory evaporation (ER) in the north eastern region of Brazil, after exposure to sun for several hours. Average environmental measurements during the observations were air temperature (TA) 32.4 °C (24.4–38.9°), wind speed (U) 1.8 m.s−1 (0.01–11.0), relative humidity 63.6 % (36.8–81.5) and short-wave solar radiation 701.3 W m−2 (116–1,295). The effective radiant heat load (ERHL) was 838.5 ± 4.9 W m−2. Values for the atmospheric transmittance (τ) were also determined for tropical regions, in order to permit adequate estimates of the solar radiation. The average value was τ = 0.611 ± 0.004 for clear days with some small moving clouds, with a range of 0.32 to 0.91 in the day period from 1000 to 1300 hours. Observed τ values were higher (0.62–0.66) for locations near the seacoast and in those regions well-provided with green fields. Effects of month, location and time of the day were all statistically significant (P < 0.01). A total of 1,092 data were obtained for cows exposed for 1 to 8 h to sun during the day; in 7 months (February, March, April, July, August, September and November), 4 days per month on the average. A principal component analysis summarised the TR, FR, C, R, ES and ER measurements into just one synthetic variable (y1); several indexes were then obtained by multiple regression of y1 on the four environmental variables and its combinations, by using Origin 8.1 software (OriginLab Corp.). The chosen equation was the index of thermal stress for cows, ITSC = 77.1747 + 4.8327 TA − 34.8189 U + 1.111 U2 + 118.6981 PV − 14.7956 PV 2 − 0.1059 ERHL with r2 = 0.812. The correlations of ITSC with TR, FR, C, ES, R and ER were 0.275, 0.255, −0.493, −0.647, −0.818 and 0.075, respectively. Correlations of the index with the physiological variables are presented, and ITSC is compared to three other indexes. © 2014, ISB. Source

Guimaraes D.V.,Federal University of Sergipe | Gonzaga M.I.S.,Federal University of Sergipe | da Silva T.O.,Federal University of Sergipe | da Silva T.L.,Federal University of Sergipe | And 2 more authors.
Soil and Tillage Research | Year: 2012

Changes in tropical land use have profound effects on soil organic matter (SOM) status. It has been suggested that alterations in the different fractions of SOM are more effective in indicating changes in soil use than total soil organic matter content. The main objective of this study was to investigate changes in the content of humic substances in an Ultisol under different land uses, in the northeast region of Brazil. Soil samples were collected from the 0-10 and 10-30. cm layers, in three agricultural areas (conventional coconut orchard, integrated coconut orchard, and citrus orchard). A native forest soil was used as reference. Organic C and total N were determined to characterize the SOM. Humic substances were chemically fractionated into fulvic acid, humic acid, and humin, based on solubility in acid and alkali. Significant loss (47.5%) of soil organic matter was observed in the surface layers of the conventional coconut and citrus orchards, compared to the native forest. There was increased SOM content in the integrated coconut orchard soil, due to the presence of cover crops as well as management of crop residues. However, in the subsurface soil of the integrated coconut orchard, cultivation modified the distribution of the more labile fractions of the soil organic matter, as measured by the ratio between humic and fulvic acids (>1.0), indicating a substantial loss of fulvic acids. The degree of humification was in the range 40-97%. The distributions of the soil organic matter fractions varied in the ranges 12-32.5% (fulvic acids), 12-34.5% (humic acids), and 40-69.5% (humin). © 2012 Elsevier B.V. Source

Baldauf C.,University of Campinas | Baldauf C.,Federal Rural University of the Semiarid Region | Maes dos Santos F.,University of Campinas
Economic Botany | Year: 2013

Ethnobotany, Traditional Knowledge, and Diachronic Changes in Non-Timber Forest Products Management: A Case Study of Himatanthus drasticus (Apocynaceae) in the Brazilian Savanna. The analysis of factors and processes that affect the traditional knowledge and the management practices deriving from it are essential for devising conservation strategies for non-timber forest products. The purpose of this study is to assess the traditional knowledge and analyze diachronic changes in management systems for non-timber forest products in a case study of an intensely exploited species from the Brazilian savanna, Himatanthus drasticus, commonly known as "janaguba." Janaguba produces a latex of commercial value, widely used in popular medicine in Brazil. Recent pharmacological evidence of its medicinal properties has increased harvesting pressure on this resource. For this reason, we carried out an ethnobotanical characterization of the management systems used to harvest janaguba latex and of the traditional ecological knowledge associated with such practices. Three management systems were identified in latex harvesting, which may have varying ecological impacts on janaguba populations, depending on the amount of bark removed and the time interval between harvestings. Among the factors that can influence changes in the management systems over time are market pressure and growing demand for the product, loss of traditional knowledge, the system of land tenure, and the biological characteristics of the species, especially its high biomass regeneration capacity. © 2013 The New York Botanical Garden. Source

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