da Silva A.R.,State University of Maringá |
de Souza Junior I.G.,DAG UEM |
da Costa A.C.S.,DAG UEMAlceu Rodrigues da Silva
Revista Brasileira de Ciencia do Solo | Year: 2010
The ferrimagnetic minerals maghemite (γ-Fe2O3) and magnetite (Fe3O4) are closely related with metal availability and P adsorption capacity. Magnetization is spontaneous in a significant percentage of Brazilian soils. In the State of Paraná (Brazil) this area represents up to 50%. The determination of the mass-specific magnetic susceptibility (χBF) is the simplest method of identification and quantification of ferrimagnetic minerals in soils. The χ LF is a quick, cheap, non-destructive technique, with satisfactory reproducibility, and can be used as a criterion in pedogenetic studies involving ferrimagnetic minerals. The aim of this paper was to verify the influence of parent rock material on χLF values of air-dried fine earth of B horizon of soil samples from Paraná. The samples were collected at 45 sites across the entire State to determine the χLF values and percentage of frequency-dependent magnetic susceptibility (χFD). The values of mass-specific magnetic susceptibility of soils formed from basic eruptive rocks were significantly higher (1,000 to 7,800 x 10-8 m3 kg-1) than of those from sedimentary and metamorphic rocks (lower than 500 x 10-8 m3 kg-1). The data show the strong influence of the parent rock material on the presence of ferrimagnetic minerals. The χFD values indicate the presence of superparamagnetic particles (maghemite) in the majority of the Paraná State soils.
Sanches A.C.,University of Sao Paulo |
Gomes E.P.,FCA UFGD |
Rickli M.E.,DAG UEM |
Fasolin J.P.,DAG UEM |
And 2 more authors.
Revista Brasileira de Engenharia Agricola e Ambiental | Year: 2015
The study was conducted from April to November, 2012, at a farm of dairy products in the municipality of Mariluz, Nortwest of Parana, with the objective to evaluate the productivity, botanical composition and nutritive value of Tifton 85 overseeding with oats, in the presence and absence of irrigation. The experimental design was a randomized block in split-plot with four replications. The plots were with and without irrigation. The subplots consisted of oats overseeding: FMS 2, IAPAR 61, IAPAR 126 and a treatment with Tifton 85 alone. The collection cycles composed the split plots. Irrigation increased pasture productivity with mean production of 2760.4 kg ha-1 cycle-1 with higher leaf/stem ratio of 2.8, increasing dry matter digestibility. The values of crude protein were higher in irrigated and decreased in non-irrigated and irrigated, along the collection cycles from 18.6 to 13.6%. The highest productivities were obtained through overseeding with oats FMS 2 and IPR 126. Tifton 85 alone showed the greatest amount of neutral detergent fiber and lesser digestibility. © 2014, Departamento de Engenharia Agricola - UFCG/Cnpq. All rights reserved.
Aprigio A.,Av. Brazil 4232 |
Rezende R.,DAG UEM |
de Freitas P.S.L.,DAG UEM |
da Costa A.R.,PGA UEM |
de Souza R.S.,PGA UEM
Revista Brasileira de Engenharia Agricola e Ambiental | Year: 2012
The objective of this study was to determine the nitrate (NO 3 -) content present in lettuce plants (Lactuca sativa L.) of the Vera cultivar, produced under hydroponic system, in function of different flow rates and post-harvest periods. The experiment was conducted in the city of Cascavel-PR, in a greenhouse of the Universidade Estadual do Oeste do Paraná (UNIOESTE). The plants were nourished by the use of a nutrient solution, characterized by mean electrical conductivity of 1.2 dS m -1 which after passing the entire growing bench, returned to the irrigation tank and restarted the process, forming a closed system. The experiment was conducted in completely randomized design with eight replications, which were represented, individually, by two lettuce plants, in the factorial scheme (3 x 4). The treatments resulted from the combination among three flow rates (0.5; 1.0; and 1.5 L min -1) and four post-harvest storage periods (0; 24; 48; and 72 h). The nitrate content was determined by the colorimetric method and the obtained values were lower than the maximum limit required by the European Community. The investigated factors influenced significantly the mean levels of nitrate.