Bartz M.L.C.,Santa Catarina State University |
Pasini A.,State University Londrina |
Brown G.G.,Embrapa Forestry
Applied Soil Ecology | Year: 2013
It is well known that earthworm populations tend to increase under no-tillage (NT) practices, but abundances tend to be highly variable. In the present study, data from the literature together with those on earthworm populations sampled in six watersheds in SW Paraná State, Brazil, were used to build a classification of the biological soil quality of NT systems based on earthworm density and species richness. Earthworms were collected in 34 farms with NT aging from 3 to 27 yr, in February 2010, using an adaptation of the TSBF (Tropical Soil Biology and Fertility) Program method (hand sorting of five 20cm×20cm holes to 20cm depth). Six forest sites were also sampled in order to compare abundances and species richness with the NT systems. Species richness in the 34 NT sites and in the 6 forests ranged from 1 to 6 species. Most earthworms encountered were exotics belonging to the genus Dichogaster (D. saliens, D. gracilis, D. bolaui and D. affinis) and native Ocnerodrilidae (mainly Belladrilus sp.), all of small individual size. In a few sites, individuals of the Glossoscolecidae (P. corethrurus, Glossoscolex sp., Fimoscolex sp.) and Megascolecidae (Amynthas gracilis) families were also encountered, in low densities. Urobenus brasiliensis (Glossoscolecidae) were found only in the forest fragments. In the NT farms, earthworm abundance ranged from 5 to 605 indm-2 and in the forest sites, from 10 to 285indm-2. The ranking of the NT soil biological quality, based on earthworm abundance and species richness was: poor, with <25 individuals per m-2 and 1 sp.; moderate, with ≥25-100 individuals per m-2 and 2-3 sp.; good, with >100-200 individuals per m-2 and 4-5 sp.; excellent, with >200 individuals per m-2 and >6 sp. About 60% of the 34 farms fell into the poor to moderate categories based on this classification, so further improvements to the NT farm's management system are needed to enhance earthworm populations. Nevertheless, further validation of this ranking system is necessary to allow for its wider-spread use. © 2013 Elsevier B.V.
Magalhaes W.L.E.,Embrapa Forestry |
Cao X.,South China University of Technology |
Lucia L.A.,North Carolina State University
Tappi Journal | Year: 2011
Aligned cellulose nanocrystals/cellulose coelectrospun nanofibers were successfully prepared by using a home-built coelectrospinning and collection system. Cellulose I was dissolved in N-methyl morpholine oxide at 120°C and diluted with dimethyl sulfoxide, which was used in the external concentric capillary needle as the sheath (shell) solution. A cellulose nanocrystal suspension obtained by sulfuric acid hydrolysis of cotton fibers was used as the core liquid in the internal concentric capillary needle after transferring from water to dimethyl sulfoxide. The resultant coelectrospun nanocomposite films were collected onto a rotating wire drum and were characterized by field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy, thermogravimetric analysis, and tensile measurements. The FE-SEM image showed that the cellulose nanocrystals did not appear to cluster in the film formed. Although the crystallinity index of nanocomposite fibers was lower than the unreinforced cellulose electrospun fibers, the cellulose type II reinforced with cellulose nanocrystals had a much higher tensile stress (about 140 MPa), almost twofold that of pure cellulose. This latter result indicated that the alignment and adhesion of amorphous cellulose nanofibers played a crucial role on the mechanical properties of electrospun cellulosic fiber mats.
Magalhaes W.L.E.,Embrapa Forestry |
Pianaro S.A.,State University of Ponta Grossa |
Granado C.J.F.,State University of Ponta Grossa |
Satyanarayana K.G.,BMS College of Engineering
Journal of Applied Polymer Science | Year: 2013
This article presents preparation of heart-of-peach palm sheath (20-40 wt %) incorporated polypropylene (PP) composites using a single screw extruder. This study is aimed at the waste disposal problem, a societal concern considering that the peach palm cultivation being an important economic activity of some countries, which generate five times more waste than actual heart-of-palm itself. Both the raw materials and their composites were characterized for specific gravity, compressive and impact strengths, softening temperature, and hardness. It was observed that with increasing filler content the compressive and impact strengths of composites continuously decreased, while specific gravity, vicat softening temperature, and hardness showed the opposite trend. However, the optimum mechanical properties were attained for 30 wt % filler, which was the same filler content at which the highest PP crystallinity index was observed. Results also indicate that the lignocellulosic residue induce beta phase on the PP matrix and decrease thermal stability of the composite. Copyright © 2012 Wiley Periodicals, Inc.
Maia C.M.B.F.,Embrapa Forestry |
Novotny E.H.,Embrapa Soils |
Rittl T.F.,Wageningen University |
Hayes M.H.B.,University of Limerick
Current Organic Chemistry | Year: 2013
Soil organic matter (SOM) holds a prominent place among the many indicators that are studied in relation to soil function. Different viewpoints are reflected in characterizing SOM, depending on the study procedures used, or the focus of the researchers. There are many possibilities for the isolation and fractionation of SOM and this has led to a plurality of interpretations and conclusions. Transformations to organic materials that lead to the more recalcitrant components of SOM are outlined, and the associations which these materials can have in the soil environment, and aspects of their compositions are referred to. A review is given of the organic matter pools in soils, of their functions, and of the controls which they have in soil systems. A succinct review is given of physical fractionation procedures for SOM. This approach is highly relevant, though rarely used in modern studies of SOM. The merits and demerits of wet oxidation procedures, relative to dry combustion for determining soil organic carbon contents are discussed, and reference is made to the emerging chemometric techniques based on the use of Near (NIR) and Mid (MIR) infrared spectroscopy. © 2013 Bentham Science Publishers.
Duarte A.P.,Federal University of Parana |
Melo V.F.,Federal University of Parana |
Brown G.G.,Embrapa Forestry |
Pauletti V.,Federal University of Parana
Biology and Fertility of Soils | Year: 2014
The survival and cast production of the tropical endogeic earthworm Pontoscolex corethrurus and the changes in chemical and physical characteristics induced by gut passage were studied over an 80-day period in soils contaminated with different levels of Pb. The soils were from a Pb mining area in the state of Paraná, SE Brazil, and ranged from clayey to sandy texture and total Pb contents from 52 to 9,716 mg kg-1. In soils with the highest total Pb contents, earthworms showed lower survival rates, reduced biomass, high Pb uptake, and negligible cast production. In soils with low to intermediate total Pb (maximum 4,278 mg kg-1), earthworm survival and cast production were higher, biomass loss was lower, and gut passage increased pH, CEC, P, K+, and Mg2+ concentrations in the casts compared to the control soil. In the sandy soil (clay <176 g kg-1), worms preferentially ingested finer soil particles, increasing organic C and silt contents in casts. However, this selective feeding also resulted in higher Pb accumulation in worm tissues. Gut passage also increased water-dispersible clay and reduced flocculation in the casts, increasing the susceptibility of the soil to erosion. Lead contamination and uptake into the tissues did not limit the ability of earthworms to select finer soil particles and to transform soil chemical and physical properties, although it affected cast production rates and survival (especially at high Pb concentrations). © 2014 Springer-Verlag Berlin Heidelberg.