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Murillo de la Rosa, Arnulfo. |
Los suelos de la sabana de Huimanguillo, se localizan en lomeríos con pendientes ligeras, son de baja fertilidad, presentan alta acidez con pH que oscilan entre 4.0 a 5.5 y contenidos de materia orgánica de 1 a 4 %, a veces hasta de 20 %. La materia orgánica desempeña un papel importante en el suelo ya que aporta una gran variedad de elementos nutritivos para las plantas, y modifica la estructura del mismo, el conocimiento sobre su aporte de nutrientes es escaso, por lo que, las estimaciones del suministro al suelo se basan más bien en el rendimiento. El presente trabajo tuvo como objetivo estimar la densidad aparente (Dap), las reservas de carbono orgánico total (COT), nitrógeno total (Nt), la relación carbono nitrógeno (C/N), el carbono orgánico soluble... |
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Palavras-chave: Acrisol; Agroecosistemas; Densidad aparente; Carbono orgánico total; Nitrógeno total; Carbono orgánico soluble; Indice óptico y relación C/N; Agroecosystems; Bulk density; Total organic carbon; Total nitrogen; Soluble organic carbon; Optical index and C/N; Maestría; Producción Agroalimentaria en el Trópico. |
Ano: 2010 |
URL: http://hdl.handle.net/10521/254 |
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Lepoupon, C; Lin, Rg; Benaim, Jy; Merks, Aga. |
The accurate classical batch method of Duursma (1961), based on the conversion of Dissolved Organic Nitrogen (DON) into NH3, is used as a basis for a new automatic DON analyser. After testing different possibilities through mechanical automation of the original batch technique, in which the conversion is preceded by the degassing of NH3 and drying of the sample, the procedure of autoanalyses has been selected. This procedure was simplified to the extent that a compact unit could be constructed, which would easily be applicable on board ship. The automatic method has a conversion phase in which in principle only DON is dissociated to NH4+, whereas both NO2- add NO3- are not reduced. This requires selective conditions and particularly high silver purity for... |
Tipo: Text |
Palavras-chave: Dissolved organic nitrogen; Analysis; Automation; Reduction; Total nitrogen. |
Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00093/20456/18128.pdf |
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Chung,TH. |
ABSTRACT This study was designed to evaluate the effects of chemical blend additives to duck litter on pH, ammonia (NH3) fluxes, total nitrogen (TN) under a small pen trial. One hundred twenty 1-day-old duck (pekin) were randomly assigned to 6 pens in a completely randomized design during 6 weeks. Control received no litter treatment whereas top-dressed treatment at rates of 50 g aluminum sulfate + 50 aluminum chloride/kg duck litter were mixed into the upper 1 cm of duck litter. Duck litter pH at 2 weeks through 5 weeks was significantly affected (p<0.05) by chemical blend treatments compared to controls, but not at 6 weeks. During the experimental periods, NH3 fluxes decreased (p<0.05) in chemical blend treatments. However, there were no remarkable... |
Tipo: Info:eu-repo/semantics/report |
Palavras-chave: Chemical blend; PH; Ammonia flux; Total nitrogen; Duck litter. |
Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-635X2017000400733 |
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Lima,Ana Lúcia da Silva; Zanella,Fábio; Schiavinato,Marlene Aparecida; Haddad,Claudia Regina Baptista. |
In general, perennial species contain higher concentrations of certain secondary compounds, such as phenolics, lower levels of nitrogenous compounds, and greater specific leaf mass (SLM) than deciduous species. The aim of this study was to verify whether the comparative data reported in the literature regarding deciduous and evergreen species, also applies to four selected species of a semideciduous tropical forest (a remnant of the Atlantic Forest). The four species chosen for this study, each with apparently different leaf life spans, were two semideciduous (Hymenaea courbaril L. var. stilbocarpa (Hayne) Lee et Lang., and Lonchocarpus guilleminianus (Tul.) Malme, and two deciduous (Enterolobium contortisiliquum (Vell.) Morong., and Peltophorum dubium... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Leaf life span; Specific leaf mass; Total nitrogen; Tannins; Atlantic forest. |
Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162006000100007 |
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