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| Núñez,Pedro A.; Demanet,Rolando; Misselbrook,Tom H.; Alfaro,Marta; Mora,María de la Luz. |
| Chilean livestock production systems have intensified over the last years, with increasing amounts of N fertilizer inputs creating the potentiality for environmental damage through N pollution of water and air, so that alternative production strategies have been developed to reduce such environmental impacts. This study assesses N losses under different grazing frequencies and intensities on permanent pasture (Lolium perenne L., Festuca arundinacea Schreb., Dactylis glomerata L., and Trifolium repens L.) on an Andisol in Southern Chile. Four grazing strategies were evaluated: frequent-heavy (FH), frequent-light (FL), infrequent-heavy (IH), infrequent-light (IL), and a no grazing control (C) treatment, and each with three replicates in a randomized complete... |
| Tipo: Journal article |
Palavras-chave: Ammonium; Grazing; Leaching; Nitrate; NH3 volatilization. |
| Ano: 2010 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392010000200007 |
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| Cartes,Paula; Jara,Alejandra A; Demanet,Rolando; Mora,María de la Luz. |
| Incubation studies were carried out to evaluate the effect of temperature and urea supply level on both the urease activity and the kinetics of N mineralization in two Andisols of Southern Chile. Our results showed that urease activity was higher in Piedras Negras soil (PNS) than Freiré soil (FS) at 24 and 48 h, and the enzyme was activated when the temperature increased from 5 to 21 °C. Urease activity followed a simple Michaelis-Menten kinetics. In PNS, the Michaelis Menten constant (Km) decreased, whereas the maximum enzyme reaction velocity (Vmax) and the catalytic efficiency increased when the temperature was raised up to 21 °C at 24 and 48 h of soil incubation. In FS, urease activity was the highest at 24 h, and it decreased at 48 h as a consequence... |
| Tipo: Journal article |
Palavras-chave: Urease activity; N mineralization; Urea; Andisols. |
| Ano: 2009 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-27912009000100006 |
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| Aguilera,Paula; Briceño,Gabriela; Mora,María de la Luz; Demanet,Rolando; Palma,Graciela. |
| The aim of this work was to establish the effect of the dose of liquid cow manure (LCM) on some chemical properties and biological activity in an Andisol. This study was carried out under laboratory conditions using an Andisol and LCM from a dairy farm located in the South of Chile. The dose of LCM were the equivalent to 0 (SO), 100 (S100), 200, (S200) and 300 (S300) thousand L ha-1. This amount is equivalent to regular agronomic LCM applications. The chemical characterization indicated that the LCM addition modified all the tested Andisol chemical properties. These begin to return to the initial conditions from 10 days on, with the exception of EC, K and DOC. The C-C0(2) evolution indicated that LCM incorporation at increasing dose enhanced the... |
| Tipo: Journal article |
Palavras-chave: Liquid amendment; Biological activities; Chemical analysis. |
| Ano: 2010 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-27912010000200007 |
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| Fuentes,Bárbara; Bolan,Nanthi; Naidu,Ravi; Mora,María de la Luz. |
| Increases in the generation of organic wastes, in addition to decreases in natural resources, make it necessary to recycle these waste materials. In soils, the application of wastes as organic fertilizers, allows to reincorporate nutrients to the biogeochemical cycles. The application of wastes in agriculture has carried out with it problems associated with phosphorus (P) overapplication in soils and contamination of water bodies. Phosphorus inside the waste matrix forms organic and inorganic compounds which have different bioavailabilities. The more important factors that influence the bioavailability of P in soils, organic wastes and soil-organic waste amendments are: the soil solution pH, adsorption reactions, organic matter, phosphatase activity and... |
| Tipo: Journal article |
Palavras-chave: Phosphorus; Bioavailability; Compost; Manure. |
| Ano: 2006 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-27912006000200006 |
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| Vistoso G,Erika Marina; Bolán,Nanthi S; Theng,Benny K. G; Mora,María de la Luz. |
| The kinetics for the sorption of molybdate and phosphate by four Chilean Andisols have been determined. About 55%o of the molybdate and 61% of the phosphate was sorbed in the first 0.5 h, after which sorption slowly increased, reaching 90%o for molybdate and 97% for phosphate after 72 h. At the same time, OH¯ ions were released into the external solution, raising its pH by 0.85 units for molybdate and by 0.65 units in the case of phosphate. These observations indicated that both anions were sorpbed by a ligand exchange mechanims. Among the five kinetic models examined (),Table, 2 the Elovich equation gave the best fit of the experimental data (R² = 0.93 to 0.97, standard error = 0.35 to 0.94). The sorption rate constant (α) for both anions was... |
| Tipo: Journal article |
Palavras-chave: Al- and Fe-oxide; Chilean Andisols; Kinetic model; Molybdate and phosphate. |
| Ano: 2009 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-27912009000100005 |
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