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| Núñez,Pedro; Demanet,Rolando; Matus,Francisco; Mora,Maria de la Luz. |
| The grazing management of grassland has a direct effect on nitrogen (N) recycling. This is an important reason why management has become an alternative to improve the grassland production and quality, in turn to make it more suitable for the environment. However, the livestock system intensification induces changes in the natural dynamics of the N cycle, accelerating gas emmisions (e.g. ammonia, NH3 and nitrous oxide, N(2)0) and leaching losses from soil under grazing. When the amount of N in the environment increases, there is an impact on smog episodes, global warming, stratospheric ozone depletion, acid rain and eutrophication of fresh water. There are different techniques to evaluate the gases emitted from the soil. This klonowledge is useful to design... |
| Tipo: Journal article |
Palavras-chave: Ammonia; Grazing; Management; Nitrogen; Nitrous oxide; Livestock. |
| Ano: 2007 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-27912007000300006 |
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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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| Ribera,Alejandra E; Mora,Maria de la Luz; Ghiselini,Vanessa; Demanet,Rolando; Gallardo,Felipe. |
| We studied the phosphorous (P) and molybdenum (Mo) relationship in soil and red clover (Trifoliumpratense L.) in a non limed and limed acid Andisol of Southern Chile. In soil, we evaluated the effect of different liming (0 and 2000 mg kg-1), P (0, 200 and 400 mg kg-1), and Mo (0, 0.58 and 0.96 mg kg-1) doses supply on soil available Mo. In addition, the availability of P and Calcium (Ca) in treated soils was determinated. In red clover, we studied the Mo and P shoot concentrations and dry matter yield in response to the different treatments applied to the soil. Also, we measured the changes produced by Mo uptake in shoot Cu concentrations. The results showed that both, lime and more strongly P and Mo additions significantly (P ≥ 0.05) increased... |
| Tipo: Journal article |
Palavras-chave: Phosphorous; Molybdenum; Andisol; Red clover. |
| Ano: 2010 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-27912010000100008 |
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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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| 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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