%0 Journal Article
%T Nitrogen Losses under Different Cattle Grazing Frequencies and Intensities in a Volcanic Soil of Southern Chile P谷rdidas de Nitr車geno bajo Diferentes Frecuencias e Intensidades de Pastoreo en un Suelo Volc芍nico del Sur de Chile
%A Pedro A. N迆ˋez
%A Rolando Demanet
%A Tom H. Misselbrook
%A Marta Alfaro
%J Chilean Journal of Agricultural Research
%D 2010
%I 
%X 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 block design. Results of the experiment indicate that N leaching losses were greater in the FH treatment (58.7 kg available N ha-1; p < 0.05) and with most of the leaching occurring in spring (39%). On average, N ammonia (NH3) losses were 10% greater in the frequent grazing treatments in relation to the infrequent grazing treatments, since there were no significant differences (P ≒ 0.05) among individual grazing events for FH, FL and IH. Results indicate that grazing frequency affects leaching losses while grazing intensity affects ammonia emissions from the grassland. Grazing with dairy cows in Southern Chile should consider this environmental constraint to ensure sustainable production over time. Los sistemas chilenos de producci車n ganadera se han intensificado en los 迆ltimos a os con el uso creciente de fertilizantes que aportan nitr車geno (N), creando el potencial de da o ambiental a trav谷s de la contaminaci車n del agua y el aire con N, de manera que se han dise ado estrategias alternativas de producci車n con el objetivo de reducir este potencial impacto. El presente estudio busca determinar las p谷rdidas de N bajo diferentes frecuencias e intensidades de pastoreo en una pradera permanente (Lolium perenne L., Festuca arundinacea Schreb., Dactylis glomerata L., y Trifolium repens L.) en un Andisol del sur de Chile. Se evaluaron cuatro estrategias de pastoreo: frecuente-intenso (FH), frecuente-laxo (FL), infrecuente-intenso (IH), infrecuente-laxo (IL), y un control (C) o tratamiento sin pastoreo, cada uno con tres repeticiones en un dise o de bloques completos al azar. Las p谷rdidas de N por lixiviaci車n fueron mayores en el tratamiento FH (59 kg N disponible ha-1; P ≒ 0,05) donde la mayor parte de las p谷rdidas ocurrieron en la primavera (39%). En promedio, las p谷rdidas de amoniaco (NH3) fueron 10% m芍s al
%K amonio
%K pastoreo
%K lixiviaci車n
%K nitrato
%K volatilizaci車n de amoniaco
%K ammonium
%K grazing
%K leaching
%K nitrate
%K NH3 volatilization
%U http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392010000200007