|
|
|
|
|
| Petersen, Søren O.; Simek, Miloslav; Stamatiadis, Stamatis; Yamulki, Sirwan. |
| Traditionally, dairy cattle spend a substantial part of the year on pastures. For organic farming within EU it is specified that ”all mammals must have access to pasturage or an open-air exercise area” which they must be able to use whenever ”weather conditions and the state of the ground permits” (Council Regulation [EEC] No 2092/91 ). Dairy production systems are characterized by a considerable N surplus, and N deposited during grazing represents a significant risk for environmental losses, including N2O emissions. Excess N is excreted mainly in the urine, the composition of which is influenced by factors such as lactation stage, sward quality and intake of supplements. Resulting N concentrations in urine patches can range from 20 to 80 g N m-2, and... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Dairy cattle. |
| Ano: 2004 |
URL: http://orgprints.org/4079/1/4079.pdf |
| |
|
|
| Petersen, Søren O.; Stamatiadis, Stamatis; Christofides, C.; Yamulki, Sirwan; Bol, . Roland. |
| Introduction For Western Europe it is estimated that, on average, 8% of total N excreted by dairy cattle is deposited during grazing (IPCC, 1997). The intake and excretion of N is influenced by factors such as feed composition, lactation stage and pasture quality, and the excretion of excess N as urea in the urine can therefore vary considerably. Urea can lead to high ammonium levels in the soil which may influence N dynamics and gaseous emissions. This laboratory study was conducted to investigate short-term effects of urea concentration on N2O emissions. Methods Solutions containing 0 (CTL), 5 (LU) and 10 g l-1 urea-N (HU) were added to sieved and repacked soil cores of pasture soil at a rate of 4 l m-2. Also, 5 g l-1 urea-N was added to soil... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Dairy cattle. |
| Ano: 2003 |
URL: http://orgprints.org/1296/1/12th_N_workshop_180903.ppt |
| |
|
|
| Petersen, Søren O.; Stamatiadis, Stamatis; Christofides, Calliopi. |
| Nitrogen excreted by cattle during grazing is a significant source of atmospheric nitrous oxide (N2O). The regulation of N2O emissions is not well understood, but may vary with urine composition and soil conditions. This laboratory study was undertaken to describe short-term effects on N2O emissions and soil conditions, including microbial dynamics, of urea amendment at two different rates (22 and 43 g N m-2). The lower urea concentration was also combined with an elevated soil NO3- concentration. Urea solutions labelled with 25 atom% 15N were added to the surface of repacked pasture soil cores and incubated for 1, 3, 6 or 9 days under constant conditions (60% WFPS, 14°C). Soil inorganic N (NH4+, NO2- and NO3-), pH, electrical conductivity and dissolved... |
| Tipo: Journal paper |
Palavras-chave: Air and water emissions. |
| Ano: 2004 |
URL: http://orgprints.org/4062/1/4062.pdf |
| |
|
|
|
