3 results
Water flow in soil from organic dairy rotations
- M. LAMANDÉ, J. ERIKSEN, P. H. KROGH, O. H. JACOBSEN
-
- Journal:
- The Journal of Agricultural Science / Volume 155 / Issue 7 / September 2017
- Published online by Cambridge University Press:
- 22 February 2017, pp. 1113-1123
-
- Article
- Export citation
-
Managed grasslands are characterized by rotations of leys and arable crops. The regime of water flow evolves during the leys because of earthworm and root activity, climate and agricultural practices (fertilizer, cutting and cattle trampling). The effects of duration of the leys, cattle trampling and fertilizer practice on the movement of water through sandy loam soil profiles were investigated in managed grassland of a dairy operation. Experiments using tracer chemicals were performed, with or without cattle slurry application, with cutting or grazing, in the 1st and the 3rd year of ley, and in winter rye. Each plot was irrigated for an hour with 18·5 mm of water containing a conservative tracer, potassium bromide; 24 h after irrigation, macropores >1 mm were recorded visually on a horizontal plan of 0·7 m2 at five depths (10, 30, 40, 70 and 100 cm). The bromide (Br−) concentration in soil was also analysed at these depths and the density of the different earthworm species were recorded. The density of macropores was not directly influenced by the factors investigated. The abundance of anecic earthworms was larger after 3 years of ley and was not affected by grazing (trampling or dung pat deposits) or fertilizer practice. The water infiltration estimated from the Br− concentration was not influenced by fertilizer practice and was reduced after 3 years of ley due to settlement, but was greater than that for the arable phase of the rotation. As shown by Br− concentration, preferential flow was induced by the grazing regime. Infiltrating water may bypass the soil matrix under similar or more extreme conditions than in the current experiment. Such hydraulic functioning in the grazing regime is expected to reduce the risk of leaching of nitrate contained in soil water.
Physics and Results from the AMANDA-II High Energy Neutrino Telescope
- Steven W. Barwick, the AMANDA Collaboration, J. Ahrens, X. Bai, S. W. Barwick, T. Becka, K.-H. Becker, E. Bernardini, D. Bertrand, F. Binon, A. Biron, S. Böser, O. Botner, O. Bouhali, T. Burgess, S. Carius, T. Castermans, D. Chirkin, J. Conrad, J. Cooley, D. F. Cowen, A. Davour, C. De Clercq, T. DeYoung, P. Desiati, J.-P. Dewulf, P. Doksus, P. Ekström, T. Feser, T. K. Gaisser, R. Ganupati, M. Gaug, H. Geenen, L. Gerhardt, A. Goldschmidt, A. Hallgren, F. Halzen, K. Hanson, R. Hardtke, T. Hauschildt, M. Hellwig, P. Herquet, G. C. Hill, P. O. Hulth, K. Hultqvist, S. Hundertmark, J. Jacobsen, A. Karle, L. Köpke, M. Kowalski, K. Kuehn, J. I. Lamoureux, H. Leich, M. Leuthold, P. Lindahl, J. Madsen, K. Mandli, P. Marciniewski, H. S. Matis, C. P. McParland, T. Messarius, Y. Minaeva, P. Miočinović, R. Morse, R. Nahnhauer, T. Neunhöffer, P. Niessen, D. R. Nygren, H. Ogelman, Ph. Olbrechts, C. Pérez de Los Heros, A. C. Pohl, P. B. Price, G. T. Przybylski, K. Rawlins, E. Resconi, W. Rhode, M. Ribordy, S. Richter, J. Rodríguez Martino, D. Ross, H.-G. Sander, K. Schinarakis, T. Schmidt, D. Schneider, R. Schwarz, A. Silvestri, M. Solarz, G. M. Spiczak, C. Spiering, D. Steele, P. Steffen, R. G. Stokstad, P. Sudhoff, K.-H. Sulanke, I. Taboada, L. Thollander, S. Tilav, W. Wagner, C. Walck, C. H. Wiebusch, C. Wiedemann, R. Wischnewski, H. Wissing, K. Woschnagg, G. Yodh, S. Young
-
- Journal:
- Symposium - International Astronomical Union / Volume 214 / 2003
- Published online by Cambridge University Press:
- 26 May 2016, pp. 357-371
- Print publication:
- 2003
-
- Article
-
- You have access Access
- Export citation
-
This paper briefly describes the principle of operation and science goals of the AMANDA high energy neutrino telescope located at the South Pole, Antarctica. Results from an earlier phase of the telescope, called AMANDA-BIO, demonstrate both reliable operation and the broad astrophysical reach of this device, which includes searches for a variety of sources of ultrahigh energy neutrinos: generic point sources, Gamma-Ray Bursts and diffuse sources. The predicted sensitivity and angular resolution of the telescope were confirmed by studies of atmospheric muon and neutrino backgrounds. We also report on the status of the analysis from AMANDA-II, a larger version with far greater capabilities. At this stage of analysis, details of the ice properties and other systematic uncertainties of the AMANDA-II telescope are under study, but we have made progress toward critical science objectives. In particular, we present the first preliminary flux limits from AMANDA-II on the search for continuous emission from astrophysical point sources, and report on the search for correlated neutrino emission from Gamma Ray Bursts detected by BATSE before decommissioning in May 2000. During the next two years, we expect to exploit the full potential of AMANDA-II with the installation of a new data acquisition system that records full waveforms from the in-ice optical sensors.
Infiltration of slurry liquid and volatilization of ammonia from surface applied pig slurry as affected by soil water content
- S. G. SOMMER, O. H. JACOBSEN
-
- Journal:
- The Journal of Agricultural Science / Volume 132 / Issue 3 / May 1999
- Published online by Cambridge University Press:
- 01 May 1999, pp. 297-303
-
- Article
- Export citation
-
Ammonia (NH3) volatilization may decrease the fertilizer efficiency of surface-applied slurry and may cause the unwanted deposition of nitrogen (N) in oligotrophic ecosystems. We studied the effect of soil water content on the infiltration of slurry liquid and how infiltration affected NH3 volatilization. NH3 volatilization was measured with dynamic chambers through which air was drawn continuously. Slurry spiked with bromide (Br−) to trace slurry infiltration was applied to a loamy sand in steel cylinders (diameter 6·7 cm and height 12 cm) adjusted to water contents of 0·01, 0·08, 0·12 and 0·19 g H2O per g soil (g g−1). At different time intervals after slurry application the soil columns were cut into slices and Br−, ammonium (NH4+) and nitrate (NO3−) concentrations were determined. At soil water contents >0·12 g g−1 nitrate content increased significantly from 24 to 72 h, and at 96 h NO3− content was equivalent to 75–130% of the NH4+ present at 0·5 h after slurry application. Nitrification may have contributed to a low NH3 volatilization from 24 to 96 h by reducing NH4+ concentration and contributing to acidity, and most of the NH3 volatilization occurred, therefore, during the first 24 h after application. Low soil water content enhanced the infiltration of slurry liquid and hence the mass transport of NH4+ into the soil. Transport of NH4+ by diffusion, on the other hand, was highest at the highest water content. Transport of NH4+ from the slurry at the soil surface down into the soil at 0·01 g g−1 reduced NH3 volatilization to c. 70% of the volatilization from slurry applied to soils at higher water contents. Diffusion of NH4+ into the soil did not significantly decrease NH3 volatilization.