خيارات البحث
النتائج 101 - 110 من 266
[How to reduce agricultural nitrogen losses?]
1993
Pedersen, C.Aa.
[Diffusion of volatile organic compounds through concrete floors]
1993
Kirkegaard, C. | Holm, J.
[Strategy in investigations of pollution]
1993
Frederiksen, J. | Winge, U. | Moeller, S.
[The Groundwater Monitoring Program: Status for pesticides]
1993
Bruesch, W. (Danmarks Geologiske Undersoegelser, Copenhagen (Denmark))
Leptospirosis
1993
Ellis, W.A. | McDowell, S.
The effect of airborne particulates on livestock health and production
1993
Hartung, J.
The state of transboundary air pollution: 1992 update. Report prepared within the framework of the Convention on Long-Range Transboundary Air Pollution
1993
Triazines in the Baltic and North Sea
1993
Bester, K. | Huhnerfuss, H. (Institut fur Organische Chemie, Universitat Hamburg, Martin-Luther-King-Platz 6, 2000 Hamburg 13 (Germany))
Agricultural sources and sinks of carbon
1993
Cole, C Vernon | Flach, Klaus | Lee, Jeffrey | Sauerbeck, Dieter | Stewart, Bobby
Most existing agricultural lands have been in production for sufficiently long periods that C inputs and outputs are nearly balanced and they are neither a major source nor sink of atmospheric C. As population increases, food requirements and the need for more crop land increase accordingly. An annual conversion of previously uncultivated lands up to 1.5 x 10⁷ hectares may be expected. It is this new agricultural land which suffers the greatest losses of C during and subsequent to its conversion. The primary focus for analysis of future C fluxes in agroecosystems needs to be on current changes in land use and management as well as on direct effects of CO2 and climate change. A valid assessment of C pools and fluxes in agroecosystems requires a global soils data base and comprehensive information on land use and management practices. A comprehensive effort to assemble and analyze this information is urgently needed.
اظهر المزيد [+] اقل [-]Water supply and pollution control
1993
Viessman, Warren | Hammer, Mark J.
