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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.
Show more [+] Less [-][Interest and limits of the use of sludges from wastewater treatment in agriculture]
1993
Perrin, D. (Faculte des Sciences Agronomiques de Gembloux (Belgium). Unite de Biologie Vegetale)
Direct and Indirect Effects and the Long-term Risks of Air Pollution on Forest Ecosystems: Effects on Soil Nutrition
1993
Guang-Jing Ma | Bai-Zhong Li | Ping Zhang | Jing-shen Liang (Chinese Academy of Forestry, Wan Shou Shan (China). Research Center for Forest Environment)
Atmospheric pollutant can cause direct effects mediated by foliage and indirect effects mediated through soil. Biotic and abiotic factors can confound relationships among nutrient cycling, growth loss and mortality and air pollution. Changes in the soils could result from acidic deposition. Changes could include increased fertility as a result of sulphur and nitrogen input to soils that are deficient in these elements or decreased fertility through ion leaching or mobilization of toxic substances as aluminium.
Show more [+] Less [-]Pedologic and nutritional aspects of enhanced carbon-dioxide storage in forest ecosystems
1993
Huettl, R.F. (Forestry Dept. Kali and Salz AG, Kassel (Germany))
Enhanced forest growth in combination with relatively high Nitrogen deposition may result in further pedologic and nutritional changes and an even greater destabilisation of forest ecosystems.
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