Growth at elevated CO2 often decreases photosynthetic capacity (acclimation) and leaf N concentrations. Lower-shaded canopy leaves may undergo both CO2 and shade acclimation. The relationship of acclimatory responses of flag and lower-shaded canopy leaves of wheat (Triticum aestivum L.) to the N content, and possible factors affecting N gain and distribution within the plant were investigated i...

Site studies have shown that conifer plantations in northern Britain have increased in General Yield Class (GYC) by 1 m ha" a" per decade or more (20-40 per cent) since the 1930s. Large increases in forest productivity have also occurred in many other regions of Europe. Are these increases due to improved silvicultural practices or to increases in N deposition, CO2 and temperature? Two process-...

High rate algae ponds fed clarified domestic wastewater and CO2-rich flue gas are expected to remove nutrients to concentrations similar to those achieved in mechanical treatment technologies, such as activated sludge. However, the energy intensity of wastewater treatment with CO2-supplemented high rate ponds (HRPs) would be less than that of mechanical treatments. In conjunction with anaerobic...

The 160 million ha of grazing land in Queensland support approximately 10 million beef equivalents (9.8 million cattle and 10.7 million sheep) with treed and cleared native pastures as the major forage source. The complexity of these biophysical systems and their interaction with pasture and stock management, economic and social forces limits our ability to easily calculate the impact of climat...

global warming and global climatic changes have attracted many concerns. the objective of this research was to examine greenhouse gas emission and its resultant global warming potential (gwp) in wheat production in gorgan, north-east of iran. to do this, six wheat fields were selected and during three consecutive growing seasons, data were gathered on input and energy use in all production prac...

Despite the importance of agriculture in California's Central Valley, the potential of alternative management practices to reduce soil greenhouse gas (GHG) emissions has been poorly studied in California. This study aims at (1) calibrating and validating DAYCENT, an ecosystem model, for conventional and alternative cropping systems in California's Central Valley, (2) estimating CO2, N2O, and CH...