Abstract: Traditional patterns of farmland soil nutrients enrichment are mainly inner-system enrichment and regional enrichment. Along with the rapid commercialization of agricultural products, large amount of grain together with large amount of nutrients contained then flow from commodity grain producing region to food processing and exporting region, from inland to coastal region, from developed region to developing region. Thus, a new pattern of farmland soil nutrient enrichment, namely transregion enrichment is formed. This trend certainly will further enlarge the gap of economic development as well as soil fertility between these two regions. The way to deal with this new situation was approached from the standpoint of ecological economy.

Key words: eddy covariance (EC) technique, urban system, carbon flux, CO₂ exchange.