Long-term Changes of Nitrogen, Carbon and Phosphor Fluxes of a Typical Agricultural Landscape in North China Plain

摘要

Biogeochemical cycles of carbon, nitrogen, phosphor and sulfur are the most important processes in agricultural landscape, which more or less contributes to global changes. Based on the resource data got from household surveys combined with land use data derived from remote sensing imagery, this article studied on the long-term changes of main life elements (C, N and P) fluxes in a typical agricultural landscape of North China Plain. The results show that C and N balances of large-scale irrigated land changed from deficits (-865kg/hm2 C and -9kg/hm2 N) in 1945 into great surpluses (1761kg/hm2 C and 213kg/hm2 N) in 2002, respectively, and P surpluses also doubled in 2002. However, C and N fluxes showed deficit during both periods with more significantly in 2002. C, N and P fluxes in whole arable landscape showed significant surpluses despite of 18.75% total arable area decrease in 2002 than that in 1945. Contrarily, C and N fluxes of arable landscape in 1945 showed overall deficits. Nutrient flux changes of arable landscape are impacted mainly by the changes of fertilizer input, land productivity, crop residue utility and arable land types.