Abstract: As a human- managed ecosystem, cropland ecosystem offers ecosystem services to and accepts ecosystem disservices from other ecosystems. According to the connotation of ecosystem services, an evaluation index and the evaluation methodology for high-yielding cropland ecosystem services were established, and the positive and negative values of cropland ecosystem services in Luancheng County in 2008 were evaluated by the methods of environmental economics. The positive and negative values of the cropland ecosystem services were 46.20×10⁸ Yuan and 4.05×10⁸ Yuan, respectively. The service value of food production was 17.61×10⁸ Yuan, contributing 38.11% of the total positive value, and being the dominant service. Irrational agricultural activities induced a decline of the overall value of cropland ecosystem services, with the ratio of net benefit value to food production value declined from 2.62:1 to 2.39:1 before and after the deduction of environmental cost. The abysmal lack of groundwater resource was the most prominent ecological problem, and its induced environmental cost occupied 76.0% of the total.

Key words: phytoplankton, functional group, taxonomy, classification, ecology.