2.2 Sample sites selection
Agriculture in the study area has a long history of corn
and soybean cultivation, and the land use types of vegetable
field and orchard have been in rapid expansion
since 1979. In this study, 38 sample sites were selected
based on agricultural land use and topographic conditions
(Fig. 1). Most vegetable field and orchard in the
study area were converted from cropland in the early
1980s. To obtain the farming management practices,
questionnaires were created and information of interest
was surveyed for each land use type at each sampling
site in the study area (Table 1).