Agroecosystem simplification, or the expansion of ag land supporting a single crop type is an important cause behind the decline in farmland biodiversity.
Ecosystem services associated with biodiversity, like nutrient recycling, microclimate regulation and natural pest control have deteriorated.
Nearly 93 million ha of land have been in corn or soybean production for at least 2 years between 2007-2010.
The three pests considered in EPIC are insects, weeds and plant diseases. Crop yields are estimated at harvest as product of simulated yield and pest factor. The pest factor is computed below and ranges from 0 (no pest damage) to 1 (total crop destruction by pests). The current approach, while being crop agnostic does not include landscape simplification into account.