In agroecosystems, farmers practice monoculture. It is a practice of growing one type of crop in the same field year after year. Monoculture is an attempt to check herbivores from eating crops. As a result population of herbivores get reduced from the food webs. Using different types of agro-chemicals such as insecticides, pesticides, weedicides also reduces number species. Therefore, the most unusual characteristic of food webs in agroecosystems is lack of biodiversity.