Polyculture chemicals into the environment such as eutrophication of fresh water or the presence of excess atmospheric nitrogen are greatly reduced in polycultures. Other negative impacts of modern agriculture are similarly reduced. Excessive tillage occurs in most modern agricultural practices, but removes essential microbes and nutrients from the soil that are conserved in polycultures, especially permacultures. Agricultural machinery not only uses fossil fuels and creates waste, but is more costly to farmers. Because polyculture relies on natural systems of crop maintenance these costs can be eliminated as well. Modern agriculture is also dependent on a very limited number of plant species.
Cultural eutrophication Cultural eutrophication Cultural eutrophication is the process that speeds up natural eutrophication because of human activity. Due to clearing of land and building of towns and cities, land runoff is accelerated and more nutrients such as phosphates and nitrate are supplied to lakes and rivers, and then to coastal estuaries and bays. Extra nutrients are also supplied by treatment plants, golf courses, and agricultural practices through the use of fertilizers. Human activities, including the ones previously listed, can be responsible for an increase in nutrients, therefore, cultural eutrophication is more pronounced in non-polar ecosystems which have higher levels of human