A form of crop farming that is based on the growing of a single crop type on a field at a given point in time. Agricultural monocultures sometimes follow a rotational pattern where different crop types such as maize, wheat or soybeans are grown successively on the same field. The use of agricultural monocultures is typically based on the principle of economies of scale. The principle here is that the costs of inputs such as machinery, labour, fuel, herbicides, fertilisers and land per unit of output (kg yield) can be kept relatively low if the diversity of crops that are grown in an agricultural landscape is minimised. Agricultural monocultures are controversial within the environmental movement. Amongst other things their efficiency is debated and critics point out that the practice of agricultural monoculture can lead to externalities (i.e. costs such as biodiversity loss, water pollution or a lack of resiliency that are not reflected in the final cost of the product) and also for the most part goes hand-in-hand with ongoing corporate consolidation in the food system.