MONOCULTURES

A summary of Altieri's report (University of California) on the problems associated with monocultures. 

Monocultures are agricultural land areas ‘devoted to single crops and year-to-year production of the same crop species on the same land’ (Altieri, University of California). Development of monocultures was enabled by agricultural mechanization, the improvement of crop varieties, and the development and increased availability of pesticides and fertilizers. Governments have encouraged this as monocultures can contribute significantly to the ability of national agricultures to serve international markets.

Intensive farming has enabled farmers to become more integrated into international economies. As a result, monocultures are ‘rewarded by economies of scale’ (Altieri, University of California). Therefore farms today are ‘fewer, larger, more specialized and more capital intensive’. However, monocultures are highly vulnerable and dependent on many chemical inputs, as the lack of rotations and diversification has taken away key self-regulating mechanisms.

Problems

-       The move from crop rotation to harvesting the same crop type each year means the same nutrients are removed from soils year after year and nutrient depletion and soil degradation becomes a huge problem and is highly unsustainable.

-       Crop types have been selected for their high yields, ‘sacrificing natural resistance for productivity’; this makes them more susceptible to pests. This is overcome by increasing the use of pesticides, however, many argue that the negative impacts of pesticides, including the reduction of beneficial insects, outweigh the positives. (As shown in Rachel Carson’s, Silent Spring, which I will look into further at a later date)

-       Monocultures are also more vulnerable to disease, as populations of the same species will have the same resistance to certain diseases, therefore whole populations can be wiped out by one disease outbreak. Protecting monocultures and treatment of disease requires a further increase in inputs, occasionally to the extent that, ‘the amount of energy invested to produce a desired yield surpasses the energy harvested’ (Altieri, University of California).

Intensified chemical controls are required to overcome the limiting factors reducing the productivity of monocultures, such as high pest potential, limited soil moisture, or low-fertility soils. The efficiency of the many inputs required to maintain monocultures are decreasing and crop yields in most key crops are leveling off, making the whole practice highly unsustainable.