The Introduction of genetically engineered cotton to Australia, which contains a toxin from the bacteria Bacillus thuringiensis, is already resulting in less use of insecticides to control bollworms and cotton weevil (Aus Dep. Environment 2001). .
The use of crops that are engineered to be more tolerant of a wide range of less persistent herbicides may in affect increase the effectiveness of weed control. Increased effectiveness may lead to less overall herbicide use and decreased demand for more species specific, more persistent herbicides. Another benefit of herbicide tolerant crops means that soil cultivation to control weeds may be reduced, decreasing the rate of soil degradation.
Crops engineered to be more efficient with the uptake of water and nutrients may lead to less pressure on the land. For example, with crops taking up fewer nutrients from the soil the need for fertiliser's maybe reduced, prolonging the fertility of the soil and reducing the risk of negative impacts such as eutrophication on surrounding waterways. Having crops that are more efficient at water uptake and storage would lessen the amount of water used in irrigation, reducing the chances of soil salinity problems, especially in countries like Australia.
Genetically engineered crops could bring a whole host of environmental benefits however there are also a number of risks that need also to be considered, such as, the potential for "super weeds" and "super pests". Without careful management it is suggested that pests and weeds will emerge that are pesticide and herbicide resistant, this may create a need for more toxic, persistent chemicals to be used. There is also the potential for herbicide-tolerance genes to transfer to wild vegetation populations, in turn increasing the need for herbicide use in non-agricultural areas. This may be detrimental to native flora species, which may not have tolerance for the herbicides needed.
