Complex sentence: An example of this can be seen in Asia, where food production per capita has increased twofold, has been achieved through not only the use of fertilisers but through the use of better crops that have been specifically designed for the area.
Split into simpler sentences: An example of this can be seen in Asia, where food production per capita has increased twofold. This has been achieved through not only the use of fertilisers, but through the use of better crops that have been specifically designed for the area.