Answer:
First of all, we need to consider the impact of chemical waste from the fetilizers or pesticides. These chemicals may help plants grow, but there is also a very high chance they will affect other creatures like insects or make there way out to the river, put creatures living there at huge risk of dying because of these toxic chemicals.
Secondly, the area of land on out Earth is not infinitive. As we expand out farmland, we also have to burn down forrests or grasslands, take in away the natural animals' shelters. Many plants species are at risk of extinction because of this.
Thirdly, the same problem can also happen with the water resources. Only 3% of the water on Earth is save for us to drink, and especially to support agriculture. This also means that we are taking away a lot of water, and this can badly affect the animals which also need water to survive.
