Answer:
Toxic and nutrient pollution.
Step-by-step explanation:
Rotating a crop simply means that one grows different types of crop in the same area in different season. This is quite useful and environmental friendly practice, since using the same crop in the same area for a longer periid of time can deplete the soil essential minerals reducing its fertility and increasing the need for fertilizers. Since growing the same crop also promotes the build-up of pathogens, rotation can reduce the need for pesticides and herbicides.
Excessive use of pesticides, herbicides and fertilizers directly leads to soil, air or even water polution.
Pesticides and herbicides are toxins used to destroy plant pathogens and weeds. If not used appropriately, they pose a great threat to human health and environment.
Fertilizers are supstances containing mostly nitrogen, phosphorus and potassium, elements needed to promote crop growth. However their excessive use can cause great changes in ecosystems, especialy water. Since they are nutrients, they promote excessive growth of algae which can have huge environmental impact.