The option that correctly identifies a result of agricultural practices is soil erosion. Agricultural practices, particularly intensive farming and improper land management, can lead to the erosion of soil, impacting its fertility and leading to environmental issues.
Other options like "water diversion" may also be a result of agricultural practices but are not as directly linked as soil erosion. "Slash and burn agriculture" is a type of agricultural practice, and "biodiversity" is generally negatively affected by such practices rather than being a direct result.