Complex sentence: Poor agricultural practices have resulted in siltation of the lake occurring far more rapidly than it should, as it was common practice for cotton and soybeans to be planted up to the water's edge until governmental agencies purchased the entire shoreline and forbade the practice.
Split into simpler sentences: Poor agricultural practices have resulted in siltation of the lake occurring far more rapidly than it should. It was common practice for cotton and soybeans to be planted up to the water's edge until governmental agencies purchased the entire shoreline and forbade the practice.