ABSTRACT
Early groups of hunter-gatherer humans figured out how to take care of the plants that fed them and kept them alive. A large population led to centralized systems of governance and economics. Despite becoming accustomed to their lifestyle, war and death brought an abrupt end to past civilizations. Plants help maintain the biology in the soil through exudates which are sugars, carbohydrates, and proteins that the plant releases through its roots to feed beneficial organisms. The zone near plant root tips is an area of intense soil organism activity called the rhizosphere. Specific microorganisms are adapted to specific plant communities and environments. The floodplains were blessed with fresh silt deposits, which meant that soil nutrients were being renewed every year. The main impact in this case was through the introduction of the metal plow. Early Roman farms were multilayered, diverse, and farmers tended them by hand.
