Research shows that Mars has optimal soil for growing plants and crops. Because Mars' gravity is only one-third of Earth's, agriculture on the red planet may require less water and fertilizer to produce a comparable yield. Additionally, the reduced gravity means water flows at a slower rate. Furthermore, settlers' waste on Mars could be used as fertilizer and to filter water because the Martian soil can repossess carbon and produce oxygen. University of California at Berkeley's biogeophysicist C