P.A. Yeomans was an Australian agriculturalist and author known for his innovative approaches to sustainable farming. He developed the Keyline Design system, which focuses on optimizing water management and soil health in agricultural landscapes. His work emphasized the importance of understanding land contours and using them to enhance productivity. Yeomans published several influential books, including "The Keyline Plan," which outlined his methods and philosophies. His ideas have inspired many in the fields of permaculture and regenerative agriculture, promoting practices that aim to restore ecological balance while improving agricultural yields.