This invention is a system for raising land and aquatic, plant and animal crops in a symbiotic-type polyculture using organic/sustainable methods of agronomy, animal husbandry, aquaculture, and hydroponics whereby yields are optimized while reducing production costs, conserving resources, and protecting...http://www.google.es/patents/US5121708?utm_source=gb-gplus-sharePatente US5121708 - Hydroculture crop production system
