How much kava powder can I get from one plant?

Difficult to answer as the variables are many such as; Kava variety, soil quality, rainfall, care, age, the number of plants per prepared plot, farmed or forest cultivation etc. Keeping in mind the many variables, a reasonable estimate for a plant grown in fertile volcanic soils of Samoa in an area with good rainfall and cared for until well established, should at 30-36 months yield 5.2 - 8kg of fresh kava roots and stump, dried and reduced to a powder this will give approximately 1 - 1.7kg.