Rudolf Steiner
Source material
1924 The Agriculture Course
https://rsarchive.org/Lectures/GA327/English/RSPC1938/Ag1938_index.html
1924 Nutrition and Health
https://rsarchive.org/Lectures/GA354/English/AP1987/NutHlt_index.html
@Karin, admin from Steiner Online (https://rsarchive.org/)
Much of what has been written about biodynamics was written after Steiner. You may enjoy the Paul W. Scharff website and the commentary on the Agriculture Course found here: https://www.paulwscharffarchive.com/index/