Organic farming using long rotations, including deeply rooted green manures developed to a high art. Turner maintained a productive organic dairy farm using subsoiling and long rotations involving tilled crops and semipermanent grass/herb mixtures.
ven der Leeden, Frits, Fred L. Troise, and David K. Todd. The Water Encyclopedia, Second Edition. Chelsea, Mich.: Lewis Publishers, 1990.
Reference data concerning every possible aspect of water.
Weaver, John E., and William E. Bruner. Root Development of Vegetable Crops. New York: McGraw-Hill, 1927.
Contains very interesting drawings showing the amazing depth and extent that vegetable roots are capable of in favorable soil.
Widtsoe, John A. Dry Farming: A System of Agriculture for Countries Under Low Rainfall. New York: The Macmillan Company, 1920.
The best single review ever made of the possibilities of dry farming and dry gardening, sagely discussing the scientific basis behind the techniques. The quality of Widtsoe's understanding proves that newer is not necessarily better.