Carol Steinfield’s book is a great introduction to the history and culture of human urine, focusing on its applications in growing food. While not a plant-based technique per se, using their own urine is a way that veganic gardeners can work toward a closed loop system through local nutrient cycling, and reduce their environmental impact by diverting their urine from the public water systems.
Urine is considered sterile in a healthy person—it’s almost always sterile, and you can’t catch new illnesses from your own urine. When we eat food, much of the nitrogen, potassium, and other nutrients found in the food is excreted in our urine. When diluted with water (10:1) or added to a mulch, we can take advantage of urine as a complementary fertilizer in our gardens, or we can simply cycle the nutrients by applying it to trees, shrubs, or our lawn (learn more about the safety and techniques of using urine here online).
The book Liquid Gold presents different perceptions and uses of urine throughout history, and explains the benefits of using urine in contemporary society, with a variety of examples and techniques for agricultural applications.
STEINFELD, Carol. Liquid Gold, the Lore & Logic of Using Urine to Grow Plants, New Society Publishers, 1st edition, 2009, 36 p.