Siehe   http://permaculturenews.org/2016/08/05/nitrogen-fixing-species-agroforestry-systems/

"When selecting plants for the Nitrogen Fixing component of this design, I was looking for species that could withstand record lows of -28 (Zone 5), tolerate some shade, were fast growing, tolerant of trimming and coppicing, able to grow in clay soils, known to provide significant quantities of nitrogen, easy to propagate from seed and provide some food for humans and other animals. The following plants fit the criteria.

• Elaeagnus angustfolia – Oleaster, Russian Olive
• Elaeagnus commutata – Silverberry, Wolfberry
• Elaeagnus umbellata – Autumn Olive. Autumn Elaeagnus
• Caragana arborescens – Siberian Pea Tree"

von   http://permaculturenews.org/2016/08/05/nitrogen-fixing-species-agroforestry-systems/