Krishna, 2013. Apple Academic Press, CRC Press, Taylor & Francis Group Document reference Krishna, K. R., 2013. Agroecosystems: Soils, Climate, Crops, Nutrients Dynamics, and Productivity. Apple Academic Press, CRC Press, Taylor & Francis GroupWeb https://books.google.fr/books?id=P6FiAgAAQBAJ&pg=PA209#v=onepage&q&f=falseCitation key Krishna, 2013Datasheets Niger (Guizotia abyssinica)
