books.google.co.nz - Plant nutrients and environment. Origin and classification of fertilizer. Availability of plant nutrients in manures and fertilizer. Yield responses to commercial fertilizer. Consumption of fertilizer in various countries. Potential fertilizer production. International trade in fertilizer. Compotetion...http://books.google.co.nz/books/about/The_World_Fertilizer_Economy.html?id=v9unAAAAIAAJ&utm_source=gb-gplus-shareThe World Fertilizer Economy
