?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.aufirst=K&rft.au=Katayama%2C+K&rft.aulast=Katayama&rft.atitle=Effects+of+NPK+fertilizer+combinations+on+yield+and+nitrogen+balance+in+sorghum+or+pigeonpea+on+a+vertisol+in+the+Semi-Arid+Tropics&rft.title=Soil+Science+and+Plant+Nutrition&rft.issn=0038-0768&rft.date=1999&rft.volume=45&rft.pages=143-150&rft.issue=1&rft.genre=article