?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.aufirst=T&rft.au=Yoneyama%2C+T&rft.aulast=Yoneyama&rft.atitle=%CE%B415N+values+of+sorghum+grains+harvested+on+a+Vertisol+in+the+semi-arid+tropics+were+positively+related+to+doses+of+fertilizer+N+but+negatively+with+the+frequency+of+legume+cultivation&rft.title=Soil+Science+and+Plant+Nutrition&rft.issn=0038-0768&rft.date=2001&rft.volume=47&rft.pages=423-427&rft.issue=2&rft.genre=article