Abstract:

Field experiments were conducted in the late season of 2007 and in the early season of 2008 to compare the differences of soil fertility factors in rice paddy under no tillage, conventional tillage with wet irrigation, alternation irrigation and water layer irrigation. Results showed that the greatest alkali hydrolysable nitrogen content was observed under water layer irrigation followed by wet irrigation and alternation irrigation; the greatest available phosphorus content was observed under wet irrigation followed by alternation irrigation and water layer irrigation; the greatest available potassium content was observed under alternation irrigation followed by wet irrigation and water layer irrigation; the greatest organ matter content was observed under wet irrigation followed by water layer irrigation and alternation irrigation; the greatest pH value was observed under wet irrigation followed by alternation and water layer irrigation. Under the same irrigation pattern, convention tillage field indicated greater contents of alkali hydrolysable nitrogen, available phosphorus and organ matter than no tillage field, while no tillage field indicated greater pH value and greater available potassium content. It can be concluded that water irrigation revealed greater impact on soil fertility than soil tillage.