ROLE OF NITROGEN FIXATION FOR SUSTAINABLE SUGARCANE PRODUCTION

摘要

Possible nitrogen input by nitrogen fixation in sugarcane was estimated by natural ~(15)N abundance method. The average nitrogen input by nitrogen fixation in three different sugarcane varieties, which were planted in the research field, was estimated to be 33%. Efficiency of nitrogen fertilizer to sugarcane was studied by using ~(15)N-labelled fertilizer. Sugarcane absorbed 41 to 45% of nitrogen fertilizer applied and percent nitrogen derived from fertilizer of the total plant nitrogen was estimated to be 18 to 31%. Results of analysis of flow of organic matter after harvesting of sugarcane suggested that leaves of sugarcane should not be burned at harvesting and filter cake should be return to the field properly to maintain a sustainable cycle of nutrients. Nitrogen fixation in sugarcane plays an important role in compensating for the nitrogen removed from the field. Return of many residues to the field and ability of nitrogen fixation enable to achieve a continuous and sustainable production of sugarcane even on infertile soil.