Biological Nitrogen Fixation in Flooded Rice Fields

摘要

This paper attempts to determine the amount of nitrogen that can be produced through biological fixation in flooded rice fields and examines the ability of biological nitrogen fixation to maintain or increase rice yields. First, the paper reviews three methods of measuring biological nitrogen fixation and nitrogen cycling. Next, a number of studies on nitrogen gains and losses in the rice field are summarized; exogenous and endogenous nitrogen sources, nitrogen sinks, and the nitrogen balance are examined. Experimental evidence is then cited which indicates that farmers can manipulate nitrogen fixers to significantly raise rice yields.