Abstract: In this paper,field experiment was conducted to investigate the differences of field ecological condition,growth and development,relevant physiological and biochemical characteristics,yield formation,grain yield,and water use efficiency of three rice varieties under conditions of film mulch,straw mulch,intensified cultivation,and no mulch.Compared to film mulch,straw mulch had great advantages in enhancing root activity,retarding leaf aging,and increasing young leaf’s soluble sugar content,but the final grain yield decreased by 12.7%～17.1% because of the lag of prophase growth.The grain yield under mulch and intensified cultivation was higher than that without mulch.Compared with no mulch,the water use efficiency under intensified cultivation was increased by 12.9%～19.3%,and grain yield was increased by 24.7%～30.2%.Therefore,intensified cultivation should be an effective technique for water utilization.

Key words: Earthworm activity, Red soil, Phosphorus fraction, Phosphorus availability