Effect of planting density and nitrogen application on yield and nitrogen uptake and utilization of japonica rice cultivar D46

【Objective】To explore the optimum nitrogen( N) application rate and planting density and N use efficiency of rice production in Chengdu plain,and provide a basis for establishment of rational cultivation management.【Method】Field experiments were carried out to investigate the interactive effect of N application rates( N 150、225、300 kg·hm- 2) and planting densities( 2. 000 × 105、2. 667 × 105、4. 000 ×105seedlings·hm- 2) on rice yield and N uptake and utilization efficiency of japonica rice cultivar D46 in Chengdu plain.【Result】Both N application rate and planting density showed significant effects on the rice yield( P 0. 05). The rice yield increased with the increase of N application rate( 225kg·hm- 2) and planting density( 2. 667 × 105 seedlings · hm- 2). The highest rice yield( 7 580kg·hm- 2) was found with the N application rate of 225 kg·hm- 2and planting density of 2. 667 × 105seedlings·hm- 2,which was significantly higher than that of other treatments( P 0. 05). Increasing Napplication amount could significantly decrease N agronomic efficiency( NAE),N physiological efficiency( NPE),N partial factor productivity( NPFP) and N use efficiency for grain output( NUEG)( P 0. 05),while harvest index( NHI) and nitrogen apparent utilization rate( NAUR) had no obvious change. NAE,NPE and NPFP decreased with the increase of planting density,especially for NAE and NPE,while the planting density had little effect on NUEG,NHI and NAUR.【Conclusion】The combination of N 225 kg·hm- 2and 2. 667 × 105seedlings·hm- 2is the best for high yield and high N use efficiency of japonica rice D46 in Chengdu plain.