Effect of root aeration methods on rice yield and nitrogen utilization

ObjectivesRhizosphere anoxia is one of the main abiotic factors that affect the rice growth and nutrient absorption. In order to define consequence of different root aeration methods and their response characteristics on rice yield and nitrogen utilization, an experiment was conducted to study rice growth dynamic, yield and nitrogen utilization status under different root aeration methods.

MethodsTwo rice cultivars, IR45765-3B (deep water rice) and Zhongzheyou No. 1 (ZZY-1, rice), were used as materials. Rice was planted in cement pools with overlay on the proof to avoid rainfall, and there were four treatments, calcium peroxide (CaO₂), micro-nano bubble water irrigation (MBWI), alternate wetting and drying (AWD) and control (waterlogging, WL). The effects of rhizosphere aeration methods on rice growth, yield and nitrogen utilization were examined.

ResultsCompared with the water logging (WL) control, the three root aeration treatments significantly increased the tillering of IR45765-3B by 10.7%-33.6%, and in case of ZZY-1 the tiller number was increased significantly under the CaO₂ and AWD treatments in some growth periods recorded. The rhizosphere aeration significantly increased the dry matter accumulation and yield, and compared with the WL control, the yields of IR45765-3B were increased by 26.3% (CaO₂), 21.8% (MBWI) and 10.7% (AWD) and the yields of ZZY-1 were increased by 51.0% (CaO₂), 52.2% (MBWI) and 29.68% (AWD), respectively. The root aeration significantly enhanced the nitrogen accumulation and utilization, and compared with the WL, the nitrogen partial factor productivity (NPFP) of IR45765-3B and ZZY-1 was increased significantly under the three aeration treatments. The nitrogen transportation efficiencies (NTE) and the nitrogen transportation contribution rates (NTCR) were decreased under the CaO₂ and MBWI treatments, while the nitrogen accumulation amounts of IR45765-3B and ZZY-1 after the full heading stage under the CaO₂ treatment were increased by 73.4% and 119.2%, and the amounts under the MBWI treatment were increased by 128.7% and 106.5%, respectively.

ConclusionsThe root aeration significantly enhanced tiller development and ear formation progress of rice, and the dry matter accumulation and yield were increased significantly. The root aeration significantly enhanced the nitrogen accumulation and nitrogen use efficiency. Comprehensively, the CaO₂ application and micro-nano bubble water irrigation are more effective than the alternate wetting and drying method.