根部增氧模式对水稻产量与氮素利用的影响

【目的】根部缺氧是影响水稻生长发育与养分吸收的主要非生物因子之一。为了明确不同增氧模式的作用效果，探明水稻产量和氮素利用效率对根部增氧的响应特征，本试验研究了不同根部增氧模式下水稻生长动态、产量和氮素吸收积累与转运特性。【方法】以深水水稻品种IR45765-3B和水稻品种中浙优1号为材料，试验在顶部用透明塑料膜遮雨的水泥栽培池中进行，试验设施用CaO₂（CaO₂）、微纳气泡水增氧灌溉（MBWI）和干湿交替灌溉（AWD）等三个增氧模式处理及淹水对照（WL）。分别测定了两品种的生长动态、产量和与氮素利用相关的指标。【结果】与淹水对照相比较，根部增氧处理均显著促进IR45765-3B分蘖的发生，增幅为10.7%~33.6%，而中浙优1号茎蘖数仅在CaO₂处理和AWD处理部分调查时期显著高于对照；根部增氧处理显著提高了两品种的干物质积累量，并显著提高两品种水稻产量，增氧处理下IR45765-3B产量较对照分别增加26.3%（CaO₂）、21.8%（MBWI）和10.7%（AWD），而中浙优1号产量较对照分别增加51.0%（CaO₂）、52.2%（MBWI）和29.68%（AWD）；根部增氧显著增加水稻的氮素吸收与利用，与对照相比较，增氧处理下IR45765-3B和中浙优1号氮肥偏生产力均显著升高；施用CaO₂和MBWI处理水稻氮素转运效率和氮素转运贡献降低，但齐穗期后两品种的氮素吸收量显著增加，齐穗期后IR45765-3B和中浙优1号在CaO₂处理下的氮素吸收量较对照分别增加了73.4%和119.2%，MBWI处理下的氮素吸收量较对照分别增加了128.7%和106.5%。【结论】根部增氧显著促进水稻分蘖发生与成穗，增加水稻干物质积累并显著提高产量；在氮素利用方面，增氧处理下水稻植株对氮素的吸收与积累显著增加，且增氧处理显著促进了水稻对氮素的利用效率；三种增氧模式中CaO₂和MBWI的效果较AWD更明显。

Effect of root aeration methods on rice yield and nitrogen utilization

Objectives]Rhizosphere 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.Methods]Two 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 .Results]Compared 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.Conclusions]The 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.