摘要：
[目的]探索一种简易、有效的盆栽土壤速效氮淋洗方法,并分析水稻花前不同时期土壤氮亏缺对不同类型水稻主功能叶及植株花后氮积累的影响,以期为阐明水稻花后氮素积累、转运特征和大田生产减氮技术应用奠定研究基础.[方法]比较了3种水稻盆栽土壤速效氮淋洗方法的减氮效果,同时探讨了水稻花前14 d和花前3 d短期亏氮对籼粳杂交稻甬优12号、籼型杂交稻中浙优1号上3叶SPAD值、氮浓度和花后植株含氮量的影响.[结果]通过淋洗结构+沙土混合基质方法进行3次淋洗,即可将土壤中85.6%的硝态氮和67.1%的铵态氮洗脱;水稻花前处理后,土壤硝态氮和铵态氮含量分别降低42.1%~59.3%和35.0%~43.9%,可实现预期的土壤减氮效果,短期内对土壤速效氮供应能力形成有效抑制.花前土壤氮亏缺导致甬优12上3叶SPAD值和氮浓度以及齐穗后10 d植株茎鞘、叶、穗和单株含氮量显著降低,且茎鞘、穗和单株含氮量在两淋洗处理间差异显著.花前14 d淋洗减氮导致中浙优1号上3叶SPAD值和氮浓度以及齐穗后10 d单株和穗部含氮量显著下降,花前3 d淋洗处理则对中浙优1号上3叶氮浓度和植株氮积累量几乎无影响.[结论]水稻对花前14 d氮亏缺的敏感性显著高于花前3 d,植株不同叶位叶片的叶色和氮浓度对土壤氮亏缺敏感度由下而上增强,两时期土壤氮亏缺对籼粳杂交稻甬优12的影响均远大于籼型杂交稻中浙优1号,意味着籼型杂交稻中浙优1号花后对土壤速效氮需求明显降低,而籼粳杂交稻甬优12减数分裂期后对土壤速效氮存在更高需求.%[Objective]This study aims to explore a simple and effective leaching method of available nitrogen in potted soil, and to reveal the effects of soil nitrogen deficiency at different periods before anthesis on nitrogen accumulation in main functional leaves and post-anthesis plant of different types rice, which would clarify the characteristics of nitrogen accumulation and translocation after anthesis, and lay the research foundation for reducing nitrogen fertilizer application.[Method]In this study, the effects of three leaching methods on available nitrogen reduction in potted soils were compared. Meanwhile, the effects of short-term nitrogen deficiency 14 d and 3 d before anthesis on SPAD value, nitrogen concentration of top-three leaves and plant nitrogen content after anthesis were discussed using indica-japanica hybirid rice Yongyou 12(YY12), and indica hybrid rice variety Zhongzheyou 1(ZZY1).[Results]The results showed that 85.6%nitrate nitrogen and 67.1% ammonium nitrogen in soil could be eluted by leaching structure + sandy /soil mixed matrix(T3) with 3 times of leaching. Under the two leaching treatments, the contents of nitrate and ammonium nitrogen in potted soil decreased by 42.1%-59.3% and 35.0%-43.9%, respectively. This could achieve the expected effect of reducing soil nitrogen to inhibit effectively the soil available nitrogen supply capacity in the short term. Affected by soil nitrogen deficiency before anthesis, SPAD value and nitrogen concentration of top-three leaves, stem-sheath, leaves, panicle and plant nitrogen content at the 10th day after heading of YY12 were decreased significantly. At the same time, there was a remarkable difference of stem-sheath, panicle and plant nitrogen content between the two leaching treatments. SPAD value and nitrogen concentration of top-three leaves, panicle and plant nitrogen content at the 10th day after heading of ZZY1 were also decreased dramatically under the leaching treatment 14 d before anthesis. However, the leaching treatment 3 d before anthesis had little effect on nitrogen concentration of top-three leaves and plant nitrogen content.[Conclusion]In conclusion, the sensitivity of rice to nitrogen deficiency 14 d before anthesis(meiosis stage) was greatly higher than that 3 d before anthesis. The sensitivity of leaf color and nitrogen concentration of leaves at different leaf positions to soil nitrogen deficiency were enhanced from bottom to top. The influence of soil nitrogen deficiency at the two leaching periods on YY12 was greater than that of ZZY1, which means that the lower demand for soil available nitrogen of indica hybrid rice ZZY1 after anthesis, and the higher demand of indica-japanica hybirid rice YY12 after the meiosis period.
