Effects of physico-chemical properties of rhizosphere soils on uptakes of nutrients by rice.

根际土壤理化性质对水稻养分吸收的影响。

• 批准号: 09460039
• 负责人: EGASHIRA Kazuhiko
• 金额: $ 4.67万
• 依托单位: KYUSHU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09460039/
• 关键词: rice; nitrogen nutrition; mass flow; diffusion uptake; ammonium ion; Smectite; allophane; Andisols; 黒ボク士

Rhizobox was constructed in which soil solution samplers nad platinum electrodes were inserted in each compartment. Rice plants were grown in this rhizobox. Allophanic and smectitic soils were used for this experiment to investigate effects of physico-chemical change of rhizosphere soil by the observation of the differences between thses soils with distinct physicochemical properties. Soil solutions of different distances from rice root were collected every week. PH, NH4, Fe(ll), organic C, inorganic C concentration were measured for these solutions.The ways of NH4 uptake were different in allophanic and smectitic soils. In smectitic soil, in both phase I and phase II, uptake by mass flow was the major N uptake mechanism. This result was contradict with ordinary explanation by which NH4 uptake in phase II is explained by diffusive uptake. In phase II, the decrease in CEO by pH reduction enhanced NH4 mobility around rice root.In allophanic soil, in phase I, uptake by mass flow was the major N uptake mechanism, but in phase II uptake by diffusion was the major N uptake mechanism. Our results indicated that in phase I N accumulation into organic N proceeded and in phase It mineralization of the organic N enhanced NH4 uptake by rice root.Next, pecial rhizobox was constructed to take subsamples from rhizosphere during growth of rice plant. Organic N profiles in rhizosphere soils were distinct between allophanic and smectitic paddy soils. Buf by rapid decrease in hydro-conductivity of rhizobox did not allow to distinguish the detailed mechanism of N uptake in AIlophanic paddy soil.

构建 Rhizobox，其中每个隔室中插入土壤溶液采样器和铂电极。水稻植物就在这个根箱中生长。本实验采用水铝土和蒙脱石土壤，通过观察不同理化性质的土壤之间的差异，研究根际土壤理化变化的影响。每周收集距稻根不同距离的土壤溶液。测量了这些溶液的PH、NH4、Fe(II)、有机C、无机C浓度。水英石和蒙脱石土壤对NH4的吸收方式不同。在蒙脱石土壤中，在第一阶段和第二阶段，质量流吸收是主要的氮吸收机制。这一结果与通常的解释相矛盾，通常的解释是 II 相中 NH4 的吸收是通过扩散吸收来解释的。在第二阶段，pH降低导致CEO的减少增强了水稻根部周围NH4的流动性。在水英土中，在第一阶段，质量流吸收是主要的氮吸收机制，但在第二阶段，扩散吸收是主要的氮吸收机制。我们的结果表明，在第一阶段，氮积累为有机氮，在第二阶段，有机氮的矿化增强了水稻根部对NH4的吸收。接下来，构建了特殊的根际盒，以在水稻生长过程中从根际采集子样本。水铝土和蒙脱石水稻土根际土壤的有机氮分布不同。通过快速降低根际箱的导水率而导致的 Buf 无法区分水肥水稻土中氮吸收的详细机制。