利用根箱法解析水稻根际土壤中氮的行为(英文)  

The Behavior of Nitrogen in the Rhizosphere of Rice Plant Using the Rhizobox System

作　　者：乌尼木仁 樗木直也 陈能场[1,2] 稻永醇二 

机构地区：[1]日本鹿见岛大学农学部植物营养实验室,日本鹿见岛890-0065 [2]广东省生态环境与土壤研究所//广东省农业环境综合治理重点实验室,广东广州510650

出　　处：《生态环境》2008年第1期368-376,共9页Ecology and Environmnet

摘　　要：为研究水田土壤中氮的行为，施给^15NH4^＋或^15NO3^-标记的硝胺（NH4^15NO3或^15NH4NO3）的沙壤土（Shirasu soil）添充在根箱里，对Japonica水稻（品种Hinohikari）进行温室栽培6周。收割后，水稻植株分地上部和根部，对各自的全氮，^15N atom％进行测定。根箱各区域的土壤按着鲜土形态进行采取后，对此全氮，NO3-N，水溶性NH4-N，KCl抽出NH4-N和其各自的^15N atom％进行测定。研究结果表明，土壤全氮含量与栽培前相比，在非根际明显降低，但在根际比非根际要高，保持了与栽培前相同的水平。土壤NO3-N浓度从非根际到根际递增，但与其栽培前相比显著地降低，在整个根箱里，施给NO3-N的79％为因脱氮而损失。土壤中NO3-N的大部分来自于土壤氮化合物，来自施肥的比例却较低，尤其是在根际。反而，施给NO3-N的残存率约仅为16％左右，但其中有机态氮所占的比率在非根际里55％～86％，在根际却达到了93％。土壤水溶性NH4-N和KCl抽出NH4-N浓度靠近根际逐渐降低，而且在非根际两者匀由1：10的比例存在，但在根际里水溶性NH4-N没被检索到。在非根际里，土壤KCl抽出NH4-N的35％～66％为来自施肥，但其比例在根际里却降到15％左右。在土壤中残存的来自施给NH4-N的氮化合物之中，有机态氮所占的比例在非根际里约为11％～65％，但在根际却达到了92％。以上结果表明，在水稻根际，氮的无机化和有机化的活性比非根际显著。Behavior of N in the rhizosphere of rice （Oryza sativa L.） plant was investigated using a rhizobox system filled with a shirasu soil applied with NH4^15NO3 or ^15NH4NO3. The rhizobox consisted of one 2-mm width center compartment（CC）, five 1-mm width compartments, and one bulk compartment（ BC ） on both sides of CC. Rice was sowed and grown in CC. After 6th weeks after clutivation, the soil from each compartment were collected and analyzed for contents and ^15N excess% of the soil total-N, water-soluble NO3-N, NH4-N and KCl-extractable NH4-N. The obtained results were summarized as follows： 1） The total-N content of soil decreased in all the compartments except CC compared with that before cultivation, but that of CC did not change. 2） The water-soluble NO3-N content of soil decreased remarkably in all the compartments compared with that before cultivation, and about 79% of applied NO3-N was lost from soil due to denitrification. The NO3-N content of soil slightly increased from BC toward CC. The most of NO3-N were derived from the soil N especially in the CC. 3） The contents of water-soluble NH4-N and KCl-extractable NH4-N decreased from BC toward CC and the ratio of water-soluble NH4-N to KCl-extractable NH4-N are 1：10 in all the compartments except CC which water-soluble NH4-N was not detected. 4） Mineralization of soil-N and immobilizaition of fertilizer-N were more actively at CC than in the other compartments.

关 键 词：水稻根际土壤 根箱法 氮的行为 氮含量 

分 类 号：S15[农业科学—土壤学]