CAJ | 학술논문

【目的】本研究旨在探明外源化肥氮在土壤不同有机氮库中的动态转化及关系，为实现化肥氮素养分高效利用的有效调控提供理论依据。【方法】利用15 N示踪技术（15 N标记尿素，丰度10.3%），以江西红壤性水稻土为研究对象，通过土壤培养试验，研究农民习惯施肥水平下，水稻不同生育期外源化肥氮在土壤有机氮库（氨基酸态氮、氨基糖态氮、酸解铵态氮、酸解未知氮和非酸解有机氮）中的转化及关系。采用通径分析方法，评估来自外源化肥氮的有机氮各组分之间的转化关系。【结果】1）土壤中氨基酸态氮和氨基糖态氮中来自外源的化肥氮（氨基酸态氮-15N和氨基糖态氮-15N）含量从分蘖期到拔节期显著升高（P <0.05），从拔节期到灌浆期显著降低（P <0.05），全生育期两个组分中来自外源化肥氮的含量最高值分别为26.5和8.4 mg/kg，均出现在分蘖期和拔节期之间；酸解性铵态氮中来自外源的化肥氮（酸解性铵态氮-15 N）含量从分蘖期到成熟期逐渐降低，全生育期的动态转化符合指数递减方程；酸解未知态氮中来自外源的化肥氮（酸解未知态氮-15 N）含量随着生育期的延长逐渐达到动态平衡，最大值接近12.8 mg/kg；非酸解性有机氮中来自外源的化肥氮（非酸解性有机氮-15 N）含量在全生育期的变化符合对称方程，最低值7.9 mg/kg出现在拔节期和灌浆期之间。2）在水稻营养生长阶段的分蘖期和拔节期，外源化肥氮分别以酸解性铵态氮和氨基酸态氮为主要方式结合到土壤有机氮库中，其含量分别占施入化肥氮的21.5%和14.8%；在水稻营养生长和生殖生长并进阶段（灌浆期）和生殖生长阶段（成熟期），外源化肥氮主要结合到非酸解性有机氮库中，分别占施入化肥氮的8.7%和12.7%。3）土壤各有机氮库中来自外源的化肥氮之间存在相互转化的关系，酸解性铵态氮库起到了“暂时库”的作用，生育前期在土壤中固持氮，当可利用性氮受限时，又可以作为有效氮库释放氮供作物吸收；在整个生长期中氨基酸态氮库对外源化肥氮的转化积累起到了“过渡库”的作用，固持在氨基酸中的化肥氮可以转化成酸解性铵态氮和氨基糖态氮。4）灌浆期和成熟期植物吸收的来自外源的化肥氮与氨基酸态氮-15 N和酸解铵态氮-15 N的关系更密切。【结论】外源化肥氮在土壤中转化的过程中酸解性铵态氮起到了“暂时库”的作用，氨基酸态氮起到了“过渡库”的作用，非酸解性有机氮可作为氮素的“稳定库”存在，外源氮在这几个主要的氮库中动态转换以保持土壤-作物体系中氮素的循环。【目的】本研究旨在探明外源化肥氮在土壤不同有機氮庫中的動態轉化及關繫，為實現化肥氮素養分高效利用的有效調控提供理論依據。【方法】利用15 N示蹤技術（15 N標記尿素，豐度10.3%），以江西紅壤性水稻土為研究對象，通過土壤培養試驗，研究農民習慣施肥水平下，水稻不同生育期外源化肥氮在土壤有機氮庫（氨基痠態氮、氨基糖態氮、痠解銨態氮、痠解未知氮和非痠解有機氮）中的轉化及關繫。採用通徑分析方法，評估來自外源化肥氮的有機氮各組分之間的轉化關繫。【結果】1）土壤中氨基痠態氮和氨基糖態氮中來自外源的化肥氮（氨基痠態氮-15N和氨基糖態氮-15N）含量從分蘗期到拔節期顯著升高（P <0.05），從拔節期到灌漿期顯著降低（P <0.05），全生育期兩箇組分中來自外源化肥氮的含量最高值分彆為26.5和8.4 mg/kg，均齣現在分蘗期和拔節期之間；痠解性銨態氮中來自外源的化肥氮（痠解性銨態氮-15 N）含量從分蘗期到成熟期逐漸降低，全生育期的動態轉化符閤指數遞減方程；痠解未知態氮中來自外源的化肥氮（痠解未知態氮-15 N）含量隨著生育期的延長逐漸達到動態平衡，最大值接近12.8 mg/kg；非痠解性有機氮中來自外源的化肥氮（非痠解性有機氮-15 N）含量在全生育期的變化符閤對稱方程，最低值7.9 mg/kg齣現在拔節期和灌漿期之間。2）在水稻營養生長階段的分蘗期和拔節期，外源化肥氮分彆以痠解性銨態氮和氨基痠態氮為主要方式結閤到土壤有機氮庫中，其含量分彆佔施入化肥氮的21.5%和14.8%；在水稻營養生長和生殖生長併進階段（灌漿期）和生殖生長階段（成熟期），外源化肥氮主要結閤到非痠解性有機氮庫中，分彆佔施入化肥氮的8.7%和12.7%。3）土壤各有機氮庫中來自外源的化肥氮之間存在相互轉化的關繫，痠解性銨態氮庫起到瞭“暫時庫”的作用，生育前期在土壤中固持氮，噹可利用性氮受限時，又可以作為有效氮庫釋放氮供作物吸收；在整箇生長期中氨基痠態氮庫對外源化肥氮的轉化積纍起到瞭“過渡庫”的作用，固持在氨基痠中的化肥氮可以轉化成痠解性銨態氮和氨基糖態氮。4）灌漿期和成熟期植物吸收的來自外源的化肥氮與氨基痠態氮-15 N和痠解銨態氮-15 N的關繫更密切。【結論】外源化肥氮在土壤中轉化的過程中痠解性銨態氮起到瞭“暫時庫”的作用，氨基痠態氮起到瞭“過渡庫”的作用，非痠解性有機氮可作為氮素的“穩定庫”存在，外源氮在這幾箇主要的氮庫中動態轉換以保持土壤-作物體繫中氮素的循環。
【목적】본연구지재탐명외원화비담재토양불동유궤담고중적동태전화급관계，위실현화비담소양분고효이용적유효조공제공이론의거。【방법】이용15 N시종기술（15 N표기뇨소，봉도10.3%），이강서홍양성수도토위연구대상，통과토양배양시험，연구농민습관시비수평하，수도불동생육기외원화비담재토양유궤담고（안기산태담、안기당태담、산해안태담、산해미지담화비산해유궤담）중적전화급관계。채용통경분석방법，평고래자외원화비담적유궤담각조분지간적전화관계。【결과】1）토양중안기산태담화안기당태담중래자외원적화비담（안기산태담-15N화안기당태담-15N）함량종분얼기도발절기현저승고（P <0.05），종발절기도관장기현저강저（P <0.05），전생육기량개조분중래자외원화비담적함량최고치분별위26.5화8.4 mg/kg，균출현재분얼기화발절기지간；산해성안태담중래자외원적화비담（산해성안태담-15 N）함량종분얼기도성숙기축점강저，전생육기적동태전화부합지수체감방정；산해미지태담중래자외원적화비담（산해미지태담-15 N）함량수착생육기적연장축점체도동태평형，최대치접근12.8 mg/kg；비산해성유궤담중래자외원적화비담（비산해성유궤담-15 N）함량재전생육기적변화부합대칭방정，최저치7.9 mg/kg출현재발절기화관장기지간。2）재수도영양생장계단적분얼기화발절기，외원화비담분별이산해성안태담화안기산태담위주요방식결합도토양유궤담고중，기함량분별점시입화비담적21.5%화14.8%；재수도영양생장화생식생장병진계단（관장기）화생식생장계단（성숙기），외원화비담주요결합도비산해성유궤담고중，분별점시입화비담적8.7%화12.7%。3）토양각유궤담고중래자외원적화비담지간존재상호전화적관계，산해성안태담고기도료“잠시고”적작용，생육전기재토양중고지담，당가이용성담수한시，우가이작위유효담고석방담공작물흡수；재정개생장기중안기산태담고대외원화비담적전화적루기도료“과도고”적작용，고지재안기산중적화비담가이전화성산해성안태담화안기당태담。4）관장기화성숙기식물흡수적래자외원적화비담여안기산태담-15 N화산해안태담-15 N적관계경밀절。【결론】외원화비담재토양중전화적과정중산해성안태담기도료“잠시고”적작용，안기산태담기도료“과도고”적작용，비산해성유궤담가작위담소적“은정고”존재，외원담재저궤개주요적담고중동태전환이보지토양-작물체계중담소적순배。
Objectives]In this study,the transformation and re1ationshiP of externa1 chemica1 N in soi1 organic nitrogen( SON)fractions were determined during one growing season of rice in order to Provide a theoretica1 basis for reasonab1e ferti1izer aPP1ication and the effective adjustment to N ferti1izer.[Methods]A Pot exPeriment was carried out on a subtroPica1 Paddy soi1 in Jiangxi Province,and a tota1 N 180. 0 kg/ha(15 N 1abe1ed urea,atom 10. 3%)was aPP1ied to a rice croP during one growing season under the conventiona1 farmer Practices. Distribution and dynamics of the chemica1 N ferti1izer in different SON fractions( i. e. ,amino acid N,amino sugar N, hydro1ysab1e ammonium N,hydro1yzab1e unknown N and acid inso1ub1e N)were measured. Path ana1ysis was used to eva1uate the transformation Process between SON derived from the ferti1izer in soi1-P1ant system.[Results]1 ) The accumu1ation of ferti1izer-derived N in different SON fractions was season-sPecific. The recovery contents of the ferti1izer-derived N in soi1 amino acid N and amino sugar N at the jointing stage are significant1y higher than those at the ti11ering stage( P<0. 05 ). The enrichments of 15 N are significant1y dec1ined from the jointing stage to fi11ing stage( P<0. 05 ). The dynamics of enrichment of 15 N in soi1 amino acid N and amino sugar N during the growing season can be fitted as a Gauss equation,the maximum contents are 26. 5 and 8. 4 mg/kg,resPective1y,which are found between the ti11ering stage and jointing stage. The enrichment of 15 N in hydro1ysab1e ammonium N is dec1ined gradua11y from the ti11ering stage to harvest stage,and the dynamics of the enrichment of 15 N in soi1 hydro1ysab1e ammonium N cou1d be exPressed as an exPonentia1 dec1ine equation. The enrichment of 15 N in hydro1yzab1e unknown N is gradua11y in a dynamica1 equi1ibrium from the ti11ering stage to harvest stage,and the dynamics of the enrichment of 15 N in soi1 hydro1ysab1e unknown N can be fitted as an exPonentia1 equation. The enrichment of 15 N in acid inso1ub1e N can be fitted as a symmetry equation,and the minimum of the enrichment of 15 N is 7. 9 mg/kg, which is found between the jointing stage and fi11ing stage. 2 )At the ti11ering stage and jointing stage of rice, Preferentia1 enrichment of 15 N is found in soi1 hydro1ysab1e ammonium N and amino acid N,accounting for 21. 5%and 14. 8% of the tota1 N of the chemica1 N ferti1izer,resPective1y. The accumu1ation of residua1 ferti1izer-derived N in acid inso1ub1e N is higher at the fi11ing and harvest stages,accounting for 8. 7% and 12. 7% of the tota1 N of the chemica1 N ferti1izer,resPective1y. 3 )The Path ana1ysis indicates that the hydro1ysab1e ammonium N is a temPorary Poo1 for raPid chemica1 N ferti1izer retention and is aPt to re1ease N for croP uPtake simu1taneous1y. In contrast,the amino acid N cou1d serve as a transitiona1 Poo1 of avai1ab1e N in soi1 system through transferring into hydro1ysab1e ammonium N and amino sugar N. 4)The ferti1izer-derived N in hydro1ysab1e ammonium N and amino acid N are c1ose1y re1ated to ferti1izer-derived N in croP uPtake.[Conclusions]In a P1ant-soi1 system,the ferti1izer N cyc1ing during a growing season is c1ose1y re1ated to temPora1 Patterns of ferti1izer N transformation into different SON fractions. The ferti1izer-derived N can be derived into three Poo1s with different avai1abi1ities. The hydro1ysab1e ammonium N fraction can serve as a temPorary Poo1 containing readi1y avai1ab1e N to be re1eased fast,whi1e the amino acid N can be considered as a transitiona1 Poo1 for the transformation of the hydro1ysab1e ammonium N and amino sugar N,and the acid inso1ub1e N is tight1y associated with ferti1izer N stabi1ization. ImPortant1y,there is an interim shift among the three substantia1 N Poo1s to maintain soi1 N cyc1ing and suPP1y in a soi1-P1ant system.