利用(15)~N示踪技术研究了硝酸磷肥的氮素效应,结果表明:①作基肥施用时,各种肥料对小麦的增产效果相同,但在小麦生长初期,不同肥料有不同的肥效,硝酸礴肥优于尿素重钙。②作物对肥料氮的吸收和利用取决于氮素形态,其顺序为:硝酸磷肥的 ...利用(15)~N示踪技术研究了硝酸磷肥的氮素效应,结果表明:①作基肥施用时,各种肥料对小麦的增产效果相同,但在小麦生长初期,不同肥料有不同的肥效,硝酸礴肥优于尿素重钙。②作物对肥料氮的吸收和利用取决于氮素形态,其顺序为:硝酸磷肥的 NO_2-N>磷铵态N>尿素态 N>硝酸磷肥的 NH_4-N。肥料氮的气态损失以硝态 N 损失最少,尿素态 N 次之,两年结果非常一致。展开更多
An improved method,suitable for collecting nitrate from surface waters in the watershed for 15 N isotope tracing analysis,was developed on the basis of the anion exchange coupled with diffusion through systematic simu...An improved method,suitable for collecting nitrate from surface waters in the watershed for 15 N isotope tracing analysis,was developed on the basis of the anion exchange coupled with diffusion through systematic simulation and comparison experiments.The results showed that the nitrate could be separated and enriched from the waters efficiently by using the improved method.Being simple and practical in operation principle and procedures,cost-economic,and highly efficient in nitrate separation/enrichment,the method met the requirements of δ 15 N mass spectrum analysis and would lay a foundation for the application of 15 N isotope tracing approach to the research on non-point source pollution in watershed.展开更多
A variable-charge （VC） and a permanent-charge paddy soil （PC） were selected to study nitrate-N （NO3^--N） and ammonium-N （NH4^＋-N） leaching with N isotopes for one consecutive year. An irrigation and intermitt...A variable-charge （VC） and a permanent-charge paddy soil （PC） were selected to study nitrate-N （NO3^--N） and ammonium-N （NH4^＋-N） leaching with N isotopes for one consecutive year. An irrigation and intermittent drainage pattern was adopted to mimic natural occurrence of rainfall during the upland crop season and drainage management during the flooded rice season. Treatments to each soil type were no-N controls （CK）, ^15N-labeled （NH4）2SO4 （NS）, and milk vetch （NV） applied at a rate equivalent to 238 kg N ha^-1 to unplanted lysimeters, totaling six treatments in triplicates. Results indicated that the soil type dominated N leaching characteristics. In the case of PC, NO3^--N accounted for 78% of the total leached inorganic N; NS was prone to leach three times more than the NV, being 8.2% and 2.4% of added ^15N respectively; and 〉 85% of leached NO3-N came from of the total inorganic N in leachate. Moreover, NH4^＋-N native N in the soil. In the case of VC, NH4^＋-N made up to 92% leaching was detected throughout the whole incubation, and was particularly high during the flooded season. NO3^--N leaching in VC occurred later at a lower rate compared to that in PC. The findings of this study indicate that NO3^--N leaching during the drained season in permanent-charge paddy soils and NH4^＋-N leaching in variable-charge soils deserve more attention for regional environmental control.展开更多
文摘利用(15)~N示踪技术研究了硝酸磷肥的氮素效应,结果表明:①作基肥施用时,各种肥料对小麦的增产效果相同,但在小麦生长初期,不同肥料有不同的肥效,硝酸礴肥优于尿素重钙。②作物对肥料氮的吸收和利用取决于氮素形态,其顺序为:硝酸磷肥的 NO_2-N>磷铵态N>尿素态 N>硝酸磷肥的 NH_4-N。肥料氮的气态损失以硝态 N 损失最少,尿素态 N 次之,两年结果非常一致。
基金supported by the Department of Science and Technology of Fujian Province,China,under theproject No. 2002H009
文摘An improved method,suitable for collecting nitrate from surface waters in the watershed for 15 N isotope tracing analysis,was developed on the basis of the anion exchange coupled with diffusion through systematic simulation and comparison experiments.The results showed that the nitrate could be separated and enriched from the waters efficiently by using the improved method.Being simple and practical in operation principle and procedures,cost-economic,and highly efficient in nitrate separation/enrichment,the method met the requirements of δ 15 N mass spectrum analysis and would lay a foundation for the application of 15 N isotope tracing approach to the research on non-point source pollution in watershed.
基金Project supported by the National Natural Science Foundation of China (No. 30390080)the Nanjing Science and Technology Bureau,China (No. 200901063)
文摘A variable-charge （VC） and a permanent-charge paddy soil （PC） were selected to study nitrate-N （NO3^--N） and ammonium-N （NH4^＋-N） leaching with N isotopes for one consecutive year. An irrigation and intermittent drainage pattern was adopted to mimic natural occurrence of rainfall during the upland crop season and drainage management during the flooded rice season. Treatments to each soil type were no-N controls （CK）, ^15N-labeled （NH4）2SO4 （NS）, and milk vetch （NV） applied at a rate equivalent to 238 kg N ha^-1 to unplanted lysimeters, totaling six treatments in triplicates. Results indicated that the soil type dominated N leaching characteristics. In the case of PC, NO3^--N accounted for 78% of the total leached inorganic N; NS was prone to leach three times more than the NV, being 8.2% and 2.4% of added ^15N respectively; and 〉 85% of leached NO3-N came from of the total inorganic N in leachate. Moreover, NH4^＋-N native N in the soil. In the case of VC, NH4^＋-N made up to 92% leaching was detected throughout the whole incubation, and was particularly high during the flooded season. NO3^--N leaching in VC occurred later at a lower rate compared to that in PC. The findings of this study indicate that NO3^--N leaching during the drained season in permanent-charge paddy soils and NH4^＋-N leaching in variable-charge soils deserve more attention for regional environmental control.
