Study of organic N transformation in red soils by ¹⁵N tracer method

Study of organic N transformation in red soils by 15 N tracer method 1 first-author 1 1 1 1 Institute of Nuclear-Agricultural Sciences, Zhejiang Agricultural University, Hangzhou 310029 Institute of Nuclear-Agricultural Sciences, Zhejiang Agricultural University, Hangzhou 310029 Uniformly 15 N -labelled ryegrass was used to investigate <math><mrow><mi>N</mi><mi>H</mi><mfrac><mn>4</mn><mo>+</mo></mfrac></mrow></math> -production, microbial transformation and humification of organic N in two types of red soils by incubating the soils amended with labelled material. The results showed that there was little significant difference in biomass N transformation in the tested soils between 15 N tracer method and conventional method, but the amount of <math><mrow><mi>N</mi><mi>H</mi><mfrac><mn>4</mn><mo>+</mo></mfrac></mrow></math> -N from ryegrass measured with 15 N method was significantly higher than that measured with conventional method. The results also indicated that there was more <math><mrow><mi>N</mi><mi>H</mi><mfrac><mn>4</mn><mo>+</mo></mfrac></mrow></math> -N released from the ryegrass in the clayey soil than in the sandy soil at all sampling time. By 120 d of incubation, humified N was less than 10% of the amount of the applied N in two types of red soils and the amount of residual N in the clayey red soil was obviously higher than that in the sandy red soil. 15 N tracer method Organic N turnover Red soil Ryegrass References Christensen B T . Soil Biol Biochem , 1987 ; 19 ( 4 ): 429 Soil Biol Biochem Russell E W . The role of organic matter in soil productivity. In: The use of isotopes in soil organic matter studies , FAO/IAEA technical meeting , Brunswick, Volkenrode, Tokyo : Pergamon Press , 1963 ; 3 The role of organic matter in soil productivity. In: The use of isotopes in soil organic matter studies Jenkinson D S . Decomposition of labelled plant material in soil . In: Hallsworth E G , Crawford D V eds. Experimental pedology , London : Butterworthsp , 1964 ; 199 Decomposition of labelled plant material in soil Goswami N N , Datta N P . J Indian Soc Sci , 1961 ; 9 : 269 J Indian Soc Sci Jenkinson D S . Soil Science , 1971 ; 111 : 64 Soil Science Ladd J N , Amato M , Oades J M . Aus J Soil Res , 1985 ; 23 : 603 Aus J Soil Res Ladd J N , Oades J M , Amato M . Soil Biol Biochem , 1981 ; 13 : 119 Soil Biol Biochem Pan Jia-Yong , Zheng Xing-Yun , Wen Xian- Fang et al . J Nucl Agric Sci (in Chinese) , 1994 ; 15 ( 1 ): 35 J Nucl Agric Sci (in Chinese) Wang Wei-Min . Acta Pedologica Sinica (in Chinese) , 1986 ; 23 ( 2 ): 97 Acta Pedologica Sinica (in Chinese) Jansson S L . Annals of the Royal Agricutural College of Sweden , 1958 ; 24 : 101 Annals of the Royal Agricutural College of Sweden Brookes P C , Landman A , Pruden G et al . Soil Biol Biochem , 1985 ; 17 : 837 Soil Biol Biochem Wen Qi-Xiao . Methods of studying organic matter (in Chinese) . Beijing : The Agricultural Publishing House , 1984 ; 112 Methods of studying organic matter (in Chinese) The Project Supported by Commission of the European Communities 1996-11-25 1997-05-01 2021-02-05 1997 Nuclear Science and Techniques 2 08