Transformations of N derived from straw under long-term conventional and no-tillage soils: A N-15 labelling study

文献类型： 外文期刊

第一作者： Liu, Xiu

作者： Liu, Xiu;Dong, Wenyi;Li, Yuzhong;Hossain, Md Elias;Liu, Enke;Liu, Xiu;Dong, Wenyi;Li, Yuzhong;Hossain, Md Elias;Liu, Enke;Jia, Shaohui;Liu, Qian;Hossain, Md Elias;Kuzyakov, Yakov;Kuzyakov, Yakov;Kuzyakov, Yakov

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关键词： Long-term no-tillage; Conventional tillage; N-15-labelled wheat straw; Labile N fractions; Nitrogen mineralization; Microbial nitrogen immobilization

期刊名称：SCIENCE OF THE TOTAL ENVIRONMENT （ 影响因子：7.963； 五年影响因子：7.842 ）

ISSN： 0048-9697

年卷期： 2021 年 786 卷

页码：

收录情况： SCI

摘要： Understanding wheat straw nitrogen (N) transformations in soil depending on tillage practices is necessary to increase the efficient N use and to protect diyland farming environments. Labile organic N pools are crucial for N mineralization but are less investigated because of their fast dynamics. The objectives of this study were to determine the effects of winter wheat straw N (N-15-labelled) on soil labile organic N transformations under long-term (27 years) no-tillage and conventional tillage. Four treatments were established under controlled conditions: no-tillage without straw (NoTill); no-tillage with N-15-labelled wheat straw (NoTill+Straw); conventional tillage without straw (ConvTill); and conventional tillage with N-15-labelled straw (ConvTill +Straw). Straw application increased the particulate organic matter N (POMN) and microbial biomass N (MBN) contents, especially in NoTill +Straw, but decreased the dissolved organic N (DON) content. This reflects intensive microbial DON immobilization at the background of plant residues with a high C/N ratio. The 40% to 80% increase in the NH4+ content after straw addition reflects fast straw and soil organic matter (SOM) mineralization, while NO3- declined by 60% to 93% over 56 days, especially in ConvTill soil. N-15 recovered in POMN after 14 d was greatest in NoTill +Straw and ConvTill +Straw, reaching 20 and 18 mg N-15 kg(-1), respectively. Overall, the straw N recovered as NO3- was 72% and 48% greater than that in NH4+ in ConvTill +Straw and NoTill +Straw, respectively, reflecting ac-celerated SOM mineralization and N mining in the presence of straw. The straw N recovered as POMN was greater through the incubation period (56 days) than that in DON and MBN, especially in NoTill +Straw, indicat-ing that the no-tillage practice reduced straw mineralization. N-15 in DON and N-15 in NO3- were higher in NoTill +Straw than in ConvTill+Straw, implying that N limitation was alleviated to a certain extent under no-tillage conditions. In conclusion, wheat straw N remained mainly in POMN after 56 days, especially under no-till condi-tions. and only a minor part was incorporated into DON and microbial biomass. This provides a theoretical basis for straw N use efficiency in agroecosystems. (C) 2021 Elsevier B.V. All rights reserved.

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