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Nitrogen storage in density and size fractions varied with tillage practices and cropping systems under residue return
  • +7
  • Yang Zhang,
  • Yan Zhang,
  • Yan Gao,
  • Dandan Huang,
  • Xuewen Chen,
  • Shixiu Zhang,
  • Xiaoping Zhang,
  • Neil McLaughlin,
  • Yang Xiang,
  • Aizhen Liang
Yang Zhang
Northeast Institute of Geography and Agroecology Chinese Academy of Sciences

Corresponding Author:[email protected]

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Yan Zhang
Northeast Institute of Geography and Agroecology Chinese Academy of Sciences
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Yan Gao
Northeast Institute of Geography and Agroecology Chinese Academy of Sciences
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Dandan Huang
Northeast Institute of Geography and Agroecology Chinese Academy of Sciences
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Xuewen Chen
Northeast Institute of Geography and Agroecology Chinese Academy of Sciences
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Shixiu Zhang
Northeast Institute of Geography and Agroecology Chinese Academy of Sciences
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Xiaoping Zhang
Northeast Institute of Geography and Agroecology Chinese Academy of Sciences
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Neil McLaughlin
Ottawa Research and Development Centre
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Yang Xiang
Jilin Agricultural Technology Extension Station
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Aizhen Liang
Northeast Institute of Geography and Agroecology Chinese Academy of Sciences
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Abstract

Residue return can prevent or restore the degradation of cropland, meanwhile, additional N input from residue return inevitably result in the changes of soil nitrogen (N) pools. Our objectives were to evaluate these changes in a 16-year field experiment. The residue return experiment consisted of no-tillage (NT) and mouldboard plough (MP), combined with continuous maize (Zea mays L.) (MM) and maize-soybean (Glycine max Merr.) rotation (MS) cropping systems, that is, NTMM, NTMS, MPMM, MPMS; conventional tillage (removal of crop residue and deep plough) with continuous maize (CTMM) was included as a control. The soil was separated into density (LF, light fraction) and particle size (sand, silt and clay) fraction. In 0-5 cm and 5-10 cm layers, soil TN content in NT was higher than MP, whereas the opposite trend was observed in 10-20 cm. Thus, the stratification ratio of soil TN was greater under NT. Cropping system affected soil TN as MM > MS. Residue return increased soil N storage by 6.44%-24.85% in the plough layer. Taking CTMM as the baseline, NTMM and MPMM increased the N storage in all physical fractions, while the decrease of silt-N storage was observed in NTMS and MPMS. Under residue return, the distribution of N storage changes in LF and sand fraction was affected by tillage practice, and that in silt and clay fraction was affected by cropping system. In summary, NTMM is effective for soil N accumulation due to its highest N storage and all physical fractions of N storage was enhanced.