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| Difference in nitrogen transformation rates between rhizosphere and bulk soil in a calcareous soil-rice system |
| Received:June 10, 2022 |
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| KeyWord:calcareous soil;rhizosphere of rice;gross nitrogen transformation rate;15N labeling;nitrification |
| Author Name | Affiliation | E-mail | | HE Xiaoqian | College of Resources, Sichuan Agricultural University, Chengdu 611130, China
Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Chengdu 611130, China | | | LIU Xini | College of Resources, Sichuan Agricultural University, Chengdu 611130, China
Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Chengdu 611130, China | | | HUANG Yuxiao | College of Resources, Sichuan Agricultural University, Chengdu 611130, China
Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Chengdu 611130, China | | | LAN Ting | College of Resources, Sichuan Agricultural University, Chengdu 611130, China
Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Chengdu 611130, China | tlan@sicau.edu.cn |
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| Abstract: |
| To better understand the differences in nitrogen transformation between the rhizosphere and bulk soil in a calcareous soil-rice system, soils were collected at the tillering stage and maturity stage of rice and differences in the gross rates of mineralization, nitrification, and immobilization were investigated in aerobic microcosmic experiments. The results showed that:The gross rates of mineralization and nitrification of the rhizosphere soil were 4.45 mg·kg-1·d-1 and 9.16 mg·kg-1·d-1, respectively, which are significantly lower than that of bulk soil(P<0.05). There was no significant difference in the gross mineralization rate(6.75 mg·kg-1·d-1) and nitrification rate(16.86 mg·kg-1· d-1) between the rhizosphere and bulk soil at the maturity stage, but these rates were significantly higher than those at the tillering stage(P< 0.05). The NH + 4-N immobilization rate at the tillering stage was higher than that at the maturity stage. The NH4+-N immobilization rate of rhizosphere soil was 19.75 mg·kg-1·d-1 at the tillering stage, which is 42.21% higher than that at the maturity stage. Additionally, the NO3--N immobilization rates of rhizosphere soil in both stages were higher than that of bulk soil. In the tillering stage, the gross mineralization rate of rhizosphere soil was significantly higher than the inorganic nitrogen immobilization rate, whereas the gross nitrification rate was decreased, enabling nitrogen retention and curbing NO3--N loss. Our results indicate that the nitrogen transformation rates of rhizosphere soil differ in different growth stages because of variations in the water content, mineral nitrogen, and root exudation. |
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