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| Speciation transformation and mechanism of phosphorus and iron in acid soils in paddy-upland rotation in central China |
| Received:January 05, 2022 |
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| KeyWord:phosphorus;iron oxide;alternation of wetting and drying;P/Fe ratio;DGT technology;phosphorus bioavailability |
| Author Name | Affiliation | E-mail | | CUI Chenyang | School of Resources and Environment, Huazhong Agricultural University, Wuhan 430000, China | | | YAN Yupeng | School of Land Resources and Environment, Jiangxi Agricultural University, Nanchang 330000, China | | | WANG Xiaoming | School of Resources and Environment, Huazhong Agricultural University, Wuhan 430000, China | | | LIU Fan | School of Resources and Environment, Huazhong Agricultural University, Wuhan 430000, China | | | FENG Xionghan | School of Resources and Environment, Huazhong Agricultural University, Wuhan 430000, China | fxh73@mail.hzau.edu.cn |
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| Abstract: |
| This study aimed to investigate the transformation of iron and phosphorus and phosphorus availability in two typical acid soils at paddy-upland rotation system in central China. Yellow Brown soil(High P/Fe)and Red soil(Low P/Fe)were collected in 2018 and 2019 after harvest. Phosphorus species, bioavailable phosphorus, and the iron Fe2+ and Feox were quantified during alternating wetting and drying via sequential extraction procedure and Diffusive Gradients in Thin-films technology. The results showed that the pH of Yellow Brown soil and Red soil increased during incubation, respectively, and tended to be neutral. During the flooding period, the Eh decreased, and the soil environment presented obvious reduction conditions. Both Fe2+ and Feox increased, and later decreased significantly after drainage. The phosphorus species mainly included iron bound phosphorus(Fe-P)and occluded phosphorus(Oc-P)in Yellow Brown soil, and Red soil mainly contained these two kinds. Both bioavailable phosphorus(DGT-P)and bioavailable iron(DGT-Fe)were released in the soil profile of 0 mm to 120 mm during incubation. The correlation was more significant in Yellow Brown soil. This study suggests that the soil redox conditions change the iron and phosphorus forms as the most important environmental factors. Fe-P and Oc-P are transformed after the soil underwent alternate wetting and drying. Red soil has low P/Fe ratio, and phosphorus is obviously occluded by iron. Yellow Brown soil has high P/Fe ratio, resulting in increase in Fe-P, and iron absorbed phosphorus as the main process. The increase in phosphorus bioavailability depends on the phosphorus level. |
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