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| Spatio-temporal characteristics and improvement of medium and mild heavy metals contaminated farmland soil |
| Received:March 30, 2023 |
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| KeyWord:brown soil;fluvo-aquic soil;heavy metal;nutrient availability;heavy metal migration;nitrogen and phosphorus synergists |
| Author Name | Affiliation | E-mail | | ZHAN Nanbiao | National Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Tai' an 271018, China | | | GU Duanyin | Vegetable Institute of Tai' an Academy of Agricultural Sciences, Tai' an 271000, China | guduanyin@163.com | | LI Ting | National Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Tai' an 271018, China | | | CUI Xiumin | National Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Tai' an 271018, China | xiumincui@sdau.edu.cn | | LOU Yanhong | National Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Tai' an 271018, China | | | ZHUGE Yuping | National Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Tai' an 271018, China | |
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| Abstract: |
| To study the spatiotemporal characteristics of heavy metals and the available nutrients in farmland soil, as well as the effects of nitrogen and phosphorus synergists on heavy metals in farmland soil, this study took acid brown soil and typical aquic soil with moderate or mild pollution as the research object and utilized field experiment, pot experiment, and laboratory analysis methods. The results showed that the contents of Cd, Cu, Pb, and Zn were significantly higher in the 0–20 cm soil layer than in the deeper soil. The Cd content in the 0– 20 cm soil layer of brown soil exceeded the standard by 204%, and the Cd and Zn contents in 0–20 cm soil layer of the fluvo-aquic soil exceeded the standard by 104% and 419%, respectively. The percentage of available heavy metal content was higher in the 0–20 cm soil layer of farmland soil than in the deep soil and was higher in brown soil than in fluvo-aquic soil. The contents of total nitrogen, alkalihydrolyzable nitrogen, ammonium nitrogen, nitrate nitrogen, available phosphorus, and available potassium were also significantly higher in the 0–20 cm soil layer than in the deep layers of brown soil and gradually decreased with greater soil depth. Only the total nitrogen, alkalihydrolyzed nitrogen, and available phosphorus contents in the fluvo-aquic soil were significantly higher than those in the deep soil. The available nutrients of the farmland soil fluctuated with time, with nitrate nitrogen and ammonium nitrogen showing the maximum fluctuations. The maximum coefficients of variation were 44.1% and 47.3%, respectively. In polluted farmland soil of wheat plants, Cd, Pb, and Cu mainly accumulated in leaves, whereas Zn mainly accumulated in grains. The migration degrees of different heavy metal elements from wheat stems and leaves to grains were quite different. Among these, the migration rate of Cd was smallest and the migration rate of Zn was largest. Nitrogen and phosphorus synergists could significantly reduce the content of available heavy metals in brown soil. The contents of available Cd, Cu, Pb, and Zn in the hydroquinone+dicyandiamide+biochar treatment were significantly lower than those of the treatment without it by 24.7%, 19.5%, 23.7%, and 18.1%, respectively. However, the application effect was not obvious in fluvo-aquic soil. The results revealed a certain correlation between heavy metals and nutrients in farmland soil, which was similar through the vertical distribution of the soil. Soil type is an important factor modulating the different effects of nitrogen and phosphorus synergists on the available states of heavy metals. |
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