| 北方农田镉污染土壤玉米生产阈值及产区划分初探 |
| 摘要点击 1813 全文点击 563 投稿时间：2021-04-17 修订日期：2021-05-27 |
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| 中文关键词 重金属镉 富集系数(BCF) 定量关系 阈值 产区划分 |
| 英文关键词 Cd bioconcentration coefficient(BCF) quantitative relationship thresholds production yield division |
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| 中文摘要 |
| 为探究我国北方镉（Cd）污染农田中玉米安全生产的土壤阈值以及产区划分，于部分北方玉米主要产区（含不同程度Cd污染）收集了129套点对点的土壤-玉米样品，分析了土壤理化性质与土壤、玉米籽粒Cd含量之间的相关性，利用多元线性回归法和物种敏感度分布曲线法（SSD）推导不同土壤情景下土壤Cd的生态阈值，并进行了玉米"宜产、限产、禁产"产区划分.结果表明，研究区土壤与玉米籽粒中Cd含量超标分别为99.62%和49.61%；玉米籽粒中Cd富集系数（BCF）与土壤pH、土壤有机质（SOM）、阳离子交换量（CEC）和土壤有效态Cd含量（DTPA浸提）均呈极显著相关性（P<0.01）.多元线性回归法的预测可解释因变量71.9%的变异量；基于研究区土壤特性以及参考资料，划分3种不同土壤情景分别为，情景1：6.5ω（SOM）=15 g·kg-1，土壤CEC=15 cmol·kg-1；情景2：7.5ω（SOM）=20 g·kg-1，土壤CEC=20 cmol·kg-1；情景3：pH ≥ 8.5，土壤ω（SOM）=17g·kg-1，土壤CEC=17 cmol·kg-1，利用SSD法中Logistic函数模型推导以上3种情景的粮食宜产区土壤Cd阈值分别为3.00、3.80和3.11 mg·kg-1；禁产区阈值为8.95、9.10和7.21 mg·kg-1，当土壤Cd含量介于宜产区阈值与禁产区阈值之间时该区域划分为粮食限产区；玉米用于饲料使用时3种情景下的饲料宜产区阈值分别为14.94、18.90和15.55 mg·kg-1，禁产区阈值分别为44.93、45.40和36.05 mg·kg-1，两者之间的区域为饲料限产区.以上方法和结果可为我国北方农田土壤的安全生产提供参考，并为土壤生态阈值的标准制定提供科学依据. |
| 英文摘要 |
| In order to explore the soil thresholds and production area division of maize in cadmium (Cd) contaminated farmland in northern China, 129 pairs of point-to-point soil and maize samples were collected from various maize-production areas with different degrees of Cd pollution in northern China. The quantitative relationships between soil properties and Cd content in soil and maize grains were analyzed. Multiple linear regression and Species Sensitivity Distribution (SSD) curve methods were used to determine the thresholds of soil Cd under different soil scenarios, and to differentiate the ‘suitable, limited, and forbidden’ production areas of maize. The results showed that the content of Cd in the soil and maize grains exceeded the permissible limits of soil and food standards by 99.62% and 49.61%, respectively. The bioconcentration coefficient (BCF) of Cd in maize grains was significantly correlated with soil pH, soil organic matter (SOM), cation exchange capacity (CEC), and soil DTPA-Cd content (P<0.01), respectively. The prediction formula established by multiple linear regression could explain 71.9% of the variation in the dependent variable. Based on the soil characteristics in northern maize-production areas, in this study, three typical soil scenarios were divided as follows:scenario 1:6.5ω(SOM)=15 g·kg-1, CEC=15 cmol·kg-1; scenario 2:7.5ω(SOM)=20 g·kg-1, CEC=20 cmol·kg-1; scenario 3:pH ≥ 8.5, ω(SOM)=17 g·kg-1, CEC=17 cmol·kg-1. According to the logistic function model of the SSD method, the soil Cd thresholds of suitable maize-producing areas were 3.00, 3.80, and 3.11 mg·kg-1, respectively, and the soil Cd thresholds of the forbidden maize-producing areas were 8.95, 9.10, and 7.21 mg·kg-1, respectively. The area with soil Cd content within a range of the suitable area thresholds and the forbidden area thresholds was considered as restricted for the maize-producing area. When maize was used as feed, the suitable production thresholds were 14.94, 18.90, and 15.55 mg·kg-1, respectively, and the forbidden thresholds were 44.93, 45.40, and 36.05 mg·kg-1, respectively. The area between them was considered as a restricted feed-production area. The results in this study can provide technical support for the safer maize production and classification management of farmland soil in northern China's maize-producing areas. |
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