生态环境学报 ›› 2023, Vol. 32 ›› Issue (1): 150-157.DOI: 10.16258/j.cnki.1674-5906.2023.01.016

• 研究论文 • 上一篇    下一篇

地下水位和长期秸秆还田对土壤镉有效性及稻米镉含量的影响

徐敏1,2(), 许超2,*(), 余光辉1,*(), 尹力初3, 张泉2, 朱捍华2, 朱奇宏2, 张杨珠3, 黄道友2   

  1. 1.湖南科技大学地球科学与空间信息工程学院,湖南 湘潭 411201
    2.中国科学院亚热带农业生态研究所/亚热带农业生态过程重点实验室/中国科学院长沙农业环境观测研究站,湖南 长沙 410125
    3.湖南农业大学资源环境学院,湖南 长沙 410128
  • 收稿日期:2022-08-02 出版日期:2023-01-18 发布日期:2023-04-06
  • 通讯作者: 余光辉(1976年生),男,教授,博士,主要从事环境管理及环境影响评价与规划。E-mail: yuguanghui107@aliyun.com
    *许超(1978年生),男,副研究员,博士,主要从事土壤重金属污染土壤安全利用及修复方面的研究。E-mail: xuchao1388@126.com;
  • 作者简介:徐敏(1998年生),女,硕士研究生,主要从事土壤与环境生态研究。E-mail: xumin4211@163.com
  • 基金资助:
    国家自然科学基金项目(42177025);国家自然科学基金项目(42077374);湖南省技术攻关“揭榜挂帅”项目(2021NK1040);湖南省高新技术产业科技创新引领计划项目(2020NK2001)

Effects of Groundwater Level and Long-term Straw Return on Soil Cadmium Availability and Cadmium Concentration in Rice

XU Min1,2(), XU Chao2,*(), YU Guanghui1,*(), YIN Lichu3, ZHANG Quan2, ZHU Hanhua2, ZHU Qihong2, ZHANG Yangzhu3, HUANG Daoyou2   

  1. 1. College of Earth Science and Space Information Engineering, Hunan University of Science and Technology, Xiangtan 411201, P. R. China
    2. Institute of Subtropical Agriculture, Chinese Academy of Sciences/Key Laboratory of Agro-ecological Processes in Subtropical Region/Changsha Research Sation for Agricultural & Environmental Monitoring, Changsha 410125, P. R. China
    3. College of Resource & Environment, Hunan Agricultural University, Changsha 410128, P. R. China
  • Received:2022-08-02 Online:2023-01-18 Published:2023-04-06

摘要:

稻田土壤镉(Cd)容易在水稻中积累进而通过食物链危害人体健康,地下水位和长期秸秆还田对水稻土Cd有效性及水稻Cd吸收积累特性的影响效应值得关注。以红壤性水稻土长期定位试验为对象,选取高地下水位(-20 cm)秸秆还田(HRS)、高地下水位施化肥(HCF)、低地下水位(-80 cm)秸秆还田(LRS)、低地下水位施化肥(LCF)4个处理,检测土壤有效态Cd、各形态Cd占比(BCR法)和水稻地上部Cd含量,分析地下水位和秸秆还田对土壤Cd有效性与形态转化和稻米Cd含量的影响。结果表明:相同水位长期秸秆还田增加了土壤Cd有效性,HRS和LRS处理土壤有效态Cd比HCF和LCF处理分别高49.4 %和53.2%。相同施肥处理低水位土壤Cd有效性高于高水位,LCF和LRS处理土壤有效态Cd含量比HCF和HRS分别高46.5%和50.2%。RS下高水位促进残渣态Cd向可氧化态和可还原态Cd转化,化肥下高水位促进酸提取态Cd向可还原和可氧化态Cd转化。相同水位秸秆还田处理稻米Cd含量显著高于化肥处理,高水位下RS处理稻米Cd含量比化肥处理高11.6倍,低水位下则高42.3%。相同施肥处理高水位稻米Cd含量显著低于低水位;RS下高水位稻米Cd含量比低水位低57.4%,化肥下则低95.2%。逐步回归分析结果表明,土壤有效态Cd含量显著地受溶解性有机碳含量的影响,稻米和稻草Cd含量显著地受土壤有效态Cd和有效态Fe含量的影响。地下水位和长期秸秆还田通过改变土壤Cd有效性及Cd形态比例,从而影响水稻对土壤中Cd的吸收积累;高低地下水位下稻田秸秆还田提高了土壤Cd有效性和稻米Cd含量,带来了稻米Cd超标风险。

关键词: 秸秆还田, 地下水位, 镉, 有效性, 水稻

Abstract:

Soil cadmium (Cd) in paddy fields is easy to accumulate in rice and thus harms human health through the food chain. The effect of groundwater level and long-term straw return on the Cd availability in paddy soils and Cd uptake and accumulation characteristics in rice tissues is worthy of attention. In this study, a long-term experiment on red loamy paddy soils was conducted. Four treatments of high groundwater level (-20 cm) with straw return (HRS), high groundwater level with chemical fertilizer (HCF), low groundwater level (-80 cm) with straw return (LRS) and low groundwater level with chemical fertilizer (LCF) were selected to determine the concentration of soil Cd (Cd) availability, each form of Cd (BCR method) and aboveground Cd in rice plant. The effects of groundwater level and straw return on the availability and transformation of Cd in soil and Cd concentration in rice grain were analyzed. The results showed that under long-term straw return and the same groundwater level, the availability of soil Cd was increased. The soil Cd availability in the HRS and LRS treatments was 49.4% and 53.2% higher than that in the HCF and LCF treatments, respectively. The soil Cd availability at low groundwater level was higher than that at high groundwater level under the same fertilizer treatment. Compared with HCF and HRS, the soil available Cd concentrations of LCF and LRS treatment were 46.5% and 50.2% higher, respectively. High groundwater level under RS promoted the transformation of residual Cd to oxidizable and reducible Cd. High groundwater level under chemical fertilizer treatment promoted the transformation of acid-extracted Cd to reducible and oxidizable Cd. The rice grain Cd concentration in the straw return treatment was significantly higher than that in the chemical fertilizer treatment at the same groundwater level. The Cd concentration in rice grain of RS treatment was 11.6 times higher than that of chemical fertilizer treatment at high water level, and 42.3% higher at low groundwater level. Under the same fertilizer treatments, the Cd concentration in rice grain at high groundwater level was significantly lower than that at low groundwater level. The Cd concentration in rice grain at high groundwater level was 57.4% lower than that at low groundwater level under RS, and 95.2% lower under chemical fertilizer treatment. The results of stepwise regression analysis showed that the concentration of soil available Cd was significantly affected by the concentration of dissolved organic carbon. The concentration of Cd in rice grain and straw was significantly affected by the concentration of soil available Cd and available Fe. The groundwater level and long-term straw returning can change the availability and proportion of Cd forms in soil, thus affecting the absorption of Cd by rice. Straw returning to the field under high and low groundwater levels increased the availability of Cd in soil and the concentration of Cd in rice grain, which brought the risk of exceeding the standard of Cd of rice grain.

Key words: straw return, groundwater level, cadmium, availability, rice

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