Wang Yale, Xing Weiqin, Liang Xuefeng, Xu Yingming, Wang Yali, Huang Qingqing, Li Liping
School of the Environment, Henan University of Technology, Zhengzhou, Henan 450001, China.
Innovation Team of Remediation for Heavy Metal Contaminated Farmlands, Agro-Environmental Protection Institute, Ministry of Agriculture, Tianjin 300191, China.
Sci Total Environ. 2022 Feb 20;808:152090. doi: 10.1016/j.scitotenv.2021.152090. Epub 2021 Dec 2.
Cadmium (Cd) contamination in wheat is a serious issue. The application of exogenous additives can effectively inhibit Cd bioavailability in soil and decrease Cd accumulation in wheat. However, a comprehensive and quantitative analysis of how additives affect wheat Cd accumulation, wheat yield, soil Cd availability, and soil properties is lacking. We conducted a meta-analysis of 65 peer-reviewed papers published before April 2021 to investigate how additives application affects Cd accumulation in wheat and soil Cd availability. The results indicated that most additives application decreased the diethylenetriaminepentaacetic acid extractable-Cd content (5.27-56.33%) in the soil, and wheat grain and root Cd concentrations (0.03-129.87% and 0.42-52.84%, respectively); the pH values of wheat-grown soil and the properties of the additives affected the reduction percentage. Overall, most wheat-grown soils were calcareous soil (42 peer-reviewed papers); in calcareous soil, the magnitude of the Cd reduction in wheat grain was the highest under treatments with clay minerals (129.87%) due to clay modification, followed by composite (75.36%) and phosphorus materials (73.55%). Moreover, most additives application increased wheat grain yield by 0.03-51.84%, which was attributed to the positive effects of additives on wheat antioxidant capacity, photosynthesis, respiration, and nutrient uptake. Additives application increased the pH value of acidic wheat soil, and positively affected the electrical conductivity, cation exchange capacity, and organic carbon content of the wheat grown soil. In addition, regression analysis showed that soil available Cd was negatively correlated with the pH value with additives application in acidic soil (r = 0.43), while a non-significant correlation was observed in neutral and calcareous wheat soils (r = 0.017 and 0.016, respectively). The results of this study can assist in the selection, modification, and utilisation of additives to remediate Cd-contaminated wheat soils.
小麦中的镉（Cd）污染是一个严重问题。外源添加剂的施用能够有效抑制土壤中镉的生物有效性，并减少小麦中镉的积累。然而，目前缺乏关于添加剂如何影响小麦镉积累、小麦产量、土壤镉有效性及土壤性质的全面定量分析。我们对2021年4月之前发表的65篇同行评议论文进行了荟萃分析，以研究添加剂施用如何影响小麦中的镉积累及土壤镉有效性。结果表明，大多数添加剂的施用降低了土壤中二乙烯三胺五乙酸可提取镉含量（5.27% - 56.33%），以及小麦籽粒和根部的镉浓度（分别为0.03% - 129.87%和0.42% - 52.84%）；种植小麦土壤的pH值和添加剂的性质影响了降低百分比。总体而言，大多数种植小麦的土壤为石灰性土壤（42篇同行评议论文）；在石灰性土壤中，由于粘土改性，施用粘土矿物处理下小麦籽粒中镉的降低幅度最高（129.87%），其次是复合材料（75.36%）和磷材料（73.55%）。此外，大多数添加剂的施用使小麦籽粒产量提高了0.03% - 51.84%，这归因于添加剂对小麦抗氧化能力、光合作用、呼吸作用和养分吸收的积极影响。添加剂的施用提高了酸性小麦土壤的pH值，并对种植小麦土壤的电导率、阳离子交换容量和有机碳含量产生了积极影响。此外，回归分析表明，在酸性土壤中施用添加剂时，土壤有效镉与pH值呈负相关（r = 0.43），而在中性和石灰性小麦土壤中观察到的相关性不显著（分别为r = 0.017和0.016）。本研究结果有助于添加剂的选择、改性和利用，以修复镉污染的小麦土壤。
