Agricultural soil Cd (Cd) pollution threatens global food safety. Based on a meta-analysis of 55 global studies involving 464 maize cultivars, this research systematically elucidates the potential of maize for safe production and remediation in cadmium (Cd)-contaminated farmland. For low to moderately polluted fields, multiple cultivars with low grain Cd accumulation were identified, including 15 cultivars such as TieYan 919 and DanYu 508, which achieved over 90% lower grain Cd content than the legislative limits. DongDan 118 demonstrated simultaneous grain Cd reduction and yield increase, while XianYu 335 and ZhengDan 958 showed comprehensive performance in Cd reduction and yield stability. Maize genotype was identified as the decisive factor for grain Cd accumulation, soil pH was the key environmental factor regulating Cd translocation to grains, and field cultivation was conducive to the expression of low-accumulation traits. Accordingly, a “production coupled with remediation” technical pathway is proposed, centered on “low-accumulation cultivars as the core, soil pH regulation as the key, and field validation as the safeguard.” For heavily polluted fields, high-Cd-accumulating cultivars such as GuangTian-2 and JinZhuMi (pot cultivation) and HuaCaiNuo3 and QiuQing88 (field cultivation) were identified. Their remediation efficiency was driven by soil available Cd content, with significant local environmental influences, necessitating a remediation strategy guided by “cultivar selection as the core, soil management as the supplement, and local validation as the prerequisite.” This study provides a cultivar selection basis and agronomic regulation framework for the tiered management of Cd-contaminated farmland.

The use of biodegradable chelating agents and fertilizer to improve phytoremediation is a cost-effective and environmental-friendly method for remediation of copper (Cu)- and cadmium (Cd)-polluted agricultural soil. A pot experiment was conducted to investigate the effects of phosphorus (P) fertilizer and the chelator ethylenediamine disuccinic acid (EDDS), both individually and in combination, on the phytoremediation efficiency of castor plants. The experiment included six treatments with three replicates, which were as follows: control (no P or EDDS), EDDS alone, P at 100 mg kg⁻¹, P at 300 mg kg⁻¹, P at 100 mg kg⁻¹ + EDDS, and P at 300 mg kg⁻¹ + EDDS. The results demonstrated that phosphorus significantly promoted the growth of castor plants. In the treatment in which 300 mg kg⁻¹ P₂O₅ and 5.0 mmol kg⁻¹ EDDS were added, the shoot dry weight and root dry weight increased by 42.0% and 67.6%, respectively, when compared to the treatment only applying EDDS, and this treatment significantly promoted the absorption of Cd by shoots of castor. In the absence of phosphorus application, EDDS significantly diminished the dry weight of castor roots by 27.3%. Nevertheless, it improved the concentrations of Cu in the shoots and roots of castor plants, which were 3.43 times and 3.27 times higher than those of the control, respectively. Furthermore, when combined with phosphorus fertilizers, EDDS further promoted the absorption of Cu and Cd in the shoots of castor, which significantly increased by 13.34 times and 0.47 times, respectively, with addition of 100 mg kg⁻¹ phosphorus and 5.0 mmol kg⁻¹ of EDDS compared with the control. Phosphorus and EDDS synergistically decreased the activity of POD enzymes in leaves and roots compared with those treated with only EDDS and alleviated the toxicity of EDDS and heavy metals to castor plants. These findings provide scientific evidence for the use of agronomic measures and chelators to optimize phytoremediation efficiency in Cu and Cd co-contaminated soils.

Screening for cultivars with low Cd in edible organs but high Cd accumulation in non-edible organs represents a sustainable strategy for “producing while remediating”. However, the potential of potato cultivars to achieve this dual goal in high-geogenic-Cd karst areas remains unclear. A field experiment was performed to investigate biomass, Cd concentration, bioconcentration factor (BCF), translocation factor (TF) and Cd removal amount (R) in various organs of 26 potato cultivars, which were then classified into different Cd risk types. The results showed that in soils with 2.05–2.98 mg·kg⁻¹ Cd, fresh tuber Cd concentrations ranged from 0.021 to 0.132 mg·kg⁻¹, with nearly 90% of tubers complying with FAO/WHO and Chinese food safety standards. Cd levels in stems, leaves and roots were 1–2 orders of magnitude higher than in tubers, supporting potato as a suitable staple for safe production in such regions. BCF followed the order stem and leaf > root > tuber, while TF followed the order root to stem and leaf > stem and leaf to tuber. Tuber Cd was jointly controlled by Cd uptake, translocation and biomass dilution, with TFstem and leaf–tuber as a key predictor. Annual Cd removal by whole plants ranged from 1082.99 to 7283.64 mg·hm⁻². Principal component analysis classified the cultivars into four types: edible-safe, safe remediation, risky remediation and high-risk types. Notably, cultivars V2, V6, V9, V13, and V18 had tuber Cd concentrations below 50% of the permissible limit, while V16, V8, and V25 achieved >5000 mg·hm⁻² Cd removal without exceeding safety limits. These findings support the dual goal of safe potato production and in situ Cd remediation in high-background karst regions by selecting cultivars with low Cd accumulation in tubers but high Cd accumulation in non-edible organs.