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.

In vegetable production, excessive nitrogen fertilizer application leads to extremely low NUE and substantial reactive nitrogen losses. Given the abundant rainfall and the high residual soil nitrogen in soil after harvest, there is a pronounced risk of nitrate leaching during the summer fallow period. This study conducted a meta-analysis to systematically evaluate the effects of catch crops on nitrogen loss and soil nitrogen accumulation during the summer fallow season. The results showed that catch crops significantly reduced total N leaching loss by 58.10% through decreasing leachate volume by 24.54% and reducing leachate concentrations of TDN (43.36%), NO₃⁻–N (34.47%), and NH₄⁺–N (56.05%), respectively. Catch crops reduced soil NO₃⁻–N storage by 36.28% and SIN storage by 40.61%, while increasing SON storage by 69.79% and MBN by 21.47%, thereby achieving a transformation from readily available mineral N to more stable organic N. Catch crops also enhanced ammonification, mineralization, and nitrification by 126%, 142%, and 42%, respectively, and altered the microbial community structure. The effectiveness of catch crops varied significantly among taxa: Poaceae exhibited the best overall performance, the genus Zea (especially sweet corn) showed the most comprehensive performance in integrated N control, while Fabaceae increased soil NH₄⁺-N. Environmental factors, including soil depth, pH, organic matter, total nitrogen, initial NO₃⁻–N, rainfall, and soil texture, collectively regulated the effectiveness of catch crops. In summary, a rational selection of catch crop species tailored to site-specific soil and environmental conditions can effectively reduce nitrogen leaching during the summer fallow period and support precision nitrogen management.