酸性稻田土壤产生的水稻籽粒中Cd超标危害人类健康日益受到广泛关注。应用有机材料(OM)和石灰(L)是用于降低晶粒中Cd浓度(CdG)的常用技术。然而,它们同时施用影响土壤系统中Cd植物利用率的机制仍然不明确。在目前的研究中,我们采用根茎盆栽试验,探讨了单施OM[稻草(RS),紫云英(MV)],L,以及它们对Cd植物有效性的共同利用及其相关机制。结果表明,应用RS,MV,L,L+RS(LRS),L+MV(LMV)使CdG显著下降26.9%,38.2%,48.6%,50.0%,53.0%,分别。Fe斑块(IP)的形成不受这些处理的影响;然而,Cd固存在IP(CdIP)中显著降低。CdIP显著降低了18.3%,23.6%,43.8%,33.1%,和41.4%,RS之后,MV,L,LRS,和LMV治疗,分别。此外,根际土壤(RHS)中有效Cd浓度显著降低11.5%,14.8%,15.1%,和18.4%,MV之后,L,LRS,和LMV治疗,分别。RHS中Cd的可利用性受pH的显著影响,溶解的有机碳浓度,Zn,Fe,锰的可用性。结构方程模式的结果表明,CdG主要受CdIP的影响,其次是Cd的可用性和RHS的pH。总之,OM对CdG的还原,L,它们的共同利用是它们降低RHS中Cd可用性的综合效应的结果,CdIP,和根对Cd的吸收。这项研究强调,CdG的减少是在修正应用后降低RHS和CdIP中Cd可用性的双重效应的结果。单独使用L或与OM结合使用是减少酸性Cd污染稻田中CdG的有效做法。
Excessive Cd in rice grains produced with acidic paddy soil is receiving increasingly widespread attention because it endangers human health. Applying organic materials (OM) and lime (L) is a common technique used to reduce Cd concentration in grains (CdG). Nevertheless, the mechanism by which their simultaneous application affects the Cd phytoavailability in soilrice systems remains ambiguous. In the current study, we adopted a rhizobag pot culture test to explore the influences of single application of OM [rice straw (RS), milk vetch (MV)], L, and their co-utilization on Cd phytoavailability and the associated mechanisms. The results showed that the application of RS, MV, L, L + RS (LRS), and L + MV (LMV) significantly decreased CdG by 26.9%, 38.2%, 48.6%, 50.0%, and 53.0%, respectively. Fe plaque (IP) formation was not affected by these treatments; however, Cd sequestration in IP (CdIP) was significantly reduced. CdIP was significantly reduced by 18.3%, 23.6%, 43.8%, 33.1%, and 41.4%, after RS, MV, L, LRS, and LMV treatments, respectively. Additionally, available Cd concentrations in rhizospheric soil (RHS) were significantly reduced by 11.5%, 14.8%, 15.1%, and 18.4%, after MV, L, LRS, and LMV treatments, respectively. Cd availability in RHS was significantly influenced by pH, dissolved organic carbon concentration, and Zn, Fe, and Mn availability. The results of the structure equation mode showed that CdG was mainly affected by CdIP, followed by Cd availability and the pH of RHS. In conclusion, the reduction of CdG by OM, L, and their co-utilization was the results of their combined effects of reducing Cd availability in RHS, CdIP, and Cd uptake by the roots. This study emphasizes that the reduction of CdG is a result of the dual effects of reducing Cd availability in RHS and CdIP after amendments application. L application alone or in conjunction with OM is an efficient practice to reduce CdG in acidic Cd-contaminated paddy fields.