College of Environment and Ecology, Hunan Agricultural University, Changsha, Hunan, 410128, PR China; Key Laboratory for Rural Ecosystem Health in Dongting Lake Area of Hunan Province, Changsha, 410128, PR China.
Hunan Center of Ecological Environment Affairs, Ecology and Environment Department of Hunan, Changsha, Hunan, 410128, PR China.
Environ Res. 2024 Dec 15;263(Pt 3):120280. doi: 10.1016/j.envres.2024.120280. Epub 2024 Nov 1.
Under the dual pressures of food security and soil cadmium (Cd) pollution in China, the use of an oilseed rape-rice rotation system and phytoremediation has been proposed as an effective measure to extract heavy metals from soil, achieve safe rice production, and alleviate soil heavy metal stress. A three-year field rotation experiment by straw removal was conducted in light to moderate Cd-contaminated soil in Hunan, China. The experiment involved rotating two oilseed rape varieties, LSYH and ZYZ, with two rice varieties, the low-accumulation variety XWX and the high-accumulation variety TYHZ. The structural equation model (SEM) indicated that the correlation coefficients of total nitrogen (N) and available phosphorus (P) with CaCl-Cd in the soil under oilseed rape-rice rotation were higher than those in rice monoculture, indicating that changes in soil nutrients have a significant impact on CaCl-Cd during rotation. During continuous rice monoculture, the Cd content in brown rice exceeded safety standards in all three years. Crop rotation effectively reduced the Cd content in the aboveground parts of rice, particularly inhibiting its transfer to brown rice. By the second year of rotation, the minimum Cd content in brown rice from XWX and TYHZ was only 0.10 and 0.11 mg kg⁻, respectively. Cd levels in rice met the safety standard (<0.2 mg kg⁻). Although the Cd content in the third-year rice was higher than in the second year, it remained significantly lower than in the first year. The TPE in the aerial portion for the ZYZ-XWX rotation was 4.88%, while for the rotation of ZYZ-TYHZ rotation, it was 6.37%. Economic benefits were enhanced by this rotation mode, with profit-to-cost ratios exceeded 1. Overall, oilseed rape-rice rotation is an economical and environmentally friendly method for remediating soil Cd contamination, but it requires selecting the appropriate varieties.
在中国粮食安全和土壤镉（Cd）污染的双重压力下，提出了利用油菜-水稻轮作系统和植物修复来提取土壤中的重金属，实现安全水稻生产，并减轻土壤重金属胁迫。在中国湖南轻度至中度 Cd 污染土壤中进行了为期三年的免耕轮作田间试验。该试验涉及两种油菜品种（LSYH 和 ZYZ）与两种水稻品种（低积累品种 XWX 和高积累品种 TYHZ）的轮作。结构方程模型（SEM）表明，油菜-水稻轮作下土壤中总氮（N）和有效磷（P）与 CaCl-Cd 的相关系数高于水稻单作，表明轮作过程中土壤养分变化对 CaCl-Cd 有显著影响。在连续三年的水稻单作中，糙米中 Cd 含量均超过安全标准。作物轮作有效地降低了水稻地上部分的 Cd 含量，特别是抑制了其向糙米的转移。到第二年轮作时，XWX 和 TYHZ 糙米中的最小 Cd 含量分别仅为 0.10 和 0.11mgkg-1。Cd 含量在水稻中达到安全标准（<0.2mgkg-1）。尽管第三年水稻的 Cd 含量高于第二年，但仍明显低于第一年。ZYZ-XWX 轮作的地上部分 TPE 为 4.88%，而 ZYZ-TYHZ 轮作的 TPE 为 6.37%。这种轮作模式提高了经济效益，利润率超过 1。总的来说，油菜-水稻轮作是一种经济环保的土壤 Cd 污染修复方法，但需要选择合适的品种。
