中文摘要：

选择野外镉（Cd）污染农田,以小麦（第一季）、水稻（第二季）为模式作物,以蒙脱土、钙镁磷肥、磷矿石、重钙、普钙为钝化修复材料（施加浓度为1.3 kg·m-2）,并配施石灰（0.52 kg·m-2）,研究其对小麦、水稻产量及籽粒中Cd含量、土壤pH以及土壤中Cd形态分布的影响,考察不同钝化剂对农田土壤Cd污染的原位钝化修复效果。结果表明：施用不同钝化剂后均显著抑制小麦和水稻籽粒对Cd的吸收,而配施石灰能更进一步抑制小麦和水稻对Cd的吸收。第一季,钙镁磷肥和蒙脱石配施石灰的抑制效果最好,钙镁磷肥配施石灰和蒙脱土配施石灰降幅分别达到78.7%和72.8%;第二季,钙镁磷肥和重钙配施石灰的抑制效果最好,钙镁磷肥配施石灰和重钙配施石灰降幅分别达到82.83%和67.43%。研究发现钝化剂显著降低土壤酸溶态Cd含量,而小麦和水稻籽粒中Cd含量与土壤pH呈极显著负相关关系,相关系数分别为-0.817和-0.718;与土壤酸溶态Cd呈显著正相关关系,相关系数分别为0.769和0.613;同时发现施用钝化剂后小麦、水稻的产量均有显著提高,增幅最大的为可溶性磷肥重钙和钙镁磷肥,原因可能是施入的改良剂减缓了Cd毒性,同时提供了作物生长所需的钙、镁、磷等必需营养元素。根据田间试验效果,钙镁磷肥配施石灰对降低小麦和水稻中Cd含量的效果最显著,可推荐作为Cd污染土壤的改良剂。旱作条件下,蒙脱石配施石灰也是Cd污染农田改良剂的较好选择,而稻作条件下则不宜使用。

英文摘要：

In-situ immobilization of heavy metal contaminated soils is a cost-effective remediation technique. However, stabilizing agents are critical to this technique. Here five amendments, including calcium-based montmorillonite（MT）, fused calcium-magnesium phosphate （CMP）, phosphorus rock（ PR ）, superphosphate（SP）, and triple superphosphate（TSP）, were chosen to remediate a Cd-contaminated farmland soil. All amendments were applied at 1.3 kg· m-2 alone or in combination with 0.52 kg· m-2 lime. Two season crops （wheat and rice ） were grown after amendment applications. Amendments significantly reduced the uptake of Cd in crop grains. CMP and MT with lime had the greatest Cd reduction in wheat（78.7% and 72.8% respectively）, while CMP and TSP with lime were the best for Cd reduction in rice （82.83% and 67.43%, respectively ）. Most amendments greatly decreased dissolved fraction of Cd in soil, due to increased soil pH. Cadmi- um contents in grains showed a significant negative correlation with soil pH, but a significant positive correlation with soil acid-soluble Cd. Applications of amendments, especially dissolvable P fertilizers, significantly increased crop production, might due to reduced Cd toxicity and improved Ca, Mg and P nutrition. The results show that CMP with lime provides the best Cd immobilization for both wheat and rice. MT with lime would also be a good amendment for wheat under limited P fertilizers.