Zhang Lu, Tang Chan, Yu Hai-Ying, Li Ting-Xuan, Zhang Xi-Zhou, Huang Hua-Gang
College of Resources, Sichuan Agricultural University, Chengdu 611130, China.
Huan Jing Ke Xue. 2023 Mar 8;44(3):1698-1705. doi: 10.13227/j.hjkx.202204134.
Exploring the effects of one-time amendment treatments on cadmium (Cd)-contaminated farmland soils is beneficial for providing a theoretical basis to effectively prevent Cd pollution in farmland soils and ensure the safe production of crops. Five amendments, including straw biochar, fly ash, sepiolite, white marble powder, and shale (particle size <0.2 mm, application rate 2.25 kg·m), were applied to the Cd-contaminated farmland soils. The soil nutrients, pH, soil available Cd, and Cd chemical forms in the soils and grain Cd concentration in the planted crops were determined to investigate the effects and persistence of one-time applications of the five amendments. The results showed that:① the application of the five amendments had little effect on soil nutrient content, but all of them could increase soil pH. Amendment treatments improved the transfer of Cd from the acid extraction fraction to residue fraction and further reduced the Cd availability in the soil. The decreasing amplitudes of straw biochar and white marble powder soil conditioner were 20.42%-22.53%, which was higher than those in the other treatments. ② The grain Cd concentrations in rice and wheat were significantly decreased under the amendment treatments with the decreasing amplitudes of 19.88%-48.77% and 5.06%-24.00%, respectively. The Cd concentrations in rice grains under the treatments of straw biochar, fly ash, and white marble powder soil conditioner were 0.195, 0.196, and 0.223 mg·kg, respectively, which were lower than those under the other treatments and were close to or approached the National Standard of Food Safety(GB 2762-2017)(0.2 mg·kg). ③ The immobilization effects on Cd in farmland soils were decreasing with time under one-time application of the amendments. The available Cd concentrations in the soil and Cd concentrations in crop grains were still lower than those in the control after three rounds of rice-wheat rotation. The straw biochar and white marble powder soil conditioner had a good and long-term effect on reducing Cd availability in soils and Cd concentrations in crop grain, making them ideal materials for safe production in Cd-contaminated soils.
探究一次性改良处理对镉（Cd）污染农田土壤的影响，有利于为有效防治农田土壤镉污染、保障作物安全生产提供理论依据。将包括秸秆生物炭、粉煤灰、海泡石、白色大理石粉和页岩（粒径<0.2毫米，施用量2.25千克·平方米）在内的五种改良剂施用于镉污染的农田土壤。测定土壤养分、pH值、土壤有效镉、土壤中镉的化学形态以及种植作物籽粒中的镉浓度，以研究一次性施用这五种改良剂的效果和持久性。结果表明：① 施用这五种改良剂对土壤养分含量影响较小，但均能提高土壤pH值。改良处理促进了镉从酸提取态向残渣态的转化，进一步降低了土壤中镉的有效性。秸秆生物炭和白色大理石粉土壤改良剂的降低幅度为20.42%-22.53%，高于其他处理。② 在改良处理下，水稻和小麦籽粒中的镉浓度显著降低，降低幅度分别为19.88%-48.77%和5.06%-24.00%。秸秆生物炭、粉煤灰和白色大理石粉土壤改良剂处理下的水稻籽粒镉浓度分别为0.195、0.196和0.223毫克·千克，低于其他处理，接近或达到食品安全国家标准（GB 2762-2017）（0.2毫克·千克）。③ 一次性施用改良剂后，农田土壤中镉的固定效果随时间减弱。经过三轮稻麦轮作后，土壤中有效镉浓度和作物籽粒中镉浓度仍低于对照。秸秆生物炭和白色大理石粉土壤改良剂在降低土壤镉有效性和作物籽粒镉浓度方面具有良好的长期效果，使其成为镉污染土壤安全生产的理想材料。
