School of Environment and Civil Engineering, Jiangnan University, 214122, Wuxi, China.
Jiangsu Key Laboratory of Anaerobic Biotechnology, Wuxi, 214122, China.
Environ Sci Pollut Res Int. 2021 Jul;28(27):36850-36860. doi: 10.1007/s11356-021-13266-1. Epub 2021 Mar 12.
To investigate the remediation potential of spent mushroom substrate (SMS) on Cd pollution in a paddy soil, a rice pot experiment was conducted to study the effects of SMS addition on the availability of Cd in soil and the uptake of Cd in rice tissues. Five percent of SMS from Pleurotus eryngii (SMS-A, treatment: A), SMS from Agaricus bisporus (SMS-B, treatment: B), or SMS-A plus SMS-B (1:1, treatment: A+B) were added into a Cd-contaminated paddy soil before planting, respectively. The treatment of no SMS amendment was set up as the control (CK). At the four main growth stages of rice, the soils and plant samples were collected to detect the soil properties, Cd concentration in soils and rice tissues, and Cd fractions in soils. Results indicated that the application of SMS-A, SMS-B, and A+B significantly increased soil pH by 14.0-22.9, 23.9-32.9, and 22.7-30%, organic matter (OM) contents by 12.9-31.5, 22.1-34.5, and 26.1-36.9% comparing with CK. While cation exchange capacities (CECs) were increased by 3.6-8.5, 4.9-13.1, and 0.4-10.0% in A, B, and A+B treatments, respectively, except those at the maturation stage in A and B treatments. However, the CaCl-Cd concentrations in soils were significantly decreased by 64.8-77.9, 76.1-98.9, 73.2-98.9% in A, B, and A+B treatments, respectively, comparing with CK. The reduced availability of Cd was attributed to the changes of Cd from soluble to insoluble fractions in soils amended with SMS and resulted in the decreased Cd uptake in rice tissues. The Cd concentrations in roots significantly decreased by 22.8-36.9, 28.6-36.6, and 26.8-42.6%, while the Cd concentrations in straw decreased by 20.1-46.4, 9.3-41.6, and 16.0-49.1% in A, B, and A+B treatments, respectively. At the maturation stage, the Cd concentrations in brown rice were reduced by 17.7, 15.9, and 19.4% in A, B, and A+B treatments, respectively. Correlation analysis revealed that the Cd concentrations in rice roots, straws, and brown rice were all positively correlated with CaCl-Cd concentrations of soils. Moreover, soil pH and OM were significantly negatively correlated with the Cd concentration in rice tissues, except that between soil pH and the Cd concentration in rice straws. Therefore, the reduced Cd availability in soil and uptake in rice plant tissues together with better soil nutrient conditions by SMS application improved the biomass of root and straw at heading, filling, and maturation stages and the rice production by 32.9-38.8% at the maturation stage. The combined application of SMS-A and SMS-B can be used as a potential method for remediation of Cd-contaminated paddy soil.
为了研究废弃菌糠对稻田土壤中 Cd 污染的修复潜力，进行了一项水稻盆栽实验，以研究菌糠添加对土壤中 Cd 有效性和水稻组织中 Cd 吸收的影响。在种植前，分别向 Cd 污染的稻田土壤中添加 5%的杏鲍菇菌糠（SMS-A，处理：A）、双孢蘑菇菌糠（SMS-B，处理：B）或 1:1 混合的杏鲍菇菌糠和双孢蘑菇菌糠（处理：A+B）。不添加菌糠的处理作为对照（CK）。在水稻的四个主要生长阶段采集土壤和植物样本，以检测土壤性质、土壤和水稻组织中的 Cd 浓度以及土壤中 Cd 形态。结果表明，A、B 和 A+B 处理分别显著提高了土壤 pH 值 14.0-22.9、23.9-32.9 和 22.7-30%，有机质（OM）含量 12.9-31.5、22.1-34.5 和 26.1-36.9%，与 CK 相比。而阳离子交换量（CEC）分别增加了 3.6-8.5、4.9-13.1 和 0.4-10.0%，除了 A 和 B 处理在成熟阶段的 CEC 有所降低。然而，A、B 和 A+B 处理的土壤中 CaCl2-Cd 浓度分别显著降低了 64.8-77.9%、76.1-98.9%和 73.2-98.9%，与 CK 相比。Cd 的生物有效性降低归因于菌糠添加导致土壤中 Cd 从可溶性向不溶性形态转化，从而降低了水稻组织对 Cd 的吸收。A、B 和 A+B 处理的水稻根中的 Cd 浓度分别显著降低了 22.8-36.9%、28.6-36.6%和 26.8-42.6%，而水稻秸秆中的 Cd 浓度分别降低了 20.1-46.4%、9.3-41.6%和 16.0-49.1%。在成熟阶段，A、B 和 A+B 处理的糙米中 Cd 浓度分别降低了 17.7%、15.9%和 19.4%。相关性分析表明，水稻根、茎和糙米中的 Cd 浓度均与土壤中 CaCl2-Cd 浓度呈正相关。此外，土壤 pH 值和 OM 与水稻组织中 Cd 浓度呈显著负相关，除了土壤 pH 值与水稻秸秆中 Cd 浓度之间的关系。因此，菌糠的应用降低了土壤中 Cd 的生物有效性和水稻组织中的吸收，同时改善了土壤养分条件，使水稻根、茎在抽穗、灌浆和成熟阶段的生物量增加了 32.9-38.8%，在成熟阶段的水稻产量增加了 32.9-38.8%。杏鲍菇菌糠和双孢蘑菇菌糠的联合应用可作为一种修复 Cd 污染稻田土壤的潜在方法。
