Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-environmental Science & Technology, Guangzhou, 510650, China.
National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangzhou, 510650, China.
Sci Rep. 2020 Feb 12;10(1):2418. doi: 10.1038/s41598-020-59409-1.
We conducted pot experiments to assess the bioavailability of cadmium (Cd) in contaminated rhizosphere soil and accumulation in rice organs in response to nitrogen (N) supply ((NH)SO, NHNO, NHCl). The results showed that the concentration of bioavailable Cd in rice rhizosphere soil was (NH)SO treatment > NHCl treatment > NHNO treatment at the same level of N application and growth period; the Cd concentration in rice roots was (NH)SO treatment > NHNO treatment > NHCl treatment; and the Cd concentration in rice straw was NHNO treatment > NHCl. The Cd concentration in rice roots, straws, and seeds at the maturity stage was (NH)SO treatment > NHCl treatment. With the same N fertilizer, excessive N promoted Cd accumulation in rice at later growth stages. This suggested that sulfate (SO) influenced Cd concentration in rice. NHCl application maintained a low Cd level in different rice organs with the same N level. This confirmed that NHCl is a safe N source for rice planting in polymetallic sulfide mining areas. The study concludes that appropriate NHCl levels for Cd-contaminated paddy soil with high-S-content could obtain rice grains with Cd concentrations below the food safety standards (0.2 or 0.4 mg·kg).
我们进行了盆栽实验，以评估在不同氮（(NH)SO、NHNO、NHCl）供应条件下，污染根际土壤中镉（Cd）的生物有效性及其在水稻器官中的积累。结果表明，在相同的施氮水平和生长时期，根际土壤中有效态 Cd 浓度为（NH）SO 处理>NHCl 处理>NHNO 处理；水稻根系中 Cd 浓度为（NH）SO 处理>NHNO 处理>NHCl 处理；稻草中 Cd 浓度为 NHNO 处理>NHCl 处理。在成熟阶段，水稻根系、稻草和种子中的 Cd 浓度为（NH）SO 处理>NHCl 处理。在相同的氮肥水平下，过量的氮会促进水稻在后期生长阶段对 Cd 的积累。这表明硫酸盐（SO）会影响水稻中的 Cd 浓度。在相同的氮水平下，施用氯化铵可以使不同水稻器官中的 Cd 保持在较低水平。这证实了氯化铵是多金属硫化物矿区种植水稻的安全氮源。研究结论是，在高硫含量的 Cd 污染稻田中，适当施用氯化铵可以获得 Cd 浓度低于食品安全标准（0.2 或 0.4 mg·kg）的稻米。
