Feng Wen-Li, Guo Zhao-Hui, Shi Lei, Xiao Xi-Yuan, Han Xiao-Qing, Ran Hong-Zhen, Xue Qing-Hua
School of Metallurgy and Environment, Central South University, Changsha 410083, China.
Huan Jing Ke Xue. 2018 Jan 8;39(1):399-405. doi: 10.13227/j.hjkx.201706233.
The objective of this study was to determine the effect of five scenarios on the accumulation of Cd in the soil-rice system, including the return of straw to the field and the lack of the return, atmospheric deposition control, use of clean water for irrigation, and the use of lime. For the field experiments, three typical paddies were selected and divided into five plots (5 m×6 m) in Xiangtan, Zhuzhou, and Liling in the Hunan province from April to October 2016. The results showed that the application of lime can increase pH by 0.87, while the available Cd concentration in the soil was decreased by 33.7%. The accumulations of Cd in roots, stems, and brown rice were decreased by 47.9%, 46.7%, and 54.8%, respectively, with a decrease in the corresponding bioconcentration factors. Irrigating with clean water and liming tended to increase the soil pH by 0.44 and 0.49, respectively, while the available Cd concentration in the soil was decreased by 18.2% and 14.5%, respectively. The Cd concentrations in roots, stems, and brown rice were decreased by 32.6%, 24.2%, and 18.0%, and 17.6%, 11.3%, and 25.4% with decreased bioconcentration factors under both treatments (irrigating with clean water and liming). The available Cd concentration in the soil was increased by 6.1% and the Cd accumulation in the rice plants also increased with the return of straw to the soil. The bioconcentration factors of the rice plants were also increased when the paddy straw was returned to the fields. The results showed that the measures, such as the use of lime, atmospheric deposition control, use of clean water for irrigation, and lack of the return of straw to the paddy soil, should be helpful for the safe production of brown rice. The possible long-term risks associated with returning straw to the paddy field should be evaluated scientifically.
本研究的目的是确定五种情景对土壤-水稻系统中镉积累的影响，包括秸秆还田和不还田、大气沉降控制、使用清洁水灌溉以及施用石灰。在田间试验中，2016年4月至10月在湖南省湘潭、株洲和醴陵选择了三块典型稻田，并将其划分为五个地块（5米×6米）。结果表明，施用石灰可使土壤pH值提高0.87，同时土壤中有效镉浓度降低33.7%。根、茎和糙米中镉的积累量分别降低了47.9%、46.7%和54.8%，相应的生物富集系数也降低。用清洁水灌溉和施用石灰分别使土壤pH值提高0.44和0.49，而土壤中有效镉浓度分别降低18.2%和14.5%。在两种处理（用清洁水灌溉和施用石灰）下，根、茎和糙米中的镉浓度分别降低了32.6%、24.2%和18.0%，以及17.6%、11.3%和25.4%，生物富集系数降低。随着秸秆还田，土壤中有效镉浓度增加6.1%，水稻植株中的镉积累量也增加。当稻草还田时，水稻植株的生物富集系数也增加。结果表明，施用石灰、控制大气沉降、使用清洁水灌溉以及不将秸秆还田等措施有助于糙米的安全生产。应科学评估秸秆还田可能带来的长期风险。
