三元土壤调理剂对田间水稻镉砷累积转运的影响

Effects of a Tribasic Amendment on Cadmium and Arsenic Accumulation and Translocation in Rice in a Field Experiment

通过镉砷复合污染稻田的土壤调理剂原位治理,研究了三元土壤调理剂QFJ(羟基磷灰石+沸石+改性秸秆炭)对稻田土壤基本理化性质和水稻各部位镉砷累积转运的影响.结果表明,在土壤Cd总量3.58 mg·kg^(-1),As总量124.79 mg·kg^(-1)污染程度下,施用QFJ后,水稻根际土壤pH值、阳离子交换量及有机质含量有增大的趋势;土壤交换态Cd和As含量可分别从0.37 mg·kg^(-1)、0.07 mg·kg^(-1)下降到0.12 mg·kg^(-1)、0.04 mg·kg^(-1).QFJ的施用,可有效降低水稻各部位中Cd和As含量,在9.00 t·hm^(-2)施用量水平,可将糙米中Cd含量从0.46 mg·kg^(-1)下降到0.18 mg·kg^(-1),无机As含量从0.25 mg·kg^(-1)降低到0.16 mg·kg^(-1),同时低于国家食品污染物限量标准0.2 mg·kg^(-1)的要求,实现水稻安全生产.施用QFJ减少了水稻根系对Cd和As的富集,降低了水稻植株将Cd从地下部转运到地上部的能力,降低了根系转运Cd的能力以及茎叶、谷壳转运As的能力.

An in-situ paddy field experiment was carried out to study the influence of a tribasic amendment（ QFJ,hydroxyapatite ＋zeolite ＋ biochar） on Cd and As accumulation and translocation in rice grown in soil contaminated with cadmium and arsenic,with the concentrations of soil Cd and As being 3. 58 mg·kg^-1 and 124. 79 mg·kg^-1,respectively. The results showed that,after application of QFJ,the pH,CEC,and OM contents of the rice rhizosphere soil tended to increase. The exchangeable concentrations of Cd and As were reduced from 0. 37 mg·kg^-1 and 0. 07 mg·kg^-1 to 0. 12 mg·kg^-1 and 0. 04 mg·kg^-1,respectively. The concentrations of Cd and As in rice tissues decreased after in-situ restoration. When 9. 00 t·hm^-2 of QFJ was applied,the Cd concentration in brown rice was reduced from 0. 46 to 0. 18 mg·kg^-1,and that of inorganic As was reduced from 0. 25 to 0. 16 mg·kg^-1,both lower than 0. 2 mg·kg^-1,meeting the requirement set by the National Food Standards（ GB 2762-2012）. QFJ application decreased the Cd and As bioaccumulation capacity of the roots and decreased the rice plant＇s capacity of Cd translocation quantity from the underground parts to the aerial parts; at same time,the Cd transferring capacity of the roots and the As transferring capacity in straw and husk were also decreased.