李小飞 代兵 何晓峰

摘要 [目的]探究不同生物有机肥施用量对稻田土壤Cd形态和糙米Cd含量的影响。[方法]采用盆栽试验研究了不同有机肥增施量对水稻主要生育期内土壤pH、有机质和Cd赋存形态的动态变化以及糙米中Cd含量的影响。[结果]与对照相比，25～45 g/kg有机肥增施量条件下，水稻分蘖期土壤pH显著提高0.40～0.42，有机质含量显著增加1.74～3.1 mg/kg，有效态Cd下降15.7%～40.7%;孕穗期土壤pH显著提高1.08～1.14，有机质含量显著增加7.48～9.68 mg/kg，有效态Cd下降13.6%～38.8%;扬花期土壤pH显著提高1.30～1.53，有機质含量显著增加8.38～9.19 mg/kg，有效态Cd下降10.0%～36.7%;成熟期土壤pH显著提高0.97～1.13，有机质含量显著增加6.54～8.81 mg/kg，有效态Cd下降9.2%～36.8%;水稻成熟后的糙米中Cd含量显著下降67.7%～72.3%。随着有机肥施用量增加，土壤pH、有机质含量以及糙米中Cd含量并无明显的变化。[结论]水稻种植过程中增施生物有机肥能有效提高酸性土壤的pH，增强土壤的酸碱缓冲能力，并显著提升土壤中的有机质含量，促使土壤中Cd由生物活性较强的弱酸提取态向可还原态转化，从而达到抑制水稻对Cd的吸收，显著减少糙米中Cd积累的目的。

关键词 生物有机肥;水稻;水稻生育期;糙米;镉

Abstract [Objective]To explore the effects of bio-organic fertilizer on soil cadmium fractions and cadmium accumulation in rice. [Method]Pot experiment was conducted to investigate the dynamic changes of soil pH， organic matter （OM）， cadmium （Cd） fractions in rice growth period and the accumulation of Cd in brown rice. [Result]Compared with CK， under the condition of 25-45 g/kg bio-organic fertilizer， the pH of soil increased by 0.40-0.42， the OM increased by 1.74-3.10 mg/kg， and the available Cd decreased by 15.7%-40.7% during tillering period;the soil pH increased by 1.08-1.14， the OM increased by 7.48-9.68 mg/kg， and the available Cd decreased by 13.6%-38.8% during booting period;the soil pH increased by 1.30-1.53， the OM increased by 8.38-9.19 mg/kg， and the available Cd decreased by 10.0%-36.7% during flowering period;the soil pH increased by 0.97-1.13， the OM increased by 6.54-8.81 mg/kg， and the available Cd decreased by 9.2%-36.8% during maturing period. In addition， the efficiency of reducing Cd increased with the increase of bio-organic fertilizer application. As the amount of bio-organic fertilizer applied increased， there was no significant difference in soil pH，OM， and brown rice Cd content.[Conclusion]The application of bio-organic fertilizer could effectively improve the pH value and acid-base buffer capacity of soil， increase the OM content， and promote the transformation of Cd in the soil from acid-extractable fraction with biological activity to reducible fraction， thus inhibiting the absorption of Cd by rice and significantly reducing the Cd content in brown rice.

Key words Bio-organic fertilizer;Rice;Rice growth period;Brown rice;Cadmium

随着工矿业的发展，大量的重金属污染物通过污水灌溉以及大气沉降等途径进入到农田土壤环境中，造成农产品重金属含量超标，严重威胁我国的粮食安全[1-2]。镉（Cd）是自然界中分布广泛的一种高危害有毒致癌类物质，易被水稻吸收，具有蓄积性强、毒性持久的特点[3]。近年来，多地出现的镉大米事件使得农田镉污染逐渐受到人们的关注，如何抑制水稻对镉的吸收，降低稻米中的镉含量已成为农业生态环境领域研究的热点之一[4-6]。……