水分管理对不同季别水稻稻米镉积累的影响

Effects of Water Management on Cadmium Accumulation in Rice

为了探究水分管理对稻米镉积累的影响,于2018、2019年通过盆栽试验分析不同淹水时间(抽穗后淹水7、14、21、28 d及全生育期淹水)处理的5个杂交早稻品种和8个一季稻品种稻米镉积累情况。结果表明:土壤镉污染水平和水分管理方式贡献了最大的稻米镉积累量总方差变异,贡献率达70%。在未污染土壤中开展早稻和一季稻生产,不存在稻米镉污染风险;在轻度镉污染土壤中开展早稻和一季稻生产,后期淹水21 d,不存在稻米镉污染风险;在中度镉污染土壤中开展水稻生产,早稻全生育期淹水,中稻及一季晚稻后期淹水28 d,可以生产出符合国家食品安全标准的稻米。株两优211、钰两优611、陵两优268、隆两优534、晶两优534、悦两优2646、隆晶优蒂占和丰两优4号等8个品种具有镉低积累特性,即使在中度镉污染土壤中种植,抽穗后淹水7 d,稻米镉含量低于0.2 mg/kg或与应急性低镉对照品种(株两优819和晶两优华占)相当。

In order to explore the effect of water management at late growth stage on cadmium accumulation in rice,pot ex-periments were conducted in 2018 and 2019 to study the effects of different flooding time(7,14,21,28 d after heading and.the whole growth period)on cadmium accumulation in five hybrid early-season rice varieties and eight single-season rice varieties.The results showed that soil cadmium pollution level and water management contributed the most to the total variance variation of rice cadmium accumulation,which was more than 70%.There was no risk of cadmium pollution in early-season and single-season rice production in unpolluted soiland and in early-season and single-season rice pro-duction with 21 days flooding management after heading in mild cadmium pollution soil,as well as early-season rice with whole growth period flooding and middle-season rice and single-cropping late rice with 28 days flooding management af-ter heading in medium cadmium concentration soil.Eight varieties,Zhuliangyou 211,Yuliangyou 611,Lingliangyou 268,Longliangyou 534,Jingliangyou 534,Yueliangyou 2646,Longjingyoutizhan and Fengliangyou 4 had the characteristic of low cadmium accumulation.Even when planted in moderately cadmium polluted soil and flooded for 7 days after heading,the cadmium content in rice was lower than 0.2 mg/kg or equal to that of emergency low cadmium control varieties(Zhulian-gyou 819 and Jingliangyouhuazhan).