灌溉方式对土壤有效镉含量与双季稻产量形成及镉累积分配的影响

摘要

以'陵两优211'和'威优46'为材料,通过大田试验比较研究了全生育期5 cm淹水灌溉与间歇灌溉对土壤有效镉含量与水稻产量形成及镉累积分配的影响.结果表明:(1)灌溉方式显著影响水稻产量,早、晚稻均以淹水灌溉处理产量较高,其原因主要是淹水灌溉处理具有较高的有效穗数、株高、叶面积和干物质积累量;(2)灌溉方式对早、晚稻土壤有效镉含量影响一致,分蘖盛期处理间有效镉含量无显著差异,孕穗阶段以间歇灌溉处理显著较高,而灌浆阶段以淹水灌溉处理显著较高;(3)镉在水稻各器官中分布不均匀,各器官镉含量呈现根系>茎鞘>叶片>稻穗的趋势;(4)除成熟期根系外,间歇灌溉条件下早、晚稻生育中后期各器官镉含量均显著高于淹水灌溉处理;间歇灌溉使水稻籽粒镉含量明显增大,且晚稻增加更明显;(5)早、晚稻成熟期茎秆镉积累量与地上部镉积累总量均以间歇灌溉处理较高.可见,灌溉方式能影响土壤有效镉含量与早晚稻产量及籽粒镉含量,实行全生育期5 cm淹水灌溉能获得较高产量,且籽粒镉含量显著降低.%A field experiment was conducted to comparatively study the effects of 5 cm flooding irrigation during whole growth duration and intermittent irrigation on soil available Cd content,yield formation and Cd accumulation and distribu-tion of rice with 'Lingliangyou 211'and 'Weiyou 46'as materials.The results showed that:(1)Irrigation mode signifi-cantly affected rice yield,and the yield of early and late rice with flooding irrigation treatment was higher because of its higher effective panicles,plant height,leaf area and dry matter accumulation.(2)The effect of irrigation mode on soil a-vailable Cd contents of early and late rice was identical.There was no significant difference in soil available Cd content be-tween treatments at tillering stage,while that of intermittent irrigation treatment was significantly higher at booting period and that of flooding irrigation treatment was significantly higher at filling period.(3)The distribution of Cd in rice organs was nonuniform,there was a trend of roots>stems and sheathes>leaves>panicles.(4)Except for roots at maturity, the Cd content in all organs at middle and late stage of early and late rice with intermittent irrigation treatment was signifi-cantly higher than that with flooding irrigation treatment.The Cd content in grains was evidently heightened by intermittent irrigation,and it was clearer in the late rice.(5)The Cd accumulation in stems and whole plant of early and late rice at maturity with intermittent irrigation treatment was higher.These results indicated that irrigation mode could affect soil avail-able Cd content,yield and Cd content of early and late rice,and 5 cm flooding irrigation could gain higher rice yield and significantly lower Cd content in grains.