氮肥对水稻吸收累积汞及其分配的影响研究

选择万山汞矿区汞污染土壤为研究对象,采用露天盆栽试验,设置5种处理组:全尿素肥按生长期3次添加常规施肥对照(CK)、尿素作基肥1次性添加(CN1)、尿素+硝酸钙+硫酸铵作分蘖肥1次性添加(NN2)、尿素+硝酸钙+硫酸铵作穗粒肥1次性添加(NN3)和尿素+硝酸钙+硫酸铵照生长期3次添加(CNN3),探究不同氮肥种类和施用方式对水稻不同部位中汞的质量及生物量的影响.结果表明,在相同施肥量条件下, 5种氮肥处理的水稻生物量无显著变化,但处理组NN2,NN3和CNN3可使水稻结实率增加,其中CNN3组最高可增加9.0%.与CK组相比,其他氮肥处理均能降低水稻对汞的吸收累积,但对水稻各部位的降低效果不同,其中NN3处理下稻米中汞降低最大,达49%, CNN3处理下水稻叶中汞降低最大,达39%.本试验研究结果显示, NN3处理对稻米中汞的吸收累计抑制效果最好,可考虑作为汞污染土壤的农艺调控措施.

Effect of Nitrogen Fertilizer on Mercury Accumulated and Distribution in Rice

Five nitrogen-treated groups of conventional urea fertilization:3 times per generation period adding (CK),urea as base fertilizer with1 time adding (CN1),urea+calcium nitrate+ammonium sulfate as tiller fertilizer with 1 time adding (NN2),urea+calcium nitrate+ammonium sulfate as ear fertilizer with 1 time adding (NN3),and urea+calcium nitrate+ammonium sulphate with 3 times adding (CNN3) were applied in heavily Hg-contaminated soils from Wanshan Hg mining area to investigate the effect on Hg accumulation in rice plants.The results show that there is no significant change in rice biomass in five nitrogen-treated groups under the same fertilizer application conditions,but NN2,NN3 and CNN3 could increase the rice seed yielding with the maximum increase of 9% being recorded in CNN3 group.Compared with CK,other nitrogen fertilizer treatments can all reduce the accumulation of Hg in rice,with the maximum decrease of 49% in grain recorded in NN3,and 39% in leaf in CNN3.The NN3 treatment exhibited the best cumulative effect on the decrease of Hg accumulation in rice and can be considered as an agronomic controlling measurement for Hg-contaminated soils.