氮肥运筹对水稻镉和矿质养分含量与转运的影响OA

To investigate the effects of nitrogen fertilizer management on the accumulation and translocation of cadmium(Cd)and mineral nutrients in rice,and to provide a theoretical basis for safe production in Cd-contaminated paddy fields,a pot experiment was conducted using two early season rice varieties,Taiyou 398 and Xiangzaoxian No.32,at the Rice Research Institute of Hunan Agricultural University from April to July 2021.A no nitrogen treatment was used as the control(CK),and four nitrogen application ratios(basal:tillering:panicle:grain fertilizer)were set as follows:5∶5∶0∶0(T1),4∶4∶2∶0(T2),6∶0∶2∶2(T3),and 3∶2∶2∶3(T4).The Cd and mineral nutrient contents in different rice organs were compared among treatments.The results showed that nitrogen application promoted the formation of iron plaque on the root surface and Cd adsorption,while inhibiting Cd translocation from roots to aboveground parts.The Fe content in the root iron plaque was positively correlated with root Cd content,but negatively correlated with stem Cd content.The brown rice Cd content of Taiyou 398 followed the order:CK>T3>T2>T1>T4,whereas that of Xiangzaoxian No.32 followed:T1>T2>CK>T3>T4.Notably,T4 achieved the lowest brown rice Cd content in both varieties.In addition,although T1 significantly reduced the Cu,Mn,and Zn contents in brown rice of Taiyou 398(by 31.63%,31.47%,and 24.72%,respectively,compared with CK),it markedly increased the brown rice Cd content of Xiangzaoxian No.32(increased by 38.6%compared to CK),indicating a variety dependent difference.Taken together,the T4 treatment exhibited the best performance in consistently reducing brown rice Cd content without adversely affecting mineral nutrient levels,and can therefore be recommended as a nitrogen management strategy for safe rice production in Cd contaminated paddy fields.