钙镁水滑石施用方式对双季稻糙米镉含量与土壤特性的影响

Effects of Calcium-Magnesium Hydrotalcite on Cadmium Content in Brown Rice of Double-Cropping Rice and Soil Characteristics

为探讨钙镁水滑石对双季稻糙米镉含量的影响及其适宜施用方式,通过2年大田试验研究了钙镁水滑石(CK,不施;T1,第1年早稻基施3000 kg/hm^(2);T2,第1年早稻基施1500 kg/hm^(2);T3,每年早稻基施1500 kg/hm^(2);T4,每季基施750 kg/hm^(2);T5,每季基施375 kg/hm^(2))对双季稻糙米镉含量与稻田土壤特性的影响。结果表明,随钙镁水滑石施入时间的延长,双季稻糙米镉含量显著降低,但降幅有品种间与年际间差异。2021年各品种糙米镉含量降幅随钙镁水滑石用量增加而增大,但T1、T2、T3处理间差异不显著;2022年糙米镉含量降幅均以T3处理最大。钙镁水滑石显著提高了土壤pH和养分含量,降低了土壤有效镉含量,2021和2022年分别以T1和T3处理效果最好。主成分分析与相关分析表明,钙镁水滑石用量与土壤有效镉含量、糙米镉含量呈显著负相关,与土壤pH及速效磷、速效钾、碱解氮含量呈显著正相关。可见,合理施用钙镁水滑石可改良土壤酸性,提高养分含量,降低土壤有效镉含量,最终使糙米镉含量下降,综上,本试验以T3为最佳处理。

In order to explore the effect of calcium-magnesium hydrotalcite(CMH)on cadmium content of brown rice in double-cropping rice and its suitable application methods,a two-year field experiment was conducted under different application methods of CMH(CK,0;T1,basal application of 3000 kg/ha in early rice in first year;T2,basal application of 1500 kg/ha in early rice in first year;T3,basal application of 1500 kg/ha in early rice per year;T4,basal application of 750 kg/ha per season;T5,basal application of 375 kg/ha per season).The results showed that CMH could significantly reduce the cadmium content in brown rice of double cropping rice,but the decrease varied between varieties and years.The decrease in cadmium content of brown rice in various varieties in 2021 increased with the increment of CMH dosage,but there was no significant difference among T1,T2,and T3 treatments.The decrease in cadmium content in brown rice in 2022 was the largest in T3 treatment.CMH significantly increased soil pH and nutrients content,and reduced soil available cadmium content,and T1 and T3 treatments were the best in 2021 and 2022,respectively.Principle component analysis and correlation analysis showed that the amount of CMH was significantly negatively correlated with the available cadmium content in soil and the cadmium content in brown rice,while it was significantly positively correlated with soil pH,available phosphorus,available potassium,and alkaline nitrogen content.It can be seen that reasonable application of CMH can improve soil acidity,increase soil nutrient content,reduce effective cadmium content in soil,and ultimately reduce cadmium content in brown rice.In summary,T3 was the optimal treatment under the experimental conditions.