奈安与腐植酸促进烤烟生长及消减烟叶镉污染的协同效应

Synergistic effects of Naian combined with humic acid on the growth promotion of tobacco and reduction of cadmium contents in tobacco leaves

【目的】明确奈安与腐植酸配施对烤烟生长及品质提升的影响,并探究其对土壤有效态镉(Cd)和烟叶Cd含量的影响及相互关系,为Cd轻度污染农田烤烟的安全生产提供技术支撑。【方法】通过大田试验,共设4个处理[T1:不施腐植酸和奈安(CK),T2:单施奈安(1.2 g a.i/ha),T3:单施腐植酸(750 kg/ha),T4:奈安(1.2 g a.i/ha)+腐植酸(750 kg/ha)配施]。于烤烟移栽90 d后调查烤烟植株农艺性状,移栽100 d后取植株样品测定烟叶产量、化学品质和Cd含量,烟叶采收结束后取5~20 cm耕层土壤样品分析不同处理的土壤有效态Cd含量、总Cd含量及土壤pH。【结果】与T1(CK)处理相比,T2处理的烟叶产量显著提高5.99%(P<0.05,下同),烟碱含量显著降低11.92%;T3处理的烟叶产量显著提高7.00%,烟叶总糖、还原糖、总氮和钾含量分别显著提高19.11%、12.65%、21.19%和9.87%;T4处理的烟叶产量显著提高14.70%,烟叶总糖、还原糖、总氮和钾含量分别显著提高23.36%、16.41%、13.25%和13.73%,而烟碱含量显著下降16.89%,烟叶化学成分的协调性最佳。施用腐植酸(T3处理和T4处理)能显著降低烟叶Cd含量,较T1(CK)处理分别显著降低0.96和1.22 mg/kg,消减率为35.80%~46.51%,烟叶Cd富集系数从8.22降至5.27~5.90,有效减轻烟叶对Cd的富集作用;施用腐植酸(T3处理和T4处理)还能显著降低土壤有效态Cd含量(11.95%~14.64%),并使土壤pH分别升高0.50和0.54。相关分析结果表明,土壤有效态Cd含量与烟叶Cd含量呈极显著正相关(P<0.01),而土壤pH与土壤有效态Cd和烟叶Cd含量均呈显著负相关。【结论】奈安与腐植酸配施对提升烤烟生长及烟叶品质具有明显的协同增效作用,且能消减阻控烟叶对Cd的富集,可作为植烟区Cd轻度污染农田进行烤烟安全生产的一项有效措施。

【Objective】This paper investigated the effects of the combinations of Naian and humic acid on the growth and quality improvement of tobacco leaves,on the available cadmium(Cd)content in soil and Cd content in tobacco leaves and their correlations,which would provide technical support for the safe production of tobacco in slightly Cdcontaminated soil.【Method】Four treatments were set up as field experiments,[T1:no humic acid and Naian added as control(CK),T2:Naian(1.2 g a.i/ha),T3:humic acid(750 kg/ha),T4:Naian(1.2 g a.i/ha)+humic acid(750 kg/ha)].Agronomic characters of tobacco plantswere investigated after 90 d of transplanting.The yield,chemical quality and Cd content of tobacco leaves were determined after 100 d of transplanting.The available Cd content,total Cd content and pH in the soil at 5-20 cm layer were analyzed after tobacco leaves harvest.【Result】Compared with T1(CK),T2 significantly promoted the yield of tobacco leaves by 5.99%and significantly reduced nicotine by 11.92%(P<0.05,the same below).T3 significantly promoted the yield of tobacco leaves by 7.00%and significantly increased the contents of total sugar,reducing sugar,total nitrogen and potassium in the tobacco leaves by 19.11%,12.65%,21.19%and 9.87%,respectively.T4 significantly promoted the yield of tobacco leaves by 14.70%,significantly increased the contents of total sugar,reducing sugar,total nitrogen and potassium in the tobacco leaves by 23.36%,16.41%,13.25%,13.73%,and significantly reduced the nicotine content by 16.89%.The coordination of chemical composition of tobacco leaves was the optimal.The application of humic acid(T3 and T4)significantly reduced the contents of Cd in tobacco leaves,and reduced by 0.96 and 1.22 mg/kg compared with T1(CK),the reduction rate was 35.80%-46.51%.The enrichment coefficient of Cd in tobacco leaves decreased from 8.22 to 5.27-5.90,which effectively reduced the enrichment effect of tobacco leaves on Cd.Humic acid(T3 and T4)reduced the contents of available Cd in soil by 11.95-14.64%and increased soil pH by 0.50-0.54.The results showed that there was extremely significant positive correlation between soil available Cd content and tobacco leaf Cd content(P<0.01),while soil pH was significantly negatively correlated with soil available Cd and tobacco leaf Cd content.【Conclusion】The combination of Naian or humic acid has obvious synergistic effects on the improvement of the growth and quality of flue-cured tobacco,and effectively reduce the accumulation of Cd in tobacco leaves.The combined application of Naian and humic acid would be an effective technology for safe production of tobacco in the tobacco planting areas in slightly Cd-contaminated soil.