恩施烟区烤烟上部叶总植物碱主控因素分析

Analysis on main control factors of total plant alkaloid in upper leaf of flue-cured tobacco in Enshi tobacco area

在恩施烟区不同土壤肥力区域布置烤烟二因素三水平大田试验,分析施氮量、移栽密度和土壤化学性状对烟草上部叶总植物碱的影响。结果表明,①与移栽密度相比,施氮量对总植物碱的影响较大,但在中低施氮量条件下,提高移栽密度有助于降低总植物碱含量;②协方差分析发现,施氮量对总植物碱的影响显著,但施氮量和移栽密度的交互作用不显著;③总植物碱与土壤速效磷呈极显著负相关,且速效磷进入了2018年和2017年逐步回归模型,对总植物碱起控制作用;④采用结构方程模型(SEM)的路径分析方法发现,随着速效磷的增加,总植物碱含量显著降低,且速效磷的间接路径系数显著;⑤速效磷与速效钾间接路径系数较大,占间接路径系数的80%左右,可通过速效钾间接对总植物碱产生影响。适度控制氮肥用量,在部分总植物碱较高区域采取高移栽密度种植措施,对总植物碱产生抑制作用;土壤速效磷为本区域调控总植物碱主要因素之一,随着土壤磷素的逐步富集,有利于降低总植物碱含量,但对烟叶其他品质因子的影响还有待于进一步探讨。

The effects of nitrogen application rate,transplanting density and soil chemical properties on total plant alkaloids of upper leaves of flue-cured tobacco were studied in a field experiment with the flue-cured tobacco plants planted in different soil fertility ar⁃eas in Enshi.The results showed that,①compared with transplanting density,nitrogen application rate had a greater effect on total al⁃kaloid content,but increasing planting density was helpful to decrease total alkaloid content under medium and low nitrogen applica⁃tion rates;②covariance analysis showed that the effect of nitrogen application rate on total alkaloids was significant,but the interac⁃tion between nitrogen application rate and transplanting density was not significant;③the total alkaloid was negatively correlated with soil available phosphorus,and the available phosphorus entered the stepwise regression model in 2018 and 2017,and controlled the total alkaloid;④the path analysis method of structural equation model(SEM)showed that with the increase of available phosphorus,the total alkaloid content decreased significantly,and the indirect path coefficient of available phosphorus was significant;⑤The indi⁃rect path coefficient of available P and available K was larger,accounting for about 80%of the intermediate path coefficient,the total alkaloid could be affected indirectly by available potassium.Proper control of the amount of nitrogen fertilizer and high-density plant⁃ing measures were adopted in some areas where the total alkaloids were easy to be high.Soil available phosphorus could be one of the main controlling factors ofthe total alkaloid.With the gradual enrichment of soil phosphorus,it would be beneficial to reducethe total al⁃kaloid,but the effects of other quality factors of tobacco leaves needs further investigation.