连作对烤烟生长及土壤氮磷钾养分的影响

为探索在同一土壤上烤烟长期连作对土壤主要养分以及烟株生长的影响,试验采用盆栽的方法,在同种土壤上种植不同季数的烤烟,分析了不同种烟季数土壤的氮磷钾状况以及对应烟株的生长量。结果表明,在连作种植条件下,烤烟根、茎、叶生物量显著下降;不宜连作的第四纪黄壤上烤烟生物量低于宜烟的黄色石灰土,并且适宜连作的黄色石灰土烤烟生物量降幅明显低于不宜烟的第四纪黄壤。正常施肥的条件下,长期连作使土壤pH显著下降,土壤有效氮、磷、钾显著上升。烤烟连作使产量降低的原因可能与土壤pH降低和根系分泌的"自毒"物质有关。

The Effect of Continuous Cropping on Tobacco Growth and Soil Nutrients

The pot experiment with planting different times of tobacco in the same soil was tested to investigate the effect of continuous cropping on tobacco growth and soil nutrients.The results showed that the biomass of the tobacco root,stem and leaf reduced significantly,the tobacco biomass planted in yellow soil was lower than that planted in yellow limestone soil,and the reduction range of tobacco biomass planted in yellow limestone soil was obviously lower than that planted in yellow soil under the continuous cropping condition.The long-term continuous cropping of tobacco decreased pH of soil and raised contents of effective N,P and K significantly under the normal application condition.The reason for causing the yield reduction of continuous cropping may relate to reduction of soil pH and poisonous substance released from its roots.