土壤速效磷对烟草生长发育及干物质积累与分配的影响

作物的磷素营养丰缺状况会严重影响其生长发育与干物质的积累与分配,为探明土壤速效磷含量对烟草生长发育及干物质积累与分配的影响,为湖南烟区磷肥的合理施用提供科学依据,以湖南省8个不同速效磷含量的植烟土壤为研究对象,采用盆栽试验,研究在不施磷肥的情况下土壤速效磷含量对烟草生长和干物质积累与分配的影响。结果表明,当土壤速效磷含量大于50mg/kg时,烟草生长发育良好,而小于30mg/kg时,则明显影响了烟草的生长发育,表现为烟株矮小,有效叶片数减少,干物质量明显降低。速效磷含量较低的土壤与含量较高的土壤相比,烟株的干物质积累量减少27%~31%,当土壤速效磷含量很低时,烟株的干物质积累量仅为速效磷含量较高土壤烟株干物积累量的3.6%。土壤速效磷含量低不仅明显限制烟草茎和叶的生长,还会导致烟叶的长宽比由2.2增大到2.7,使烟叶呈狭长形。烟草移栽后76~90d是烟株干物质积累最快的时期,当土壤速效磷含量较低时,该时期的干物质积累比例为55.2%~69.2%,明显高于速效磷含量高的土壤,即当土壤速效磷含量较低时,烟株不仅生长缓慢,而且干物质的积累还明显滞后。

Effects of Soil Available Phosphorus on Tobacco Growth and Dry Matter Accumulation and Distribution

The abundance and deficiency of phosphorus in crops seriously affect their growth and dry matter accumulation and distribution. This study was conducted to explore the effects of soil available phosphorus on tobacco growth and development and dry matter accumulation and distribution, and provide a scientific basis for the rational application of phosphorus fertilizer in the Hunan tobacco area. The pot experiment was conducted to study the effects of soil available phosphorus on tobacco growth and dry matter accumulation and distribution in eight tobacco-growing soils with different available phosphorus contents in Hunan province. The results showed that tobacco grew well when the soil available phosphorus content was more than 50mg/kg. When the content of available phosphorus in soil was less than 30mg/kg, it had a significant impact on the growth and development of tobacco which was characterized by the short tobacco plant, the decrease of effective leaves number, and the significant reduction of dry matter. Compared with the soil with higher available phosphorus content, the dry matter accumulation of tobacco plants in the soil with lower available phosphorus content decreased by 27%-31%. When the soil with lower available phosphorus content, the dry matter accumulation of tobacco plants was only 3.6% in the soil with the higher available phosphorus content. The low content of soil available phosphorus not only restricted the growth of tobacco stems and leaves but also increased the length-width ratio of tobacco leaves from 2.2 to 2.7. 76-90 days after transplanting was the fastest period of dry matter accumulation, and when the soil available phosphorus content was lower, the proportion of dry matter accumulation in this period was 55.2%-69.2%, which was significantly higher than that in the soil with high available phosphorus content. When the soil available phosphorus content was lower, the tobacco plant not only grew slowly but also the accumulation of dry matter was significantly lagged.