不同土壤类型烟草根系发育特点研究

Characteristics of tobacco root development on different types of soil

不同土壤烟草根系干重的变化趋势相同。即打顶以前缓慢增加 ,打顶至圆顶期迅速增加 ,并于圆顶期达到最大根重 ,并且砂姜黑土 >潮土 >褐土 ,圆顶期以后迅速减少。褐土根重前期增加较快 ,中期较慢 ,后期减少也慢 ,根重变化相对缓和 ;砂姜黑土根重前期增加缓慢 ,中期较快 ,后期衰老也快 ,根重变化相对剧烈 ;潮土居中。不同土壤烟草根系总长度在旺长前增加缓慢 ,旺长期至圆顶期增加较快 ,圆顶期以后仍有少量增加。圆顶期烟根长度差异最大 ,且褐土 >潮土 >砂姜黑土。烟草根重、根长、根表面积及活跃吸收面积的垂直分布均为 :0～ 2 0 cm>2 0～ 4 0 cm>4 0～ 6 0 cm>6 0～ 80 cm,且 0～ 2 0 cm耕层各项指标远远大于其他土层之和。不同土壤根重垂直分布特点为 :砂姜黑土浅而集中 ,褐土深而分散 ,潮土居中。根长分布特点为 :砂姜黑土浅而集中 ,潮土深而分散 ,褐土居中 ,且根长最大期褐土 >砂姜黑土 >潮土。根表面积及活跃吸收面积分布特点为 :潮土浅而集中 ,褐土深而分散 ,砂姜黑土居中 ;其大小顺序为 :砂姜黑土 >潮土 >褐土。砂姜黑土根重、根长横向分布窄而集中 ,褐土和潮土宽而分散。

Dry weight of tobacco root on different types of soil had the same growth tendency increasing slowly before topping, increasing quickly 10 days after topping and decreasing rapidly there after.Root dry weight on Cinnamon soil increased most quickly in early period and slowly during middle period, and also decreased slowly in later period, so it changed comparatively peacefully; on Shajiang black soil, it increased most slowly in early period, and fastest during middle period, and decreased most rapidly in later period. On Alluvial soil, it changed in the between. During the maximum root dry weight stage, dry weight of tobacco root in different types of soil were: Shajiang black soil>Alluvial soil>Cinnamon soil. Tobacco root length in different types of soil extended in the same tendency extending slowly before June 10th, quickly from June 10th to July 18th, and keeping extending slowly after wards. On July 18th the root length of different types of soil were: Cinnamon soil> Shajiang black soil>Alluvial soil.\;Tobacco root weight, length, total surface area and active absorption area had the same vertical distribution the values of different arable layers were:0~20cm>20~40cm>40~60cm>60~80cm. The characteristics of vertical distribution of root dry weight on different types of soil were that RDW on Shajiang black soil was shallow and intensive, and on Cinnamon soil was deep and extensive, and on Alluvial soil was in the between. The characteristics of root length vertical distribution were that root length of Shajiang black soil distributed shallow and intensive, and that of Cinnamon soil deeply and extensively, and Alluvial soil in the mediate degree. As to the characteristics of root total surface area and active absorption area vertical distribution, Alluvial soil distributed shallow and intensively, Cinnamon soil deeply and extensively, and the Shajiang black soil in mediate degree; furthermore, the root surface area and active absorption area of different types of soil were: Shajinag black soil>Alluvial soil>Cinnamon soil. Root weight and length of Shajiang black soil distributed most narrowly, and of Cinnamon soil and Alluvial soil most widely.