窄冠刺槐根系的研究

2006年10月用全挖法和分层分段挖掘法,研究了窄冠刺槐根系的分布特征、根系生物量以及不同密度林分根系空间分布特征.结果表明:窄冠刺槐个体根系水平分布在株间可达到6.6 m,在行间可达到5.0 m;主根可深达2 m以上,侧根垂直分布集中在10～40 cm土层内.窄冠刺槐根系生物量占全株生物量的16.82％,主根、侧根的生物量在根系生物量中分别占87.13％、12.87％.窄冠刺槐林分根系生物总量和根总长分别为6 160.2～10 940.55kg·hm-2和970.35～1 607.4 km·hm-2,并呈现出根系生物总量和根总长与林分密度成正相关的规律.在垂直方向上,林分根系中直径D<15 mm的根主要分布在地下0～20 cm土层内,而直径D≥15 mm的根主要分布在地下20～40 cm土层内;在水平方向上,直径D≥5 mm的根数量随距树干距离增加而减少,而直径D<1 mm的根数量则随距树干距离增大而增大,主要集中分布在距树干0.5～1.5 m范围内.

Study on Root System of Narrow-Crown Clone of Black Locust

A study was made on the distribution characteristics and biomass of individual tree root system as well as root distribution characteristics of stands in different densities of the narrow-crown clone of black locust(Robinia pseudoacacia cl.Zhaiguan),by using the methods of digging out whole root system of the individual and digging out root pieces in different vertical and horizontal locations in the soil of the stands.The result showed that the root distribution between the individual trees and tree lines extended horizontally to 6.6 m and 5 m respectively;and the taproot vertically extended to 2 m below the ground surface with its lateral roots mainly distributing in the soil from 10 cm to 40 cm below the ground surface.The biomass of whole root system accounted for 16.82% of the biomass of whole individual tree,with the biomass of taproot and lateral root taking about 87.13% and 12.87% of the biomass of whole root system.The total biomass and length of the roots of Zhaiguan clonal stands were 6 160.2-10 940.55 kg·hm^-2 and 970.35-1 607.4 km·hm^-2 respectively,and showed a positive relation with the stand densities.In vertically,the roots with diameter less than 15 mm mainly distributed in the soil from 0 to 20 cm below the ground surface,while the roots with diameter more than 15 mm mainly distributed in the soil from 20 to 40 cm below the ground surface.In horizontally,the biomass and length of the roots with diameter equal to or more than 5 mm decreased while the biomass and length of the roots with diameter less than 1 mm increase with the increasing of distance from tree stem in the stand.The roots with diameter less than 1 mm mainly distributed horizontally from 0.5 m to 1.5 m away from the tree stem in the soil of the stand.