采煤沉陷区不同裂缝处小叶杨根系损伤特性

Damage Characteristics of Populus Simonii Root Systems at Different Cracks in Mining Subsidence Area

[目的]探究矿区采煤沉陷对小叶杨(Populus simonii)根系的损伤程度,为后期小叶杨人工林治理恢复提供理论依据。[方法]观测记录李家塔采煤沉陷区不同坡位处不同裂缝间小叶杨根系的损伤状况,运用数理统计软件分析根系损伤率、损伤类型与坡位、裂缝类型、错位差、裂缝宽和根距裂缝水平距离间的关系等反映小叶杨根系损伤特性。[结果](1)小叶杨水平根主要分布在0—60 cm土层内,0—10 cm土层内根数最多,占40.1%~43.2%,50—60 cm内根数最少,占0.63%~3.71%。根系数量随土层深度增加而逐渐减少。(2)塌陷型和滑动型裂缝处伤根类型有扯断、扭曲、皮裂和拉出,其数量表现为:扯断>皮裂>扭曲>拉出,而拉伸型裂缝处无拉出损伤根系,表现为:皮裂>扭曲>扯断,塌陷型裂缝处根系损伤最严重。(3)根系损伤数量随着根系径级增粗呈现逐渐递减的趋势。根径<2 mm近乎全部扯断,<5 mm损伤以扯断为主,>5 mm以皮裂为主,扯断次之。根越粗扯断越少,皮裂越多。当根径>11 mm时皮裂根数急促地增多。(4)根据相关性由大到小,造成根系损伤的主导因素依次是:裂缝宽、错位差和根裂距。裂缝越宽,错位差越大,小叶杨根系损伤越严重。根裂距越小,根系损伤数量越多。根裂距<1 m时根系损伤最为严重。[结论]不同类型裂缝下根系损伤程度亦不相同。采煤沉陷区植被恢复治理过程中,不同塌陷地应根据不同裂缝类型制定适宜的治理措施。

[Objective]The degree of damage to small leaf poplar(Populus simonii)by coal mining subsidence was studied in order to provide a theoretical basis for the later restoration of artificial forests.[Methods]Damages in the Lijiata mining area to P.simonii root systems at different cracks in different slope positions were observed and recorded.The relationships between root damage rate and damage types and slope position,crack types,dislocation differences,crack widths,and the horizontal distances from roots to cracks were analyzed by using mathematical statistical software in order to characterize damage characteristics of P.simonii root systems.[Results]①The horizontal P.simonii root system was mainly distributed in 0—60 cm soil layer.The number of roots in 0—10 cm soil layer was the largest,accounting for 40.1%—43.2%of the root system,and the roots in 50—60 cm soil layer accounted for 0.63%—3.71%of the root system.The fraction of the root system gradually declined with increasing soil depth.②Root damage was most serious on slopes.All types of root damage existed in the subsidence cracks and sliding cracks,with damage following the order of pull apart>skin crack>twist>pull out.There was no pull out damage in the sliding cracks,and damage followed the order of skin crack>twist>pull apart.Root damage in the subsidence cracks was most serious.③The number of damaged root systems decreased gradually as root diameter increased.Roots with diameters less than 2 mm were almost pulled apart,and roots with diameters less than 5 mm were mainly pulled apart.Roots with diameters bigger than 5 mm were dominated by skin cracks,and then were pulled apart.The thicker the root was,the less the pull apart occurred,and the more skin cracks were observed.When roots were bigger than 11 mm in diameter,the number of skin cracks increased rapidly.④The main factors causing root damage can be ranked from large to small as crack width,dislocating difference,and distance from root to crack.The wider the crack,the greater the dislocation difference was,and the more serious was the P.simonii root system damage.Smaller root crack distance resulted in greater amounts of root damage.When the root crack distance was less than 1 m,the root damage was most serious.[Conclusion]The degree of root damage under different types of soil cracks differed.Different treatment measures should be formulated for vegetation restoration suitable to different fracture types in coal mining subsidence areas.