紫花苜蓿根系拉拔试验研究

Study on anti-pulling test of Alfalfa root system

为了研究紫花苜蓿根系的拉拔力学性质和评价其根系固土力学机制的增强效应,采用室外原位拉拔试验分析了影响苜蓿根系拉拔力的因素。试验结果表明:①紫花苜蓿根系拉拔力随着直径、根长、根系表面积的增大而增大,抗拉力与直径增长趋势呈指数关系,根长L2(20~30 cm)比根长L1(10~20 cm)平均拉拔力增大了69.62%,根长L3(30~40 cm)比根长L2平均拉拔力增大了61.7%,根长L3平均拉拔力比根长L1增大156.16%。②拉拔力随根系表面积的增大而增大;根长L2、L3的平均根系表面积分别是根长L1的2.28倍和5.17倍;根长L2、L3平均拉拔力分别是根长L1的1.70倍和2.66倍。③紫花苜蓿根系拉拔力与植物根径呈负相关,满足幂指函数关系。拉拔强度T的大小为T3(30~40 cm)>T2(20~30 cm)>T1(10~20 cm),根长L2、L3的平均拉拔强度比根长L1的减小了14.70%,53.71%。

In order to study the anti-pulling strength of Alfalfa root and the mechanical mechanism of root soil fixation,the outdoor in situ anti-pulling test was conducted to analyze the influencing factors for the anti-pulling force of Alfalfa root system.The results showed that:(1)the anti-pulling force of Alfalfa root increased with the increase of diameter,root length and root surface area,and the growth trend of resistance to tension and diameter presented an exponential function relationship.The average anti-pulling force of root length L2(20~30 cm)was 69.62%more than that of root length L1(10~20 cm).The average anti-pulling force of root length L3(30~40 cm)was 61.7%more than that of root length L2.The average anti-pulling force of root length L3 was about 156.16%more than that of root length L1.(2)The average root surface areas of L2 and L3 were 2.28 and 5.17 times of that of L1,and the average anti-pulling force of L2 and L3 were 1.7 and 2.66 times of that of L1,respectively.(3)The anti-pulling force of Alfalfa rootwas negatively correlated with diameter,showing a exponential function relationship.The tensile strengths from high to low was T3(30~40 cm)>T2(20~30 cm)>T1(10~20 cm),and the average anti-pulling strength of L2 and L3 were 14.7%and 53.71%lower than that of L1.