不同土层深度苜蓿断根后对其株高生长的影响

Effect of root pruning in different depth on height of alfalfa growth

对苜蓿进行不同土层深度断根处理,以阻断其不同深层根系对土壤水分的吸收,研究苜蓿地上部分株高生长的反馈特征。结果表明:苜蓿在不同土层断根当年,各深度的断根处理均使苜蓿株高生长受到一定抑制,与对照相比有所降低。不同层次断根的苜蓿在断根当年浅层次断根(20、406、0 cm)受到的水分胁迫较其它处理严重。在断根初期(半个月)与对照呈极显著差异;在收获期株高与对照(26.70 cm)相比,株高分别降低了13.10、12.851、1.30 cm,表现为断根越浅,影响越大。各处理在断根的次年,苜蓿返青期的株高变化曲线十分平缓。收获期断根处理20、402、30 cm的苜蓿株高比对照(37.96 cm)分别降低了5.08、5.34、5.30 cm,较对照差异性极显著(P<0.01),各断根处理较断根当年株高的生长量均有显著提高。两年的数据表明浅层次断根处理的株高生长受到水分胁迫较深层断根处理严重。不同土层断根处理的株高生长受抑制程度为:浅层次处理>中层次处理>深层次处理。

Study was made on the growth situation of alfalfa root in the different soil depths after cutting lateral root.The results showed that in the current year of cutting lateral root,alfalfa height growth was inhibited and decreased compared with the control.Alfalfa root in the shallow depths（20 cm,40 cm and 60 cm depths） treatment had more serious water stress,than other treatments.There were very significant differences（P0.01） between the early stage of cutting lateral root and the control.In the harvest period, plant height decreased by 13.10 cm,12.85 cm and 11.30 cm compared to the control respectively.It showed that the shallower the root cutting was made,the more seriously it affected alfalfa.In the second year of cutting lateral root,the alfalfa height curve is very flat in the green stage.In the harvest period of cutting lateral root at 20 cm,40 cm and 60 cm depths,the plant height decreased by 5.08 cm,5.34 cm and 5.30 cm compared to the control（37.96 cm） respectively.The differences were significant（P0.01）.The data in two years showed that the alfalfa height growth in shallow level treatments was more seriously affected by water stress than other treatments.The level of alfalfa inhibition growth of different soil layers by different cutting lateral root is shallow level treatmentmedium level treatmentdeep treatment.