聚丙烯酰胺添加浓度对种基盘特性的影响

Effects of polyacrylamide concentration on the properties of seed-base

种基盘绿化技术是一种改善公路边坡补栽的新技术,添加适宜浓度的聚丙烯酰胺能够有效提高种基盘基质的抗压强度,改善保水性能,有利于根系特别是主根的扩展。本研究在种基盘基质中添加5个浓度梯度(0.2‰、0.4‰、0.6‰、0.8‰、1‰)聚丙烯酰胺,不添加聚丙烯酰胺为对照,研究其对种基盘的抗压强度、保水特性及根系扩展特性的影响。结果表明:添加聚丙烯酰胺对种基盘抗压强度和根系扩展性均有显著影响(P≤0.05),对保水特性影响较小。当种基盘含水量在15%的情况下,聚丙烯酰胺用量为0.4‰和0.6‰时,基盘强度分别为0.72 kN和0.82 kN,均高于对照与其他水平,有利于种基盘的稳定;聚丙烯酰胺对基质保水效果影响不显著,其中高浓度1‰条件下基盘蒸发失水比最高,持水效果最差;每个处理的基盘孔外的根系长度均高于孔内,其中,聚丙酰胺添加浓度为0.2‰、0.4‰、0.6‰时,根系长度以及根系扩展性均优于对照,根系扩展性好。综合分析,聚丙烯酰胺用量0.6‰时,种基盘的抗压强度、保水性能以及改善植物根系扩展特性均达到最优。

Seed-base technology is a new technology to improve the roadside replanting.Adding a suitable concentration of polyacrylamide can effectively increase the compressive strength of the substrate and improve the water retention performance,which is beneficial to the expansion of the root system,especially the tap root.Five different concentrations(0.2‰,0.4‰,0.6‰,0.8‰,1‰)of polyacrylamide were added to the seed-base,with no addition of polyacrylamide as the control(CK).The study aimed to investigate the effects of polyacrylamide on the compressive strength,water retention characteristics and root expansion characteristics of the seed?base.Our results showed that the addition of polyacrylamide had significant effects on the compressive strength and root expansion of seed-base,but little effects on the water retention characteristics.When the water content of seed-base was 15%and the concentration of polyacrylamide at 0.4‰and 0.6‰,the strength of seed-base was 0.72kN and 0.82kN,which were higher than that in CK and the other levels.The addition of polyacrylamide had no significant effect on the water holding capacity of substrate,with the highest evaporation loss and the lowest water holding capacity at 1‰polyacrylamide.The root length outside the hole was higher than that inside.Root length and root expansion at 0.2‰,0.4‰and 0.6‰polyacrylamide were greater than in the control.In summary,when the concentration of polyacrylamide was 0.6‰,the compressive strength,water retention performance,and improvement of root expansion characteristics of the seed-base were all optimal.