土壤颗粒组成及黏着剂对类芦种子萌发和幼苗生长的影响

南方红壤侵蚀区土壤表层沙砾化影响植被植物种子萌发和幼苗生长,是限制其植被恢复的主要限制因子之一。为了促进沙砾化土壤植被恢复,本研究以水土保持先锋草本植物类芦种子为材料,采用不同土壤颗粒组成模拟5种不同沙砾化程度的土壤,添加不同含量土壤黏着剂PAM(0、0.125、0.250和0.500 g·kg^-1),研究土壤颗粒组成及土壤黏着剂对类芦种子萌发及幼苗生长的影响。结果表明:添加PAM使类芦种子发芽提前1~2 d,提高种子发芽率和促进幼苗生长;黏着剂含量对类芦种子萌发和幼苗生长有极显著影响,黏着剂含量为0.125 g·kg^-1时最有利于种子萌发;0.250和0.500 g·kg^-1较有利于幼苗生长。黏着剂对幼苗生长影响还与土壤颗粒组成有关,随着土壤粗颗粒比例增加,黏着剂的添加量增加对幼苗高生长有利。土壤颗粒组成对种子萌发及幼苗生长存在显著影响,在土壤粗细颗粒比例适中(>2 mm、1~2 mm、<1 mm配比为2∶3∶3)时适宜类芦种子萌发,粗颗粒(>2 mm)含量比例较大(≥75%)时可以促进类芦幼苗生长。研究结果为类芦在水土流失区的植被恢复和边坡治理应用提供了理论参考。

Effects of soil particle composition and adhesives on seed germination and seedling growth of Neyraudia reynaudiana

In the red soil erosion region of southern China,coarse soil surface texture(high proportions of sand and fine gravel)seriously affects soil nutrient and water holding capacity,and therefore plant growth,and is a constraint to vegetation restoration.Soil adhesive additives can improve the soil environment and enhance plant seed germination and seedling growth.This study investigated the effects of differing soil particle size composition and addition of soil adhesive(polyacrylamide,PAM)on seed germination and seedling growth of Neyraudia reynaudiana.The experiment comprised different soil particle compositions to simulate five different soil erosion levels,and four different soil conditions created by different PAM concentrations added to the soil(0,0.125,0.250 and 0.500 g·kg^-1).It was found that both the concentration of PAM and the soil particle composition significantly influenced seed germination and seedling growth of N.reynaudiana.Addition of PAM increased the germination rate and shortened the emergence time of N.reynaudiana by 1-2 days.The low soil adhesive concentration(0.125 g·kg^-1)was optimal for seed germination,while high soil adhesive concentrations(0.250 or 0.500 g·kg^-1)were best for seedling growth.The effect of PAM on seedling growth depended on soil particle composition.The soil with 25%coarse particle content was propitious for seed germination,and a high proportion of coarse-grained soil was beneficial for seedling growth.With increasing proportion of coarse particles,the seedling shoot height increased.The results of this research provide a theoretical guidelines for vegetation restoration and slope treatment using N.reynaudiana in the red soil erosion region.