梭梭不同密度与配置固沙效果风洞模拟试验

Sand-fix effects of Haloxylon ammodendron forests under the different densities and patterns under wind tunnel test

梭梭(Haloxylon ammodendron)是干旱荒漠区典型的固沙造林树种。文中利用风洞模拟试验,研究了石羊河流域民勤县、凉州区和古浪县雨养条件下梭梭不同适宜造林密度在均匀、随机、一行一带和两行一带4种配置模式的固沙效果。结果表明:在4种配置模式下,梭梭林下沙面均表现为风蚀,林带后为堆积;不同配置梭梭离上风向越远,林下风蚀深度越小,带后堆积越大;在相同风速下,两行一带最不易风蚀,随机配置最易风蚀;在低覆盖度条件下,行带式配置固沙效果明显好于均匀和随机配置;当植被覆盖度达到32.37%时,行带式配置固沙效果与其它配置相比,固沙效果差异不显著。

Haloxylon ammodendron is a good shrub species for sand fix and afforestation in arid desert region.The sand fix effects for four spatial patterns of H.ammodendron that are uniform pattern,random pattern,one-row in one-belt pattern and two-row in one-belt pattern respectively were tested by using wind tunnel under three coverages of 11.77%,23.54%and 32.37%in Minqin,Liangzhou and Gulang counties along Shiyang river.Results showed that the sand-wind erosion occurred on the surface below forest belt and sand accumulation occurred after forest belt.The farther the forest belt was away from the upwind,the less the sand surface suffered from the wind erosion,and the more the sand accumulation was after forest belt.The power of wind erosion resistance was the biggest under the two-row in one-belt pattern,and the smallest under the random pattern than that of other three patterns under the same wind speed.Under shrub low-coverage,the sand-fix effect in belt patterns was obviously batter than that of in uniform and random patterns.If the shrub coverage was more than 32.4%,the sand-fix effect in belt patterns had not significant difference comparing with that of other patterns.