永安曹远工程侵蚀林地土壤生境变化分析

以未受工程侵蚀的林地为对照,对永安曹远工程侵蚀地的土壤生境变化进行分析。结果表明:工程侵蚀后的林地植被几乎被破坏殆尽,坡面上遗散的岩石矿物碎块平均质量3 528.73 g.m-2,并具有锋利、尖削的棱角结构,长期的摩擦,加剧了坡面的水土流失;工程侵蚀的土层剥蚀厚度达15~30 cm,土壤腐殖质层全部或大部分以悬移方式流失,土壤胶结能力下降,分散率提高,粒径>0.25 cm的水稳性团聚体0~20 cm和20~40 cm土层分别比对照减少18.03%和16.87%,土壤结构体破坏率0~20 cm和20~40 cm土层分别比对照增加21.87%和20.2%;土壤养分含量、蓄水能力和渗透力明显下降,土壤板结恶化,林地土壤肥力下降1~3个单位,加大了地面径流,进一步加剧水土流失,给林地生态恢复增加了困难,必须探索有效的生态恢复途径。

The change of the forestland ecological environment with engineering erosion in Caoyuan Yong'an

Taking the forestland without engineering erosion as the control,this paper analyzes the change of the forestland ecological environment with engineering erosion in Caoyuan Yong'an.The results show that the forestland vegetation is totally destroyed after engineering erosion.The average weight of the dispersed rocks left on the slope is 3 528.73 g·m-2.These rocks have sharp edges and corners,and the long-term friction accelerate the erosion of the slope.The denudation thickness of the soil with engineering erosion is 15～30 cm.The soil humus totally or mostly is eroded by the ways of suspending and drifting.The soil cementation ability decreases while the dispersion rate increases.Compared with the control,the water steady aggregate particles with the diameter >0.25 cm reduces 18.03% and 16.87% in the 0～20 cm and 20～40 cm layer,respectively,and the destroyed rate of the soil structure particles increase 21.87% and 20.2% in the 0～20 cm and 20～40 cm layer,respectively.The nutrient content,water-holding capacity and permeability decrease obviously.The soil degrades with crust and causes soil fertility descends 1～3 units.The soil furface runoff increases,which accelerates the soil erosion,leading to the difficulty in ecological recovery,so the effective methods should be worked out for the ecological recovery.