Study on the Evaluation Method of Subgrade Slope Green Protection Effect in Dry-Hot Valley of Sichuan-Tibet Railway

Table 5

Index data.

Indexes	1	2	3	4	5	6
Volumetric weight of soil (g·cm^−3)	1.15	1.19	1.23	1.13	1.11	1.21
Total soil porosity (%)	57.4	59.8	61.3	58.2	56.7	62.5
Organic matter content (g·kg^−1)	18.2	17.6	17.3	19.4	18.5	17.9
Duration of soil PWP (month)	4	4	3	3	4	6
Soil infiltration rate (mm·h^−1)	27.3	26.5	29.7	31.2	28.4	32.2
Total N (g·kg^−1)	1.49	1.8	1.5	1.4	2.05	1.8
Available P (P2Q5) (g·kg^−1)	0.013	0.014	0.016	0.018	0.019	0.013
Available K (K2O) (g·kg^−1)	0.09	0.095	0.093	0.088	0.11	0.07
Ability of soil to preserve moisture and fertility	Strong	Strong	Medium	Strong	Medium	Strong
Soil expansion and contraction	Weak	Weak	Weak	Medium	Weak	Weak
Coverage of vegetation (%)	91.3	88.4	89.7	87.9	88.2	90.8
Vegetation survival rate (%)	81.7	89.2	84.5	91.5	79.6	86.1
Incidence of pests and diseases in vegetation (%)	34.5	41.7	40.9	35.3	40.1	37.5
Vegetation species richness index	0.97	1.03	0.95	0.99	1.06	0.92
Rationality of vegetation spatial collocation	Reasonable	Reasonable	Reasonable	Reasonable	Reasonable	Reasonable
Ability of vegetation to resist drought and heat	Very strong	Strong	Strong	Strong	Strong	Strong
Vegetation tolerance to barrenness	Strong	Strong	Very strong	Strong	Strong	Strong
Slope resistance to leaching erosion	Strong	Strong	Strong	Strong	Very strong	Strong
Antiscouring ability	Strong	Strong	Medium	Strong	Medium	Strong
Ability of slope to protect against wind and sand	Strong	Medium	Strong	Strong	Strong	Strong
Slope resistance to natural disasters	Medium	Strong	Strong	Medium	Strong	Strong
Ability of slope to prevent water and soil loss	Strong	Very strong	Strong	Strong	Strong	Medium