| The segment from Nehe to Nenjiang of the National highway G111 is more serious sandstorm area. Filtering the types which of higher soil-hold efficiency have important significance for the Highway slope vegetation restoration. In our study, we selected eighteen northeastern common plants to discuss these soild-hold effectiveness by using undisturbed-soil trough scouring method for Soil anti-scourability enhancement and hydrostatic collapse method for soil anti-erodibility, and finally using principal components analysis analyzed the factors which related to soil corrosion resistance. The main research results are as follows:1. Shrubs:(1) The root distribution in soil for eight shrub species had great difference;The soil antiscourability for the same species increased with the increase of the soil depth, decreased with the increase of the slope and decreased with the increase of the precipitation;The biomass of the roots whose length are less than 1 mm, the length of the whole root, and the contents of organic matter and available potassium were very important to determine the soil antiscourability by the principal components analysis, which had stronger effects under the heavy rain washing. The common factor variances for above root and soil factors in the principal component analysis were 0.99,0.98,0.98, and 0.97 respectively; the order of the soil antiscourability for eight shrubs is Syringa oblata> Forsythia mandshurica> Cornus alba> Ligustrum obtusifolium subsp. suave> Weigela florida> Platycladus orientalis> Prunus tomentosa> Caragana arborescens. We recommended the first four species as the plants of vegetation recovery in this area.(2) Different tree species with distinct enhancement effect on soil anti-erodibility, as with the soil depth increase, the corrosion index goes downward. Besides, the relationship between the soil erosion index (S) and the immersion time (t) is a three times function curve in each different species (R2≥0.82). Micro-aggregates, Organic matter, Available K> 5 mm,0.5-2 mm large soil aggregates,< 1 mm root biomass and root length are all riding key roles on the soil anti-erodibility enhancement effect, and their common factor variances are all more than 0.90. The order of the enhancement effect for the 9 species is:Syringa oblata> Caragana arborescens> Climbing cypress> Cornus alba> Northeast forsythia> Ligustrum obtusifolium subsp. suave> Amorpha fruticosa> Prunus tomentosa> Weigela florida 'Red Prince'. We recommend that the first 5 species could be widely popularized and applied in road vegetation recovery.2. Grasses:Different herb with distinct enhancement effect on soil corrosion resistance. As with the soil depth, slope gradient or rainfall increase, the soil anti-scourability enhancement index goes downward, while the relationship between the soil anti-erodibility enhancement index (S) and the immersion time (t) is a three times function curve in each different herb type (R2≥0.88). From the principal component analysis obtained that Micro-aggregates, Organic matter, net leaf weight, thick root length, fine root length and biomass all accounted for a leading role in soil corrosion resistance enhancement effect, and their common factor variances are all more than 0.81. The order of the soil corrosion resistance enhancement effect in soil anti-scourability is:Poa pratensis> Medicago sativa> Viola philippica> Rudbeckia hirta> Clematis heracleifolia> Kalimeris indica> Cosmos bipinnata> Hemerocallis fulva> Sedum elatinoides, while in soilantierodibilityis:Medicago sativa> Sedum elatinoides> Poa pratensis> Rudbeckia hirta> Hemerocallis fulva> Viola philippica> Clematis heracleifolia> Cosmos bipinnata> Kalimeris indica.Thus we obtained the final conclusion that Poa pratensis, Medicago sativa and Rudbeckia hirta are the best types for soil corrosion resistance enhancement effect, and we recommend they could be widely popularized and applied in road vegetation recovery.
|
PDF Full Text Request