Characteristics Of Morphological Changes Of Silicon,aluminum And Iron In Different Ecological Soil Profiles In Mountainous Areas Of Guizhou

By studying the content,spatial variability,conversion between different forms and the relationship between each form and soil chemical index of soils with different ecological types in the soil of different ecological types in the mountainous areas of Guizhou,the relationship between the forms of Si,Al and Fe elements was discussed The existing conditions provide a reference for vegetation restoration and ecological reconstruction in the mountainous areas of Guizhou.In this paper,according to the stepwise chemical extraction of Si and Al,and the BCR chemical analysis method of extracting Fe,the soil of different ecological types profile soil in Qinglong County,Guizhou Province As the main research,Including Cultivated Land?CL?,Returned Farmland to Grassland?RFL?,Wild Grassland?WGL?,Shrub Land?SL?,Forest-Grassland intercropping?FGL?,Woodland?WL?the effects of different ecological types on the chemical forms of Si,Al,Fe in the soil were studied.The results show that:?1?The content of soil SiO₂ generally increases with the depth of the soil layer,and the content of forest soil SiO₂ increases the most on the profile?15.37%?.The content of ORB-Si and FMH-Si in forest-grass intercropping and woodland soil decreased with the increase of soil layer depth,and the content of EF-Si and AM-Si in soil returning to farmland and grassland and forest-grass intercropping field increased with the increase of soil layer depth.?2?The Al₂O₃ content of the soil converted from farmland to grassland,barren grassland,and forest-grass intercropping generally increases with the increase of the soil layer depth.The Al₂O₃content of the shrub land and woodland soil mainly accumulates in the 20-40cm soil layer,and the Al₂O₃ content of the arable land soil is in the profile The upper part is mainly accumulated in the0-10cm soil layer,and the bottom soil?40-60cm?is the most affected by the parent material.The content of EF-Al,ORB-Al and AM-Al in the forest-grass intercropping soil increased with the depth of the soil layer,and the content of EF-Al and FMH-Al in the forest soil was mainly concentrated in the 10-20cm soil layer.?3?The Fe₂O₃ content of cultivated land,barren grassland,shrubland,and woodland soil generally increases with the increase of soil layer depth,and the Fe₂O₃ content of soil converted from farmland to grassland and forest-grass intercropping is mainly accumulated in the 10-20cm soil layer.The content of WAT-Fe and EX-Fe in cultivated land,returning farmland to grassland,waste grassland,forest-grass intercropping,and woodland soil decreased with the increase of soil layer depth,and the content of RED-Fe and OXI-Fe in shrub land increased first in the profile After lowering.?4?Correlations among different forms of soils such as Si,Al and Fe generally exist in different types of soils:EF-Si and ORB-Si,EF-Al and AM-Al,EF-Si and FMH in forest and shrub land-Si,ORB-Si and AM-Si in arable land and waste grassland,EF-Si and FMH-Si in arable land,returning farmland to grassland,and shrub land are significantly positively correlated;EX-Fe and RED-Fe in returning farmland to grassland and forest-grass intercropping,EF-Al and ORB-Al in abandoned grassland,grassland and wasteland,FMH-Al and AM-Al in wasteland,shrubland and woodland were significantly negatively correlated.?5?The forms of Si,Al and Fe in different ecological types of soil are correlated with the soil chemical indicators.The soil pH is positively correlated with EF-Si and negatively correlated with FMH-Al,WAT-Fe and OXI-Fe;OM is associated with ORB-Si,AM-Si,OXI-Fe are positively correlated with EF-Al,AM-Si and OM are negatively correlated;TN,TP are positively correlated with ORB-Si,OXI-Fe,TN is negatively correlated with AM-Al,TP is negatively correlated with EF-Al;TK is positively correlated with EF-Si and AM-Si?except for forest land?,negatively correlated with ORB-Al,FMH-Al and TK?positively correlated with forest and grassland?,TK is correlated with RED-Fe is positively correlated?negatively related to returning farmland to grassland?;AN is positively correlated with FMH-Si,OXI-Fe?negatively correlated with forest and grassland?,and EF-Al,AM-Al,T-Al,T-Fe There is a negative correlation;AP is positively correlated with FMH-Si,and negatively correlated with RED-Fe,T-Al,T-Fe;AK is positively correlated with ORB-Si,FMH-Si,and ORB-Al,FMH-Al,RED-Fe is negatively correlated.