Study On Soil Characteristics Of Plantations At Different Slopes On The Northern Slope Of Daqing Mountain

Daqing Mountain north slope is a typical loess hilly gully area,in the slope of artificial afforestation of suitable tree selection has always been a problem,in order to explore the soil characteristics of the plantation on the north slope of Daqing Mountain on different slopes,this thesis selected the Pinus tabulaeformis pure forest,HippopH 值 ae rhamnoides pure forest,Picea asperata + Pinus tabulaeformis + Caragana korshinskii mixed forest,HippopH 值 ae rhamnoides + Caragana korshinskii mixed forest,Pinus tabulaeformis + Pinus sylvestris mixed forest and grassland as the research object,to determine the difference in soil pH 值 ysical and chemical properties of different plantations on different slopes,The principal component analysis method and soil fertility index method were used to comprehensively evaluate the soil fertility under the forest,which provided a reference basis for artificial afforestation and soil sustainable development on the slopes of Daqing Mountain.The following conclusions are mainly obtained:(1)At different slope positions,the bulk density of Pinus tabulaeformis pure forest,Picea asperata + Pinus tabulaeformis + Caragana korshinskii mixed forest,HippopH 值ae rhamnoides + Caragana korshinskii mixed forest,and Pinus tabulaeformis + Pinus sylvestris mixed forest is on the slope > mid-slope > down-slope,while HippopH 值 ae rhamnoides and a grassland are the opposite,which is manifested as a slope < the middle of the slope < down the slope.On the same slope,the bulk density of different plantations increases with the deepening of the soil layer.On the up slope,the Pinus tabulaeformis pure forest is the largest,the grassland is the smallest,and in the middle slope,HippopH 值ae rhamnoides pure forest is the largest,grassland is the smallest,down the slope,HippopH 值 ae rhamnoides pure forest is the largest and Pinus tabulaeformis pure forest is the smallest.The soil porosity of each plantation is obviously different,which is opposite to the bulk density.At different slope positions,the water content of each plantation is that the water content of the lower slope is higher than that of the upper slope.At the same slope position,the water content of the Pinus tabulaeformis forest and Pinus tabulaeformis + Pinus sylvestris mixed forest is significantly higher than that of the HippopH 值 ae rhamnoides pure forest and grassland water content.At different slope positions,the 0-10 cm and 10-20 cm soil layers of each plantation showed that the particle size > 2 mm was the smallest under the slope,the largest on the slope,and the largest proportion under the slope.On the same slope,different plantations The particle size > 2mm and 1-2 mm size decreased with the deepening of soil depth,and the aggregates of0.1-0.25 mm and < 0.1 mm size increased with the deepening of soil depth.In different slope positions,the stability of soil aggregates was better downhill than upH 值 ill,and the surface layer was better than that of the bottom layer.In the same slope position,the stability of soil aggregates of mixed forest was better than that of pure forest.(2)Overall,the pH 值 of the plantations was not very different,roughly around 7.The organic matter,alkaline nitrogen,available pH值ospH值orus and available potassium of each plantation decreased with the deepening of the soil layer,showing surface aggregation effect.The total content of soil organic matter in each plantation at different slope positions is the smallest on the slope,and at the same slope position,Pinus tabulaeformis + Pinus sylvestris mixed forest and Picea asperata + Pinus tabulaeformis +Caragana korshinskii mixed forest has higher content.HippopH 值 ae rhamnoides pure forest and grassland content is low.In different slopes,the alkaline nitrogen content in the slopes of Pinus tabulaeformis pure forest and spruce + Pinus tabulaeformis + Caragana sinensis mixed forest appeared to have the highest alkaline nitrogen content,and other plantations showed the downhill content.On the same slope position,the alkali-solving nitrogen content of Pinus tabulaeformis pure forest and Pinus tabulaeformis + Pinus sylvestris mixed forest was higher.On different slope positions,the soil available pH 值ospH 值 orus content of each plantation showed the order of down-slope > mid-slope > on the slope,on the same slope,the content of available pH 值 ospH 值 orus is higher in pure arborvitae forests and mixed forests.At different slope positions,the soil available potassium in the Pinus tabulaeformis pure forest and Picea asperata + Pinus tabulaeformis+ Caragana korshinskii mixed forest showed the maximum value in the slope,similar laws appear with soil alkaline nitrogen content.At the same slope position,the arbor forest and the arbor mixed forest higher content.(3)The soil fertility under plantation was evaluated by principal component analysis and soil fertility index.,the final comprehensive score of the principal component soil fertility ranges from-0.68 to 0.83.Pinus tabulaeformis + Pinus sylvestris mixed forest >Pinus tabulaeformis pure forest > HippopH 值 ae rhamnoides + Caragana korshinskii mixed forest > Picea asperata + Pinus tabulaeformis + Caragana korshinskii mixed forest> HippopH 值 ae rhamnoides pure forest > Grassland,in the down-slope and mid-slope positions: Pine tabulaeformis + Pinus sylvestris mixed forest > Pinus tabulaeformis pure forest > Picea asperata + Pinus tabulaeformis + Caragana korshinskii mixed forest >HippopH 值 ae rhamnoides + Caragana korshinskii mixed forest > HippopH 值 ae rhamnoides pure forest > Grassland.The comprehensive score range of soil fertility comprehensive index method is between 83.6% and 20.2%.Except for HippopH 值 ae rhamnoides + Caragana korshinskii mixed forest and Pinus tabulaeformis + Pinus sylvestris mixed forest,The fertility status of undergrowth soil of other plantations is better under slope than on slope.The evaluation results of the two methods are basically consistent.