Effect Of Pennisetum Sinese On Soil Physicochemical Properties Improvement In Panxi Dry-hot Valley

The dry and hot valley of Jinsha River belongs to a typical ecologically fragile area in China.Vegetation restoration and reconstruction of its degraded ecosystem is a hot issue in ecological management in recent years.It is particularly important to explore the improvement effect of introduced species on soil physical and chemical properties.In order to understand the different slopes of Jinsha River in the dry and hot valley area of Panxi River,Pennisetum sinese.The changes of the physical and chemical properties of the post-soil in the region were analyzed,with a view to providing a theoretical basis and basis for the study of the ecological restoration of the giant bacteria in the region,and the samples were investigated in the soil of the main introduction area,the middle and the next three slope positions in the two seasons of drought/ rain.The physical properties and nutrient contents were determined respectively,and the effect of the introduction of the Pennisetum sinese on the water retention and fertilizer retention capacity of the soil was analyzed,and the difference of the soil characteristics between the different slope positions in the introduction area was compared.The results show that:(1)After three years of continuous observation,Megacephalus can survive and grow normally on the upper,middle and lower slopes of the core area of the Dry-hot Valley in Panxi,Jinsha River.The average plant height,basal diameter,fresh weight and dry matter per mu of Megacephalus are 2.99 ± 0.09 m,4.72 ± 0.2 cm,4213.27 kg and1390.92 kg respectively.Pennisetum sinese showed strong adaptability in the experimental plot.(2)The improvement effect of soil nutrient index was remarkable in the introduced sample plot.The three-year average growth rates of organic matter,total nitrogen,total phosphorus and total potassium in the introduced sample plot were 61.19 %,28.33 %,32.38 % and 45.02 % respectively,compared with the control sample plot.The organicmatter increment was the highest,and the soil nutrient properties were significantly improved.The introduction of Pennisetum sinese had no significant effect on soil physical indicators,but the indicators had a trend of improvement with the introduction of Pennisetum sinese.(3)The change of soil physical and chemical properties is different among different slope sites in the introduction area.According to the parameters of each index,the effect of mid-slope introduction is the best,followed by downhill introduction,and the effect of uphill introduction is the lowest.The physical and nutrient indicators in the sample plots tended to degenerate with time,and the physical and chemical indicators in the sample plots tended to develop benignly with time.In conclusion,the introduction of Pennisetum sinese has a significant positive effect on soil nutrient properties in introduction area,with the largest increase in organic matter content.There was no significant change in physical properties in all plots,but all indexes of soil physical and chemical properties tended to develop benignly.The effects of different slope sites on soil improvement are different,the specific effects are middle slope > downhill > uphill.Therefore,in the process of vegetation restoration in the west section of Jinsha River dry and hot valley,Pennisetum sinese can act as a pioneer specie adapted to ecological construction and vegetation restoration in the dry and hot valley of Panxi,which has a high application prospect.