| The Panxi arid-hot valley is one of the most severe areas on the planet.The severe climatic conditions make the Panxi arid-hot valley extremely unsuitable for vegetation growth.The distinct dry season and damp season cause serious desertification and desertification of the land and ecological Governance faces huge difficulties and challenges,and the local ecological environment and social and economic development are greatly restricted.Vegetation restoration and reconstruction is the basis of ecological management in the region,and soil is an important factor in the assessment of vegetation restoration effects.As a kind of high-quality multi-purpose grass,the giant fungus(Pennisetum sp.)was introduced as a vegetation restoration species in the region,and showed good adaptability.In order to understand the impact of giant fungus on the soil during the vegetation restoration process,artificial vegetation of giant fungus was planted on different slopes in the typical valley of Panzhihua arid-hot valley to study the physical and chemical properties of giant fungus on soil and the content of microbial biomass carbon and nitrogen Impact,in the hope of provide a reference for the vegetation restoration of giant fungus grass in dry and hot valley areas.The main achievements of our studies are as following:(1)In the introduction of uphill and middle slopes in arid-hot valley,the soil bulk density decreases and the soil porosity and maximum water holding capacity increase.The soil bulk density in different seasons is 0.85?0.99 times of the control,and the soil porosity is 1.11?1.23 of the control.Times,the maximum water holding capacity is 1.12?1.25 times that of the control,and there is no significant difference in each period of downhill(P>0.05).(2)The total nitrogen content and organic matter content of the soil in the dry,hot valley on the upper,middle and lower slopes have been significantly improved.The soil organic matter is 1.18?1.61 times the control and the total soil nitrogen is 1.23?1.53 times the control.Total potassium in the soil increased significantly only in the alternating period and the wet season(P<0.05),and there was no significant difference in slope positions in other periods.The total phosphorus content of the soil decreased significantly in the upslope position in different seasons(P<0.05).The total phosphorus content of the soil was0.64?0.73 times of the control,and the difference between the middle and downhill slopes was not significant.Due to the low pH of the soil conditions in the arid-hot valley,the introduction of giant fungus has no obvious effect on improving the soil pH.(3)The contents of soil MBC and MBN in each period of uphill and middle slope were significantly improved.The MBC and MBN of uphill soil were 1.18?1.75 times and1.61?1.79 times of the control respectively,and the MBC and MBN of mid-slope soil were respectively the control 1.36?1.42 times,1.37?1.73 times,the MBC and MBN content of the downslope soil in each period did not change significantly.(4)Comprehensive evaluation of each index of uphill,middle slope and downhill slope.The U value of the membership function of uphill and middle slope is obviously higher than that of downhill slope in the alternating period and wet season,and the difference between the slope positions in the dry season is not obvious.Fully mechanized,the introduction of giant fungus grass in the dry and hot valley area has a certain soil improvement effect,and the introduction of giant fungus vegetation on the middle and uphill slopes is the best. |
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