The Effect Of Community Distribution Of Ammopiptanthus Mongolicus And Its Associated Species On Soil Physical And Chemical Properties In Western Ordos Region

In order to clarify the mechanism of accompanying species’ effects on soil sediment characteristics in composite communities.This study focuses on the rare and endangered sand holly community in the West Ordos National Nature Reserve.By measuring and analyzing the morphological characteristics and soil sediment characteristics of the Ammopiptanthus Mongolicus community and Ammopiptanthus Mongolicus-Zygophyllum xanthoxylon complex community with different degrees of decline(non decline,mild decline,moderate decline,and severe decline)in the study area.Exploring the distribution,morphological characteristics,and interaction of soil physicochemical factors under shrubs of different degrees of decline of the Ammopiptanthus Mongolicus and its accompanying species,Zygophyllum xanthoxylon.To provide theoretical basis for protecting endangered species resources and maintaining biodiversity.The main conclusions are as follows:(1)The overground parts of the Ammopiptanthus Mongolicus and Zygophyllum xanthoxylon shrubs exhibit a creeping growth pattern in the horizontal direction that is greater than the vertical direction.The height of both plants has the greatest impact on the volume of shrubs(0.5327,0.4477).The correlation between the width of undeveloped Ammopiptanthus Mongolicus shrubs and the crown area was the highest(p<0.01),with a correlation coefficient of 0.990.The correlation between the morphological indicators of the Zygophyllum xanthoxylon is relatively low compared to that of the sand holly(0.986).The correlation between shrub morphology indicators decreases with the severity of decline,and the parameters of various indicators in the Ammopiptanthus Mongolicus shrub exceed those in the Zygophyllum xanthoxylon shrub during the severe decline stage.The correlation between the volume of slightly declining Ammopiptanthus Mongolicus shrubs and the crown area of Zygophyllum xanthoxylon is the highest(p<0.01),with a correlation coefficient of 0.996.(2)The order of soil clay content from large to small is the windward side of the Ammopiptanthus Mongolicus shrub(0.51%)>the leeward side(0.35%)>the composite community of Ammopiptanthus Mongolicus(0.29%)>and Zygophyllum xanthoxylon(0.28%).The soil particles of single community Ammopiptanthus Mongolicus shrub on the windward and leeward sides,composite community sand holly,and Zygophyllum xanthoxylon soil are mainly fine sand particles.The correlation between the leeward flour of Ammopiptanthus mongolicus in a single community and the fractal dimension was the strongest(0.89),and the correlation coefficient between the soil flour and the average particle size of the non declining shrub was the largest(0.92).(3)The content of organic carbon,total nitrogen,total phosphorus,and available phosphorus in the soil of the composite community of Ammopiptanthus mongolicus is0.20g/kg,0.03g/kg,0.06g/kg,and 2.83mg/kg higher than that of the Zygophyllum xanthoxylon,respectively.Soil organic carbon,total phosphorus,available phosphorus,and available potassium were 0.39g/kg,0.12g/kg,5.35mg/kg,and 1.91mg/kg higher than those of a single community of sand holly.There were significant differences in soil nutrients among different degrees of decline(p<0.05).The coefficient of variation of total phosphorus content in the windward soil of the moderately declining composite community of Ammopiptanthus mongolicus is 40.51%,and the coefficient of variation of total phosphorus content in the leeward soil is 37.80%.The coefficient of variation of available phosphorus in the soil of the severely declining composite community of Ammopiptanthus mongolicus is 57.59%,and the coefficient of variation of total phosphorus in the slightly declining Zygophyllum xanthoxylon soil is 60.25%.(4)The soil C:N and C:P on the leeward side of the undiminished single community of Ammopiptanthus mongolicu shrub are the largest,with values of 10.25 and43.38,respectively.The soil N:P of the slightly declining Zygophyllum xanthoxylon shrub is the highest,at 5.68.The moderately declining Ammopiptanthus mongolicu has the strongest enrichment effect on soil total phosphorus and available phosphorus(0.35,0.38);Zygophyllum xanthoxylon had the strongest enrichment effects on soil total nitrogen and alkaline nitrogen,respectively(0.36,0.41).The non declining Zygophyllum xanthoxylon has the strongest effect on soil available potassium enrichment(0.22).