Study On Soil Physical Properties And Plant Diversity Of Grassland In Wusun Mountain

Taking the natural grassland of Wusun Mountain in Zhaosu County and Qapqal County of Yili as the research object,the soil particle and micro-aggregate composition of grassland in different slopes,altitudes and soil depths were determined.using typical sample survey method to investigate and analyze grassland plant diversity in different slopes and altitude gradients,and explore the spatial variability of soil particle and micro-aggregate composition,and plant community species diversity in Wusun Mountain grassland.The results showed that:(1)The silt is the highest in the soil particle composition of the grassland on the north and south slopes of Wusun Mountain in Yili,which is 77.34%～90.19%,83.16%～91.65%,the average is 85.22% and 87.46%;followed by sand,which is3.31～18.24%,2.64～13.01%,the average is 8.95%,7.67%;the clay content is the lowest,2.73～8.39%,2.95～6.59%,and the average is 5.84%,4.88%.The sand and clay content of the south slope is higher than that of the north slope,and the silt content is lower than the north slope.(2)The average of soil particle and micro-aggregate composition of the grassland on the south and north slopes showed different results at different altitudes.The content of sand and micro-aggregates of 0.05～0.25 mm showed a wave-shaped decrease as the altitude increased.The micro-aggregates of 0.002～0.05 mm showed a wave-shaped increase.The content of clay particles and micro-aggregates of <0.002 mm varies in a wave-shaped manner.The particles of various sizes and the micro-aggregates vary unevenly with soil depth.(3)There are 18 families,39 genera,and 52 species on the south slope;17 families,30 genera,and 37 species on the north slope.the number of plant species in the grassland on the south and north slopes increased first and then decrease trend with altitude increasing.At the same altitude gradient,there were more species on the south slope than on the north slope.On the south slope,the diversity index showed a bimodal pattern along the altitude changes;On the north slope,The relationship between species diversity index of grassland plant community and altitude,apart from the Patrick index showing a bimodal pattern,the Simpson index,Shannon-Wiener index,and Pielou index showed a relatively special wave-shaped change trend that first increased,then decreased and then increased.(4)At the 0～20 cm soil depth on the south slope,sand and silt particles showed extremely significantly negative correlation,and clay showed significantly negative correlation with community height and coverage.Micro-aggregates of 0.05～0.25 mm showed extremely significantly negative correlation with micro-aggregates of0.002～0.05 mm and <0.002 mm,and micro-aggregates of 0.002～0.05 mm showed extremely significantly positive correlation with <0.002 mm.At the 0～20 cm soil depth on the north slope,sand and silt particles showed extremely significantly negative correlation,and micro-aggregates of 0.05～0.25 mm showed significantly positive correlation with sand and Simpson index,and significantly negative correlation with silt particles,0.002～0.05 mm micro-aggregates showed extremely significantly negative correlation,and the Simpson index showed negative correlation with 0.002～0.05 mm micro-aggregates.At the 20～40 cm,40～60 cm soil depths on the north and south slopes,microaggregates of 0.05～0.25 mm showed significantly negative correlation with altitude,and micro-aggregates of 0.002～0.05 mm showed significantly positive correlation with altitude,and significantly correlation with the micro-aggregates of 0.05～0.25 mm,sand and silt particles showed extremely significantly negative correlation.On the south slope,there is a significant positive correlation between microaggregates of <0.002 mm and clay particles,while there is no significant correlation between micro-aggregates of <0.002 mm and clay particles on the north slope.