| Desert grassland is a transitional area between grassland and desert.The local economic sources are mainly obtained through animal husbandry.Due to the unreasonable use of human beings,the environment of desert grassland is deteriorating,species diversity is decreasing and degradation occurs.In order to understand the present situation of herbaceous community biomass in different desert steppes,the types and composition of herbaceous community,and the relationship between biomass and soil factors.Taking the desert grassland herbaceous plants in Wulatzhong Banner as the research object,the community type,habitat conditions,height and coverage were measured and recorded on the spot.Quadrat harvesting method was used to measure biomass,analyze the relationship between biomass and soil factors,as well as the distribution of underground biomass,in order to provide theoretical basis for future research on plant diversity,biological productivity and its prediction in desert steppe.It is of great significance to the restoration and protection of desert grassland ecological environment.At the same time,it provides data support for the establishment of the database of main desert plant communities in China,so as to compile the atlas of various types of desert plant communities in China.It provides a reference for the protection,development and utilization of local plant resources.The main results are as follows:(1)The desert grassland in Wulatzhong Banner has low vegetation coverage,less precipitation and relatively simple species composition,mainly xerophytic,super—xerophytic and salt—alkali—resistant plants.The dominant species and the founding species in the herbaceous community are mainly Allium mongolicum Regel,Stipa krylovii Roshev,Stipa klemenzii Roshev,Alliumpolyrhizum Turcz.ex Regel,Corispermum mongolicum Iljin,Eragrostis minor Host,Stipa glareosa P.Smirn,and Enneapogon borealis(Griseb.)Honda.(2)The aboveground biomass,underground biomass and total biomass of herbaceous communities were 9.14—24.49 g/m~2,153.33—270.22 g/m~2,174.42—279.36 g/m~2,with the average values of 14.67 g/m~2,198.12 g/m~2 and 212.79 g/m~2.The underground biomass is much larger than the aboveground biomass,which is 13.5 times the average aboveground biomass.(3)Total biomass was positively correlated with aboveground biomass and underground biomass(R~2=0.43,P<0.01,R~2=0.99,P<0.01),and aboveground biomass was positively correlated with underground biomass(R~2=0.38,P<0.01).(4)Aboveground biomass,underground biomass and total biomass of herbaceous community were positively correlated with soil water content(R~2=0.86,P<0.01,R~2=0.43,P<0.01,R~2=0.46,P<0.01).The aboveground biomass,underground biomass and total biomass of herbaceous community were positively correlated with porosity(R~2=0.70,P<0.01,R~2=0.35,P<0.01,R~2=0.30,P<0.01).Aboveground biomass,underground biomass and total biomass were negatively correlated with soil bulk density(R~2=0.15,P<0.01,R~2=0.17,P<0.01,R~2=0.02,P<0.01).(5)The vertical distribution of underground biomass decreases with the increase of soil depth.Among them,the 0—20 cm soil biomass of 8 communities ranges from 102.94 g/m~2 to 176.78 g/m~2,accounting for 61.11%to 74.79%of underground biomass,and the proportion is relatively large.The fitting degree with total underground biomass was better(R~2=0.91).The underground biomass of 20—40 cm soil layers ranged from 29.50 g/m~2 to 72.78 g/m~2,accounting for 16.59%to 26.93%.The underground biomass of 40—60 cm soil layers ranged from 7.50 g/m~2 to 23.92 g/m~2,accounting for 4.66%to 12.43%.The total biomass can be predicted by the underground biomass of 0—20 cm soil layer. |
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