Effects Of Bryophytes On Soil Properties And Heavy Metals In Protected Areas Of Hohhot City

The protected area can control the climate environment inside the shed and improve the land use efficiency.However,it is semi-closed all year round,with high temperature,high humidity,large evaporation,high multiple cropping index,and large application of chemical fertilizers and pesticides,was resulted the soil nutrient imbalances and heavy metal accumulation.Five different protected areas in Hohhot was selected.The bryophytes was investigated to compared the effect of moss coverage on the physical and chemical properties and heavy metal content in the greenhouse.To explore the improvement of physiochemical properties of bryophytes in protected fields and the absorption and adsorption of heavy metal pollutants in soil.Explore the use of bryophytes to improve and restore soil in protected areas.The main findings are as follows:(1)With the change of the soil layer,the contents of Available N,Organic matter,Available P,Available K are the highest in the surface soil.Total P,Total K and pH values are similar between soil layers.With the change of seasons,the contents of Available N,Organic matter,Available P,Available K were highest in April 2019.The values of Total P,Total K and pH remained similar in the three seasons.(2)Compared with the soil outside and inside shed,the contents of Available N,Organic matter,Available P,Available K are highest in the shed.There is no significant change in the content of Total P,Total K and pH.Abundance analysis found that,Organic matter,Available P,Total P,Total K all exceeded their normal standard values beside Available N and Available K,and there was a certain degree of accumulation.(3)The comparison of soil nutrients in inner-soil,outer-soil and below-soil showed that the content of Organic matter,Total P and Available P in the inner-soil and below-soil higher than outer-soil.Available N,Total P,Available P and pH are higher in the outer-soil than the inner-soil and below-soil.(4)With the change of soil layers,Ca,Cr,Mn,Fe,Ni,Cu,Zn,As,Cd,and Pb are the highest in the top soil,and there is no significant difference between the three layers.As the seasons change,the 10 heavy metals have the highest content in August 2018(autumn).(5)Through comparative research,the above 10 kinds of heavymetal elements all exceeded the background value of soil elements in Inner Mongolia,and Cr,Mn,Ni,and Cu exceeded the heavy metal element values of urban areas in Hohhot.Evaluation and analysis of single factor pollution index,Nemero comprehensive pollution index and comprehensive ecological pollution index,Ca,Cr,Mn,Fe,Ni,Cu,Zn,As,Cd,Pb have a certain degree of pollution,the most serious pollution is Cd element,followed by As and Cu The pollution of the five plots is ranked as follows: QBTQ> MLS)> NKY> QBM> DXC.(6)Comparison of plants,inner-soil and below-soil.Ca,Cr,Mn,Fe,Ni,Pb is the below-soil is higher than plants and inner-soil.Cu and Cd is the plants are higher than inner-soil and below-soil.Zn and As elements in the inner-soil are higher than the plants and below-soil.Comparing the soil below-soil and the outside-soil,all the ten heavy metal elements are higher in the soil outside the moss.(7)Comparing the enrichment ability of different types of bryophytes to heavy metals,it is found that the strongest enrichment ability is Funaria hygrometrica,Ditrichum pallidum,Bryum argenteum,and all have strong enrichment ability for Ca,Cu,Zn and Cd.There is a certain degree of accumulation of soil nutrients and heavy metal elements in the protected area of Hohhot,Bryophytes can absorb and adsorb excess nutrients in the soil,especially Organic matter,Available P,Total P and As,Cu,Zn,Cd have significant enrichmenteffects,It can be used to improve and rehabilitate the soil protected by facilities and promote the sustainable development of facility agriculture.