Effects Of Common Forest Types And Human Activities On Soil Moisture In Beijing Parks

The functional role of urban forests in urban hydrology is one of the hotspots of international concern.Urban forests have a strong role in reducing urban rain and floods and improving groundwater recharge in urban areas,and are important components of sponge action.At the same time,the urban forest is also an important space for frequent public activities,and is also a green space with a higher level of management and protection.The influence of frequent human activities on the soil water storage and water infiltration capacity of urban forests has gradually been paid attention by academics,and some studies have been carried out,recognizing that soil compactness and litter have significant effects on soil moisture characteristics.However,there are few reports on systematic research in this area,especially on the urban typical forests in Beijing.Therefore,in this paper,in the typical urban forests of Beijing,the soil of various forest structure types was selected as the research object,and the cumulative amount of falling objects(0t/hm~2?4t/hm~2,4t/hm~2?8t/hm~2,8t/hm~2?12t/hm~2),trample level(light,medium,heavy),herb coverage(0,0%?50%,50%?100%)and other typical human disturbance activities on soil water holding,water penetration related traits And conducted research,the main results are as follows:(1)The coefficient of variation of the soil moisture of the double-layer forest is only37.72%?53.77%of the single-layer forest.The change layer is significantly shallower than the single-layer forest,and below 80 cm are relatively stable layers of soil moisture.This means that the richer the layer,the more stable the soil moisture tends to be.(2)Rainfall and stand structure will also lead to differences in soil moisture response.After light rain,the water content of the shallow soil of the single-layer forest increased rapidly by 53.3%,and that of the double-layer forest increased slightly by 10.94%,and the deep layers were basically unresponsive.After heavy rain,the water content of the shallow soil of the single-layer forest increased rapidly by 104.4%?120.8%,and the depth of the deep soil increased by 57%?92%,followed by a rapid decline,then slowly decline.The linear regression between rainfall and soil water content shows that shallow slope>deep slope,shallow surface soil can be faster,and it is more obvious to respond to rainfall.(3)The impact of forest stand structure is mainly achieved through leaf area index,canopy density,litter thickness,etc.,all of which are significantly negatively correlated with shallow soil water content(P<0.05)or extremely significantly negatively correlated(P<0.01).(4)The degree of trample and the amount of litter accumulation have a significant effect on the soil water holding capacity and water seepage capacity(P<0.05),while the effect of the coverage of the herb on the soil water holding capacity and water seepage capacity has not reached a significant level(P>0.05).Among them,soil water holding capacity and soil penetration rate were significantly positively correlated with soil porosity and negatively correlated with soil bulk density.Therefore,man-made interference affects the soil's ability to hold water and infiltrate precisely by changing the degree of soil aeration.(5)The soil water holding capacity increases with the decrease of compaction and the increase of litter accumulation(R~2=0.562),the two have a synergistic effect,which can be significantly increased by 43%,while the soil water infiltration capacity increases with the compaction The degree of decrease increases,and the impact of litter is weaker.