| Pinus sylvestris var.mongolica and poplar,as the main afforestation species in the three northern regions of China,play an important role in windbreak,sand fixation and carbon sequestration.Semi-arid sandy land plantation in Northwest Liaoning Province,as an important part of the Three-North Shelterbelt,plays an important role in ecological security of Liaoning Province.However,due to its fragile ecological environment,it has been increasingly affected by climate change in recent years.In this study,Pinus sylvestris var.mongolica plantation and poplar plantation in sandy land of semi-arid area of Northwest Liaoning Province were selected as the research objects.The indexes of trunk runoff,penetrating rain,canopy interception and soil moisture of Pinus sylvestris var.mongolica plantation and poplar plantation were continuously observed,and their effects on the content of material elements in rainwater were also studied.1.In poplar forest,canopy interception and trunk runoff accounted for a larger proportion in the process of natural rainfall redistribution,while penetrating rainfall was smaller;in Pinus sylvestris var.mongolica forest,canopy interception and penetrating rainfall were larger,while trunk runoff was smaller.The trunk runoff of Pinus sylvestris var.mongolica and poplar showed a very significant positive correlation with the rainfall outside the forest.The trunk runoff rate and the rainfall outside the forest showed a good exponential function relationship.At the same time,the penetrating rainfall of Pinus sylvestris var.mongolica and poplar showed a very significant positive correlation with the rainfall outside the forest(p<0.01);the interception of Pinus sylvestris var.mongolica and poplar canopy showed an exponential function with the rainfall outside the forest.But the correlation between them is not significant.2.The soil water holding capacity of Pinus sylvestris var.mongolica forest is better than that of poplar forest.In summer and winter,the soil water holding capacity of Pinus sylvestris var.mongolica forest is more prominent.For example,the average soil water holding capacity of Pinus sylvestris var.mongolica in winter is 18.64%,that of poplar is 14.19%,and that of Pinus sylvestris var.mongolica and poplar in spring is 14.72%and 14 The water-holding capacity of surface soil in poplar forest is similar to that of Pinus sylvestris var.mongolica forest,but with the increase of soil depth,the water-holding capacity gradually begins to show significant differences,which indicates that the influence of different tree species on soil water content not only exists in the surface soil,but also in the deep soil.After the rainfall event,the soil moisture of the Pinus sylvestris var.mongolica forest increased with the passage of time at each section depth,indicating that the water slowly penetrated downward in the soil;while the downward infiltration of the soil moisture in the poplar forest was mainly in the 0-60 cm soil layer,which was not obvious after the 60 cm depth.3.Sample collection and element determination after rainfall redistribution showed that compared with the natural rainfall outside the forest,the effect of runoff from the trunk of Pinus sylvestris var.mongolica and poplar on water quality improvement was more significant Potassium ion,sodium ion,nitrate nitrogen,total nitrogen,total phosphorus and calcium and magnesium plasma in the trunk runoff of Pinus sylvestris var.mongolica increased significantly to varying degrees.On the other hand,the increase of ion content in poplar trunk runoff and penetrating rain was similar.In a word,there are great differences between Pinus sylvestris var.mongolica and Poplar in the distribution of rainfall and the content and movement of soil moisture after rainfall.At the same time,they have different effects on elements in rainfall.This may be related to their own growth characteristics and management measures,which provides a reference for better management of sandy plantation under future climate change in the region. |
PDF Full Text Request