| Soil erosion,as one of the most important environmental problems in the world,is also the number one ecological and environmental problem in China.Arid valley is located in the ecologically fragile area,the climate and terrain are complex and changeable,and the soil erosion is particularly serious.Therefore,this study takes the typical land use patterns（economic fruit forest land,agricultural land,grassland）in the arid valley of the Dadu River as the research object.Through the combination of field experiments and indoor water scouring,the soil erosion resistance,anti-scourability and shear resistance characteristics and their influencing factors under different land use patterns were studied to reveal the influence mechanism of regional land use on soil erosion,and provide theoretical basis and data support for the sustainable utilization of soil resources and ecological environment construction in arid valley areas.The main results are as follows:（1）Under different land uses,the index of soil macroaggregates showed that the stability of soil aggregates in grassland was the best,followed by fruit forest land and farmland.The relationship between MWD,GMD,soil anti-erodibility index and water stability index of water-stable aggregates was:grassland>fruit forest land>farmland,while the relationship between water-stable aggregates D was:farmland>fruit forest land>grassland.Among the microaggregates,on the sunny slope,the soil aggregate status,aggregate degree and structural particle index showed that the stability of aggregates in the fruit forest land was the best,followed by the grassland,the weakest in the farmland,and there was no obvious law on shady slope,.（2）In this study,bulk density,total porosity,initial water content,mechanical composition,microaggregate composition,>0.25 mm water-stable aggregate content,organic matter,total nitrogen content,total pHospHorus content,root weight density,root length density,and root surface area density all had significant effects on soil anti-erodibility（P<0.05）.Soil anti-erodibility>0.25 mm water-stable aggregate content,>0.5 mm water-stable aggregate content,MWD,GMD,water stability index,structural particle index,anti-erodibility index,dispersion coefficient,aggregate destruction rate PAD,unstable aggregate index ELT,aggregate fractal dimension D,dispersion rate and soil anti-erodibility were extremely significant（P<0.05）or significant（P<0.01）relationship,which can be used as the main index to evaluate soil anti-erodibility in this area.（3）With the continuous scouring time,the soil anti-scourability index increased in a wave form,and the overall performance was the best anti-scourability of grassland.The sunny slope:grassland（16.21 min/g）>fruit forest land（11.48 min/g）>farmland（6.24min/g）;the shady slope:grassland（43.03 min/g）>fruit forest land（28.92 min/g）>farmland（19.35 min/g）,and the shady slope anti-scour index of the same land use type is greater than the sunny slope.In addition,the soil anti-scourability of different land use types in this study was mainly affected by water-stable aggregates,microaggregates（<0.001 mm particle size content）,total nitrogen content,and specific root length（P<0.05）.（4）The results of soil shear strength showed that the shear strength of farmland was the worst.The shear strength of sunny slope grassland（8.62 kg/cm2）was significantly higher（P<0.05）than that of fruit forest land（7.93 kg/cm2）and farmland（5.91 kg/cm2）.The shady slope was fruit forest land（12.07 kg/cm2）>grassland（8.59 kg/cm2）>farmland（7.75 kg/cm2）,and the soil shear strength was mainly affected by water-stable aggregates（P<0.05）.In summary,grassland has the strongest erosion resistance and good soil and water conservation benefits,while agricultural land needs to further strengthen the prevention and control of soil erosion.This study provides a theoretical basis and data support for the sustainable utilization of land resources and ecological environment construction in arid valleys. |
PDF Full Text Request