Effect of Tillage Practices on Soil Pore Structure Characteristics in Shajiang Black Soil
[Objective]Shajiang black soil is one of the major soil types with low or medium productivity in China and is mainly distributed in the Huai River North Plain.As the soil is high in clay content and its parent material is dominated by montmorillonite,it suffers from swelling/shrinkage,low infiltration and strong strength.Suitable tillage is widely considered an effective measure to improve soil structure.However,how tillage practice impacts the pore structure of Shajiang black soil is not clear.Therefore,the objective of this study was to assess the effect of different tillage practices on soil pore structure characteristics in Shajiang black soil.[Method]Intact soil columns(20 cm height,10 cm diameter)were sampled from three tillage treatments including no-tillage(NT),rotary tillage(RT)and deep ploughing(DP)at Longkang Farm in Anhui Province,and then were scanned using X-ray computed tomography at a voxel resolution of 60 μm,and followed by saturated hydraulic conductivity(Ks)measurement.After reconstruction of CT images,characteristics of soil macropore(>60 μm)morphology and networks were quantified with Image analysis.[Result]Compared to no-tillage,rotary tillage and deep ploughing increased soil macroporosity by 192.7%and 261.1%(P<0.05),respectively.Rotary tillage and deep ploughing significantly increased the hydraulic radius,compactness,fractal dimension and global connectivity of soil macropores(P<0.05),but decreased the degree of anisotropy and Euler number(P<0.05).The Ks was significantly improved under rotary tillage and deep ploughing.Deep ploughing improved soil structure and Ks better than rotary tillage did.A significant correlation was observed between Ks and macropore structure characteristic parameters(P<0.05),in which the connected largest macroporosity was the highest(r=0.833**,P<0.01).[Conclusion]Deep ploughing enhanced pore hydraulic radius,connectivity and complexity,built a good soil pore morphology and network structure and consequently improved hydraulic conductivity and reduced structural obstacles of Shajiang black soil.
Shajiang black soilDeep ploughingComputed tomographyPore structureSaturated hydraulic conductivity
万方数据
维普
