Atterberg Limits and Tillability of Different Types of Lime Concretion Black Soil
SHI Fugang
ZHANG Jiabao
YAO Jian
Abstract：Poor tillability and structural property are characteristics for lime concretion black soil.The determination of Atterberg limits is of great significance for preventing the degradation of cultivated land,improving cultivation quality,and reducing consumption of tillage energy.Different types of lime concretion black soil in the main allocation region of Henan province with other soil types in the same region as control were investigated and sampled.The Atterberg limits of different soil types were tested and their correlations with other soil physical properties were investigated.The results showed that the plasticity indexes of all samples of the control were not higher than 15.00,while the overall plasticity indexes of lime concretion black soil were higher.The plasticity indexes of over 3/4 of the common lime concretion black soil were higher than 15.00,which meant a strong plasticity.The topsoil of the common lime concretion black soil and the residual black layer showed the lowest average shrinkage limit,with the strongest shrinkage capacity.The bleached lime concretion black soil showed higher shrinkage limit than the control.The correlation of soil activity and Atterberg limits showed that,although the plasticity and shrinkability had positive relationship with clay content,the activity which reflected the dominant clay mineral type of this fraction had different influences on these properties.The order in which plasticity increased with the clay mineral type was kaolinite,illite and smectite respectively,while it was reverse for shrinkability.The hygroscopic water content showed a better correlation with Atterberg limits than clay content.Linear regression models between maximum hygroscopic water content and Atterberg limits were constructed and the residual standard deviations of the models were less than 2％.So the Atterberg limits can be predicted accurately with maximum hygroscopic water content.Highly plastic and expansive soils have wider moisture range between plastic limit and shrinkage limit,and tillage is suitable between these limits.But concerning their low soil moisture availability,the demand of seed germination and cultivation,the optimal moisture condition for plowing is at the moisture content close but not higher than the plastic limit.
Keywords：lime concretion black soiltillabilityAtterberg limitsplasticitysoil shrinkagesoil activity
Publication Date：2017-12-01
Online Publishing Date：2026-09-12(First online date of this platform, not the publication date of the document)
Pages：6( 59-64 )