【Objective】The Shanxi-Shaanxi-Inner Mongolia adjacent region is one of the most important
coal energy bases in China，and also one of those the most fragile in ecology. In recent years，the ecological
system and the landform therein has been severely and widely destructed as a result of the environment of
opencast coal mining，which has also triggered a series of ecological and safety crises. And then how to rapidly
and effectively improve the reconstructed soil（especially in soil water holding capacity）on a large scale
at overburden disposal sites formed during coal mining has become an important scientific problem to land
reclamation and ecosystem restoration. At present，the soil in these sites has some main problems，that is，
relatively thin in soil layer（less than 50 cm），and relatively coarse in texture，（over 70%，sands 0.02～2
mm in particle size），which means that the soil is rather low in water holding capacity. Besides，in the arid
and semi-arid region，the precious soil moisture is mostly lost through evaporation and leakage. To save as
much as possible soil water from evaporating and leaching，a series of measures are designed and adopted，
such as incorporating soft sandstone，which contains about 30% of montmorillonite and weathered coal into
the local sandy loess，and spread a layer of soft sandstone or a water-proof plastic sheet underneath the soil to
prevent water leaching.【Method】In order to investigate dynamics of soil moisture content in reconstructed
soils relative to composition pattern（sandy loess，soft sandstone，weathered coal）and impervious layer
（soft sandstone or plastic sheet），an experiment was carried out，designed to have 6 treatments and 3
replicates for each treatment，making up a total of 18 experimental plots. 【Result】Results show as follows.
（1）The overburden disposal sites are subject to a wet season（July-October）and a dry season（November-
June）in a year as affected by the climate in the region，and natural rainfall，evapotranspiration and leaching
are the main factors affecting the soil moisture content therein；（2）During the wet season when rainfall
is rich，the effect of the existence of a impervious layer was significant，raising soil moisture content by
9.65%～13% in the soil body as a whole（p＜ 0.05，the same below）and by 21.6% in the bottom layer
as compared with their respective treatments without the layer，but no significant difference was observed
between the treatments with soft sandstone as impermeable layer and the treatments with plastic sheets in
the effect. However，on the other hand，the existence of an impervious layer weakened temporal and spatial
stability of soil moisture，especially in deep soil layers；（3）Incorporation of weathered coal increased
soil water loss through surface evaporation，which is no good to improving soil water holding capacity，while
incorporation of soft sandstone affected soil water holding capacity reversely. So in the practice，it still calls
for further study on feasibility of the use of weathered coal as soil amendment from the view point of efficient
utilization of water sources. Incorporation of soft sandstone increased soil water content by 3.36%～9.57% in
the 0～30 cm layer and 11.16%～13.65% in the 30～40 cm layer. In addition，laying of an impervious layer
is more effective than incorporation of soft sandstone and/or weathered coal in increasing water content of theartificial soils in the overburden disposal sites. 【Conclusion】To sum up，incorporation of soft sandstone
significantly enhances the soil water retention and water holding capacity of the soil，and the impervious layer
effectively controls soil water leaching and hence has a positive effect on soil holding water like a reservoir.
Besides illustrating the effects of the soil amelioration measures on spatial and temporal variation of soil
moisture content and the improvement of soil water regime，the study provides some references for choosing
schemes for reconstruction of farmland soil using different components in mining areas.
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