Optimum of interlayers in reconstructed soil with Yellow River sediment
for restoring subsided coal mined land to farmland
Abstract
Underground coal mining causes land subsidence, a large area of
cultivated land is destroyed. The Yellow River interlayer filling
reclamation technology is the powerful way to restore cultivated land.
Understanding the mechanism of action of interlayers in reconstructed
soil filled with Yellow River sediments is essential to achieving
sustainable land management in the Yellow River regions. Column
experiments and Field experiments were conducted to optimum of
interlayers in reconstructed soil with Yellow River sediment for
restoring subsided coal mined land. Our findings show that the inclusion
of interlayers in the sediment reduced water leakage and moisture
evaporation, and improved the water-holding capacity of the material in
comparison to conventional reconstructed soil profile (Ck2). When the 30
cm thickness of interlayer, putting 2 interlayers in sediment (T6) was
the optimal profile with the highest water-holding capacity. In
comparison to CK2, the migration rate of wet front decreases by 32.16%,
the cumulative evaporation decreases by 16.29%, the volumetric water
content of filling layer (θ_fl) increases by 121.56%, and the
water-holding coefficient (CWR) increases by 59.47%. It is also proved
by field experiments. The wheat and maize yields of T6 improved 51.84%
and 54.80%, respectively, as compared with CK2, that closer to
undisturbed farmland (CK1). This study provides a valuable framework for
subsided land reclamation regarding the method of placing interlayers
into Yellow River sediment for enhancing water retention and
productivity.