Effect Of Coversoil Thickness On Reconstruction Soil Respiration Characteristics In Coal Mining Areas

As the coal resource exploitation,the current research focus on the reuse of subsidence damage to land and seeking for the best soil thickness during reclamation work,As an important indicator of soil quality evaluation,research on soil respiration can backfill subsidence area reclamation and soil maturation process.Based on the two ecological restoration area in Panji mining area of Huainan city as the research object,the static closed chamber with alkali absorption method was used to measure soil respiration rate of Dongchen ecological park and Panyi ecological restoration area of coal gangue filling reconstruction;the root biomass extrapolation method was used to measure soil root respiration in Panyi mine ecological restoration area;and the indoor culture method was used to measure the mineralization rate of soil organic carbon.Diurnal and monthly variation of soil respiration was analyzed and the response of soil respiration and environmental factors on the coversoil thickness was revealed in this paper to provide data support and engineering practice for soil reconstruction and surface curing technology of application of coal mine subsidence.The main conclusions are as follows:(1)The diurnal and monthly variation of soil respiration rate showed a single peak curve,the maximum value of diurnal variation appeared in 12:00-14:00,and its minimum appeared in 08:00 or 18:00.And the daily mean of soil respiration rate can be expr-essed by the soil respiration rate of 10:00 or 16:00 on the same day;The maximum value of monthly variation appeared in May to July,its minimum appeared in January,there are many differences of soil respiration rate between different soil thickness areas,but there is no obvious regularity between them;The relationship between the soil respiration rate in the study area and the control area are:Dongchen ecological park<Control area<the area of Panyi ecological restoration.(2)The trend of root respiration rate was consistent with the soil respiration rate in Panyi ecological restoration area,which showed a single peak curve.The contribut-ion of root respiration to soil respiration was between 8.6%-60.1%.The average contribution rate of root respiration to soil respiration was 31.2%,34.4%and 17.9%.,respectively,when the coversoil thickness was 0-20cm,20-40cm and 40-60cm.(3)As the main environmental factors affecting soil respiration,the relationship between soil respiration with soil temperature rate and soil respiration with humidity rate can be expressed by exponential function model and polynomial function model,the relationship between soil respiration rate and the two factors can be expressed by power function model;Soil temperature and humidity can be used to explain the variation of 26%?89%and 13%?96%in soil respiration as a single factor,which can be used to explain the variation of 35%?95%in soil respiration.(4)Reconstruction of soil organic carbon mineralization during the culture showed the first fast after the slow trend of the final trend of change.The accumulation of soil organic carbon mineralization increased during the whole culture period.And the growth rate was fast in the beginning and slower in the later time,and finally stabilized.The relationship between cumulative mineralization and mineralization rate can be expressed by power function model.The process of reconstruction of soil organic carbon mineralization can be simulated by the first order kinetics equation in very high degree of fitting(R2>0.95),Through the analysis of the experimental data and the fitting parameters,the soil carbon sequestration capacity in the 60-100cm area was the strongest,So the 60-100cm can be used as a suitable coversoil thickness in the reclamation work of subsidence area.