Changes Of Root Respiration Rate In Reconstructed Soil Filled With Goal Gangue And Its Response To Gas-thermal Gradient

In this paper,the coal gangue filling reclamation area in the coal mining subsidence area of Panyi mining area in Huainan is taken as the research object,and the plant root respiration in the coal gangue filling reclamation area is comprehensively studied by means of field research and laboratory experiments.In order to explore the dynamic changes of root respiration in reconstituted soil filled with coal gangue with different soil cover thickness and its contribution to soil,the collapsed ecological restoration area of Panyi Coal Mine in Huainan,China was selected as the research object.According to the soil cover thickness,the research area was divided into 4 types of monitoring areas:A?10-25 cm?,B?25-45 cm?,C?45-55 cm?,D?55-60 cm?.During the whole non-growth season from November 2017 to April 2018,soil respiration rate,root respiration rate,topsoil temperature and humidity of 5cm,and root biomass in different monitoring areas were measured respectively to analyze the dynamic changes of root respiration and its sensitivity to topsoil temperature and humidity.Through indoor simulation of the effects of different carbon dioxide concentrations and temperatures released from the bottom of coal gangue on the respiration rate of soil plant roots,data support and engineering practice basis are provided for the application of soil reconstruction and surface soil curing technology in coal mine subsidence areas.The main conclusions of the article are as follows:?1?The daily variation range of root respiration rate in non-growing season of reclaimed soil filled with coal gangue in the study area is between 0.047 umol/m²/s and 1.33?mol/m²/s,with an average value of 0.478 umol/m²/s.The variation trend is approximately consistent with the surface soil temperature and presents a unimodal distribution.The highest peak generally occurs between 12:00 and 14:00,and the highest peak occurs between 14:00 and 16:00 in March and April 2018.Compared with different soil cover thicknesses,the root respiration rate of reclamation thickness of 25-45cm is higher than that of other monitoring areas.From the perspective of root respiration rate change,25-45cm should be the most favorable soil cover thickness for plant growth in the reconstruction of coal gangue filled reclaimed soil profile in the research area.?2?The root respiration rate in monitoring areas with different soil cover thickness has a significant exponential relationship with the surface temperature of5cm,and the correlation coefficient is between 0.7116 and 0.9520.The change of soil water content has little contribution to root respiration.The soil temperature is still the main control factor for the non-growth season change of plant root respiration rate in the study area.?3?During the whole observation period,the contribution rate of root respiration to root respiration in the study area increased with the increase of temperature,with the overall contribution ratio ranging from 16.16%to 83.02%,with an average value of 51.13%.Compared with different soil cover thicknesses,the order of contribution ratio of root respiration to soil respiration in each monitoring area is B>D>A>C,which is 61.94%,56.54%,43.59%and 42.88%respectively.?4?Under different aeration time conditions,the effects of CO₂ concentration on the physiological characteristics and root respiration rate of mint are different.With the increase of CO₂ concentration during aeration for 5min/d,except that the leaf area index increases first and then decreases,the aboveground and underground biomass and root respiration rate all show an upward trend,reaching the maximum at 3L/Min.When ventilated for 10min/d,with the increase of CO₂ concentration,except the leaf area index?LAI?,the aboveground and underground biomass and root respiration rate all showed an upward trend and then a downward trend.The ventilation concentration reached the maximum at 2L/Min.Comprehensive comparison of ventilation for10min/d and 5min/d showed that the root biomass and root respiration rate decreased by 17%and 8%,respectively,while the LAI and aboveground biomass increased slightly by 1%and 9%,respectively.?5?Mint root respiration rate has significant correlation with root biomass and surface biomass,but has no significant correlation with leaf area index,and the correlation coefficient R² is:root biomass?0.428?>surface biomass?0.408?.Figure[34] Table[12] Reference[125]...