Study On Biological Properties And Their Changes Of Reclaimed Soil By Filling Methods In Coal Mining Area

This study investigated the soil biological characteristics and variations in reclaimed sites. Our conducted the following studies in paper: evaluate age chronosequence effects on soil biological indicators by spatial sequence instead of time-series; The effect of materials(coal gangue, fly ash and lake sediment) on Soil biological properties in reclaimed soil; Changes of biological characteristics in reclaimed soil responses to C and N supplementation through priming effect. The main results are as follows:(1) The soil biological indicators in reclaimed soil(1-12 year) were compared with adjacent undisturbed soil. The results show that soil microbial quantity, microbial carbon biomass(MBC), microbial nitrogen biomass(MBN), soil respiration, β-glucosidase activities, acid phosphatase activities, urease activities, catalase activities and arylsulphatase activities were the lowest in the youngest(1 year) site and increased with increasing age to the oldest(12-year) site. The microbial metabolic quotient was decreased with increasing reclaimed age.(2) Reclaimed soil quality were calculated and selected evaluationsoil quality indicators based on correlation analysis and principal component analysis. We chose TDS and MDS as soil quality evaluation method during filling restoration in mining region. Contrasting analysis two way of SQI calculation which based on the 11 soil quality indexes and the 23 soil quality factors, we found that both of them had same change trend with restoration year. It tested and verified that the 11 soil quality evaluation indexes were highly representative and practicability.(3) The soil biological index in lake sediment reclaimed soil were significantly higher than coal gangue reclaimed soil and fly ash reclaimed soil. The index of soil bacteria, fungi, actinomycetes, MBC, MBN, soil respiration, microbial metabolic quotient, β-glucosidase activities, acid phosphatase activities, catalase activities, urease activities in lake sediment site were 4 %, 49.6%, 11.5%, 43.1%, 1.2%, 39.8%, 5.2%, 9.9%, 3.7% and 8.7% higher than those in control soil.(4)Reclaimed soil quality were calculated and selected evaluation soil quality indicators based on correlation analysis and principal component analysis. We chose TDS and MDS as soil quality evaluation method in reclaimed soil. The SQI rankings in four sites as follows: control soil >lake sediment reclaimed soil > coal gangue >fly ash reclaimed soil. Contrasting analysis two way of SQI calculation which based on the 11 soil quality indexes and the 23 soil quality factors, we found that the 11 soil quality evaluation indexes were highly representative and practicability.(5)The coal gangue and fly ash suppressed thegrowth characteristics of winter wheat(root length, root biomass root vigor, root to shoot ratio)in jointing stage, flowering stage, mature stage in reclaimed sites. Compared with the control site, coal gangue and fly ash decreasedproduction rateof winter wheat root exudatesⅠ, Ⅱ, Ⅲduring wheat growing season. These increases in production rate of root exudates were positively correlated with the root activity in reclaimed soil.In addition, we show that the soil exposed to coal gangue and fly ash decreased their soil nitrogen transformation rates, polyphenol oxidase activity and urease activity in the reclaimed sites. The altered physiologicaltraits of the roots exposed to coal gangue and fly ash could be responsible for this variation in reclaimed soil.(6) Microbial biomass, enzyme activities and respiration rate were significantly increased in all the experimental additions of carbon compared with the control soil. Add glucose(10 mg·g-1) to improve soil microbial carbon content of 276.7%(7 days) and 184.4%(30 days), microbial nitrogen 129.8%(7 days) and 148.9%, β-glucosidase activity 89.1%(7 days) and 102.9%(30 days), acid phosphatase activity 164.4%(7 days) and 130.3%(30 days), aryl esterase activity 541.1%(7 days) and 317.6%(30 days). The study show that supplementation in simple(C6H12O6) and complex forms(glucose and NH4NO3) can increase the biological characteristics of reclaimed soil.