Effect of low-rank coal inoculated with coal solubilizing bacteria on edaphic materials used in post-coal-mining land reclamation: a greenhouse trial

摘要

BackgroundThis study assessed, under greenhouse conditions, the use of low-rank coal (LRC) generated in the “El Cerrejón” (La Guajira Colombia) mine as a source of humified organic matter, which is released by the activity of coal solubilizing bacteria (CSB), in order to improve the properties of edaphic materials (EM) used in post-mining land reclamation processes. MethodsIn this trial, using pots with 10?kg of EM, the effect of LRC applications was tested, in contrast with applications of LRC inoculated with CSB at two different doses and EM without LRC. The responses of the cation exchange capacity (CEC), soil respiration, and fluorescein diacetate hydrolysis (FDA) were evaluated in each treatment. The contents of P and N and the dry weight were measured in maize seedlings. Soil microaggregates were observed with scanning electronic microscopy. ResultsAfter 12?months of treatment with LRC, an increase of 75?% was registered in the CEC, along with an increase of up to 59?% in the EM respiration (CO₂ production) and up to 50?% in the FDA activity. The LRC caused a significant increase in the dry weight and the total contents of N and P in the maize seedlings; the observations with the scanning electronic microscopy showed evidence of the formation of bigger aggregates, as compared to the control, and the presence of organic material on mineral particles in the treatments with LRC inoculated with CSB. Conclusions These results provided evidence that supports the use of LRC, alone or inoculated with CSB, as a humic amendment to improve the EM in soil reclamation processes (Technosols construction) after mining activities. Open image in new window Graphical LRC and CSB as possible humic amendment to technosols construction in post-coal-mining land reclamation