Slit seeded grass-legume mixture improves coal mine reclamation

Abstract

Slit seeding (sowing into shallow cuts to the soil surface) was evaluated on coal mine reclamation in the North Bohemian Brown Coal Basin (Czech Republic) between 2001 and 2008, on plots both with and without biodegradable waste enrichment. Prior to experimentation (in 2000, once) were applied dehydrated, anaerobically digested wastewater sludge, 200 (41) t/ha fresh mass (dry mass), together with paper mill waste, 400 (131) t/ha, and bark substrate Envima, 400 (145) t/ha. Spontaneous herbaceous cover was enhanced each end of April from 2001 to 2003 by slit seeded grass-legume mixture containing Festuca pratensis L. (46%); Lotus corniculatus L. (22%); Coronilla varia L. (18%); Festuca rubra L. (9%); and Medicago lupulina L. (5%). All slit seeded species proliferated better on surface strip mine deposits without biodegradable waste enrichment and brought beneficial changes in a number of parameters over the ensuing five years due to lower competition with native expanding eutrophic species including Calamagrostis epigejos L.; Cardaria draba L.; Urtica dioica L.; and Galium aparine L. Available organic carbon (extracted from field-moist soil by 0.5 mol/L K<sub>2</sub>SO<sub>4</sub>) showed a notable tendency toward values 10–66 mg C/kg DM (dry mass), microbial biomass 302–1131 mg C/kg DM, basal respiration 3.9–5.8 mg C/kg DM/h, and metabolic quotient (basal respiration/microbial biomass carbon) × 1000 = 5.2–7.9.