Organic matter dynamics in a compost‐amended anthropogenic landfill capping‐soil

Abstract

The application of municipal waste compost and other organic materials may serve to improve fertility and organic carbon (C) stocks of soils used in land reclamation activities, particularly in the recovery of degraded areas at exhausted quarries, mines and landfill sites amongst others. We investigated long-term organic matter dynamics in such anthropogenic soils by collecting samples at different depths over a 10-year chronosequence subsequent to compost application to the top layer of a landfill capping-soil. Variations in the stable isotope composition ( 13 C and 15 N) of the soil samples showed that, even after 10 years, amended topsoils were enriched in compost-derived organic matter. The addition of compost to the superficial layer also resulted in an input of soluble organic compounds that was subject to leaching along the soil profile. Sorption isotherms for compost-derived water-extractable organic matter onto mineral materials used for landfill covering suggest that sorptive preservation was primarily responsible for the increase in C content and the shift in the C isotopic signature to values similar to that of the applied compost, in the deeper soil horizons over the 10-year period. This was also confirmed by the accumulation of lignin-derived phenolic compounds in the deeper horizons. Nevertheless, analysis for non-cellulosic carbohydrates in soil samples and their respective water-extractable fractions suggest that a proportion of the compost-derived, labile organic matter fraction is leached through the profile and potentially lost from the soil system.

Greenhouse gas (GHG) emissions from soils amended with digestate derived from anaerobic treatment of food waste

“…). This approach is often used to evaluate the effects of organic amendments on the 13 C and 15 N isotope signatures in soil and vegetation . The soil δ 13 C values were higher in the CNT than in the DG‐amended soils till the end of August (−28.4 ‰), despite the fact that the applied digestate was enriched in 13 C (δ 13 C values of −21 to −22‰).…”

Influence of compost amendments on the hydraulic functioning of brownfield soils

“…Consequently, opportunities to utilise compost to return brownfield land to productive use have received increasing attention. Compost can facilitate remediation (Semple et al ., ), while improving the physical (Wanas & Omran, ), chemical (Said‐Pullicino et al ., ) and biological properties of degraded soils (Gandolfi et al ., ). With increasing pressure on conventional land and as renewable energy targets advocate an expansion in energy crop production (Charles et al ., ), one potential use for neglected land is biomass crop cultivation.…”

Symbiotic fungal endophytePhomopsis liquidambari-rice system promotes nitrogen transformation by influencing below-ground straw decomposition in paddy soil

“…It is important to note that the stable organic materials (here the rice straw) may contain a significant proportion of hydrolysable sugars (Said‐Pullicino et al . , ), which might affect the adjacent microflora. We proposed that the soil decomposers around the straw sphere might be affected by the straw characteristics rather than the external environment.…”